FOOD AND DRUG
ADMINISTRATION
CENTER FOR DRUG EVALUATION
AND RESEARCH
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CARDIOVASCULAR AND RENAL DRUGS
ADVISORY COMMITTEE
MEETING
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The
Advisory Committee met at
PRESENT:
JEFFREY S.
BORER, M.D. Chairman
PAUL W. ARMSTRONG, M.D. Member
BLASE A. CARABELLO,
M.D. Member
SUSANNA L. CUNNINGHAM, Ph.D. Consumer Rep.
ALAN T. HIRSCH, M.D. Member
JOSEPH KNAPKA, Ph.D. Patient Rep.
BEVERLY H. LORELL, M.D. Member
STEVEN E. NISSEN, M.D., F.A.C.C. Member
THOMAS PICKERING, M.D. Member
EDWARD PRITCHETT, M.D. Consultant (Voting)
RONALD PORTMAN, M.D. Member
DORNETTE SPELL-LESANE, M.H.A.,NP-C Ex. Secretary
SPONSOR PRESENTERS:
LUIZ BELARDINELLI, M.D.
EUGENE BRAUNWALD, M.D., F.A.C.C.
PETER KOWEY, M.D., F.A.C.C.
JEREMY N. RUSKIN, M.D., F.A.C.C.
MICHAEL SWEENEY, M.D., F.R.C.P.
ANDREW A. WOLFF, M.D., F.A.C.C.
FDA REPRESENTATIVES:
ROBERT TEMPLE, M.D.
DOUGLAS THROCKMORTON, M.D.
AGENDA ITEM PAGE
OPENING REMARKS:
Jeffrey Borer..................................... 3
CONFLICT OF INTEREST STATEMENT:
Dornette Spell-LeSane............................. 3
RANOLAZINE INTRODUCTION:
Michael Sweeney................................... 6
RANEXA FOR CHRONIC ANGINA - AN UNMET NEED:
Eugene Braunwald................................. 11
CLINICAL EVALUATION OF RANOLAZINE EFFICACY &
SAFETY:
Andrew Wolff..................................... 18
CLARIFICATION QUESTIONS:......................... 32
SAFETY DATA:
Andrew Wolff.................................... 100
QUESTIONS:...................................... 105
QT INTERVAL EFFECT:
Peter Kowey..................................... 124
MECHANISTIC EVALUATION OF REPOLARIZATION:
Luiz Belardinelli............................... 131
CLINICAL CHARACTERIZATION OF RANOLAZINE:
Andrew Wolff.................................... 142
BENEFIT RISK ASSESSMENT OF RANOLAZINE:
Jeremy Ruskin................................... 155
QUESTIONS:...................................... 162
VASOVAGAL REACTIONS:
John Camm....................................... 191
COMMITTEE QUESTIONS:............................ 201
RANEXA DEVELOPMENT PROGRAM DISCUSSION/
COMMITTEE QUESTIONS:............................ 264
ADJOURN:
Jeffrey Borer................................... 389
P-R-O-C-E-E-D-I-N-G-S
8:01
a.m.
CHAIRMAN
BORER: This is an FDA Advisory Committee
and we don't have the FDA representatives here yet to advise, so we'll wait a
few more minutes. The advisees have
arrived. Glad you could join us, Doug.
DR.
THROCKMORTON: Always glad to be here.
CHAIRMAN
BORER: Okay. We will begin. Today is the second day of this meeting. The Committee will discuss the new
application, a New Drug Application, NDA 21-526, CV Therapeutics, proposed
trade name Ranexa, generic ranolazine, 375 milligrams and 500 milligram tablets
for prevention of chronic stable angina.
The Executive Secretary Dornette Spell-LeSane will read the Conflict of
Interest statement.
SECRETARY
SPELL-LESANE: Good morning. The following announcement addresses Conflict
of Interest issues with respect to this meeting and is made a part of the record
to preclude even the appearance of impropriety at this meeting. I can't say that word. The Conflict of Interest Statutes prohibit
special Government employees from participating in matters that could affect
their own or their employer's financial interests.
All
participants have been screened for conflicts of interest in the competing
products and firms that could be affected by today's discussion. The Food and Drug Administration has granted
waivers to the following individuals, because it has determined that the need
for their services outweighs the potential for a conflict of interest: Ronald Portman, M.D., has been granted a
waiver under 21 USC Section 355(n)(4), amendment of Section 505 of the Food and
Drug Administration Act, for ownership of stock in a competitor.
The
stock is valued at less than $5,001.
Because the value of the stock falls below the de minimis exemption
allowed under 5 CFR 640.202(a)(2), a waiver under 18 USC 208(b)(3) is not
required. Dr. Portman has been granted a
waiver under 18 USC 208(b)(3) for a consulting contract with a competitor
through his employer. He receives less
than $10,001 annually.
Paul
Armstrong, M.D., has been granted a 208(b)(3) waiver for speaking and
consulting for a competitor on unrelated matters and for serving on a
competitor's data safety and monitoring board on unrelated matters. He receives less than $10,001 annually from
each. In addition, also waived is his employer's
grant from a competitor to study an unrelated product. The grant generates between $100,001 and
$300,000 a year.
Jeffrey
Borer, M.D., has been granted a 208(b)(3) waiver for his consulting for a
competitor on unrelated matters. He
receives between $10,001 to $50,000 annually.
Edward
Pritchett, M.D., has been granted a 208(b)(3) waiver for his consulting for a
competitor on unrelated matters. He
receives between $10,001 to $50,000 annually.
He has also been granted a waiver under 21 USC Section 355(n)(4) for
ownership of stock in a sponsor of a competing product. The stock is valued between $5,001 to
$25,000. This interest is not included
in his 208(b)(3) waiver, because the value of the stock falls below the de
minimis exemption allowed under 5 CFR 640.202(a)(2).
A
copy of the waiver statements may be obtained by submitting a written request
to the Agency's Freedom of Information Office, Room 12A-30 of the Parklawn
Building. In the event the discussions
involve any other products or firms not already on the Agency for which an FDA
participant has financial interest, the participants are aware of the need to
exclude themselves from such involvement and their exclusion will be noted for
the record.
With
respect to all other participants, we ask in the interest of fairness that they
address any current or previous financial involvement with any firms whose
products they may wish to comment upon.
Thank you.
CHAIRMAN
BORER: Thank you very much. Introductory comments from Doug Throckmorton
will not be presented, because he doesn't have any. Therefore, we will begin the sponsor
presentation.
DR.
SWEENEY: Thank you. Good morning, Mr. Chairman and Committee
members. My name is Dr. Michael
Sweeney. I'm vice president of Medical
Affairs at CV Therapeutics. I will
present a brief outline of the presentations this morning to orient the
Committee to its presentations which will provide more detailed data later.
First,
on behalf of CV Therapeutics, I would like to thank the Committee and the
Agency for the opportunity to present data on ranolazine or Ranexa, which we
believe represents the first novel therapy for angina in 25 years. As described in both CVT and the FDA's
briefing documents, Ranexa has shown to be effective in the treatment of angina
in patients with severe coronary artery disease. Ranexa achieves this by a unique
pharmacodynamic profile, which does not depend on changes in heart rate, blood
pressure or contractility, unlike existing therapies to treat angina.
Ranexa
offers the potential to be complimentary treatment to existing agents,
particularly where the patient's hemodynamics or concomitant diseases limit the
use of these agents. This morning we
will present data which demonstrates that the extensive Ranexa Development
Program addresses the issues raised by the Agency. Today, we seek the Committee's support for
the approval of Ranexa for the treatment of chronic angina in patients with
severe coronary artery disease as functionally defined by severe angina pain
and impairment of exercise tolerance.
The
proposed initial dose will be 500 milligrams twice daily upwardly titrated to
750 or 1000 milligrams twice daily depending on patient response and
tolerability. Today, the Committee is
tasked with balancing the quantifiable measures of benefit, anti-anginal and
anti-ischaemic efficacy, achieved with minimal hemodynamic effects and as
demonstrated during the Ranolazine Development Program, the fact that it is
well-tolerated, with the adverse effects and the theoretical risk of torsade
due to prolongation of the QTc interval.
Prolongation
of the QTc interval is not the sole determinant of a dose propensity to cause
torsade. Dr. Luiz Belardinelli will
describe in detail an approach to assessing the pro-arrhythmic potential based
on evolving new science that, when integrated with clinical findings, provides
a better indicator of the actual risk of torsade. Both CVT and the FDA agree that Ranexa is
associated with a small increase in the duration of cardiac repolarization.
To
definitively characterize this effect, CVT has undertaken a comprehensive
clinical and preclinical electrophysiological assessment of ranolazine. There is a small mean increase of 2 to 3
milliseconds in QTc at normal doses and up to 20 milliseconds under conditions
of maximal metabolic inhibition with cytochrome P450 3A4 inhibitors, its
predominant metabolic pathway. The
conclusion of this comprehensive clinical and preclinical electrophysiology is
that Ranexa is fundamentally different to all drugs which cause torsade.
In
particular, Ranexa does not lead to early afterdepolarizations, the recognized
trigger for torsade, nor does it increase the dispersion of intramural
ventricular repolarization, the recognized substraint for torsade. In fact, ranolazine reverses these effects
when produced in the laboratory by other drugs known to cause torsade. As a consequence, Ranexa has a very low
potential to cause torsade, further evidenced by the fact there is no reported
cases of torsade in the Clinical Development Program.
CVT
has prepared a detailed presentation this morning focused on questions asked of
the Committee by the FDA. To commence
our presentation, Dr. Eugene Braunwald, from Brigham and Women's Hospital in
Boston, will describe the unmet need for the treatment of angina patients and
how persistent angina continues to impact the lives of patients despite current
therapies and despite revascularization.
Dr. Andrew Wolff, from CVT, will then describe the efficacy and safety
data for Ranexa.
Prior
to the discussion of electrophysiology by Dr. Belardinelli and by Dr. Wolff,
Dr. Peter Kowey, from Lankenau Hospital, Philadelphia, will place into context
the utility of the new science to evaluate pro-arrhythmic effects of drugs
preclinically in the absence of reliable clinical predictors for pro-arrhythmic
effects. And finally, Dr. Jeremy Ruskin,
from Massachusetts General, will summarize the risk benefit for Ranexa and to
look at its possible place in the therapy of angina.
In
view of the groundbreaking nature of much of the data which will be presented
by CVT, we have asked a number of independent experts in addition to the
speakers, who have advised CVT, to attend, to be available to answer the
Committee's questions and provide further clarification. Our guests include Dr. Charles Antzelevitch,
Dr. John Camm, Dr. Bernard Chaitman, Dr. Gary Koch, Dr. Samuel Lee, Dr. Marek
Malik, Dr. Craig Pratt, Dr. Dan Roden and Dr. Peter Stone.
I
would now like to hand over to Dr. Eugene Braunwald of Brigham and Women's
Hospital to describe the current unmet need for the treatment of angina. Dr. Braunwald?
DR.
BRAUNWALD: Good morning. I think all of us in this room realize that
angina pectoris remains a serious and frequently disabling condition, despite
currently available therapies. Now,
angina was first described by William Heberden in 1772, and his description is
really quite accurate today, and it is useful to reflect on his exact
wording. It would be "There is a
strong disorder in the breast. The seat
of it, and the sense of strangling and anxiety with which it is attended, may
make it not improperly be called angina pectoris. Those who are afflicted with it are seized
while they are walking with a painful and most disagreeable sensation in the
breast, which seems as if it would take their life away, if it were to continue
or increase."
So
in other words, angina pectoris has been recognized for more than two centuries
as the heart's cry for energy and the drugs we have available, the treatments
that we have available are really a response to that cry. Now, there have been many developments in the
treatment of angina, but despite the use of traditional anti-anginal agents,
beta blockers, calcium blockers, nitrates, as well as revascularization
procedures, the American Heart Association estimates that there are more than
6.5 million Americans who continue to suffer with angina pectoris.
Despite
these therapeutic advances, it is estimated that 13 million episodes of angina
occur each week and that translates into about 1,000 episodes every
minute. On average, patients treated for
angina experience two episodes daily, making this a major and significant
problem. So the improvement in the
treatment of angina is an important medical goal.
Now,
patients with angina frequently have comorbid illnesses, and in one VA population
it was shown that about a quarter to a third have diabetes mellitus, about 1 in
5 have obstructive pulmonary disease, a quarter have peripheral vascular
disease and about 1 in 5 also have congestive heart failure. So angina remains a problem, as I have said,
despite contemporary drug therapy.
Pepine has reported that despite the use of anti-anginal agents, that is
beta blockers, calcium antagonists and nitrates, patients still report an
average of two attacks a week.
Now,
a significant percentage of patients, especially those with comorbidities,
can't tolerate the full doses of beta blockers, calcium channel blockers and
nitrates. Beta blockers and calcium
blockers have similar depressive effects on blood pressure, heart rate and AV
nodal conduction. Clearly, something
else is needed, and it would certainly be desirable to develop an anti-anginal
drug without these limitations.
Now,
the use of mechanical revascularization, of course, has been very important and
has improved the treatment of angina.
What isn't generally recognized is that many patients who have had
successful PCI still continue to experience angina. The data shown on this slide come from the
NHLBI Registry published about a year ago.
They show the frequency of angina a year following PCI in several groups
of patients, those with or without a previous myocardial infarction, those with
and without previous coronary bypass grafts, those with and without previous
PCI, and angina was persistent in all of these groups.
The
bottom line is that among patients who underwent successful PCI the overall
prevalence of angina was still 26 percent.
Now, the ARTS trial was an important trial which compared complete
revascularization by means of coronary bypass grafting and PCI by
stenting. Twelve months after
intervention, there was still a large number of patients with angina. Seventy-nine percent of those in the stenting
group were free of angina, which means that 21 percent still experienced it.
The
surgical patients did better, but even 10 percent of those had angina. Now, even among the surgical patients, only
41 percent did not require anti-anginal medications. The bottom line in this trial, in which successful
revascularization was carried out, 60 to 80 percent of patients were still
taking anti-anginal medications and despite revascularization and
pharmacological therapy, 10 to 20 percent of patients still experienced angina.
The
impact of angina on the quality of life has been studied extensively. I'll give just two brief examples. A self-rating of health for angina patients
showed that physical function, body pain, vitality and general health were all
markedly diminished in patients with angina.
Depression is a very serious problem in patients with angina and, from
this study, you can see that the percent of patients who were depressed rose as
the frequency of angina pectoris increased.
So
angina continues in many patients despite medical and mechanical
intervention. The personal burden can
deprive patients of their independence, forcing them to downsize their lives,
leave employment or take reduced employment.
The economic toll, therefore, is huge and it is important to develop new
methods of therapy. When angina cannot
be eliminated by current drugs, we should remember that it is typically due to
their additive effects on blood pressure, heart rate and AV conduction.
There
are other important side effects that we shouldn't forget: depression, fatigue, sexual and sleep
disorders, which preclude complete relief and new therapies are needed to help
fill the large void. So angina is a
growing problem in the United States. It
has been estimated that there were about a million people with angina at the
beginning of the 20th Century, and that we now, as we've heard from the American
Heart Association data, have about 6.5 million Americans with angina, and the
prevalence is rising and is expected to continue to rise as the population
ages, as the epidemic of diabetes increases and as the number of patients
surviving acute myocardial infarction increases.
It
is interesting on this last slide to look back on the history of the treatment
of angina. There actually have been only
five really important therapies for angina in 125 years. Nitrates were introduced by Lauder Brunton in
the 1880s. Beta blockers came along in
the 1960s, calcium antagonists in the late 1960s, coronary bypass grafting in a
major way in 1969, calcium channel antagonists in 1975, percutaneous coronary
intervention in 1977.
Now,
the presumed mechanisms of action of these classic treatments for angina are
shown below. For the first five of
these, the balance between oxygen supply and demand tends to be restored. And here as we're entering 2004, you're being
asked to consider a novel compound whose principal mechanism of action appears
to be metabolic. And it is notable that
ranolazine can be added to any, or any combination, of these earlier therapies.
I
believe that you will find the experience with ranolazine, which is about to be
presented, that this experience will open a new and significant chapter in the
treatment of the condition described by Heberden. Thank you.
CHAIRMAN
BORER: Thank you very much, Dr.
Braunwald. Are there any questions or
comments? If not, thank you very much.
DR.
WOLFF: Well, thank you, Dr. Borer. I am Dr. Andrew Wolff from CV Therapeutics,
and I will now discuss the efficacy and safety of Ranexa in the treatment of
chronic angina. As we will see, the
anti-anginal and the anti-ischemic effects of ranolazine have been demonstrated
in five double-blind, randomized, placebo-controlled studies. They are related both to the dose of the drug
and the resulting plasma concentration, as we have demonstrated across a
broadly representative population of patients with chronic angina due to severe
coronary artery disease.
The
anti-anginal effects don't depend upon decreases in blood pressure or heart
rate and in one study they were demonstrated to be as large or larger than
those of atenolol at 100 milligrams once a day.
In another study that we will review, the anti-anginal and anti-ischemic
effects of the drug were demonstrated in patients receiving treatment with
either atenolol or diltiazem at doses of those drugs that were felt to be
optimal by their treating physicians.
The
five studies demonstrating the efficacy of ranolazine included two pivotal
Phase 3 studies performed with the sustained-release or SR formulation intended
for marketing. One of these two trials,
MARISA, evaluated patients withdrawn from beta blockers, calcium channel
blockers and long-acting nitrates, that is, MARISA was the study of ranolazine
as anti-anginal monotherapy.
The
second and larger pivotal trial CARISA studied ranolazine in patients who are
also receiving treatment with a standard dose of a beta blocker or a calcium
channel blocker. Together, these two
studies enrolled over 1,000 patients. In
addition to the two pivotal trials, three other studies enrolled 500 further
patients with chronic angina and used in an earlier immediate-release or IR
formulation. Now, these three
immediate-release studies provide further support for the anti-anginal and
anti-ischemic effects of the drug, as we'll see.
Together,
MARISA and CARISA enrolled a broadly representative population of chronic
angina patients. About three quarters of
the patients were men. Over half were
over the age of 65 and over 10 percent were over 75 years old. The concomitant illnesses that commonly occur
with chronic angina were well-represented.
About a quarter of the patients had diabetes and about a quarter had
heart failure, two-thirds had a history of hypertension, more than half have
had a prior myocardial infarction and about a third of our study population had
undergone some type of myocardial revascularization procedure.
The
patients randomized into MARISA and CARISA all had severe coronary artery
disease based on their Duke treadmill exercise score. The Duke score is an index of coronary
disease severity with prognostic significance and it is calculated from the exercise
duration, the degree of ST-segment depression and the presence and severity of
exercise-induced angina during exercise testing. The entry criteria for MARISA and CARISA
stipulated a Duke score at maximum of -10 at randomization. Current guidelines jointly issued by the
American Heart Association and the American College of Cardiology classify
patients with a Duke score more negative than -10 as high risk with an annual
mortality of approximately 5 percent. And
as you can see here, the average Duke score in our population was about -14.
I
will now turn briefly to the MARISA study, a monotherapy assessment of
ranolazine in stable angina. In MARISA,
191 patients withdrawn from other anti-anginal drugs were randomized into a
four-period, crossover design study, in which patients received a week of
treatment with each of these three active therapies, as well as placebo, in
random order in a double-blind, double-dummy fashion for a total of three weeks
of treatment with active ranolazine.
Patients would come to the clinic in the morning, 12 hours after their
prior dose, the evening before that is at the time of trough plasma levels.
Following
that exercise test, patients would take the final morning dose from that
treatment regimen and then four hours later at the approximate time of peak
plasma levels, they would have another exercise test. Here are the treadmill efficacy data for
MARISA. Compared to placebo, each of the
three ranolazine regimen studied caused statistically significant increases in
each of the three major treadmill exercise parameters, exercise duration, time
to angina and time to ST-segment depression.
These
effects were clearly dose-dependent and were greater at peak than at
trough. Most importantly, the primary
endpoint of exercise duration at trough was met with increases with respect to
placebo of 24, 34 and 46 seconds. The
effects on the two secondary exercise end points, the time to ST-segment
depression and time to angina, were actually all greater, 45 seconds or more.
The
second pivotal study was CARISA, a Combination Assessment of Ranolazine and
Stable Angina. We intended for CARISA to
be an assessment of the drug in a "real-world" clinical practice
setting with each patient receiving one of these three background therapies at
the stipulated doses which were chosen because they are the most commonly
prescribed anti-anginal drugs in the world at their most commonly prescribed
doses.
CARISA
randomized 823 chronic angina patients into 12 weeks' treatment with ranolazine
at doses of either 750 or 1000 milligrams twice daily or matching placebo and
the randomization was stratified over these three background therapies. In this parallel group study then patients
underwent exercise testing at trough, again, 12 hours after their prior dose,
after two, six and 12 weeks of treatment and also had exercise tests at peak
after two and 12 weeks of treatment.
Once
again, each of the three major treadmill exercise parameters was improved by
ranolazine versus placebo and, in particular, once again, the primary end point
of exercise duration at trough was met.
In addition to treadmill exercise performance, angina frequency in
nitroglycerin consumption were also assessed in CARISA. And you can see here that ranolazine reduced
both angina frequency and nitroglycerin consumption to a statistically
significant degree and in a dose-related fashion.
In
both MARISA and CARISA, the ranolazine dose predicted the plasma
concentration. The relationship between
dose and plasma concentration was generally linear and is shown here. Now, as the dose predicts the plasma
concentration, in turn, so does the plasma concentration predict the
response. A large population based
analysis of the concentration- response relationship for exercise duration
included data from four different clinical trials. MARISA and CARISA, which I have just
discussed briefly, and two earlier studies done with the immediate-release
formulation.
This
analysis included data on nearly 1,400 patients and nearly 11,000 pairs of
exercise tests and plasma concentration data points. In this analysis, age, weight, race,
congestive heart failure class, diabetes and the presence, absence or type of
background anti-anginal therapy each had no influence upon the slope of the
relationship between the ranolazine plasma concentration and the increase in
exercise duration.
This
analysis thus indicates that the data from MARISA and CARISA obtained
respectively with ranolazine is monotherapy or ranolazine in combination with
the beta blocker are consistent with one another. The population analysis also showed a
difference between men and women, with women having a somewhat lower slope for
the relationship between plasma concentration and exercise duration. Ranolazine is an effective anti-anginal in
women. Exercise duration in women
increases with plasma concentration and, as indicated by the 95 percent
confidence intervals around the slope, this is a statistically significant
non-zero slope.
So
women do, indeed, respond to ranolazine with increases in their exercise
performance. The increase they
experience is somewhat less than what we observed for men, but this is also
true for many other types of anti-anginal therapies, including drugs, bypass
surgery and percutaneous intervention.
But this doesn't necessarily mean that the response of women in the
treatment of angina with ranolazine or these other drugs is actually less. It may be that exercise testing is not as
fine a tool for the detection of therapeutic response in women.
And
consistent with that possibility, is the fact that angina frequency and
nitroglycerin consumption were decreased similarly by the two doses of
ranolazine in both men and women. Thus,
ranolazine does appear to be an effective anti-anginal in women, increasing
exercise performance and decreasing angina frequency and nitroglycerin use.
Ranolazine
was studied in a broadly representative group of chronic angina patients and we
specifically examined those types of patients who might be more difficult to
treat with some of the current anti-anginal medications, because of their
depressive effects on hemodynamic parameters as described earlier by Dr.
Braunwald. For example, this slide
illustrates the subgroup analysis focused on patients with systolic blood pressures
less than 100 millimeters of mercury, heart rate slower than 60 beats per
minute or PR intervals longer than 200 milliseconds.
You
can see that in the CARISA trial this actually included about a third of the
patients randomized. These p-values given
here represent the treatment by subgroup interaction. In these analyses, a statistically
significant p-value would indicate a major significant difference between the
effect of ranolazine in the subgroup of interest and the effect in the other
patients. But none of these p-values are
close to statistically significant, which indicates that there is no major
difference in the response to ranolazine between those patients with borderline
hemodynamics and the others.
Now,
these patients with low blood pressures and slow heart rates and long PR
intervals could be viewed as resistant or possibly resistant to current
anti-anginal drugs, because they are all having angina and exercise-induced
angina and ischemia at a very low work load in the presence of at least one
hemodynamic parameter that could give pause before the initiation or upward
titration of the hemodynamically acting drug.
In
addition to the analyses in patients with borderline hemodynamics, we performed
analogous subgroup analyses focused on other groups of patients not likely to
tolerate the hemodynamic or other effects of current anti-anginal drugs. Patients with reactive airway disease,
patients with congestive heart failure and patients with diabetes. In each of these analyses, the effect of
ranolazine in the subgroup of interest was consistent with the effect
demonstrated throughout the broad population.
Now,
to put the magnitude of ranolazine's efficacy into perspective and to compare
the anti-anginal pharmacodynamic profile of ranolazine to that of the
hemodynamically acting agent, we'll turn to one of the Phase 2
Immediate-Release Studies RAN080.
Chronic angina patients were identified using entry criteria that were
essentially identical to those used to enroll MARISA and CARISA, and they were
randomized then into a three-period, crossover design in which they received a
week of treatment with placebo, a week of treatment with immediate-release
ranolazine at a dose of 400 milligrams three times daily and a week of
treatment with atenolol at 100 milligrams once a day, a good dose of atenolol
and, of course, in a randomized, double-blind, placebo-controlled fashion.
The
ranolazine dose chosen at the time of exercise testing produced a plasma
concentration of approximately 1700 nanograms per mL, which is right in the
middle of the range of what is produced during dosing with sustained-release
preparation at 750 milligrams three times daily. So it's a relevant dose for consideration. Here then are the treadmill exercise data
from RAN080, and you can see both ranolazine, in these cream colored bars in
the middle, and atenolol in the bright green bars on the end, both produced
statistically significant increases in the three major treadmill exercise
parameters.
Now,
ranolazine and atenolol both produced similar improvements in time to angina
and time to ST depression. But in this
trial, the effective ranolazine was significantly greater than that of 100
milligrams of atenolol. Thus, in this
study, the efficacy of ranolazine was at least as good as that of atenolol at
100 milligrams a day. More importantly,
perhaps, however, was the way in which this effect was achieved.
The
pharmacodynamic profile associated with ranolazine's improvement in exercise
performance was very different from that of atenolol. Here are the data on rate-pressure
product. As would be expected, atenolol
decreases rate-pressure product at rest and even more dramatically at the end
of exercise. In contrast to those
effects of atenolol, ranolazine had no effect on rate-pressure product at rest,
and was associated with a small but statistically significant increase in the
rate- pressure product at the end of exercise.
So
these patients' hearts then were able to do more mechanical work for a longer
period of time before the symptoms and electrocardiographic evidence of
myocardial ischaemia supervened. And
this is consistent then with an improvement in the efficiency of myocardial
oxygen utilization.
In
another Phase 2 study, immediate- release ranolazine was studied in patients
treated with atenolol or diltiazem at doses of those drugs considered to be
optimal by their physicians. Patients
received a single dose of immediate-release ranolazine or matching placebo on
alternate study days in a two-period, crossover design. Exercise testing was done at 2.5 to 3 hours
after dosing with these drugs, and so consequently it's important to realize
that background therapies for themselves were also at their peak effects.
The
240 milligram immediate-release dose was studied in 25 patients, 15 of whom
were on atenolol, 12 receiving a dose of 100 milligrams a day and 10 on
diltiazem and again these were considered to be doses optimized by their
physicians. As seen here, the 240 milligram
immediate-release single dose, which produced plasma concentrations equivalent
to those generated by 500 milligrams twice daily at trough, produced
statistically significant and clinically meaningful improvements in each of the
three major treadmill exercise parameters when studied over background
treatments of optimal doses of atenolol or diltiazem at the time of the peak
effects of those drugs.
In
summary then, with respect to efficacy, we've demonstrated the anti-anginal and
anti-ischaemic effects of ranolazine to be both dose- and concentration-dependent. The effects are consistent throughout a broad
population of chronic angina patients and don't depend upon decreases in blood
pressure or heart rate. They've been
demonstrated in one trial to be at least as great as those of atenolol at 100
milligrams once a day and in another trial they have been demonstrated over
background treatment with optimal doses of atenolol or diltiazem.
I
will now turn to the safety of ranolazine in chronic angina. In overview, shall I go ahead, Mr. Chairman?
CHAIRMAN
BORER: Yes. Just a moment, Dr. Wolff, I think there are
some clarification issues here. Paul?
MEMBER
ARMSTRONG: Could we see CE-7 slide,
please? I just want to go between CE-7
and CE-9 to get a little better understanding.
In this instance, the efficacy data shows -- I'm just trying to get a
proportionate change, because the next slide is plotted somewhat
differently. This is about a what, about
a 5 to a 7 percent increase in the left panel over the baseline? Would that be about right?
DR.
WOLFF: The increases on the primary
endpoint are 24, 34 and 46 seconds. And
with respect to placebo, yes, I mean, it's in that range.
MEMBER
ARMSTRONG: That ballpark. Okay.
And then if you go forward to CE-9, please? Now, in this instance, the plod is a change
from baseline. I wasn't clear. So the presentation of the data is different
here than it is in the previous slide.
DR.
WOLFF: It is. The two studies are different.
MEMBER
ARMSTRONG: Sure.
DR.
WOLFF: I mean, because MARISA is
crossover.
MEMBER
ARMSTRONG: So just in terms of the
baseline that we're talking about, what kind of baseline exercise performance
would we be talking about here? Just so
I can get a sense of going back and forth.
DR.
WOLFF: Yes. Well, I'm going to ask my statistical
colleague, Dr. Mike Crager to give the numbers there.
DR.
CRAGER: Mike Crager, CVT
Biostatistics. The baseline is about 416
seconds.
MEMBER
ARMSTRONG: Okay. And as I understand it, patients would have
received either amlodipine or, I'm sorry, is it diltiazem?
DR.
WOLFF: Amlodipine, diltiazem or
atenolol. One of the three.
MEMBER
ARMSTRONG: So how do we tell which is
which?
DR.
WOLFF: Well, these are the data for all
the background therapies combined.
MEMBER
ARMSTRONG: I understand that.
DR.
WOLFF: Right.
MEMBER
ARMSTRONG: So what I'm trying to
understand is whether it makes a difference as to which background was chosen
relative to what change you see. How
much heterogeneity versus homogeneity just so I could understand.
DR.
WOLFF: Sure. We did do a similar analysis to one of the
others I described earlier where we looked at the treatment by background
therapy interaction, and we saw no statistical significance there. Here, in fact, you can see the data
plotted. And, of course, when you slice
and dice the data you will get some variability. But the treatment by background interaction
statistic is 0.63, which indicates that there is no significant difference in
the effect of ranolazine across the three background strata.
MEMBER
ARMSTRONG: And when was the background
therapy given relative to -- I wasn't clear in terms of it --
DR.
WOLFF: They were given at the same time
as ranolazine in the morning. They were
all once daily, so they were given in the morning with the ranolazine.
MEMBER
ARMSTRONG: Thank you.
CHAIRMAN
BORER: Before you leave that CE-7 slide,
and before we get to our Committee reviewer's questions, can you go back to
that CE-7? This was a crossover design,
this study?
DR.
WOLFF: Yes.
CHAIRMAN
BORER: And in order for me to understand
the effect of the drug relative to placebo, it would be easiest to make a
determination after the first interval.
Do you have the data to show us the relation of the effect of the drug
to placebo after the first interval? I
understand that we're dealing with a quarter as many patients there or a third
as many patients, but I would like to see that if I can, so that we can avoid
issues of carryover effect.
DR.
WOLFF: I think we're putting up the
slide with the first period analysis.
Here, this shows the data by periods and we'll have Dr. Michael Crager
come to the podium again to describe what we have done to exclude a carryover
effect in the MARISA Study.
DR.
CRAGER: So this slide shows the
treatment effects by period. As you can
see, the treatment appears to be closer together in the first period. However, if you look at the error bars around
the treatment means you can see that there is a lot of variability in the
data. And if we put confidence intervals
around those points, they would be twice as wide as the error bars.
When
you look at a test for whether the treatment effects differ by period, the
p-value for that test is 0.57. That
indicates that any apparent differences between the effects of the treatment
and the different periods is well within the limits of chance variability. So the most appropriate analysis to look at
all of the data from the entire study, which is the results that Dr. Wolff
presented earlier.
DR.
TEMPLE: But it does seem to show a
training effect, doesn't it? I mean,
everything is getting better as the study keeps going.
DR.
WOLFF: There is a training effect, yes,
and I think that is typical for angina studies, but they all improve and the
improvements are roughly parallel across the treatment groups.
CHAIRMAN
BORER: Ed?
DR.
PRITCHETT: What did you do with patients
who didn't complete the study, who dropped out without getting all the
crossovers? How did you handle dropouts?
DR.
WOLFF: The primary analysis was
specified to be an analysis of what we call the all or near completers. And so it was data from patients who
completed at least three of the four.
And if that -- this was prospective identified -- population was greater
than 75 percent of the enrollment, then that was going to be the primary
analysis. In fact, it was over 90
percent of the patients. They had over
three of the four periods end, and the great majority of them had all four
periods. Then in order to try to analyze
all the data, including those from patients that had even fewer than three
periods, there was an analysis which Dr. Crager could describe, if necessary,
using a generalized estimating equation which allows incomplete patients to be
analyzed in a crossover design method.
DR.
PRITCHETT: That's not necessary.
DR.
WOLFF: Okay.
CHAIRMAN
BORER: Blase?
DR.
WOLFF: And they were very similar. The GEE methodology and the primary analysis
showed very similar results.
MEMBER
CARABELLO: One of the natural niches for
the drug would be for patients who are already optimally treated for their
angina. And usually that requires
several agents, at least most of my patients are on several agents. Further, that would test the hypothesis that
this is adding a new mechanism of ischemia relief. Do you have experience with the use of the
drug in patients who are already maximally treated with other agents?
DR.
WOLFF: We don't have double-blind,
randomized, placebo-controlled efficacy data.
We do have patients that are receiving one, two, three other
anti-anginal drugs in the Long-Term Open-Label Studies which have been ongoing
in which patients have continued some of them for well over two years, and they
do seem to be doing well, but we can't speak from controlled experience in that
kind of patient population.
MEMBER
CARABELLO: Thank you.
CHAIRMAN
BORER: Bob?
DR.
TEMPLE: You showed a study, I guess,
with an IR form that suggested an increase in rate- pressure product, something
that on the whole no other anti-anginal -- well, CCBs and beta blockers can't
achieve that anyway. But we've discussed
this previously, so I know what you said last time, but you may have looked
further. The later studies, though, with
the controlled release product have not shown an increase in rate-pressure
product or maximum oxygen utilization or anything like that, right?
DR.
WOLFF: Not a statistically significant
one. At 500 milligrams twice daily at
peak, the rate-pressure product is higher than on placebo in MARISA, but it's
not statistically significant. So if we
could, do you want to pursue this a bit more?
DR.
TEMPLE: Well, it has something to do
with whether there is a brand new mechanism here.
DR.
WOLFF: Well, I think --
DR.
TEMPLE: I don't know how persuasive
people would find that.
DR.
WOLFF: I would like to present the data
table, which shows the exercise performance data in relationship to the
exercise rate-pressure product, as well as the heart rate and blood pressure,
because I think this is instructive to how the drug is working. Okay.
We have one that is a little less busy, but I can work from this
one. Yes, this is good. Okay.
Thank you.
Okay. So this is a crowded slide, but I think it
walks us through the question that you are asking, Dr. Temple. Here you've got the standing and exercise
heart rate and the systolic blood pressure on these two rows, and then their
product, the rate-pressure product at the end of exercise for both MARISA and
CARISA put together. Here is the 500
milligram dose for MARISA and then the 1000 and the 1500 from MARISA and then
the 750 and 1000 milligram doses from CARISA are shown here in the blue
box. And here are the data on exercise
duration as a measure of exercise performance for each of those doses.
So
in the first instance, you can see that there is really no effect at all on
rate-pressure product at the 500 milligram twice daily dose, while there was a
statistically significant improvement in exercise duration. So this is the first piece of evidence that
the effect of the drug can't depend upon any decrease in blood pressure or
heart rate, because there really aren't any here.
Now,
in the CARISA Study, as you mentioned, we do begin to see some slight decreases
in rate-pressure product that do achieve statistical significance. However, again, you can tell that they can't
entirely explain the effect of the drug on exercise performance for the
following reason, and that is that, for example, here on 750 milligrams the
exercise performance effect of the drug is greater at peak than it is at
trough. But the slight decline in
rate-pressure product is greater at trough than it is at peak. And it's similarly true for 1000 milligrams
as well.
So
while there are some small decreases in rate-pressure product that we did
observe in the later clinical trials, they can't explain the effect of the drug
to improve exercise performance completely.
It can't exclude that there may be some small contribution from them,
but they can't overall explain it. And
then finally, just observationally, these effects are much smaller than those
of hemodynamically acting drugs. And in
the RAN080 Study, I showed you the rate-pressure product on atenolol was down
by several thousands of units, rather than just a few hundred.
DR.
TEMPLE: Jeff, can I follow that up? I know beta blockers leave you with a lower
rate-pressure product, because they lower the heart rate so much. But the point was to show an increased
rate-pressure product at maximal exercise to show that somehow oxygen
utilization or some aspect of the heart's work is improved. And having it go down only slightly, doesn't
make that case.
DR.
WOLFF: I think the best I can say is
that in one study it does go up. It goes
up significantly and it goes up in a patient population similar to what we
observed in the other two. And in
another study it doesn't go down at all, at a very similar dose and
concentration. As you get the higher
doses, as I say, I can't exclude that there may be some additional
contribution, but I think it is clear from the discussion we just had that the
decreases can't fundamentally explain what is happening. There has to be some other contribution.
DR.
TEMPLE: I guess I don't understand
that. My impression is that calcium
channel blockers leave rate-pressure product more or less unchanged. The idea being that somehow heart rate and
exercise at peak are decreased enough so that you can exercise more before you
reach whatever the critical level is, and that seems to be the same here.
DR.
WOLFF: Well, these data go a little
further. Here you can see the data from
the CARISA Study at the time of peak plasma levels at the end of the study. The rate-pressure product is very close to
the placebo line on drug, but one of the points that is consistent with what
you are saying is that on the 1000 milligram group, some patients went from
Stage 3 to Stage 4. Now, they didn't all
do that. But it is interesting to note
that none of them did it on the lower dose or on placebo.
So
some patients actually did get to a higher overall work load than on
placebo. But yes, some patients stopped
in here as well, and so the overall effect was not to have an average increase
in rate-pressure product. But where it
did occur, it occurred on ranolazine and only on the higher dose.
DR.
TEMPLE: Okay.
CHAIRMAN
BORER: Tom?
MEMBER
PICKERING: Were any of these patients on
long-acting nitrates? And do you have
any data on long-acting nitrates?
DR.
WOLFF: We didn't study long-acting
nitrates, again, as a background treatment in either of the two pivotal
studies. There are a few patients that
were receiving long-acting nitrates in the earlier immediate-release
studies. We didn't choose long-acting
nitrates for background therapy for MARISA or CARISA, because at the time of
trough plasma levels, that effect would have to be at zero if they are dosed
properly, so, you know, they only work during part of the day. We do have a number of patients that have
then gone on into open-label therapy and have been treated with long-acting
nitrates, and so there is open-label safety data with those patients.
CHAIRMAN
BORER: Alan and then Blase.
MEMBER
HIRSCH: I have three questions. First, regarding the unmet clinical
need. You know, the study designs are
helpful if they really inform us how a product might be used in the
"real-world." So my question
is, because I actually don't know the answer, like Blase, what fraction of
American angina patients take one, two and three anti-anginal medications
currently?
DR.
WOLFF: Do we have a slide that shows
that? We do have a slide that shows the
fraction of patients dosed with the doses of drugs that were used in CARISA,
but that's not directly to your question.
That shows that the great majority of patients taking those drugs are on
the doses that we used.
MEMBER
HIRSCH: Right.
DR.
WOLFF: If my memory serves me correctly,
and I'm going only from memory, and I probably won't be able to show you data,
but this comes from market research, I think it is somewhere on the order of 5
to 10 percent of patients are taking three drugs. The majority in every study where we've ever
looked at this take more than one. Most
are taking two and some few are taking three.
There's usually around 55 or 60 percent are taking two or three drugs.
MEMBER
HIRSCH: The second question, if I could,
regarding the dose-response. In the
MARISA Study seeing that dose-response is somewhat reassuring, but many of us
like to see a minimal effect or a no-impact effect of what might be received at
something less than 500 twice daily.
Have you defined that?
DR.
WOLFF: We have from our population
analysis where we've got an awful lot of plasma concentration data that covers
the range, essentially, down to zero.
And the analysis looks as though there is a zero intercept to the
relationship between exercise duration and plasma concentration. So it just continues to go down linearly at
lower and lower concentrations.
And
so you could then predict that if we studied -- well, if we got a 24-second
improvement at trough in exercise duration on 500, then at 375 it would be on
the order of about 18 seconds, and at 250 it would be on the order of about 12
seconds. And I think then the question
becomes where is your judgment about a clinically relevant increase? But it does appear to be related to
concentration really down to zero.
MEMBER
HIRSCH: I hear that, but again is there
clinical exercise that you can show us that's something less than 500 twice
daily?
DR.
WOLFF: We have an abundance of data with
the immediate-release formulation that produced plasma concentrations below
those that we now generate with the sustained-release, and those studies
weren't effective. Here is one study
that actually does give you some information there. This was one of the immediate-release studies
in which three different regimens of ranolazine were studied at both peak,
which was an hour after dosing, and trough, which was eight hours after dosing
for two of the three times daily regimen, and it was done 12 hours after dosing
for a twice daily regimen.
And
what you can see if you look through is that at peak, there were generally
significant increases in treadmill exercise performance and there weren't any
at trough. And in this study, the lowest
plasma concentration that was associated with efficacy was on the order of
around 1300. The highest plasma
concentration at trough was around 500.
So putting the totality of the data together, it looks as though if you
were to speak of a threshold, it would be at around 800 nanograms per mL, which
is what we get about at trough with 500 milligrams twice a day.
But
it really isn't a threshold when you model all the data, because there is
really a linear function there. But it
is where we begin to demonstrate statistically significant efficacy in the
usual range that people want to see of 20 seconds, 30 seconds.
MEMBER
HIRSCH: One more potentially challenging
follow-up, which is mechanism. I realize
for many medications we don't really ultimately know how pharmacokinetics
translates to clinical impact, but what we're thinking of here is obviously
something quite novel in that we're disassociating with the heart rate and
blood pressure impact. So my question is
how do we know this has a cardiac effect at all?
DR.
WOLFF: I think we know it's a cardiac
effect, because there were significant improvements in time to ST-segment
depression in all of the studies. So, I
think, I get your drift. There could be
effects on skeletal muscle as well, and we do have preclinical data in skeletal
muscle and the same kinds of metabolic shifts were seen. We know there has to be an improvement in
myocardial performance because of the data on ST-segment depression.
MEMBER
HIRSCH: So when this medication is given
to healthy animals or normal volunteers, is there any change in exercise
performance?
DR.
WOLFF: We haven't done that in normal
volunteers. We've done it in
investigating heart failure in normal dogs, and in normal dogs we don't see any
effect. And then after heart failure is
induced in the animals, we do see then interesting improvements in left
ventricular systolic performance that occur without increases in heart rate,
without increases in blood pressure or decreases and really do appear to be a
central myocardial effect, because oxygen consumption actually trends slightly
downward in those animals. But normal
dogs we see nothing at the same dose.
CHAIRMAN
BORER: Blase?
MEMBER
CARABELLO: I had the same question. That last question was already answered. Thank you.
CHAIRMAN
BORER: Before we go on to a different
set of questions, we have Bob and Beverly and then we'll go on to Steve's
list. The issue of extrapolating from
the short-acting preparation or the long-acting preparation in part depends on our
accepting the relation between effect and plasma level which, you know, at
first glance might be reasonable, but it may not be.
And
with that in mind, on your slide CE-9 on which you commented in your briefing
book as well, it seems as if the effects are greater at trough, at least the
absolute effect is greater at trough, the absolute exercise time is greater at
trough than at peak. The differences
between placebo and active drug seem to be greater at peak than at trough. But the exercise times on placebo, the change
from baseline on placebo is less at peak than at trough. This is an unusual set of data. It's not necessarily inconsistent with the
idea that peak plasma levels are most effective, but I wonder if you can
comment on this apparent discrepancy?
DR.
WOLFF: Certainly. What we're seeing here is the change from
baseline in exercise performance. And so
at baseline, in the morning when we did the baseline "troughs" --
they really weren't troughs yet, because we hadn't begun the study, but we did
the baseline at trough in the morning -- the background therapies of the
amlodipine, atenolol and diltiazem were also at trough. And then when we did the baseline times in
the afternoon for the peak tests that were to follow, the effects of the atenolol
and the diltiazem and the amlodipine were at their peak effect.
And
so, consequently, the changes from baseline in the afternoon were all, as
you've noted, generally smaller than the changes from baseline in the morning,
because there was potentially a background effect of the drug. But as you note, the differences from placebo
are clearly greater at the time of peak plasma than at trough.
CHAIRMAN
BORER: Bob and then Beverly and Steve.
DR.
TEMPLE: Only one of your trials was more
than one week duration, and we thought we saw some decline in effect over
time. So I guess, I think, you should
discuss the duration of trials, the crossover trial really exposed people to
just one week of treatment per period, I guess.
DR.
WOLFF: But there were three total weeks
of ranolazine.
DR.
TEMPLE: Right. But it really hadn't been analyzed in terms
of duration there. Maybe you could do
that. So I think you should comment on
that. I have to tell the Committee we
haven't seen anything quite like that before.
Trials are usually longer and we are worried about duration, so why
don't you address that to the extent you can?
DR.
WOLFF: Okay. Well, here are the data by week from CARISA
and as Dr. Temple points out, the difference at 12 weeks is slightly smaller
than the difference at two. But, in
general, you again see the learning effect, as we discussed before, on
placebo. But the two active treatments
are shifted upward in the generally parallel direction. And again, the arrows of the measurement are
sufficient that really this is consistent with a parallel and maintained
effect.
We've
already seen the slide then from the MARISA Study which showed the learning
effect and the difference sort of being maintained over the four week duration
of that study. And then the only other
data that I can speak to that go to chronicity of effect again come from
CARISA, but from the withdraw portion of the study, which we haven't
discussed. But at the end of the CARISA
trial, the patients were re-randomized to look for evidence of rebound
increases in angina with abrupt withdrawal.
And
so the patients that had been on placebo all just remained on placebo. But the patients on the two active doses were
randomized, so that half of them were abruptly withdrawn to placebo and the
other half continued on their active dose in a double-blind fashion and then
there was an exercise test that was done 48 hours after the final dose. And as you can see here now, the improvements
in exercise tolerance in the patients who continued on treatment remain, but
the exercise performance in the patients who were withdrawn declined back down
to placebo levels.
They
didn't go lower than on placebo, indicating no evidence for any rebound
increases in angina or decreases in exercise performance with withdrawal. So to Dr. Temple's question, these people are
still exercising longer and in the same range that we were seeing after two,
six and 12 weeks of treatment.
CHAIRMAN
BORER: Before you take that away, the
withdraw period was 48 hours, but the time to study state plasma level is three
days, according to the data you sent us.
Why did you choose 48 hours as your testing time when presumably there
should be some drug remaining?
DR.
WOLFF: Well, after the last dose then
the intrinsic half-life that is appropriate is the intrinsic half-life of the
drug, not the apparent half-life due to the formulation, which is longer. And so dosing with the SR takes about three
days to get the steady state, but after the final dose you just have
elimination kinetics, and so by 48 hours everything should be gone. And you can see that it was. And, in fact, also we measured plasma
concentrations to demonstrate that and they were effectively zero.
CHAIRMAN
BORER: Beverly?
MEMBER
LORELL: I would like to return for a
moment to Dr. Temple's discussion about a unique mechanism for this agent since
it pertains to our consideration of potential benefit versus risk. In many animal studies, one can profoundly perturb
the utilization of glucose versus fat as a substrate for ATP generation based
on the ambient energy source. And I
suspect that, as in traditional clinical practice, most of these exercise tests
were performed with minimal food intake prior to that. Is that correct?
DR.
WOLFF: The exercise tests at trough were
done fasting or after a light breakfast, but then we had to let the patients
eat and so the effects at peak were actually done fed, and so you could use
peak and trough as a surrogate, I suppose, for fed and fasted. And in the population analysis, the
concentration-response at peak isn't different from the concentration-response
at trough.
MEMBER
LORELL: Did you ever formally, even in a
small number of patients, examine whether the anti-anginal effect was modified
by intake of standard dose of carbohydrates?
DR.
WOLFF: No.
MEMBER
LORELL: Okay. Thank you.
CHAIRMAN
BORER: Okay. Steve?
MEMBER
N0ISSEN: Okay. Now, obviously, I think everyone in the room
knows that what we're really trying to do here is to balance risk and benefit,
so it's an efficacy safety question. So
I want to probe with you just a little bit on the efficacy side. Although, I think, you know, the data you
presented are reasonably compelling.
Could
you put up slide CE-4? You know, we
heard, I thought, a very nice presentation from Dr. Braunwald about the unmet
need, and one of the points that was made is that patients are treated now
maximally. I mean, everybody gets an
angioplasty. I mean, it's like if you
come to the Cleveland Clinic, you go home with an angioplasty. That's easy.
So
I was just amazed at this slide, which showed that only a third of the patients
in your control trials had had previous revascularization, and so the immediate
question that came to mind was what countries was this done in? Did you do this in the third world where
revascularization is less commonly available, because I really want to know for
those patients that come to the Cleveland Clinic and get their beautifully
performed angioplasty, but occasionally have angina thereafter, what's going to
happen. And yet, very few of your
patients had been revascularized.
DR.
WOLFF: The study wasn't done, I don't
think, in the third world, but it was done at some centers outside the United
States from Central Europe and Eastern Europe, and it is true that the use of
interventions in those countries is lower.
But I think there are two pertinent points to the observation that you
make. One of them is that we did do an
analysis similar to one of the ones I described earlier, looking at patients
who had been revascularized versus those who had not been revascularized, and
there was no evidence for a major difference.
The drug was effective in the patients following revascularization.
And
then also pertinent was we did a similar analysis looking at the region to see
if there was an effect of the region on the result and, again, the treatment by
region interaction was not at all significant, suggesting that the effects were
generally similar across the different regions in which the trial was
performed.
MEMBER
NISSEN: But again, relating to the unmet
need, if the problem is in the U.S. that despite revascularization, we need
better and more anti-anginal agents, it would seem to me that you want to try
to make that case. And you know, the
other problem is what is the power here?
I mean, if you ask the question about differences in revascularization
versus no revascularization, you know, you're now talking of the 1,000 or so
patients, really only about 300 or so of them have actually had
revascularization.
DR.
WOLFF: The differences are not large and
here is one of the examples, and we have done this for MARISA and for CARISA at
peak and at trough. So I mean, we could
actually run through all four of those slides, so you could get an impression
of the totality of the data. Here you
see CARISA at trough. The treatment by
subgroup interaction, p-value is 0.22, and the effects are generally similar.
I
think it would be instructive to look at CARISA at peak and the MARISA at peak
and trough for the patients who have been and who have not been revascularized
if we could get those other three slides up.
Yes, great.
Here
it is at peak in CARISA and again, you know, you can see that the treatment by
subgroup interaction statistic is far from statistically significant. The blue bars are bigger than the placebo
blue bar or the red bar is bigger than the placebo red bar. In MARISA we see very, very similar results
across the three treatments, whether the patients are revascularized or
not. And again, a very high p-value for
the treatment by subgroup interaction.
And
then exercise duration at peak, again, treatment by subgroup interaction, the
p-value is very high. The balance of
patients in the revascularized versus not revascularized group is pretty
reasonable, so I think it's concludable that the drug works whether or not
patients have been revascularized.
MEMBER
NISSEN: Okay. Thank you for that. Now, I would like to see CE-7. The maximum dose that you are recommending
that be approved is what?
DR.
WOLFF: Is 1000 milligrams twice a day.
MEMBER
NISSEN: So would you suggest then that
we ignore the efficacy data for 1500 milligrams bid, because we're not going to
be considering that?
DR.
WOLFF: I think they are instructive in
understanding the drug and its properties, but I think when we review the
adverse event data, you will see that the increase in adverse events from 1000
to 1500 is probably disproportionate to the more linear increase in efficacy,
and so it's more for the tolerability reasons that we recommend against higher
doses than 1000.
MEMBER
NISSEN: Yes. I really wanted to bring this up just to
point out to the other members of the Committee that we're looking at data here
for doses that are beyond the range at which we're going to consider. So I just think we have to keep that in mind
as we look at this.
And
now, let's see CE-8. I find CARISA much
harder to analyze than MARISA and let me see if I can tell you some of the
problems that I have and see if you can help me with them. One is that there is a drug-drug interaction
going on here. I think we know from the
PK data that diltiazem substantially elevates the serum levels of ranolazine,
and so those patients that are in the arm that get diltiazem, you would expect,
and I presume that they did have higher serum levels than those that got
amlodipine or atenolol.
DR.
WOLFF: They did. They are about 30 or 40 percent higher.
MEMBER
NISSEN: Okay.
DR.
WOLFF: Which is what we expected and why
we designed the study this way.
MEMBER
NISSEN: Right. Okay.
And so that's an issue. The other
issue is that atenolol, while it's given once a day for hypertension, has a
half-life of about six hours. So now,
the question is was this done? These
measurements were made at both peak and trough?
Is that correct?
DR.
WOLFF: Correct.
MEMBER
NISSEN: Yes. So did you see any difference in the effect
at peak and trough in the atenolol arm related to the fact that you were at
trough, the atenolol was no longer present or not to certainly a significant
extent? Do you see the issue there?
DR.
WOLFF: Yes.
MEMBER
NISSEN: You have two drugs that are very
long-acting, amlodipine and diltiazem you're comparing, and one drug is very
short-acting, atenolol. And so I'm
trying to understand what happens when you mix those drugs together.
DR.
WOLFF: Well, here are the data at
trough, and we should probably then show the data at peak, as well, for the
three background therapies. And again,
the treatment by background interaction statistic is not significantly
different. So while you do see, for
example, on the diltiazem, you know, maybe a more clearly dose related
increase, still the effects are generally within the range of one another on
the three backgrounds. And here is the
slide with the data at peak, and you can see that the increase -- I don't
believe we have a slide where I can put peak and trough right next to one
another for you, but the increases actually are somewhat bigger in the atenolol
stratum at peak than at trough.
MEMBER
NISSEN: Yes. Go ahead.
UNIDENTIFIED
SPEAKER: No, I'm okay.
MEMBER
NISSEN: Okay. All right.
Okay. Again, it's really tough,
because obviously when you have a drug-drug interaction, you have got more than
one thing going on. You have got the
question of added efficacy, but you also have the question of diltiazem
elevating the serum levels. So I just
want to make sure that I understand this.
DR.
WOLFF: We did do an analysis where we
reduced in theory the efficacy that would have come from the higher plasma
levels in the diltiazem patients proportionally, and it really made very little
difference to the overall outcome. Dr.
Crager can describe that to you.
DR.
CRAGER: So for this analysis, we used
the linear relationship between plasma concentration and efficacy and put in
the known elevation of diltiazem to ranolazine concentrations and here are the
results. So from that, the first column
of results there is the primary efficacy analysis. The second one is what you get when you
adjust as though there were no plasma concentration elevation effect of
diltiazem, and as you can see it doesn't make all that much difference.
MEMBER
NISSEN: Okay. All right.
That actually is very helpful.
Thank you very much.
I'm
still having a great deal of difficulty understanding why the apparent effects
at trough are greater than peak in CARISA.
Could you just explain to me what your hypothesis is for why that's
happening?
DR.
WOLFF: Sure. If we could, why don't we put up CE-9 again,
because I think it's easier to look at that way. The CARISA efficacy data. So again, these are changes from baseline. And what I don't have presented here, but if
it's worth looking at, maybe we could tee up a table that gives the baseline
data for the CARISA trial. I do believe
we have -- I think we have a data table with baseline on it. But the baseline in the morning is a good bit
shorter. I think it's about 70 seconds
shorter in the morning than in the afternoon.
Now,
we don't have data comparing to placebo the effects of the background
therapy. They were background and they
were baseline. But the baseline in the
afternoon was a good bit longer and presumptively it's because the effects of
the atenolol and the diltiazem and the amlodipine were about at their peak at
four hours after they were given as well.
And so --
MEMBER
NISSEN: Well, no. That's not possible. I mean, amlodipine has a half-life of 50
hours and so you have steady, it's very much steady state. So at least on the amlodipine arm, that's
very unlikely and diltiazem, you know, sustained-release is pretty much a
zero-order kinetic model as well. So
that doesn't make any sense, does it?
DR.
WOLFF: Well, what the data were and for
whatever reason --
MEMBER
NISSEN: Yes.
DR.
WOLFF: I won't hypothesize on the
reason. The data are that the baseline
exercise duration at the time of peak, so, you know, four hours after dosing,
but in the absence of dosing with ranolazine, because it's at baseline, was a
good bit longer. And so consequently,
the changes from baseline, from that higher baseline, were smaller at peak, but
the difference from placebo was bigger.
So that is why these changes from baseline are smaller at peak, but the
drug effect, which is the difference between the colored bars and the gray bar,
is bigger at peak than at trough.
CHAIRMAN
BORER: It may be why. I mean, we don't really know why the change
from morning to afternoon occurs, and the fact that it does occur doesn't a priori
mean that the changes should be smaller on placebo or on drug just because the
baseline was higher. I mean, we don't
know that, but it doesn't matter. I
mean, these are the data.
Before
you on with the questions, Steve, Bob and Alan, I think, had some points to
make.
MEMBER
NISSEN: Sure, sure.
DR.
TEMPLE: Just on the last point, that is
why you have a placebo group, because we don't understand everything as well as
we should. Placebos keep you from
needing to. On the question of the
ability of ranolazine to add to the effect of existing therapies, I just want
to provide a little bit of context.
Ordinarily
for a new angina drug, we don't ask that it be better than anything else. We don't particularly ask that it show in the
additive effect when you add it to other drugs.
Although, that would be interesting to know. The reason that's relevant here is that we're
trying to balance potential risks, as Steve said earlier. So these studies use very modest doses of the
drugs. I don't remember the
dose-response for diltiazem anymore, but I know amlodipine at 5 milligrams is
sort of barely there as an anti-anginal.
It doesn't work very well even if it's very popular. It doesn't produce much edema at that
dose. And atenolol 50 once a day, you know,
12 hours later or something or 24 hours later is also barely there.
So
in some sense, our worry about interpreting this is if you gave a person -- if
you compared 10 milligrams of amlodipine with 5 milligrams of amlodipine, the
10 would look better, but that wouldn't exactly be an additive effect. That would be called getting to the right
dose. So I guess the question here is,
and I'm flushing this out, because it was one of the questions we raised, I
want to give you an opportunity to answer it. We didn't think this was very good evidence on
whether a person on reasonably identified maximum doses of some or other drug
could get an added benefit because of a different mechanism or whatever the
reason might be.
I
wondered if you wanted to address that, because one of the things we asked for
in the letter was a study that really pinned this down. So I just think I would like to hear what you
-- you need to present what you think about that.
DR.
WOLFF: Okay. Well, we have looked already a couple of
times at the background strata data for CARISA, and I would point out that at
the time of peak plasma, well, at the time of peak exercise testing, and that's
about four hours after dosing with the background treatment with atenolol, and
so according to Tenormin labeling, the early effect of atenolol is maximal, not
of that dose, but of the drug is maximal after doses of about 50 milligrams is
what it says. And so one could then
argue that showing efficacy at peak with ranolazine was efficacy under conditions
of the maximal effect available from atenolol.
So there are those data.
And
then if we look at the data from 072 again and consider the doses of atenolol
and diltiazem that were used then, the atenolol dose was 100 milligrams once a
day, which I think people would agree is a fairly healthy dose. It was 50 in three patients. It was 100 in 12. And they were supposed to have been optimized,
so we can only presume the patients that were on 50 couldn't tolerate a higher
dose. We did demonstrate efficacy over
that dose. And then diltiazem was
administrated in that trial to those patients at 180 milligrams three times
daily. I'm sorry, 60 milligrams three
times daily, which is perhaps not sounding like a large dose, but it's
interesting to consider the pharmacokinetics of diltiazem and when the exercise
tests were done.
If
you look at this slide here, it shows the plasma levels that would be predicted
of diltiazem given as 60 milligrams three times daily as it was in Study
072. And exercise testing was then done
in this interval right here, which interestingly is very analogous to the
plasma concentration at trough with 300 milligrams a day. And if we do look at the product labeling for
various diltiazem formulations, the effect of diltiazem with the once daily
dosing at trough is plateaued at around 300.
So
I think these data do support that there is a drug effect that is measurable
and clinically meaningful over the maximal effect of atenolol or
diltiazem. Here are the data that I was
just mentioning with respect to the effects of diltiazem. You can see that here, 360 milligrams from
this product's label would appear to be a plateau. Here it's somewhere between 240 and 360. So at around 300 once daily of the once daily
formulation of diltiazem, you're at something of a plateau effect, and these
are the conditions under which those exercise data were obtained.
CHAIRMAN
BORER: Steve?
MEMBER
NISSEN: Yes. I think what Bob is probing, and I was also
wanting to go there, as well, is that in judging the relative risk and benefit
here, one of the things that would make a big difference, I think, at least to
me, I'm not sure about other members of the Committee, is that if we knew that
this agent produced significant efficacy in those patients that were on
maximally tolerated doses of anti-anginal agents or couldn't tolerate them, and
these are refractory patients, patients that we can't help any other way, then
that would be a very important mitigating factor, you know, against the
potential safety concerns.
And
so I'm looking for what evidence you can provide us with that people that I
just can't treat, you know, in any other way can be benefitted by the agent in
terms of significant prolongation of exercise time.
DR.
WOLFF: Well, I think these data may go
to that point most directly. These are
the subgroup data looking at the effect on exercise duration in patients who
have had systolic blood pressures less than 100, heart rate is less than 60 or
a PR interval greater than 200 milliseconds.
Now, in CARISA that particular parameter was over a background of
amlodipine or diltiazem in many of the patients and -- I'm sorry, atenolol or
diltiazem, amlodipine and the others.
And
so, you know, one could argue that these patients with these vital signs
wouldn't be receptive to higher doses of hemodynamically acting anti-anginal
drugs. And yet, we see ranolazine did
provide efficacy, generally speaking, in that subgroup that was comparable to
the patients who had normal vital signs and AV nodal conduction.
We
did similar analyses to these not just for exercise duration, but for time to
angina, time to ST-segment depression and for angina consumption, I'm sorry,
angina frequency and nitroglycerin consumption in CARISA and they all look like
this. There is an effect that is very
similar in the population with the borderline hemodynamics or AV nodal
conduction to the patients without. So
that indicates that you could expect to see efficacy in those folks that is
about the same as in the general population we studied.
MEMBER
NISSEN: That was half of my question
though. The other half would be, you
know, people that come in and they have adequate blood pressure and heart rate
to tolerate maximal anti-anginals, and so you push their anti-anginals to
maximum including nitrates and they still have angina. So now, you add ranolazine and you find out
if those patients that are on triple therapy can get -- I mean, it would be
very powerful, persuasive to me as a cardiologist, to see data.
I
was also troubled by the fact that there is nothing about nitrates in any of
this database. I mean, why were nitrates
just ignored here? It is certainly a
very commonly used anti-anginal agent and they don't appear anywhere in the
data.
DR.
WOLFF: Well, they do appear insofar as
nitroglycerin consumption was allowed, ad lib, in both the studies and it was
measured in CARISA and we did see that there was a decrease in nitroglycerin
consumption in CARISA. We didn't use long-acting
nitrates as a background therapy because of the need to demonstrate efficacy at
trough ranolazine levels as a primary endpoint.
And because of the nitrate holiday that's necessary daily in order to
maintain responsiveness to nitrates, at trough in the morning nitrates would
have effectively been placebos. So it's
true, we don't have double-blind, randomized, placebo-controlled efficacy data
over a background of nitrates.
But
there is no pharmacological reason to expect that it wouldn't work, and we do
then have patients who go on to open-label treatment and receive long-acting
nitrates because, as you say, they are very commonly used, and we have seen no
problem in co-administration of long-acting nitrates with ranolazine nor
mechanistically with nitrates would we expect any.
MEMBER
NISSEN: Right. No increase in syncope, for example?
DR.
WOLFF: Well, we'll get to syncope later
and I can address that issue.
MEMBER
NISSEN: Yes, I want to come back to
that, because one of the things I have got to know as a cardiologist, and the
FDA has to know in writing a label, is to tell people how they might mix this
into the therapeutic regimen the patients are on, and I must tell you most of
my patients with medically significant refractory, particularly refractory
angina, are going to be on long-acting nitrates. And I just don't have anything in your
database that tells me what to do with those patients.
CHAIRMAN
BORER: Alan and then Tom.
MEMBER
HIRSCH: Well, my question might extend a
little bit of how we might use this medication in practice, so I want to
explore the efficacy dose-response one more time. You know, in this database you have, I think,
shown to me that there is a clear efficacy signal and a dose-response, but you
have also stated that we tend to want to look at pushing the dose, so we get
maximal symptom relief, because what the patient is looking for is symptom
relief.
So
what I want to ask is if this drug were applied in practice, I would tend to
increase the dose until I achieve some net clinical benefit or a wall of
adverse effects. Is there anything in
the large database even with individual release or short-term usage that shows
the dose-response of individuals up to peak efficacy or tolerance?
DR.
WOLFF: I think the best data come from
MARISA where it wasn't really a titration, per se, because the order of the
doses was random, but you do see very clearly there in a crossover design study
where the doses are being applied repeatedly to the same individual, a clear
dose-response, and you also will see when we get to the adverse events, I
think, a clear dose relationship to the more clearly drug-related adverse
events. And in our open-label
experience, we do allow -- in fact, that's how they are designed. Patients start at 500 and they titrate to 750
and go to 1000. So we have that kind of
experience with titration.
CHAIRMAN
BORER: Tom?
MEMBER
PICKERING: The issue here is not whether
this agent prolongs survival. In fact,
there are questions about whether it might have adverse effects, but whether it
makes patients feel better. And I am
having some difficulty interpreting what a 20-second prolongation of exercise
time on a treadmill test means to a patient.
You also said that the number of anginal attacks goes down from, I
think, about 3.5 to 2.5 a week, but there is also side effects. Something like 5 or 10 percent experience
nausea and dizziness.
And
I wonder do you have any evaluations, particularly in CARISA, about overall
quality of life and whether patients actually felt better while they were
taking ranolazine as opposed to placebo?
DR.
WOLFF: We don't have data specifically
on a quality of life index. The angina
frequency decrease was actually from more than about four attacks per week at
baseline, and the decrease was a little fewer than two per week on a lower dose
and a little more than two per week on the higher dose, which was greater than
on placebo.
With
respect to the -- if we could have the slide that was up there, please? With respect to the meaningfulness of 20
seconds, I would like in a moment to ask Dr. Peter Stone to comment on the
magnitude of improvements in exercise performance with anti-anginal drugs, but
I will make a few points first, which I think are sort of interesting.
And
that is to recall that the improvement in exercise time comes at maximum
exercise performance, which is a level of exercise that is not typical of the
patient's day-to-day life. And so if you
take the increase in mets that occurs during that increased exercise time and
imagine that it would be translated into stage zero exercise performance at the
beginning of the exercise test, then the improvements that the patients would
see at the lower work load are, in theory then, quite a bit longer.
And
I think then the other instructive point is that improvements on the order of
20 or 30 seconds as we saw across our trials were at least as great as what we
saw in the same patients in the Crossover Design Study with 100 milligrams once
daily of atenolol, which I think, you know, we all have a feeling for in terms
of its efficacy. But maybe, please, Dr.
Stone could also address this topic.
DR.
STONE: Thank you very much. Peter Stone from Brigham and Women's
Hospital. It's interesting to point out
that for decades of evaluation now, the standard improvement in the
anti-anginal therapies is in the range of 25 to 35 seconds really across all
forms of therapy. In addition, it's
interesting and I think quite impressive that even despite combination regimens
or coexistent therapies, there is still an incremental 25 to 35 percent or
35-second increase in exercise duration.
And
interestingly in a broader context, the recently reported RITA-2 Study from
JACC a month or so ago noted that the difference between angioplasty associated
improvement in exercise duration versus medicine is also 25 to 35 seconds. So really all of our therapies have been in
that range of improvement. Thank you.
CHAIRMAN
BORER: Bob?
DR.
TEMPLE: Well, I would endorse that,
too. In the old days, which nobody
except perhaps Jeffrey will remember, we used to have people with enough angina
attacks that you could actually see quite a nice improvement in the angina
rate. They would have 10 a week or
something and it would drop to three a week or something and that was good.
Nowadays,
as you could see here, and actually there are more here than in a lot of trials
we have seen, the main benefit of anti-anginal drugs is that you can exercise
on a treadmill a little longer. You can
spend 10 seconds, 20 seconds, 30 seconds more on a treadmill. But we have always believed, foolishly or
not, that that corresponded to the kind of effect on angina episodes that you
would see if you had a population that had angina episodes.
My
recollection, this is old. Usually,
people fail as the stage of the test is increased. So it's not two minutes or three minutes into
a stage that you see the 40 millisecond difference. It's how long you can do when somebody
increases the exercise burden and not surprisingly when you have done that,
it's a fairly big change. They fail
pretty rapidly. So a 20, 30-second
increase is sort of what we have seen with all the drugs. That's what all of the approved drugs we're
looking at have done also.
CHAIRMAN
BORER: Doug?
DR.
THROCKMORTON: Dr. Hirsch, I want to take
you back to a comment you said. You said
you think you have a good handle on dose.
Did I misunderstand that, because one of the things that the Agency had
looked at was the sort of numbers in the two pivotal studies and at least there
was a suggestion. You know, if you look
at the 3033, and I'm sorry, Andy, I don't remember which name that one is.
DR.
WOLFF: That was CARISA.
DR.
THROCKMORTON: Thank you. Sorry.
DR.
WOLFF: Sure.
DR.
THROCKMORTON: 750 and 1000 are at 30 or
sorry, 27 seconds and 26.8 seconds at the end of 12 weeks for effect, and 500
in the other study for what that's worth.
It was roughly at the same number.
And then 1000 and 1500 in the 3031, in the CARISA Study, were at 50 and
55. I'm not sure if those are different
or not.
So
help me understand how well you think you understand the dose, as opposed to
concentration, because I think I would say, like Dr. Wolff, that the Agency
believes there is a concentration effect relationship here that has been
well-characterized. We don't disagree
with that. It's the nature of the
subject, intersubject variability, and the difficulties describing dose. So help me out here.
MEMBER
HIRSCH: Well, I just want to be very
precise. I feel some clarity that there
is efficacy in that 500 to 1000 twice daily signal. Let me first move up. I am less clear about, obviously, the
dose-response moving upward to 1500 twice a day and I am uninformed moving below
500 twice a day. And I only raise this
question now, so that later when we talk about safety, we can come back to
that. Clear?
DR.
THROCKMORTON: Okay. And so then you believe 1000 is more than
500?
MEMBER
HIRSCH: Currently, yes.
DR.
THROCKMORTON: Okay.
CHAIRMAN
BORER: Before we go on to Steve's
questions again, I want to go back to the issue of atenolol's background. First of all, I have to note yesterday I
mentioned the 1982 aspirin hearing and Steve said he hadn't been born yet and
now, you indicate quite correctly that I do remember the previous studies of
anti-anginal drugs. And one of them --
DR.
TEMPLE: It's okay, Jeffrey. The best years are ahead.
CHAIRMAN
BORER: Right. One of them involved the development of
bepridil and I'm raising this issue because of what I think I heard was a
standard because of the potential safety concerns. When bepridil was developed it did involve
QT prolongation. It was an effect of anti-anginal drug and ultimately,
it was approved for patients who were refractory to other treatment or who
needed additional treatment after other treatment, who couldn't tolerate other
treatment in a study of patients who could not tolerate diltiazem.
DR.
TEMPLE: Didn't respond to
diltiazem. They were then randomized
back to bepridil versus diltiazem and bepridil won.
CHAIRMAN
BORER: Right. That's the point though. It was one drug. And what I'm hearing here is the suggestion
that unless you can show that you're better than a combination of all the drugs
you can tolerate, you know, that we may have a concern in terms of
benefit-to-risk relationship, and that may be right. I just point out that the last time this came
up, that wasn't the standard we used and that ought to be considered as we
think about standards now.
I
would like to go back to the atenolol slide, the background therapy slide that
you showed. I'm not sure that I fully
understood it and I don't want to overstate this issue, because, in fact, the
numbers are relatively small and subgroup analyses weren't pre-specified,
etcetera, etcetera. But can you put up
the slide where you showed the effective placebo and of drug at two different
doses on the different background therapies?
Okay.
Now,
as I look at that, this is a trough. Can
you tell me if there is a difference between the effect of placebo on the
background of atenolol and the effect of ranolazine 1000 milligrams twice a day
on a background of placebo? I just can't
--
DR.
WOLFF: This is one of the smaller
differences and it is as you say, when you begin to get into subgroup analysis,
the variability in the data increase.
And so it is true that at trough in CARISA, the improvement over placebo
on atenolol actually was numerically bigger than the improvement at 1000. But again, in general, the effects of
ranolazine were consistent across the three background strata as indicated by
the treatment by subgroup interaction, p-value of 0.63. So we'll always find these sorts of increased
noisiness as you slice the data more and more.
CHAIRMAN
BORER: Yes. I mean, that may well be the case. And show the peak, the peak effect, as well,
please. There, too, is there a
difference? Maybe it's the angle at
which I'm looking.
DR.
WOLFF: It's small.
CHAIRMAN
BORER: And it wasn't in our briefing.
DR.
WOLFF: It is small.
CHAIRMAN
BORER: Yes.
DR.
WOLFF: The 1000 milligram dose over the
atenolol background in CARISA had numerically smaller effects at both peak and
trough.
CHAIRMAN
BORER: Okay. Steve, did you want to go on with your
questions again?
MEMBER
NISSEN: I just wanted to answer. I wanted to make sure that you
understood. I wasn't trying to set a new
standard here, but I wasn't really asking that ranolazine beat combination
therapy. I was asking that it show some
benefit in those patients that were maximally treated, and it's a very different
question.
DR.
TEMPLE: Right. I think what bepridil was asked to do was
very difficult, beat another member of the same class. I mean, you really don't expect it to be able
to do that, but it did.
MEMBER
NISSEN: Yes.
DR.
TEMPLE: The thought we have had in the
letter was you're asserting that this is a different mechanisms. Well, then it ought to add to things that
have the same old mechanisms. So that's
what we thought.
MEMBER
NISSEN: And what I was trying to opine
here is that if I could see very convincing evidence that on a background of
maximal treatment, there was an incremental benefit, clinical benefit for
patients, that would mitigate to some extent against the safety concerns,
because it would make me believe that I was going to offer patients something I
couldn't offer them any other way.
DR.
TEMPLE: Yes. Well, that is certainly the thought we
expressed in the letter.
MEMBER
NISSEN: Yes.
DR.
TEMPLE: There is a lot to discuss about.
MEMBER
NISSEN: Yes, there are lots of --
DR.
TEMPLE: It's necessary and all that.
MEMBER
NISSEN: Yes, lots to discuss. Now, one last question and it's just a flyer
here, but there would be potentially a way to look at mechanism and that would
be to do PET scanning and look at F-18 deoxyglucose uptake. Has anybody proposed or even done a small
study to look at fluorinated, you know, glucose as a way of detecting whether
glucose utilization is actually going up?
It should be very sensitive.
DR.
WOLFF: That study has been proposed many
times. It has not yet been done. We have one concern about, you know,
measuring uptake instead of oxidation, but in animal studies where we have
looked at glucose uptake and free fatty acid uptake, we have in several
different models of the ischemia seen that ranolazine does tend to increase the
glucose uptake and decrease the free fatty acid uptake. But the PET Scan Study has just not been done
yet.
CHAIRMAN
BORER: Beverly?
MEMBER
LORELL: In line with that question, you
talked about the diabetic subgroup very briefly and I think for many of us on
the Committee, this is a group of great interest since they can be, as alluded
to in Dr. Braunwald's presentation, one of the more challenging groups to treat
with available agents. On the other
hand, if there is, in fact, a novel mechanism, one could think of some
scenarios where the ability to use glucose as substrate might be in part
limited by the physiology of diabetes itself.
Rather
than showing that relationship between dose concentration and exercise time,
which is your only comment about the diabetic in your presentation, do you have
a bar graph for diabetics, for an exercise time?
DR.
WOLFF: Here are the data from CARISA at
trough and again, you know, we have four different graphs and if you found it
instructive, we could look at all four of them.
I think we should. So here are
the data and the blue bar is the patients with diabetes and the red bar is the
patients without, and the treatment by background interaction statistic was
.89, indicating again not a major difference between those with diabetes and
those without.
Here
are the data at peak. Again, you see the
effect of the drug to increase exercise duration in both subgroups, and here
are the data from MARISA at trough and then MARISA at peak. And I guess the other thing that's worth
mentioning, it's in the CARISA study, because it was a parallel group study of
12 weeks duration, and we also measured the hemoglobin A1c in the diabetic
patients and we found that it declines over the 12 weeks of treatment to a
significant degree at about 1 percentage point in a more or less dose relation
fashion.
So
also, there were no untoward effects on lipid parameters neither in the general
population nor in the diabetics. So it
did appear to be a generally safe and equally effective drug in the diabetics
and in those without diabetes.
MEMBER
LORELL: Thank you.
CHAIRMAN
BORER: Alan?
MEMBER
HIRSCH: I was going to avoid subgroup
discussions, but as long as we're getting there, let's slice and dice a
bit. I want to talk about the subgroup
of women. We spent a lot of time
yesterday at the panel making sure that we clarified the efficacy in this, more
than half of Americans who also have angina.
And I know you have stated in the briefing booklet that you have looked
for reasons why the change in exercise time for PK might be different. But just to go on the record, is there
anything else we can learn about the difference in efficacy in women? And I want to go back to use of anti-anginal medications. Now, something that Steve said, background
use of PCI. What Bev said, even dietary
fat intakes and, you know, what's eaten, something different about the
population.
DR.
WOLFF: What I can show you in addition
to what we have already discussed, I mean, we have seen the slope is positive,
but lower in women. The decline in
angina and in nitroglycerine use is very similar between men and women. We can see that briefly again here. The other data that we have in our database,
that I think are instructive to your point, come from RAN080, which we
discussed briefly. And let me show those data divided
between the men and the women. You will
recall this was a three-period, crossover study in which patients received a
week of treatment with placebo, a week of atenolol at 100 a day and a week of
ranolazine, and you will recall that both ranolazine and atenolol were superior
to placebo in improving treadmill exercise performance.
Here
you see the data for men and women broken up with men in this column, women
over here, and then here are the data for increase in exercise duration on
atenolol compared to ranolazine. Now, in
this particular study, the improvement in total exercise duration was very
similar between men and women, not quite so similar for atenolol.
Interestingly,
when you look at the other primary, not primary, but major exercise variables,
again, we do see that women were afforded somewhat less of an increase on
ranolazine compared to the men. But the
difference on atenolol at a healthy dose, a drug I think that we're all very
familiar with and confident with, the difference was actually worse for the
atenolol between men and women than it was for the ranolazine. So it suggests that this is something not
about ranolazine, but about the differences that we're coming increasingly to
appreciate between angina and coronary disease in men and in women.
CHAIRMAN
BORER: To complete the sub-population
issue, the analysis of sub-populations, you mentioned that there was equivalent
effect across the various sub-populations you looked at based on race and age
and what have you. Do you have a slide
where you can just show us those numbers for non-Caucasian and age?
DR.
WOLFF: Why don't we run through what we
call the city plots and look at all of them, because I think you will see that
the totality of the data is just generally instructive. Okay.
So here we have the group that we focused on in the main presentation of
the patients with the borderline vital signs or AV nodal conduction. Here are the patients with heart failure,
diabetes, reactive airway disease and then on the bottom we have represented
the effect in patients that are in any one of these subgroups.
And
again, although the bars are certainly not going to all be the same height, the
effect is always in the same direction and generally similar at trough in
CARISA throughout all the subgroups.
Looking again at peak, we see again insignificant treatment by
background interactions and probably more importantly, just examining the data,
a generally similar effect in patients within the subgroup compared to those
not in the subgroup.
Moving
then on to the MARISA trial where we have the three different doses. Again, you see that there are no
statistically significant treatment by background interactions, generally
similar responses in the patients in the subgroup of interest compared to those
not in the subgroup of interest. And then at peak in MARISA, one of
the few times where we actually did see a statistically significant treatment
by background interaction was in the patients with heart failure in the MARISA
trial. And here you can see that that
was actually because the patients with heart failure at peak had a
statistically significantly greater improvement in their exercise performance
on ranolazine than did the other patients.
DR.
THROCKMORTON: Jeff, I think you asked
about gender and age.
CHAIRMAN
BORER: Right.
DR.
THROCKMORTON: And race, those things.
CHAIRMAN
BORER: Right.
DR.
THROCKMORTON: They are in the FDA, Dr.
Targum's review, Targum's and Friedlin's review on page 30.
CHAIRMAN
BORER: Yes, that's --
DR.
THROCKMORTON: Oh, I'm sorry, 31 of the
review and 32.
CHAIRMAN
BORER: That's why I was asking for them
to be put up, so we could discuss them.
DR.
THROCKMORTON: Right. Those numbers are there.
CHAIRMAN
BORER: Do you have a plot of those
data? If not, we can go to page 35, the
Committee can.
DR.
THROCKMORTON: Page 31 and 32 of Dr.
Friedlin's and Targum's review, Table 11.
It's in the FDA review. It's in
the green book.
MEMBER
HIRSCH: Since we have spent time looking
at subgroups, I think just to put for the record, the numbers are so small that
it really is challenging to find a signal in subgroups, isn't it?
DR.
THROCKMORTON: But it might be worthwhile
looking at the female demographic numbers precisely though. The effect in the women did seem strikingly
smaller, again, whether or not other reasons.
CHAIRMAN
BORER: Okay. Now --
DR.
TEMPLE: It's actually at both doses in
that study, too, on page 31.
CHAIRMAN
BORER: Right. I don't see any data here and didn't see any
data based on racial differences. Do we
have any information at all?
DR.
WOLFF: We do from the population
analysis in which race was not a significant covariate, and so the slope in
non-Caucasians was the same as in Caucasians.
CHAIRMAN
BORER: How many non-Caucasians were
involved in the pivotal trials?
DR.
WOLFF: There were fewer than 5 percent.
CHAIRMAN
BORER: Okay. Okay.
Are there any other issues about efficacy? Bob?
DR.
TEMPLE: No. I was just going to say both doses in that
study seemed to work less well in women and there was at least a little trend
to work better in younger people.
Whether one should make anything of that is not clear. The heart failure stuff is interesting,
too. Maybe for the future.
CHAIRMAN
BORER: Paul?
MEMBER
ARMSTRONG: Just one. In some of the early data, you had tracked
sinal ischemia with Holter monitoring over time as another robust way of looking
at the effects on ischemia. Do you have
any information in relationship to the more recent data?
DR.
WOLFF: No. We have no Holter data for MARISA and CARISA.
MEMBER
ARMSTRONG: Thank you.
CHAIRMAN
BORER: Okay. If there are no other issues, questions to
raise about efficacy?
MEMBER
NISSEN: I just had one.
CHAIRMAN
BORER: Yes.
MEMBER
NISSEN: I'm sorry to be persistent, but
one more question and that is any studies using anything other than simple
exercising testing, such as a nuclear scintigraphy, you know, thallium or
Sestamibi scans, exercise echo? If there
is any data, now would be a good time to see it, because I think it would help
us to understand efficacy.
DR.
WOLFF: No, there aren't. Other than the angina frequency and nitroglycerin
consumption, which were the other non-exercise endpoints which were assessed
and which were significantly reduced in CARISA, we don't really have anything.
MEMBER
NISSEN: Okay.
CHAIRMAN
BORER: Steve, why would you have wanted
to see those kinds of data? I mean, we
have seen ST-segment depression data, unless we think they are invalid somehow,
because the mechanism by which this drug may act? What difference would it make if we had --
MEMBER
NISSEN: Well, it wouldn't be an
approvability issue, but, I mean, the more information there is that amplify
upon the robustness, the mechanism. I
mean, the fact is is that, you know, many patients today who are being
evaluated for ischemia are being evaluated with imaging stress tests and so, you
know, while it's not necessarily the standard that the Agency has set for
approval, it certainly is meaningful to clinicians to see, for example, a
change in a profusion abnormality would be very compelling from my perspective
to suggest that there really is something going on there in the myocardium.
CHAIRMAN
BORER: Okay. Well, let's go on to the presentation of the
safety data.
DR.
WOLFF: Okay. So in overview, the integrated summary of
safety, which we submitted to support the ranolazine NDA contained data from
over 2,700 patients and subjects who were exposed to various formulations of
ranolazine for a total of over 1,700 patient-years of exposure. You will see as we go forward that adverse
events on ranolazine are generally dose-dependent and, therefore, manageable by
proper dose initiation and titration.
And furthermore, we have no evidence for an adverse effect on survival.
Ranolazine
has been administered to over 2,700 patients and subjects, over 1,400 of whom
received the sustained-release formulation.
Of particular note also are the more than 500 patients who were treated
with the immediate-release dose of 400 milligrams three times a day. This dose is relevant to the consideration of
the safety of ranolazine, because it results in maximum plasma concentrations
equivalent to those produced by 750 twice a day and an overall exposure
equivalent to that produced by 500 milligrams twice a day.
So
if you look at the 1,460 that were treated with sustained-release and the 518
treated, I'm trying to get the slide to advance, there we go, there is almost
2,000 patients that are treated with a dose of ranolazine that is relevant to
the analysis of safety and tolerability, which is well in excess of the 1500
recommended by ICH guidelines. And then,
of course, there are other additional exposures with IV and immediate-release,
as well.
The
duration of exposure is shown here. As I
have mentioned, we have had over 1,700 total subject patient-years of exposure
to the drug most of which, nearly 1,300 patient-years, was in angina patients
on ranolazine SR. The mean duration of
exposure of these angina patients to the sustained- release formulation was
well over a year at 495 days. 850 have
been treated for more than a month, 500 or more for over a year and over 250
for more than two years.
This
slide shows the adverse events for MARISA and CARISA, which occurred in at
least 2 percent of patients on a given treatment and they were more frequent on
at least one dose level of ranolazine than on placebo. Most of these adverse events were reported as
mild or moderate in severity and didn't result in discontinuation of
treatment. Dizziness, nausea, asthenia
and constipation were the most clearly dose related adverse events. Of note is the 500 milligram dose, which you
will recall was effective throughout the dosing interval in MARISA. It was very well-tolerated with an adverse
event profile quite similar to that of placebo.
Also
of note, the increase in adverse events, and particularly the most clearly
dose-related adverse events on 1500, was a disproportionate increase going from
1000 to 1500 compared to the generally linear increase in exercise
performance. And so, accordingly, we
don't recommend the 1500 milligram twice daily dose for clinical use.
This
slide gives the rates of sudden death, cardiovascular death and all-cause
mortality on ranolazine and placebo from the four month safety update. For each of these three endpoints, the 95
percent confidence intervals around the ranolazine estimates are contained
completely within the 95 percent confidence interval around the placebo
estimate.
However,
there really are relatively few events overall and another confounding factor
is that the exposure to ranolazine in this analysis is more than tenfold that
of the exposure to placebo. And so to
take a look at these kinds of data in a controlled setting where the duration
of exposure to placebo and to ranolazine is more similar, we turn to the
controlled studies.
And
here we see estimates of mortality on ranolazine versus placebo, in the Phase 2
and 3 IR and SR controlled studies, in the two Phase 3 SR controlled studies
and then in CARISA, which was itself the longest double-blind, randomized,
placebo-controlled parallel group experience with ranolazine SR in patients
with angina. And again, for each of
these endpoints, the 95 percent confidence interval lies within or actually
exactly overlaps the 95 percent confidence interval for placebo.
In
summary then, the efficacy of ranolazine has been demonstrated in five
double-blind, randomized, placebo-controlled trials. The drug has been observed to be generally
safe and well-tolerated. Those adverse
events, which do occur, are generally dose-dependent and, therefore, should be
manageable by appropriate dose initiation and titration. And finally, there is no evidence for any
adverse effect of ranolazine on survival.
Thank you.
CHAIRMAN
BORER: Beverly?
MEMBER
LORELL: Even though you are not
proposing use of the higher dose, there may be some information useful to the
Panel in understanding the dose-dependent increase in the symptom of
dizziness. Can you amplify a little bit
on what is believed to be the mechanism of that?
DR.
WOLFF: Yes, I can, and I will have more
data to talk about dizziness and other effects later on in the presentation
after Dr. Belardinelli discusses the preclinical electrophysiology, but the
dizziness appears to be a central nervous system phenomenon. When you look at the blood pressures of the
patients who complain of dizziness, they are actually not lower than the
patients who don't complain of it.
And
as you will see later when we talk about a controlled overdosing study that we
did with IV infusion of ranolazine, the dizziness and nausea are probably kind
of the leading edge of a constellation of symptoms that if you get the plasma
concentration higher and higher, begin to include nystagmus and diplopia and
even some disturbances of the sensorium and the, you know, complete loss of
consciousness, which is reversible completely upon discontinuation and occurs
again, I would emphasize, at high plasma concentrations well beyond those
necessary for therapy. But the
beginnings of that, I believe, is the dizziness that we see at the therapeutic
doses.
MEMBER
LORELL: I'm sorry. One more quick question while we're on this
topic. Was that symptom more or less
common or no different in either women versus men or diabetics versus
non-diabetics? I know we're slicing and
dicing.
DR.
WOLFF: No, it's fair to ask. There weren't any generally appreciable
differences in the adverse event rates between men and women or diabetics and
non-diabetics and, in fact, if we have the adverse events in diabetics, they
actually look a little bit better than in the patients without diabetes.
The
only place where we saw a difference in adverse events in the different
subgroup where we looked, I think, was relatively predictable. Elderly patients did have more adverse events
than younger patients, although the types of adverse events, dizziness, nausea,
asthenia, constipation were very much the same, but they happened more
frequently in them.
MEMBER
LORELL: Thank you.
MEMBER
CARABELLO: Do you have any data in heart
failure patients with long-term exposure to the drug?
DR.
WOLFF: The best data that I could give
you would be the data from the safety database in patients with heart failure
and those without. We have a look at
their adverse events. Here are the data
from the Phase 2, 3 controlled SR studies.
This is basically MARISA and CARISA and you can see that the adverse
events in heart failure are not more common than in the patients without heart
failure.
MEMBER
CARABELLO: But in those trials, the
exposure was relatively short-term?
DR.
WOLFF: That's right. And I don't have them broken out by subgroups
for the long-term going forward, but I can tell you when you look at the
long-term safety data, we don't see any difference in the pattern of occurrence
of adverse events. Dizziness, nausea,
asthenia and constipation are the clearly dose-related ones and they tend to
occur early if they are going to occur.
MEMBER
CARABELLO: My specific concern would be
of worsening heart failure. No data to
suggest that?
DR.
WOLFF: None.
CHAIRMAN
BORER: Bob?
DR.
TEMPLE: One of the things we said in our
letter was that we thought your total safety database for people at relevant
doses and reasonable duration was on the low side. Just let me make it clear. We think the number of people exposed for six
months and a year is within line of standards and is not a problem. But if you discount people who got single
doses, very low doses of the immediate-release, and then the total number of
exposures is pretty low.
The
ICH suggestion is about 1500. It's not
precise on whether you should include people who got a single dose, but clearly
that was not what they had in mind. So
this remains on the light side. I think
we thought there were about 800 people exposed to relevant doses for at least a
month. I just wondered if you want to
comment on that. That's about half of
what we would usually expect, and I guess I should emphasize if the drug did
something really important, you shade that.
If it's another of a sort of thing that you already have, you're more
interested in a reasonable sized safety database.
DR.
WOLFF: Well, the overall database in the
ISS, the four month safety update, was 2,783 exposures. So those are the low doses, the single doses,
so forth and so on.
DR.
TEMPLE: Right.
DR.
WOLFF: The sustained-release formulation
is the one that we intend to market.
There were 1,400 exposures there.
It says any exposure and then as you go up to greater than a month, you
do lose a lot of them, but that's because you lose all the MARISA patients who
got three weeks of exposure, not a month of exposure.
DR.
TEMPLE: Right. No, I know why. I just want to know what you want us to
believe about it.
DR.
WOLFF: So that's there. And then I do think it's quite relevant to
consider the dose for 400 milligrams three times a day, because the plasma
concentrations and the exposure are well within the range of what is produced
by the sustained-release. And so then --
DR.
TEMPLE: Right, but none of those were
over 30 days either. Is that right?
DR.
WOLFF: That's not entirely true, but it
would be difficult for us to know how many were.
DR.
TEMPLE: Okay.
DR.
WOLFF: Because 400 milligrams three
times daily is a dose that was allowed during the Open-Label Follow-On Studies
from the immediate-release trials. And
we do have patients that went on and were on 400 milligrams three times a day
for sometime, but it would be difficult because of the allowance of upward and
downward titration. We weren't able to
say exactly how many for more than 30, more than 90 and more than 365,
although, they did take that dose in open-label treatment.
CHAIRMAN
BORER: Tom?
MEMBER
PICKERING: Could you review the data on
sudden death? My impression was that
about 50 percent of the patients on ranolazine died a sudden death, and that
seems to me a rather high proportion, but I don't know what you would expect in
this population.
DR.
WOLFF: There were 23 sudden deaths out
of 56 overall deaths. I think there were
21 of them on ranolazine out of 42 cardiovascular deaths. And I think I would ask Dr. Braunwald to
comment on the incidences of sudden death in patients with severe coronary
artery disease, but we had half of our cardiovascular deaths that were sudden,
and I believe the literature quotes often two thirds of these deaths would be
expected to be sudden. Dr. Braunwald?
CHAIRMAN
BORER: Alan?
MEMBER
HIRSCH: I want to come back to Dr.
Lorell's question about the dizziness signal.
Even though you're not looking for an indication at 1500 milligrams
twice daily, this is a medication that will be intended to help patients feel
better and really what patients are looking for is a subjective sense of
well-being. I'm going to ignore all the
exercise tolerance, time to ST depression and mechanistic data that
demonstrates a real central cardiac effect.
So
I want to ask what is the meaning of the dizziness in the absence of any clear
blood pressure change or rhythm disturbance, and I think you have implied that
this is interpreted to be a CNS effect?
DR.
WOLFF: Correct, yes.
MEMBER
HIRSCH: So my question is if we know
that there is a potential signal somewhere between maybe 1000 and 1500
milligrams in the CNS, is there any other information on other more robust
measures of how this medication might affect cognitive function? In other words, really, is there any effect
in the sensorium on cognitive function marketed to a large group of Americans
sort of like the statin motif? There may
be questions about beyond the classic AE description of what it does to
cortical function.
DR. WOLFF:
Well, I can't really speak with clinical data to cognitive function,
because that was never formally assessed.
What I can do is amplify on my prior response about how this appears to
be part of a constellation of symptoms.
And you can see here that average ranolazine concentration in patients
that are having some of these adverse symptoms that we believe are part of the
CNS constellation.
Now,
to put this into perspective, recall, and I don't know if you can recall, I'm
not sure I have told you, but the average plasma concentration on the top dose
that we recommend of 1000 milligrams twice a day is 2,500. And so 3,200 is already over the mean
concentration. The 95 percent upper
limit for patients treated with 1000 bid is on the order of around 5,000. So you're at the high end here anyway.
And
so this is the average concentration in patients who complained of nausea and
vomiting. Here, dizziness and
vertigo. Here are the patients with
syncope. Here are the patients with
abnormal vision and diplopia. And by the
time you get to the clearly CNS-related effect of paresthesias and confusion,
the plasma concentration is more than twice as high on average.
So
as I say, I think there is some degree of nausea. Well, we clearly see dose related nausea and
dizziness at the higher end of the recommended dose range in some few patients,
but I don't think that you get clearly into the CNS until you get to higher
concentrations.
CHAIRMAN
BORER: Tom?
MEMBER
PICKERING: On the same lines, do you
have any information about depression, which is obviously a problem in this
group, but is something the patient might not volunteer unless asked?
DR.
WOLFF: We don't have anything
perspective that way.
CHAIRMAN
BORER: Doug?
DR.
THROCKMORTON: Yes, just a small point on
the syncope and the dizziness. I guess
Andy will be talking about that a bit more, but the package that you received
this morning included an analysis from the FDA on the relationship between serum
concentration and the reported incidence of dizziness and syncope and that's on
pages 35 and 36 of that document if you're interested. There appears to be a curvolinear
relationship at least in some circumstances.
The
other thing, Dr. Wolff I guess will be getting back to this, the attribution of
the source of this syncope and the dizziness and things like that. You're attributing it to a central
effect. You know, that will be
interesting. There are, of course,
reported effects of ranolazine on the alpha adrenergic receptors and things
like that that at least raise the possibility of other mechanisms, as well.
DR.
WOLFF: Yes, and we will address that
later.
CHAIRMAN
BORER: Okay. Steve is our Committee reviewer, but before
he gets started on his inventory, I want to make one point and obviously, Bob
and Doug can comment on or modify this if you like. We're being asked to consider a drug for the
prevention of angina, not to prolong life, not to prevent myocardial
infarction, not to do anything else, but to prevent angina. If there are symptoms that are caused by the
drug that aren't importantly dangerous, that don't constitute serious adverse
events, totally different issue, and I think Steve will get into that and we
all will as we go into the QT issues.
If
there are other adverse events that are not serious, not imminently life
threatening, the presumption is that a patient can determine whether the
reduction in angina, if it occurs, is more important to him or her than the
adverse event. So while I think we have
to know about these quality of life issues, I think we have to consider this
application in that context. I mean,
this is a drug for the prevention of a symptom, not for anything else.
Now,
if it's doing harm, that's a different issue and serious harm and, of course,
we have to understand the extent to which it is or it isn't or might. With that having been said, Steve, why don't
you go ahead?
MEMBER
NISSEN: Okay. Yes.
I'm going to hold a lot of safety questions until we get to the later
portions, but I had a few of them. Let
me test a hypothesis on you just for a second.
Would you agree with me that we have a drug here that has a fairly
narrow therapeutic index? That is at
doses that are 1.5 or certainly two times the recommended dose, patients tend
to get into a lot of side effect problems.
Would that be a fair statement?
DR.
WOLFF: I don't know that I would agree
that there are a lot of side effect problems.
I think that you can see a dose relationship and we do agree that 1500
is a dose higher than we would recommend use.
MEMBER
NISSEN: Yes. I know you must agree, because you are
obviously not asking us for approval for a 1500 milligram dose.
DR.
WOLFF: Right, right.
MEMBER
NISSEN: So, you know, 1000 is the
efficacious dose. 1500 was not acceptable,
and so we are talking -- I mean, some drugs that we administer to patients
have, you know, fairly wide therapeutic index.
Some of them have a fairly narrow one.
That's not necessarily a huge approvability issue, but it is a
characterization that I think would be correct.
Would you agree?
DR.
WOLFF: We would agree that the
appropriate dose range for most patients is 500, 750, 1000 milligrams twice a
day.
MEMBER
NISSEN: So what I want to understand and
explore is a concern for me that I need reassurance about, is that I have a
sense for who I think is likely in this country to get the drug, and let me see
if I can describe it. You know, first of
all, younger patients, patients who are, you know, in the, you know, middle
ages and maybe even the young-old tend to get treated very aggressively with
revascularization and other strategies.
Older, frailer, sicker patients, maybe those that are beyond
revascularization are the ones most likely to get the drug at least initially,
and I have a bunch of them in my patient population. They tend to be diabetes. They have had a couple of bypasses. They still have angina. They are not doing well.
They
also are, however, patients that tend to be much frailer, somewhat older, have
more concomitant diseases, such as hepatic or kidney disease, etcetera. And so one of the things that we need to
understand, I think I want to make sure the Committee understands, because I
read this massive amount of documents that we got from the FDA, in fact, I am
going to be filing a Workmen's Compensation claim for carrying all this stuff
around for a few weeks, is that there is some evidence here that patients with
liver disease and kidney disease, for example, have elevated serum
concentrations.
And
I would like you to share with the Committee the relationship between these
concomitant conditions and the elevations of serum levels, because if levels
are going to be one and a half or two times higher in patients with
concomitant, other organ system disease, we need to know about that as we
consider the safety profile.
DR.
WOLFF: Yes, we will address that
specifically this afternoon.
MEMBER
NISSEN: Okay. All right.
Fine, then I will hold on that.
But I just want to make sure we get to review the relationship between
serum concentrations and concomitant diseases.
And that also includes concomitant drugs?
DR.
WOLFF: Yes, it does.
MEMBER
NISSEN: Okay.
DR.
WOLFF: I will treat them both this
afternoon or later on today.
MEMBER
NISSEN: Okay. Then that helps a little bit, because I think
we can move along toward our break.
The
syncope issue. There were a couple of
dozen patients or so that had syncope.
And what do you know, what do we know about the patients that had
syncope? Would any of them have syncope
during electrocardiographic monitoring?
DR.
WOLFF: Yes, some of them did, in fact,
some of the subjects. This all actually
comes up later.
MEMBER
NISSEN: Okay.
DR.
WOLFF: But I would be happy to answer
that now.
MEMBER
NISSEN: Yes.
DR.
WOLFF: I mean, because it's a simple
answer, yes.
MEMBER
NISSEN: Yes.
DR.
WOLFF: Several of the subjects in the
Controlled Overdose Study that I will present later on where we infused the
drug to the highest concentrations literally that patients could tolerate, did
have events that coded to the term syncope while they were being
electrocardiographically monitored continuously and they were just in sinus
rhythm, which is more the reason why we believe this is a CNS effect at these
very high concentrations.
MEMBER
NISSEN: Did their blood pressures fall?
DR.
WOLFF: No.
MEMBER
NISSEN: Did anybody have syncope?
DR.
WOLFF: Some component of an alpha-1
adrenergic effect and postural hypotension though can also be a component of
syncope, and if we get more into syncope, I think it might be useful to wait
until --
MEMBER
NISSEN: Okay. We will wait.
But I do want to see also about whether there was any interaction with
sublingual nitroglycerin. In other
words, if you have angina on ranolazine and you take a sublingual nitro, are
you more likely to go to ground than somebody who is on placebo? I mean, that's a question that would
obviously come up for clinicians to know about, is whether that would occur.
DR.
WOLFF: What's true is that among the 38
patients who had syncope, their use of vasoactive medications in general, ACE
inhibitors, long-acting nitrates, calcium channel blockers and alpha-1 blockers
was about twice that in the overall patient population. So a third of the patients that had syncope
roughly were on two other vasoactive medications known to be associated with
syncope and another third were on three or more.
MEMBER
NISSEN: So there is some issue of
potentiation of the effects of those agents by ranolazine?
DR.
WOLFF: Well, there was more use of
vasoactive medications in the patients who had syncope.
MEMBER
NISSEN: All right. With that in mind, I think, you know, since
we are going to hear much more about the pharmacokinetic and other
interactions, maybe we ought to just table this and kind of move along.
CHAIRMAN
BORER: Okay. Beverly?
MEMBER
LORELL: A quick clarification. In that interesting and helpful slide you
showed us of the spectrum of CNS side effects, was that drawn from the
deliberate excess dosing study that you're going to talk about this afternoon
or was that from the two pivotal trial experience that we're discussing this
morning?
DR.
WOLFF: I believe that was from a
population that included the overdose study, as well as the pivotal
trials. It was from ISS. It was from the -- so is this from the four
month safety update then or is it from the original NDA ISS?
UNIDENTIFIED
SPEAKER: NDA.
DR.
WOLFF: Okay. So this is from the ISS safety database then,
that slide. So that has got angina. It has the Phase 2, 3 studies. It has got the immediate-release
studies. It has the Controlled Overdose
Study, as well.
CHAIRMAN
BORER: Okay. We'll stop here and take a break until 10:30
and then we'll resume.
(Whereupon,
at 10:17 a.m. a recess until 10:33 a.m.)
CHAIRMAN
BORER: Okay. It's 10:34.
You have gotten four extra minutes, so we're going to begin. Dr. Wolff?
DR.
WOLFF: Yes?
CHAIRMAN
BORER: Andy, do you want to have Peter
Kowey begin? Is that the next
presentation?
DR.
KOWEY: All set, Jeff? Dr. Borer, members of the Advisory Committee,
Ladies and Gentlemen, my name is Peter Kowey.
I am from Mainline Heart Health Center in Philadelphia. The sponsors presented efficacy and safety
data this morning from a number of well done clinical trials for a drug that
has a novel pharmacodynamic effect.
Clearly,
the drug has the potential to fill the unmet medical need described by Dr.
Braunwald. The major impediment to its
approval and acceptance is its QT interval effect and its putative risk of
causing torsade de Pointes. FDA and the
sponsor felt that this issue needed to be addressed comprehensively. That has been accomplished. My job is to preview that information and to
put it into some kind of context for the Committee.
In
fact, three parallel approaches were taken and will be presented by subsequent
speakers. The first was a comprehensive
preclinical assessment. We realize that
preclinical data of this nature is not a common presentation to an Advisory
Committee of this kind. However, we
think that it's critically important in understanding the torsade potential for
this particular drug.
Dr.
Belardinelli, who will come to the podium after me, will share some of his vast
experience and that of several internationally renowned scientists. Included will be work with the model that has
been employed in our basic electrophysiology laboratory that makes use of the
myocardial wedge preparation. Our experience
has been that use of the myocardial wedge in a female rabbit provides an
exquisitely sensitive assessment of the risk of torsade.
Dr.
Belardinelli will further orient you to this model. In essence, this model allows us to measure
three very important electrophysiological parameters. In addition to QT interval measurement, the
model also allows us to measure a parameter called transmural dispersion of
repolarization, which we will be referring to as TDR. This means that there is a difference or a
potential difference in repolarization across the thickness of the myocardial
wall. You may regard that as a substrate
for the development of torsade.
The
model also allows us to assess the possibility of there occurring early
afterdepolarizations, so it's for potentials which occur during Phase 2 of the
action potential. These potentials can
be thought of as the triggers for torsade de Pointes. In many cases, you can think of this as the
precursors of torsade.
On
this slide we examine the effect of several agents known to prolong the QT
interval on these three parameters that I just described. In general, drugs that prolong the QT
interval and prolong transmural dispersion of refractoriness also cause early
afterdepolarizations.
There
are two exceptions. One is a drug with
which I'm sure most of the people on the Panel are very familiar, amiodarone,
which does not cause early afterdepolarizations and for which torsade de
Pointes is considered a decidedly rare event.
The other exception to the rule is ranolazine, which causes neither
transmural dispersion of repolarizations or early afterdepolarizations in this
very sensitive model that I have described.
Preclinical
data, no matter how comprehensive and compelling, can never be relied upon to
tell the entire story with regard to the risk of lethal arrhythmias. In lieu of an impossibly large clinical trial
to count actual torsade events, we need a surrogate. The FDA has chosen the QT interval to be that
surrogate. I have been heard to say not
only in other venues, but while sitting at a table just like that, that the QT
interval is a poor surrogate for what we really want to know.
There
are many reasons why we believe the QT interval was not a great surrogate. One has to do with the variability of the
measurement itself. Another has to do
with changes in QT interval under diverse physiologic conditions, and there are
very mundane issues with the QT interval, including how to correct for changes
in heart rate.
Nevertheless,
it is the best we have and the truth is that the magnitude of QT prolongation
does appear to correlate with the risk of developing torsade. Dr. Wolff following Dr. Belardinelli will
return to the podium after the preclinical talk to show you the QT data on
ranolazine. I believe that you will
agree after you see that information that the magnitude of the central tendency
change with ranolazine is akin to what has been seen with other drugs that are
regarded to have a low or a very low risk of causing torsade, and I believe
that the outlier analysis that you will see will convince you of the same thing.
The
third element of QT risk assessment is the counting of clinical events. As I said, there have been no cases of
torsade described and there have been no clinical events that could be
interpreted as a complication of QT interval prolongation. Once again, Dr. Wolff will present
information with regard to pertinent clinical events in his presentation that
will follow Dr. Belardinelli.
Therefore,
the assessment of the risk of torsade should be appreciated as a multifaceted
and highly complex undertaking. We would
love to be able to show you an adequately sized clinical trial in which
episodes of torsade could be counted in patients who receive drug versus a
positive comparative or a placebo. But
the truth of the matter is that the number of patients that would need to be
included in such an analysis is prohibitive.
We
agree that the QT interval is an adequate surrogate, but we also believe that a
very large and robust preclinical package supplements the information regarding
the QT interval and provides independent information regarding this putative
risk. I believe that the data set that
you are about to see represents by far the most sophisticated data set with
regard to the question of QT interval prolongation and risk assessment and
should represent, in truth, a paradigm shift with the way we consider the risk
of drugs that prolong the QT interval and their potential for causing malignant
ventricular arrhythmias.
Jeff,
unless there are some questions, I would very much like to bring Dr. Belardinelli
to the podium to follow this.
CHAIRMAN
BORER: Yes. I think we'll run through the entire
presentation on QT and arrhythmias and then perhaps we can ask whatever
questions we have. And, Peter and Andy,
I would urge you since I'm looking out in the audience and I see John Camm and
Jeremy Ruskin and Dan Roden and Craig Pratt, and there may be others I don't
see who are, in addition to yourself, highly respected experts in this area who
we all know, I would suggest, if you want, make liberal use of them in
answering any of the questions that we may have.
DR.
KOWEY: You betcha.
DR.
BELARDINELLI: Mr. Chairman, Committee
members, Ladies and Gentlemen, today I will describe some of the effects of
ranolazine on ventricular repolarization.
But before I do that, I would like to start by showing some animal data
that demonstrates that the QT interval prolongation is not the sole determinant
of the potential of a drug to cause torsade.
In
this slide on horizontal axis is the magnitude of the increases in QT interval
by various drugs, and on the vertical axis is the respective incidence of
torsade de Pointes in a canine model that is highly susceptible to the
induction of this arrythmia. Note that
equal prolongations of the QT interval by d-sotalol and dofetilide, that is 55
milliseconds, resulted in markedly different incidence of torsade, a 5 percent
for d-sotalol and 67 percent for dofetilide.
On
the far right we have amiodarone and almokalant. Both prolong QT interval by about 70 to 75
milliseconds. Whereas, amiodarone in
this model did not cause torsade, almokalant did in, approximately, 64
percent. Based on this animal data and
other data, prolongation of QT interval is not the sole determinant of the
potential of a drug to cause torsade.
Therefore,
in addition to QT interval, other markers of pro-arrhythmia are needed. Depicted on this slide are the major
electrophysiological events known to play a role in the genesis of torsade de
Pointes, from herein simply torsade.
Drugs
that reduce the repolarizing potassium current, IKr, cause prolongation of
ventricular action potential and, consequently, of the QT interval. This increase in action potential duration
may lead, but not always, to two arrhythmogenic events. They are the induction of early
afterdepolarizations, EADs, and to increases in the dispersion of ventricular
repolarization from, herein referred simply as, dispersion.
Therefore,
EADs as the trigger and increasing dispersion as the substrate are key events
in the initiation and perpetuation of torsade de Pointes. Before I describe the effects of ranolazine,
I will tell you a little more about the roles of EADs and increased dispersion
of ventricular repolarization on the genesis of torsade.
EADs
give the rise to ectopic beats that is extrasystoles. The prolongation of the action potential
duration facilitates the induction of EADs, which give rise to ectopic beats
that in turn initiate torsade. Shown on
the right is a prolonged action potential with two EADs that give rise to two
ectopic beats on the surface electrocardiogram.
When inward depolarizing currents, such as sodium and calcium, are
increased they generate the upstroke of EADs.
Hence, inhibition of IKr prolongs the action potential. Whereas, the reactivation of the inward
currents would elicit EADs.
Therefore,
drugs that prolong the action potential duration while EADs are in use may
generate ectopic beats and thus, have the potential to cause torsade. Shown in this slide are the differences in
action potential duration across the left ventricular wall. Depicted is a transmural wedge of the left
ventricle and representative action potentials from the epicardium,
mid-myocardium and endocardium.
The
numbers on the right are the action potentials in milliseconds and not shown,
the QT interval is the composite of these action potential durations from all
ventricular cells. But importantly, note
that the action potential duration of the mid-myocardial cells is longer than
that of the endocardial and epicardial cells.
In this example, this maximal difference is 59 milliseconds. Thus, the dispersion is 59 milliseconds.
The
normal differences in action potential duration that you see here when
increased, for instance by drugs, create a substrate for arrhythmias. An example is shown next. Drugs that inhibit IKr, such as sotalol,
cause greater prolongations of the action potentials of the mid-myocardium than
either the epicardium or the endocardium.
Consequently, the dispersion is increased to 98 milliseconds. Therefore, drugs that accentuate the normal
dispersion of ventricular repolarization create a substrate for arrhythmias and
not surprisingly had been found to be pro-arrhythmic.
The
strategy used to assess the potential pro-arrhythmia risk of ranolazine was
based on the electrophysiological events associated with drug induced
torsade. Hence, we determined the
effects of ranolazine on ion currents, on the ventricular action potential in
QT intervals, induction of EADs and fourth, the dispersion of ventricular
repolarization.
Experiments
were carried out in preparations at such doses listed here on the left. Very importantly, they were carried out under
conditions known to increase the risk for torsade, such as bradycardia,
hypokalemia, pharmacological of ion channel mutations in diseases. First, I will describe the effects of
ranolazine on ion currents. I will only
report to you on the two most sensitive currents to ranolazine, the outer
current, IKr, and the inward current, late INa.
Inhibition
of IKr leads to the lengthening of the action potential and hence, prolongs the
QT interval. Ranolazine inhibits this
current with a potency of 12 micromolar.
On the other hand, inhibition of late INa leads to a shortening of the
action potential and, consequently, shortens the QT interval. Ranolazine inhibits late INa with a potency
as low as 5 micromolar.
The
inhibition of late INa is expected, therefore, to counterbalance the
arrhythmogenic effects of the inhibition of IKr, such as induction of early afterdepolarizations. Ranolazine, you already heard, prolongs the
action potential and QT interval, but in contrast, through IKr blockers, this
effect is not heart rate-dependent.
Drugs
that inhibit IKr often cause greater prolongation of the action potential in QT
interval at slow heart rates than a fast heart rate. This is relevant, because you know that
bradycardia is a major factor for drug induced torsade. Shown in Panel A is the relationship between
pacing rate and the prolongation of the monophasic action potential.
The
IKr blocker E-4031 caused a 40 millisecond prolongation of the action potential
when the rate was fast, that is 150 beats per minute, but caused a much greater
effect, almost double, when the rate was slow, 60 beats per minute. In contrast, 5 micromolar ranolazine caused
the same prolongation of the action potential whether the pacing rate was fast
or slow. The slope of this relationship
for ranolazine was near zero, that is was rate independent, whereas the slope
for E-4031 was much steeper.
Shown
now in Panel B is a bar graph of these slopes, of the relationship between QT
interval and heart rate in humans before and after administration of E-4031,
dofetilide and ranolazine. Similar to
the results in isolated hearts, the slope of this relationship, i.e., between
QT and heart rate for ranolazine was near zero.
Whereas, the slope for E-4031 and dofetilide were much steeper. Therefore, during bradycardia the
prolongation of QT interval by ranolazine would not be exaggerated.
Using
seven different types of cardiac preparations and the numerous conditions that
I listed earlier for you, known to increase the risk of torsade, EADs did not
occur in the presence of ranolazine. On
the contrary, as summarized here, ranolazine reverses the action potential
duration prolongation and suppresses EADs and ventricular tachycardia caused by
one, IKr blockers, such as sotalol and E-4031, two, the IKs blocker, chromanol,
and three, the late sodium current enhancer, the anemone toxin, ATX-II, all
known to mimic the ion channel dysfunctions associated with long QT
syndromes. Therefore, ranolazine does
not induce EADs, ectopic beats or torsade.
It suppresses the arrhythmogenic activity caused by other QT prolonging
drugs.
Next,
I will show an example with sotalol followed by an example with E-4031. Shown in green is a controlled action
potential recorded from a Purkinje fiber and now in blue is an action potential
with a large EAD recorded after the application of d-sotalol. Still in the presence of this sotalol, 5
micromolar of ranolazine suppressed the EAD and shortened the action
potential. 10 micromolar ranolazine
caused an additional shortening of the action potential. This effect that I am showing here to you of
ranolazine was also observed in cardiomyocytes and in whole hearts when EADs
were induced by quinidine, the anemone toxin by E-4031 and other drugs.
Next,
I will show you an example with E-4031 in a female rabbit heart. The rabbit, in particular, the female rabbit
heart is exquisitely sensitive to the arrhythmogenic effects of QT prolonging
drugs. Shown in Panel A here are
monophasic action potentials recorded during controlled conditions. As mentioned earlier, bradycardia in long
pauses are risk factors for torsade. In
this experiment, the heart was paced at a constant rate of 60 beats per minute
except when a three-second pause was introduced to sensitize the preparation to
the arrhythmogenic effects of QT prolonging drugs.
As
you can see, under controlled conditions following the pause, no arrhythmic
activity was noted. In Panel B,
ranolazine at a concentration that is sixfold higher than the upper limit of
its therapeutic range. As expected, it
prolonged the action potential, but importantly, following the pause, neither
EADs nor any other arrhythmic activity was observed.
In
Panel C in the presence of E-4031 following the pause, EADs in short runs of
ventricular tachycardia were observed.
Now, in Panel D, 5 micromolar ranolazine still in the presence of E-4031
abolished the arrhythmic activity caused by E-4031. Therefore, ranolazine does not induce EADs,
does not induce ectopic beats or initiate ventricular tachycardia, whereas,
E-4031 does. On the contrary, as shown
here in Panel D, ranolazine suppresses the arrhythmogenic activity caused by
E-4031.
Ranolazine,
unlike drugs that cause torsade, does not increase dispersion. Specifically, it does not increase transmural
dispersion of repolarization, TDR. As
can be seen in contrast, d-sotalol and the toxin ATX-II caused large increases
in dispersion, 83 and 123 milliseconds respectively, both known to cause
torsade.
To
further evaluate the effect of ranolazine on dispersion, experiments were
carried out during hypokalemia, a condition well-known to be a risk factor for
torsade. The results are now
summarized. Similar to the results at
normal kalemia, during hypokalemia, that is 3 millimolar, and as low as 2
minimolar extracellular potassium, ranolazine at a concentration ranging from 1
to 100 micromolar caused no significant changes in TDR.
But
very importantly, irrespective of the extracellular potassium concentration be
it for 3 or 2, in the presence of ranolazine transmural dispersion remained
below 40 milliseconds, that is within the normal range, and there were no EADs
nor arrhythmias. EADs and increases in
dispersion of ventricular repolarization predict the occurrence of torsade in
humans. Listed in the table are drugs
known to inhibit IKr, prolong the action potential in QT interval. Pentobarbital and ranolazine are two drugs
that have not been reported to cause torsade in humans.
On
the other hand, quinidine, d-sotalol, terfenadine, erythromycin and cisapride
have all been reported to cause torsade in humans, and found to be capable of
inducing EADs and increasing transmural dispersion of repolarization. Thus, ranolazine does not induce EADs nor
increase transmural dispersion in a preparation that other drugs known to cause
torsade do induce EADs and do increase transmural dispersion of repolarization.
In
summary, drugs that cause torsade de Pointes do so by inducing EADs in
accentuating the dispersion of repolarization present in the normal heart. Ranolazine prolongs the action potential
duration in QT interval, but it does not induce EADs nor does it increase
dispersion. On the contrary, ranolazine
suppresses the arrhythmic activity effect of a number of QT prolonging
drugs. Therefore, ranolazine would not
be expected to cause torsade de Pointes.
CHAIRMAN
BORER: Okay. Thank you very much. Are you going to present anymore formal?
DR.
WOLFF: Thank you, Dr. Borer. Well, now, having examined the basic
electrophysiological properties of ranolazine, let us now then turn to our
clinical characterization of the effect of ranolazine on ventricular
repolarization.
As
you will see, the effect of ranolazine on the QTc interval has been very
well-characterized throughout and even beyond its therapeutic range, including
plasma concentrations up to 10,000 nanograms per mL and exceeding tolerability. Throughout this entire range, the
relationship between the ranolazine plasma concentration and the change in the
QTc remains linear at about 2.4 milliseconds per 1000 nanograms per mL.
Thus,
over the recommended dose range of 500 to 1000 milligrams twice daily, the
average increase of QTc on ranolazine is 2 to 5 milliseconds and it remains
less than 20 milliseconds or about equal to it on average during maximal
inhibition of the major elimination pathway of ranolazine, cytochrome P450 3A4,
by ketoconazole. And as Dr. Belardinelli
has just demonstrated, the cellular electrophysiology underlying the QTc
prolonging effect of ranolazine is fundamentally different from that of drugs,
which prolong the QT and which are known to cause torsade.
Our
database contains over 25,000 QT measurements from nearly 2,400 subjects and
patients treated with ranolazine for a total of 1,700
subject/patient-years. Again, over 250
patients have been followed for over two years with serial
electrocardiograms. All the electrocardiograms
obtained in CVT-sponsored studies have been read under the direction of Dr.
Bernard Chaitman at the single core laboratory in St. Louis University. I will also present the results of the
population QTc analysis that included nearly 16,000 pairs of QTc measurements
and simultaneous steady-state ranolazine plasma concentrations.
This
slide summarizes the study designed for CVT 3111 in which we evaluated the
effects of ranolazine on the QTc interval during intravenous infusion of the
drug to the limits of tolerability. In
effect, this was a controlled overdosing situation. A total of 16 women or, I'm sorry, 16 men and
15 women were enrolled into a study, which was planned to achieve target
ranolazine plasma concentrations of 4000 nanograms per mL, 10,000 nanograms per
mL and 15,000 nanograms per mL. For
perspective, 4000 nanograms per mL then is at the upper end of the distribution
of concentrations achieved with our highest proposed dose of 1000 milligrams
twice daily.
10,000
nanograms per mL is a concentration higher than was observed in any of the
chronic angina patients receiving 1000 milligrams twice a day in MARISA or
CARISA and 15,000 milligrams was chosen as the target plasma concentration,
which we had, at that time, never achieved in any subject or patients.
All
subjects and patients or all subjects under a single-blind infusion for 24
hours and then there was a double-blind infusion where most of the subjects got
ranolazine and some got placebo. As you
can see, vital signs, samples for measurement of ranolazine plasma levels and
electrocardiograms were obtained very frequently both during single-blind
placebo infusion, as well as during double-blind treatment.
Of
note, only seven patients received the infusion targeting the 15,000 nanograms
per mL dose. The trial was discontinued
after the treatment of those seven subjects, because intolerable symptoms
developed in each of them and the sponsor and the investigators agreed it would
not be ethical to continue to expose additional subjects to that treatment.
Here
are the data from CVT 3111. First,
notice that the range of variability in the absence of ranolazine on placebo
encompasses the entire range of changes seen during treatment with the drug. We did achieve a broad range of plasma
concentrations in the study. Here these
lines represent the 50th percentile of concentrations achieved on 1000
milligrams twice a day in MARISA and CARISA.
Here at about 5500 is the 95th percentile for that population and here
is the highest concentration that was achieved in MARISA and CARISA.
Thus,
CVT 3111 studied a range of concentration, which exceeded those likely to occur
during treatment of chronic angina patients even at the highest proposed dose
of 1000 milligrams twice a day. As I mentioned
before, the target plasma concentration of 15,000 nanograms per mL, which would
have been out here somewhere, couldn't be achieved in any subject because of
dizziness, nausea, postural hypotension, diplopia, somnolence, syncope and
paresthesia.
Of note, the QTc was never observed to
increase by more than 60 milliseconds from the baseline in this study. Overall, the relationship between the plasma
concentration and the QTc was linear throughout this entire range of
concentrations with a slope of 2.29 milliseconds per 1000 nanograms per
mL. And I think I better have a little
water here.
So
our conclusions from CVT 3111, the controlled overdosing experiment, was that
the relationship between the plasma ranolazine concentration and the QTc remains
linear with a slope of about 2.29 milliseconds per 1000 nanograms per mL over
the entire achievable concentration range, and that plasma concentrations
approaching 15,000 nanograms per mL are unlikely to be tolerated by angina
patients in clinical practice, because that concentration could not be achieved
or really even approached in the study.
And
finally, syncope was observed at high plasma concentrations in this study
during continuous electrocardiographic monitoring with no evidence of
arrhythmia. The findings from CVT 3111
were confirmed and extended in a population analysis that combined nearly
16,000 pairs of QTc measurements and steady-state plasma concentrations from
over 1,300 subjects across 15 different studies.
Once
again, the slope of this relationship was observed to be linear with a similar
value from that obtained in CVT 3111 of 2.4 milliseconds per 1000 nanograms per
mL. This slope was not altered by the
heart rate, by the patient's sex, by the presence of heart failure, by
treatment with diuretics, by the patient's age or by the absence, presence or
type of background anti-anginal therapy.
This
is a very different phenotype from what is observed on drugs, which prolong the
QT interval and are known to cause torsade de Pointes. Several of those other drugs have been
reported to cause larger changes in women for a given plasma concentration and
in patients with heart failure. The
slope of this relationship was found to be somewhat steeper in patients with
hepatic impairment.
Outlier
values were generally infrequent and sporadic.
Consistent with the population analysis, changes from baseline greater
than 60 milliseconds were more obviously related to the dose that were absolute
values greater than 500 millisecond.
It's noteworthy that these outlier value rates reflect a much larger
number of ECGs per patient than is often submitted in a safety database with
outlier patients having experienced 14 to 15 ECGs per patient on average. It's also noteworthy that the duration of
treatment and the number of ECGs per patient obtained on treatment is
substantially greater than that for placebo, which comes solely from the
controlled experience while these contain measurements from long-term
open-label follow-up.
As
we characterize the ranolazine plasma concentration as a major determinant of
the QTc effect, we have in turn characterized the determinants of the
ranolazine plasma concentration. The
kinetics of ranolazine are generally unaffected by the patient's sex or age, by
the presence or absence of food and by common comorbidities, such as congestive
heart failure and diabetes. Atenolol,
amlodipine, digoxin and simvastatin do not affect ranolazine plasma
concentration. Because the major
elimination pathway is known to be cytochrome P450 3A4 with some contribution
from cytochrome P450 2D6, a number of formal drug-drug and drug-disease
interaction studies were undertaken, which are summarized on the next slide.
The
most extreme condition we found was complete inhibition of the major elimination
pathway, cytochrome P450 3A4 with ketoconazole at 200 milligrams twice a
day. This resulted in roughly a fourfold
increase in plasma concentrations as you can see here, and the increase in QTc
was proportional. Accordingly, as the
average increase in the QTc on 1000 milligrams of ranolazine twice daily is
about 5 milliseconds in the absence of ketoconazole, during this study the
average increase in QTc on the combination of ranolazine and ketoconazole was
20 milliseconds.
The
recent preliminary concept paper regarding the evaluation of the effects of
drugs on the QTc interval advises particular attention to the adverse events
shown on this slide. We have already
discussed dizziness as a very clearly dose related phenomenon observed in the
Phase 3 studies and, especially, along with other central nervous system
symptoms at high concentrations in the Controlled Overdose Study, CVT 3111.
None
of these others appear in a dose related pattern, except possible syncope,
which occurred in five patients that were randomized to direct treatment with
1000 milligrams twice daily in CARISA and to three patients receiving
randomized treatment with 15,000 milligrams twice daily in MARISA.
So
let's then consider the issue of syncope in a bit more detail. Syncope on ranolazine appears to be related
to postural hypotension at higher doses.
The occurrence of postural blood pressure changes in healthy volunteers
is a clearly dose related phenomenon, especially when they have been treated
with doses as high as 2000 milligrams twice daily during early dose defining
clinical pharmacology studies of the sustained-release formulation.
During
those early trials, some of those volunteers were sufficiently orthostatic to
be unable to stand up for vital sign measurements at the peak effect of these
very supra-therapeutic doses. This
orthostatis is consistent with a weak alpha-1 adrenergic receptor antagonism
that becomes apparent in nonclinical pharmacology studies at the upper end of
the therapeutic concentration range and beyond.
Similarly,
as mentioned earlier, syncope was observed in a Controlled Overdosing Study,
CVT 3111, in the absence of arrhythmias during continuous electrocardiographic
monitoring. The chronic angina patients,
as we discussed this earlier actually, who experienced syncope in the Phase 2,
3 controlled trials and their open-label follow-on were more likely to be
taking other vasoactive medications that are also known to cause syncope. And I think I said earlier about a third of
them were on two such medications and another third of those who experienced
syncope were on three or more. And
finally, there was no electrocardiographic evidence for torsade de Pointes in
any patient on ranolazine, including the ones with syncope.
Overall,
the rate of syncope on ranolazine is about 2 percent per patient-year of
treatment, which is similar to that given in the labeling for other alpha-1
adrenergic blockers. The placebo rate
appears to be lower. However, once
again, the experience on ranolazine is more than tenfold greater than the
experience on placebo and, as a consequence, once again the 95 percent
confidence interval about the ranolazine estimate fits completely within the 95
percent confidence interval for the placebo estimate.
In
summary then, the effect of ranolazine on the QTc interval has been
well-characterized throughout and beyond the range of tolerable plasma
concentrations remaining linear throughout this range at about 2.4 milliseconds
per 1000 nanograms per mL. Even with
controlled overdosing in Study CVT 3111, we have been unable to achieve a
plasma concentration approaching 15,000 nanograms per mL, which indicates that
intolerability will tend to prevent exposures to plasma concentrations
associated with larger QTc increases.
And finally, as we heard earlier from Dr. Belardinelli, the cellular
electrophysiology underlying this QTc effects is fundamentally different from
that of drugs, which prolong the QT and which are known to cause torsade.
Having
considered then the efficacy, safety and electrophysiological profile of
ranolazine, a rationale for dosing can be constructed. We have shown the ranolazine plasma
concentration to increase with dose and in turn, the efficacy to increase
linearly from 500 to 1,500 milligrams twice daily in MARISA and with the plasma
concentration in a large and robust population analysis. In contrast to the generally dose and
concentration dependent increase in efficacy, adverse events increase
disproportionately from 1000 milligrams twice a day to 1,500 milligrams twice a
day.
Accordingly
then for most patients, we propose dosing should begin at 500 milligrams twice
a day with upward titration as needed according to the clinical response
through 750 milligrams twice a day to 1000 milligrams. For patients with severe renal disease,
hepatic impairment or those taking higher doses of diltiazem or verapamil, a
lower dose range of 375 to 750 milligrams is recommended. Thank you.
CHAIRMAN
BORER: Dr. Ruskin?
DR.
RUSKIN: Dr. Borer, Committee members, ladies
and gentlemen, I'm Jeremy Ruskin and I would like to offer some brief
concluding comments about the benefit risk assessment of ranolazine. As you've heard, many patients face recurred
episodes of angina that limit their physical activity and significantly impair
their quality of life. Epidemiologic
data suggests that a significant minority of patients with angina are not
adequately treated with available therapies and would benefit from additional
pharmacological options.
As
you've also heard, a year after PCI resurgery for the relief of ischemia, as
many as 20 percent of patients still experience angina pectoris despite the
fact that as many as 80 percent of them are still taking anti-anginal
medications. Familiar to everyone in
this audience are the limitations to uptitration of currently available
anti-anginal drugs and these include bradycardia, hypotension, fatigue and/or
depression for beta blockers, bradycardia, hypotension and left ventricular
dysfunction for calcium channel blockers and headache, hypotension and the need
for a drug free interval with nitrates.
Ranolazine
has the potential to offer benefit in all of these situations. As you've heard, ranolazine is a novel agent
that is pharmacodynamically distinct from other anti-anginal drugs. At standard therapeutic concentrations it is
hemodynamically neutral with no significant effect on heart rate, blood
pressure or ventricular function. And
the drug is safe and effective both alone or in combination with other
anti-anginal drugs.
Ranolazine also demonstrates consistent
benefit across a broad spectrum of patient cohorts including those with heart
failure, diabetes, lung disease, prior myocardial infarction or
revascularization, as well as in patients with borderline heart rates or blood
pressures, and the drug is effective in these cohorts both alone and in
combination with other anti-anginals.
This
slide summarizes for you the mean increases in placebo corrected exercise times
observed with ranolazine, as well as with three other anti-anginal drugs. And although this comparison is subject to
the limitation of cross study comparisons, it is interesting to note that the
effect size observed with ranolazine is quite similar to that observed with
atenolol, diltiazem and transdermal nitroglycerin. And this is occurring in the setting of
ranolazine being tested in patients with severe angina pectoris and markedly
limited exercise tolerance.
With
regard to safety, the adverse effects of ranolazine are generally mild to
moderate with no serious organ toxicity.
Discontinuations are infrequent and when the option arose a large
preponderance of patients elected to continue therapy with ranolazine. There are drug-drug interactions, but these
are well-characterized and most important for today's discussion, as you've
heard, ranolazine does have a concentration dependent effect on the QTc
interval.
These
two graphs compare for you the effects on QTc of ranolazine and terfenadine
alone and in the setting of maximum metabolic inhibition with
ketoconazole. In the absence of
metabolic inhibition, both drugs have a modest effect sub-10 milliseconds on
the QTc. But in the setting of metabolic
inhibition with ketoconazole one sees a tenfold increase in the effect size on
QTc resulting in a mean increase of approximately 80 milliseconds with
terfenadine. A pattern that is quite
different from that seen with ranolazine.
It
should also be emphasized that the preclinical profile of terfenadine is quite
different from that of ranolazine and the drug's pro-arrhythmic potential is
readily detected in preclinical models.
This slide depicts for you the relationship between ranolazine plasma
concentration and change in QTc for the entire population studied in red, as
well as for a series of high risk subsets, including women, patients with heart
failure, the elderly, patients with bradycardia and patients with coronary
disease compared with healthy volunteers.
And
it is reassuring to note that the slope of this relationship is not different
among these high risk subsets when compared with the general population. In addition to being reassuring, this is a
profile that differs somewhat from a number of drugs known to cause torsade.
With
regard to preclinical profile, it is important to underscore what you have
heard already about the critical underpinnings of drug induced torsade, and
that is the following triad. The
prolongation of ventricular action potential resulting in QTc prolongation, one
factor. Second and perhaps most
important an increase in dispersion of refractoriness, which creates the
substrate for reentry. And third the
induction of early afterdepolarizations which may serve as a trigger for
torsade.
As
you have also heard, ranolazine does not induce early afterdepolarizations and
it does not increase dispersion. It also
does not cause arrhythmias in any of seven experimental models tested. In contrast, ranolazine suppresses early
afterdepolarizations and reverses both dispersion and ventricular arrhythmias
caused by drugs that commonly cause torsade.
In
summary, the QTc effects of ranolazine are well-characterized and linearly
related to plasma concentration.
However, adverse side effects primarily CNS and GI will, in a larger
percentage of patients, limit exposures to concentrations in excess of 8000
nanograms per mL. Syncope does occur
with ranolazine and is often viewed as a surrogate or a potential surrogate for
ventricular arrhythmias. But among observed
cases, there has been no evidence for an arrhythmic mechanism.
There
has been no case of torsade observed in more than 1,700 patient-years of
exposure and spontaneous ventricular arrhythmias are not more frequent on
ranolazine than they are on placebo. And
finally, an extensive nonclinical program demonstrates a unique electrophysiologic
profile with no evidence of pro-arrhythmia.
In
conclusion, ranolazine is an effective and well-tolerated anti-anginal agent
with a unique hemodynamically neutral clinical profile. The drug also has a unique preclinical
profile in two respects. First, at least
in my experience, this represents the most comprehensive preclinical assessment
of any drug with an effect on cardiac repolarization. And second, the results of that comprehensive
assessment provide a level of reassurance that has not previously been
possible.
And
that reassurance derives from the observations that despite the fact that
ranolazine does prolong the QT interval, it does not increase transmural
dispersion. It does not cause early
afterdepolarizations. And it does not
cause ventricular arrhythmias in any of seven animal models tested, including
the most sensitive model, for the detection of drugs which cause torsade in
humans.
Thus,
we are left with a theoretical risk associated with a small degree of QTc
prolongation. The combination of a
unique and hemodynamically neutral clinical profile and a comprehensive and
uniquely reassuring preclinical profile mitigates strongly in favor of the
management of this small theoretical risk by a combination of strategies, including
dose titration, appropriate labeling, physician and patient education and post
marketing studies to which the sponsor is committed. Thank you.
CHAIRMAN
BORER: Thank you very much, Jeremy. Is there any further formal presentation?
DR.
RUSKIN: No.
CHAIRMAN
BORER: Okay. We'll take some time for questions now. I would like a clarification of the data
before we begin that. Please, Dr.
Belardinelli, you gave a very impressive, I thought, presentation. I'm wondering though if I understood your
data correctly, none of the animal studies explored the possible effects of
drug disease interaction as a substrate or an arrhythmogenic effect of this
drug. Now, none of these animals had
induced ischemia, I don't think. Is that
right or is that not?
DR. BELARDINELLI: No, we did.
Ranolazine has been a study in animal models with ischemia reperfusion
and also in isolated perfused hearts.
And ranolazine actually decreases the incidents of ventricular
fibrillation in these models at a concentration started at 1 micromolar and up
to 10 micromolar.
CHAIRMAN
BORER: Can you show us some of those
data, please?
DR.
BELARDINELLI: Yes. Let me start, okay, here we go. We have here, this actually was a study done
awhile ago while this drug was at Syntex.
And what is shown here is the incidence of ventricular fibrillation in a
model of ischemia/reperfusion in rat isolated working heart. As you can see here, ranolazine at 100 nanomolar
decreased the incidents by about 25 percent and about 36, 37 percent at 1 in 10
micromolar.
DR.
THROCKMORTON: Sorry. Dr. Belardinelli, just a question. Does the rat have IKr?
DR.
BELARDINELLI: The rat, if you produce an
IKr blocker, will prolong the action potential.
On the other hand, I should point it out that IKr, I don't know of any
evidence that IKr would promote EF.
DR.
THROCKMORTON: I take that as a no.
DR.
BELARDINELLI: Actually, an IKr blocker
would decrease reentry by prolonging the action potential.
DR.
THROCKMORTON: Yes, and sorry, I was just
asking a mechanism-based sort of question.
I wasn't sure exactly what this model would inform if we didn't have IKr
present.
DR.
BELARDINELLI: And by the way, these that
are here, the designs of the heart, that's also data in anesthetized animals as
well.
CHAIRMAN
BORER: Do you have similar data in other
models with intact animals?
DR.
BELARDINELLI: Okay. Can we go back to the previous slide? The one that we have all the different
conditions where we tested ranolazine.
Okay. I have listed here, Dr.
Borer, eight well-accepted risk factors or principles and conditions for
torsade de Pointes. We have tested
ranolazine in almost all of these conditions, and we have provided reports in
almost all of them. There is a few
exceptions.
We
did study the ranolazine and I want to point it out, Item 5. We did a number of studies which I didn't
show in my formal presentation to you where we attempted what I think is the
ultimate test for this is to simulate ion channel mutation, a sodium channel
ion mutation, and then we add drugs on top, I add ranolazine on top of that
situation and we showed actually ranolazine actually suppressed arrhythmias
caused under those conditions.
As
far as other diseases since you alluded, number 6, is heart failure, which probably
would be most people's concern, we have reported a study in which human
ventricular myocytes from explanted hearts, terminal heart failure, this is
done by Dr. Stanley Nattel, and in this study Dr. Nattel also failed to induce
EADs. Although, he did prolong the
action potential by about 12 to 13 percent.
So we have vigorously pursued to find a situation where we could find a
signal with ranolazine and results are here are no, no and no. We cannot find a signal with this agent that
would produce a pro-arrhythmic signal that we mentioned earlier, EADs or
increased transmural dispersion.
CHAIRMAN
BORER: Okay. I think these are all very impressive and
interesting. I think probably what most
people would be interested in is the interaction with ischemia, though, because
that's what you want to give them.
DR.
BELARDINELLI: Yes. Ischemia is listed here.
CHAIRMAN
BORER: Right. And what we've heard about is a rat model.
DR.
BELARDINELLI: Yes.
CHAIRMAN
BORER: An isolated perfused heart.
DR.
BELARDINELLI: Correct.
CHAIRMAN
BORER: Rat model that doesn't have
IKr. Now, do we have other data?
DR.
WOLFF: It might be useful to look at the
occurrence of arrhythmias during ischemia induced by exercise during clinical
testing, and we have those data displayed here.
And you can see, and we didn't subject these to statistical analysis,
but the occurrence of ventricular arrhythmias during both exercise and then
during recovery was actually trending downward with dose with ranolazine in
pivotal trials.
DR.
BELARDINELLI: Dr. Borer, to address your
question, as I mentioned, we do have study of ranolazine in rat, anesthetized
rat, LAD ligation followed by reperfusion.
And again, ranolazine decreased induction EF, decreased the frequency of
ventricular tachycardia. This data,
unfortunately, has not been reported to the FDA.
CHAIRMAN
BORER: I would be interested just to --
Doug, did you want to make a point here first?
DR.
THROCKMORTON: Yes. I mean, Dr. Belardinelli, elegant
presentation. Thank you for presenting
an overview of the data from the sponsor's conclusions here. It's probably just worth noting that the FDA
reviewers contested some aspects of the interpretation that you've presented
today and just informed us, in fact, that the reviewers did conclude that there
was evidence of transmural dispersion under conditions of hypokalemia. I understand that you and they have had an
opportunity to talk about that and disagree with that interpretation. But low, and now we're talking about 2
millimolar potassium concentration evaluation.
I
guess, Charlie, you did those experiments.
You may want to stand up and talk about it. But under those conditions, we believe we did
-- there was evidence both from TPT and other sorts of things as well as
transmural dispersion for -- under other evaluations for evidence for
transmural dispersion. And so I just
wanted to leave that with the audience to make sure that there was -- if we
needed to have a conversation, we could.
DR.
BELARDINELLI: I think I did show a
slide. Maybe we should go back to the
slide of core presentation and we can see what are the observations. But also, I think it is important to point it
out that 2 millimolar, and I think all of you would agree with me, is an
extreme condition. 2 millimolar
potassium by itself is pro-arrhythmic.
It would increase ventricular ectopy.
And under even these extreme conditions, ranolazine, Dr. Antzelevitch
was not able to see any arrhythmias in this preparation.
So
we are very reassured that even under extreme condition of 2 millimolar, we
didn't see any arrhythmogenic activity and this is the issue, I think, that
we're arguing here or discussing is that a 2 millimolar, that's this small,
increase that you see here from 16, 28 back to 15 and back to 35. It's important to know that in no occasion
these numbers here went above 40 milliseconds, and in no occasion they approach
the 90 or 80 milliseconds that is the threshold that Dr. Charlie Antzelevitch has
demonstrated to be necessary to induce torsade.
Charlie?
DR.
ANTZELEVITCH: Thank you, Luiz. Charlie Antzelevitch, Masonic Medical
Research Laboratory. Maybe I should
preface my remarks by saying that we've had a revolution I think in our
understanding and also in the methodologies that we have available for
assessing QT prolonging drugs. And these
are models that we have available today that are able to detect drugs that
produce torsade de Pointes that have been problematic drugs, such as cisapride
and terfenadine and most recently mibefradil have been identified as causing
torsade, and these are all drugs that have recently been withdrawn from the
market.
Ranolazine
is all of the models that have been tested and all of the stresses that it has
been subjected to has failed to produce an arrhythmogenic signal. And this is one of them. If we could see that slide once more, 2
millimolar. Okay. Thank you.
2 millimolar potassium is a concentration that really presents the
ultimate test of any drug, even a drug like verapamil that we know to be very
safe will produce transmural dispersion, very serious transmural dispersion
under these conditions. Yet, ranolazine
fails to do so.
One
of the interesting facets with respect to this slide is that this concentration
of potassium reduces the space constance, so that electrotonic interaction is
facilitated and transmural dispersion is reduced dramatically on the baseline
conditions. And what the drug does, in
fact, is just bring this up just a bit, but we're still well within the normal
range.
DR.
THROCKMORTON: Charlie, help me
remember. You had to go to 2 millimolar
potassium to see terfenadine's effect.
Is that correct?
DR.
ANTZELEVITCH: With terfenadine, we were
able to see it at 4 millimolar as well as 3 millimolar. I don't believe we ever tested it at 2.
DR.
THROCKMORTON: Okay. All right.
DR.
TEMPLE: But it wasn't the sort of
stand-up that hit you in the face kind of thing, right? I mean, it needed to be pushed?
DR.
ANTZELEVITCH: Yes, with terfenadine and
we found the same to be true with mibefradil, that long exposures are necessary
in order to unmask the arrhythmogenic actions of the drug.
DR.
TEMPLE: Of course, that's not true
clinically for terfenadine. You see it
right away. If you get its concentration
up to where it's at.
DR.
ANTZELEVITCH: Right. It's a matter of loading the cell with the
drug. And time is a function that allows
you to load the cell.
DR.
THROCKMORTON: Charlie, one other thing
about these data. You didn't show it,
but you had obviously done a whole graph, whole series of other measures in
this particular experiment TPT and APD 50s and 90s in the M cell region as well
as the epicardium, although showed a consistent dose-response that, again this
is 2 mL or more of potassium, again that didn't give you any pause, I guess?
DR.
ANTZELEVITCH: No, it did not, because we
are within the normal range. As Dr.
Belardinelli indicated, TDR never exceeded 40 milliseconds. In the arterially perfused wedge preparation
from the dog, the threshold is 90 milliseconds for the induction of reentry and
the induction of torsade.
DR.
THROCKMORTON: And tell me how many
compounds that, it sounds like might lie in the sand, this is based on?
DR.
ANTZELEVITCH: In fact, the slide
enumerates the compounds that have been tested in these various models, and if
we focus just on two columns, this column that indicates whether torsade de
Pointes has been reported in the clinic with this particular drug and the other
is the transmural dispersion of repolarization that has been noted with these
experimental models. You'll note that in
every case in which torsade has been reported in the clinic, there is an
increase in transmural dispersion of repolarization. When transmural dispersion has not been
detected in the models, there is no indication or report of TdP. The only exception being amiodarone.
If
we could have the next slide, please? So
that more recently, we have calculated the sensitivity and the specificity of
these models and the sensitivity being 90 percent and the specificity being 100
percent, and the sensitivity is limited only by the amiodarone experience,
which, I think, we all recognize is a far lower incidence of torsade than we're
used to seeing with other QT prolonging drugs.
DR.
TEMPLE: Could you go back to the
previous slide? It's very hard to
read. Which are the drugs that prolong
QT that are not a problem, other -- leaving aside amiodarone? I just can't see the names there.
DR.
ANTZELEVITCH: Quinidine in high
concentrations, verapamil.
DR.
TEMPLE: Verapamil, you're counting
verapamil as prolonging the QT?
DR.
ANTZELEVITCH: Verapamil normally does
not, but under hypokalemia conditions will prolong QT.
DR.
TEMPLE: Okay. So that's a little iffy. What are the others?
DR.
ANTZELEVITCH: Sodium pentobarbital.
DR.
TEMPLE: Yes, well.
DR.
ANTZELEVITCH: IKs block and the presence
of beta blockers and the final one is ranolazine.
DR.
TEMPLE: Okay. But that's not a whole lot of drugs that
prolong the QT by a meaningful amount and that don't cause dispersion and turn
out to be clean. I mean, how many were
there? Quinidine at high doses and
mibefradil? No, mibefradil does, you
said.
DR.
ANTZELEVITCH: Yes.
DR.
TEMPLE: We actually have that.
DR.
ANTZELEVITCH: We have nine drugs and
conditions that prolong TDR and have been reported to produce TdP.
DR.
TEMPLE: Right. But they also prolong the QT. I was interested in the ones -- I mean, the
case you are making for ranolazine is sure it prolongs the QT, but it doesn't
do this other bad thing that causes problems.
And how many drugs help make that case in the negative way, that is they
prolong the QT, but they don't cause repolarization and therefore we have
reason to hope that ranolazine wouldn't.
DR.
ANTZELEVITCH: Right.
DR.
TEMPLE: I mean, I don't know what to
make of pentobarbital. I'm not sure
anybody uses it much any more, but there are not a lot of members in that set,
are there?
DR.
ANTZELEVITCH: I agree. If we could go to AN8?
DR.
THROCKMORTON: Now, wait a minute. Before you go, so moxifloxacin you are
asserting now increases dispersion and supported to cause torsade so that I
guess the dispersion part I wasn't familiar with.
DR.
ANTZELEVITCH: Okay. If we could to go -- before we go to AN8, if
we could go to AN3? Thank you. This is the dose-response effect of
moxifloxacin in isolated epicardium and M cell preparations showing that there
is a remarkable effect of the drug, particularly at high doses, to prolong the
action potential of the M cell, but not
that of epicardium, such that this is the dose-response relationship in the M
cell and epicardium.
And
as a consequence, we see a dramatic increase in transmural dispersion of
repolarization. And this occurs at
concentrations of moxifloxacin that are 1 to 2 orders magnitude above the
therapeutic range. But yet, it's
sensitive enough to pick up a drug that perhaps produces torsade in one in a
million cases, that's the estimate today.
DR.
THROCKMORTON: Right. Okay.
The lower right hand panel is what you're talking about now,
Charlie. The control, if I see -- am I
reading those very small letters over there right? The control is 100?
DR.
ANTZELEVITCH: That's correct. These are isolated tissues.
DR.
THROCKMORTON: Right. No, I understand the difficulties.
DR.
ANTZELEVITCH: Yes.
DR.
THROCKMORTON: I'm just back to the 90
sand line.
DR.
ANTZELEVITCH: No.
DR.
THROCKMORTON: That you had said earlier
and I guess it's hard to have a line. I
mean, you're right. Isolated tissue,
it's got to be hard to do those kinds of things.
DR.
ANTZELEVITCH: Right. The threshold is different in isolated
tissues than it is in the wedge. Because
here the tissues are not electrotonically connected to each other.
DR.
TEMPLE: But you're really saying that
moxi, if you could test such a thing, would be torsadogenic at a rate of one in
a million. You don't think you know that
yet, do you? I mean, I don't even know
what the background rate for torsade is or would be.
DR.
ANTZELEVITCH: We've begun to do those
experiments in the wedge preparation, and we have one occurrence of torsade.
DR.
BELARDINELLI: I just want a moment to
expand a little bit on what Dr. Antzelevitch presented to you.
MEMBER
LORELL: That's interesting.
DR.
BELARDINELLI: First of all, our
conclusion that we will not expect ranolazine to cause torsade is not solely
based on the work done on the wedge preparation that you heard very elegantly
by Dr. Antzelevitch, include other preparations. Second point that I want to make to you is
for every condition that Charlie has used to induce torsade with terfenadine
and others the long exposures he tested equally with ranolazine.
I
think what we can safely say is that the axis that we use in their totality,
left ventricular wedge, the rabbit female isolated heart, and I should point it
out that in rabbit female heart, Dr. Luc Hondeghem from Belgium published in
March of this year that terfenadine causes EADs and causes ventricular
tachycardia in 13 percent of the hearts and cisapride was in 80 percent of the
hearts. We use exactly the same model
and conditions used by Dr. Hondeghem.
So
I think it's safe to say, therefore, that the sensitivity of the methods, the
axis and conditions that we use, that I readily use for this test, our axis are
sensitive enough that they would have detected the pro-arrhythmic signals of
agents such as you heard here, cisapride, moxifloxacin, terfenadine. No matter how difficult it is to induce these
arrhythmic signals with these other agents.
DR.
TEMPLE: Jeffrey, just one thing. Nobody I know thinks that ranolazine is
terfenadine, which, you know, causes a rate as high as anything if you inhibit
its metabolism. Nobody thinks that. The question is whether it is at some lower
level of risk that is still real. And I
don't know what to make of the moxi data.
We're not sure there are any human cases. There are some that are up for debate. So I don't know what to make of that.
And
the thing we've all been struck by, we actually have somebody working on this,
is that it's not easy to find out what all of the known human torsadogens do
with respect to all of these things.
We're not bad on some of the newer ones, but we don't really know much
about some of the older ones. And this
may all be absolutely true, but there's not a lot of human examples to base it
on it seems to me. I mean, it's a lot
about cisapride and terfenadine and that could be considered reassuring. I don't know what to make of mibefradil,
which we never thought was torsadogenic anyway.
So there's a fair amount of ambiguities.
I'm sure the future will lay all this out in a perfect way. A question for everybody to think about is
whether we know that yet.
CHAIRMAN
BORER: Can I ask, you know, I take it
that no one who has studied this drug believes that there is an important
potential interaction between drug and disease, that is ischemic disease, that
might be arrhythmogenic in an important way.
Before we let it go, I would like to hear from Peter or Jeremy or anyone
of your consultants who deal with this clinically about why you believe that
there isn't an important interaction in Craig Pratt Study, which was, you know,
a seminal study in the late '80s, alerted us to the importance of the drug
disease interaction when ischemia becomes acute. So I would like to know why we believe on the
basis of the data we have preclinical or clinical that there is no important
drug disease interaction here.
DR.
KOWEY: Jeff, it's a very tough question,
obviously, because the models that we use for the detection of the event that
we're all most concerned about, which obviously is torsade, does not
necessarily take into account ischemia.
And, in fact, the truth of the matter is I'm not aware of any database
in which that has been comprehensively studied.
There is a piece of clinical data that you might find interesting that
Andy will describe that has to do with the slope of QT and volunteers versus
patients with ischemic heart disease.
Andy, did you want to share that information? That might help you a bit, Jeff.
DR.
WOLFF: In the Population QTc Analysis,
the slope of the relationship between the changing QTc and the ranolazine
plasma concentration was the same in the healthy volunteers as it was in the
patients who had severe ischemic heart disease as exercise testing showed. And then the other piece of information, I
think, we've already look at was we just didn't see an increase in the
incidence of exercise induced arrhythmias when we were creating ischemia in
these patients and, in fact, it went in the other direction.
UNIDENTIFIED
SPEAKER: What about that slide?
CHAIRMAN
BORER: You know, if it's Slide CR-9 that
you're referring to, those slopes sort of look sort of like they are the same,
but they are not really the same. A CAD
subgroup actually I couldn't see, because it was underneath the red line at the
top.
DR.
WOLFF: Well, no, it's actually
underneath the white line for that.
CHAIRMAN
BORER: Oh, then I really couldn't see
it.
DR.
WOLFF: Yes. So actually the patients greater than the age
of 65 and with CAD actually have a slope that's somewhat lower than those
overall.
CHAIRMAN
BORER: Okay.
MEMBER
NISSEN: So let me just follow on that a
little bit with CS-5. Okay. And go ahead and put those limits on
there. And, you know, I was struck by
this, obviously, that even when you force levels to very high levels, nobody
goes more than 60 milliseconds above baseline.
Is that right? Okay. Now, let's look at CS-8. So these are normal volunteers, are they not?
DR.
WOLFF: Correct.
MEMBER
NISSEN: Yes, these are not
patients. Now, let's look at CS-8 and we
see that there are patients in the patient population that do go, you know, 14
in a thousand or 6 patients at 1,500. So
in terms of the outlier analysis, it looks like there is a difference
here. That in the normal volunteers, you
can push this dose to the level of toxicity and you can't get QTc to go up by
more than 60 milliseconds, but you can get it at therapeutic concentrations.
DR.
WOLFF: Well, I think that what's
important here that is not on the slide is the number of ECGs that this
reflects and the duration of exposure and time, so that, you know, the data on
placebo come just from the MARISA and CARISA placebo periods. The data on the other doses, excluding 1,500,
which isn't allowed in open-label treatment, are a combination of the
controlled data and the open- label data.
And so when we look at these outliers, we see outlier values not outlier
patients.
You
know, there is an occasional extreme value as you noticed from the 3111 data
plot, even on placebo. There is a range
of change from, you know, decreases to increases of around 16
milliseconds. So the measurement
oscillates quite a lot even under normal conditions. And so over time, you know, patients will hit
an outlier value, either an outlier change or an outlier absolute value, but no
patient has ever had the majority of their ECGs be an outlier. And, in fact, the majority of patients who
had had ever an outlier had one single outlier value out of all their ECGs.
UNIDENTIFIED
SPEAKER: That's a good point.
CHAIRMAN
BORER: Okay. Peter, is that the conclusion of your
response?
DR.
KOWEY: I think Jeremy.
DR.
RUSKIN: May I add a comment, Jeff?
CHAIRMAN
BORER: Yes, please.
DR.
RUSKIN: To this question about the
potential for a drug interaction here?
CHAIRMAN
BORER: Please, do.
DR.
RUSKIN: Because I think it's an
important question and very difficult to answer. I just wanted to add one potential comment and
that is that there is from a mechanistic standpoint, this would not be a class
of drug in which you would expect an interaction with ischemia. For example, IKr blockers like d-sotalol are
used routinely in the setting of ischemia and are safe. And even a drug like dofetilide, which is a
potent IKr blocker and known to cause torsade, has a neutral mortality effect
when studied in a post MI population.
The
drugs that have been clearly proven to be dangerous are the sodium channel
blockers, whose ECG signature is QRS prolongation. And there is no signal, based on the profile
of this drug, that would put it into that category, and that's about as close
as one can get, I think, to addressing that question.
CHAIRMAN
BORER: Is that true despite that fact
that if I remember correctly this does block sodium channel as well as
potassium channel or have I misunderstood?
DR.
RUSKIN: The late sodium channel, but
doesn't affect the upstroke. It doesn't
affect the fast inward sodium current.
DR.
BELARDINELLI: Correct. Ranolazine is a quite selective late INa
inhibitor has little effect on peak INa in concentrations to produce, decrease,
to rate or rise with the actual potential which will give an indication of the
peak INa. You have to go to 50 to 100 micromolar.
CHAIRMAN
BORER: Jeremy, I'm remembering QRS
prolonged widening, and I don't remember in what study, but it would have been
a preclinical study, is my guess. I seem
to remember QRS widening seen in one of the models.
UNIDENTIFIED
SPEAKER: It's a tiny bit of inhibitor,
INa.
DR.
WOLFF: Yes, in MARISA and CARISA, the
QRS interval, I mean, because we've -- especially in MARISA with the crossover
design has such sensitivity, it does increase slightly. It's less than 1 millisecond or at about 1
millisecond at 1500. I don't know if we
have -- we do. We'll show it in a moment
here.
DR.
THROCKMORTON: And start with different
from what you would see with the sodium channel.
DR.
WOLFF: Yes. Okay.
Let's project that. There you
go. There is the data on that, on a QRS
interval for MARISA and it actually, you know, is a matter of here, for
example, at peak. This is 2
milliseconds. At trough, this is 0.6
milliseconds. It's not statistically
significant at 1500. It's marginally
significant at 1.3 milliseconds and then it is significant at 3 milliseconds.
DR.
THROCKMORTON: You must have looked at
that in the infusion study as well, which would have had less random collection
of ECGs. Do you know what it showed
there? I don't remember.
DR.
WOLFF: I believe there were similar very
small on the order of a millisecond change.
DR.
THROCKMORTON: All right. So right.
There is an effect on the QRS. It
seems very small. Well, I guess that
would probably be the more appropriate way to characterize this effect rather
than there is nothing here.
DR.
WOLFF: Sure enough. But in order of magnitude below what you
would see with the Class 1A or C drugs certainly.
CHAIRMAN
BORER: Alan?
MEMBER
HIRSCH: Well, just one more question
regarding things that might potentiate this arrhythmia is I couldn't quite tell
from the patient populations how many individuals had structural heart disease,
known LV dilation, etcetera.
DR.
WOLFF: We characterized the patients
presence or absence of congestive heart failure clinically only. And so in the Phase 3 trials we excluded
patients with Class 3 or 4 congestive heart failure. And so in the thousand plus patients in the
Phase 3 clinical studies about a quarter of the patients had a history of
congestive heart failure, but we didn't measure their ejection fractions or
anything quantitative.
CHAIRMAN
BORER: Ed, I was waiting for you to
weigh in here.
DR.
PRITCHETT: Yes, Andy, I want to go back
to some of the clinical observations you made about syncope. And you implied, you know, I guess, I think,
you know, to me syncope is loss of consciousness accompanied by loss of
postural tone. You fall down because
your head doesn't work. And in the
infusion studies, syncope was reported.
These were normal volunteers who were hooked up to an ECG machine lying
down in bed with an IV running into them, and yet something happened that was
reported at syncope. What on earth was
that? I mean, what did the people who
were there describe? Not what did it map
to in a med return.
DR.
WOLFF: No, I understand.
DR.
PRITCHETT: What really went on there?
DR.
WOLFF: I think my colleague, Dr. Markus
Jerling, was primarily responsible for this trial, and so he was the one in
direct contact with the investigators. I
think he is in best position to describe just what you're asking.
DR.
JERLING: Thank you. I'm Markus Jerling, clinical pharmacologist
at CV Therapeutics. It is true that
these patients had or subjects had in the continuous infusion, they had also continuous
monitoring ongoing. We still attempted
to take erect blood pressure. They still
had to go to the bathroom. And every
single thing occurred in the erect or the sitting position. And what typically happened was that they
already had, I would say, quite manifest systems of nausea, but this was a
study where both we and the side tried to push it a bit.
And
a typical event can be when someone was then up for an erect blood pressure and
then they develop this syncope as well.
We had one index case actually where also we had a reduction in the
vigilance and since it started to become known in the trial there was a
neurologist onboard as well who confirmed that this was associated then with
nystagmus and other CNS effects, so it seems to be a combination of CNS effect
that this real high concentration and then the postural situation.
DR.
PRITCHETT: And the ECG monitoring at the
time this occurred wasn't bradycardia? I
mean, these patients, at the time this happened, were having vasovagal?
DR.
JERLING: Yes, when they actually then
developed the vasovagal, it wasn't the bradycardia, but immediately prior to
that, no.
DR.
PRITCHETT: No.
DR.
JERLING: So you didn't typically see
reduction in heart rate all the time, but it was when the very event occurred.
DR.
PRITCHETT: Okay. Now, what about the patients? There were several patients in CARISA who
were reported to have syncope. What was
that? I mean, what do we know about
those events? Andy, do you know?
DR.
WOLFF: I think probably the most
instructive overview of the 38 patients, who had syncope, can be made by
Professor John Camm. He has had an
opportunity to review all of them in some detail. And I think his opinion of what is going on
is as instructive as we'll be able to get.
DR.
CAMM: Dr. Borer, ladies and gentlemen,
John Camm from London in the U.K. I have
had the opportunity at looking at the 38 patients who are reported in the
ranolazine dossier. What I have been
able to do is look at the narratives.
The narratives are not always complete by any means and they are not
totally instructive. But what I can say
about it is that of the 38 patients, 15 occasions were clearly situational
reflex orthostatic. And in two of the
cases where there wasn't sufficient information to really judge that myself, at
least the verbatim records suggested vasovagal reactions. So that is 17 out of 38 instances.
There
were several instances in which syncope occurred against the background of an
arrhythmia. In several instances, two I
think, it was described as sinus node disease.
It may well have been due to co-medications such as beta blockers and
calcium antagonists and such like, but there is very little detail, other than
the comment that the investigator felt that sinus node disease might be
responsible. There were two instances in
which there was a recording of ventricular arrhythmia.
In
one case, syncope was said to occur and it was a non-serious event due to
ventricular fibrillation, which the investigator felt was serious. It was in the setting of an acute coronary
syndrome and quite clearly is an ischemic induced arrhythmia, not a polymorphic
ventricular tachycardia like torsade.
The second instance was a case where ventricular tachycardia occurred
and this was related to an acute myocardial infarction which had occurred some
five days previously. This was a
monomorphic arrhythmia.
In
both of those instances, there are electrocardiograms recorded either before or
after the event, which clearly don't show any marked QT prolongation, so they
don't seem to be torsade related arrhythmias.
There was one instance in which a patient had syncope when he had atrial
fibrillation, and the QT was measured at this time, and was reported as 521 milliseconds. In fact, this is the only instance where
syncope occurred in someone with a QT interval over 500 milliseconds.
This
patient was taking propafenone at the time, and what part that played in the
prolongation of the QT interval, I don't know.
But when the patient was back in sinus rhythm and off the propafenone
but still on the same dose of ranolazine, the QT interval was back in the
normal range at 300-something milliseconds.
DR.
PRITCHETT: Did you see the ECG of atrial
fibrillation?
DR.
CAMM: No, I didn't see the ECG. I have looked only at the narratives.
DR.
PRITCHETT: I see.
DR.
CAMM: So I didn't see the
electrocardiogram, but there was a little bit more information. They said the patient had atrial fibrillation
and atrial flutter. He was taking
propafenone. My own feeling was it might
well have been intermittent increase conduction to the ventricals that was
causing this problem, but there wasn't a smack of torsade about that particular
case. Now, those are the only cases where
an arrhythmia is mentioned in the storyboard of these 38 patients.
Steve's
question this morning about glycerol trinitrate involved me looking back
through the narratives during the break this morning to see exactly how many
patients that might apply to. There were
-- I found 14 patients of the 38 where glycerol trinitrate was listed in the
co-medications, and you've already heard Andy Wolff's description of how many
of them were taking other vasodilator compounds.
In
only one instance is there a clear story that the patient took two puffs of
glycerol trinitrate and within a minute or so had collapsed with a syncope
event. There is another instance where a
patient was wearing a nitroglycerin patch that might have contributed to the
syncope as well, but that was a protocol violation. So there remains, of course, a number of
cases where we have precious little information about what causes syncope. But looking at the dossier as a whole, the
one thing that you don't get from it is the impression that QT prolongation
non-sustained ventricular tachycardia torsade, etcetera, is part of the
story. It just doesn't emerge at all.
DR.
PRITCHETT: Okay. Can I ask another question?
CHAIRMAN
BORER: Yes.
DR.
PRITCHETT: Something flew by about
patients with hepatic disease and the slope of the concentration QT interval
curve. Can we see those data again? I mean, it looked like a striking outlier.
DR.
WOLFF: It is. The only population that we have identified
that has a steeper slope than the others and it's about 7 milliseconds a
thousand.
DR.
PRITCHETT: Compared to 2.4.
DR.
WOLFF: Compared with around 2.4 and
everyone else.
DR.
PRITCHETT: And can you elaborate on what
you think is going on there? I mean, can
you explain that based on the way those data were collected in those patients
or the study?
DR.
WOLFF: Well, I'm going to ask my
colleague, Dr. Sam Lee, to come to the podium and talk about QT measurements in
patients with clinically evident liver disease.
But we do know that their QTs start out longer and we don't know of any
other data that we can find about the drug response to QT prolonging drugs and
cirrhosis. This is what we found.
DR.
PRITCHETT: Do you have the slide that
has those data on it? Can you just put
it up?
DR.
WOLFF: This isn't the one I showed. Can we just show the slide form the core
presentation, please? There we go.
DR.
PRITCHETT: But just help me
understand. The patients with hepatic
impairment was that a special study that you did, you know, pharmacokinetics?
DR.
WOLFF: Yes, it was.
DR.
PRITCHETT: It was.
DR.
WOLFF: Yes, it was.
DR.
PRITCHETT: So those weren't patients out
of CARISA, for instance?
DR.
WOLFF: No, they weren't. These were patients with very clinically
evidence hepatic disease, either mild or moderately impaired, and they all had
signs and symptoms of obvious hepatic impairment. Dr. Jerling could actually describe those
occasions.
DR.
PRITCHETT: Well, I mean, what was the
study? I mean, the slope?
DR.
WOLFF: The study was a study that was
done to look at the pharmacokinetics of ranolazine in patients with hepatic
impairment, which I think you know you would do in any drug development program
for chronical therapy. And as we always
did throughout the program, we collected frequent ECGs and had them read at a
single core laboratory in order to try as best as we could to characterize this
effect. And it is only when you put the
hepatic patients into the population analysis, as the Agency did, that they
fall out as a population with the separate slope of about 7 milliseconds per
1000 nanograms per mL.
So
I think the observation we agree with, the meaning of it is a little tougher to
sort out. As I said before, Dr. Lee will
comment. Patients with cirrhosis have
longer QTs, whether their response is more prominent to the effects of QT
prolonging drugs, we're not able -- we searched the literature. We can't find any similar kind of study.
DR.
LEE: I'm Dr. Sam Lee. May I have 411, please. I think it underscores that we know
relatively little about how the heart functions in people with cirrhosis, but
what we've discovered over the past 15 or so years is that despite a
hyperdynamic circulation in increased cardiac output at baseline in patients
with cirrhosis, they have a blunted systolic and diastolic contractile response
to various stimuli and about almost half have a prolonged QT interval.
However,
there has been no increased risk of torsade de Pointes, at least in the world
literature up to now, in patients with cirrhosis in the absence of a known
torsadogenic event, such as hypokalemia.
And if the Committee wants to be bored, I'll be happy to elaborate on my
research on mechanisms of this effect.
DR.
PRITCHETT: I think that covers it on
that capacity. What you have told me is
what we know.
DR.
CAMM: Thank you.
CHAIRMAN
BORER: It is 12:05. We'll have a break now so that people who
need to check out can do so. We're not
going to take a formal lunch break.
We'll come back here at 12:30 and get started again. And at 1:00, we'll take a moment to ask for
public comment and then we'll finish.
We'll take the remainder of the afternoon to complete the evaluation
with questions and the FDA advisory questions.
(Whereupon,
the hearing was recessed at 12:06 p.m. to reconvene at 12:35 p.m. this same
day.)
A-F-T-E-R-N-O-O-N
S-E-S-S-I-O-N
12:35
p.m.
CHAIRMAN
BORER: Let's begin with the questions
that we didn't handle before the break.
There was one from Tom Pickering and one from Ron Portman and then maybe
some others. Tom, why don't you start?
MEMBER
PICKERING: Okay. I wanted to return to this question of the
syncope. This morning we heard that it
is not a drug that lowers blood pressure and yet the syncopal episodes, I
think, are being attributed to postural hypotension, which in turn are being
attributed to alpha-1 blockade. And I
think you said that the incident is similar to that is seen in alpha-1
blockers. But alpha-1 blockers, in
general, lower blood pressure in a predictable way and so, there seems to be
some disconnect there if this is not an antihypertensive drug.
And
one of the other things about alpha-1 blockers is that you get a first dose
effect whereby you may get a very marked reduction after the first dose that is
not seen in subsequent doses. So, one
question I would have is have you looked to see if there is a first dose effect
and are you sure that the syncope is due to postural hypotension and vagal
bradycardia?
Also,
in the younger patients, I think, in Table 59, 58, I'm sorry, you report 11
cases of syncope in the young, healthy people, but by my reading only 5 of
these were on what you might call mega doses with plasma levels above 2000 or
on doses, oral doses above 1500. So, it
looks as though it occurs within the proposed therapeutic range.
DR.
WOLFF: If I could have this slide,
please? Here you see the data from a
Controlled Overdose Study, CVT 3111, and you see the incidence of nausea and
vomiting in the pink bars, dizziness in the blue bars and then postural hypotension
as the target plasma concentration by infusion was increased. And you can see there is a fairly clear dose
related effect in these healthy volunteers.
On
the next slide, this is from a study in which we were evaluating 1500
milligrams twice a day and 2000 milligrams twice a day, and it really should be
noted this is bid and it's steady-state.
And you can see that as you get to the higher plasma levels, which here
is around 7500 on 2000 milligrams twice a day, something over 5000 nanograms
per mL at 1500, the orthostatic blood pressure change does increase or, in
other words, there is a bigger change in orthostatic blood pressure upon
standing.
The
fact of the matter is these concentrations are well above where the therapeutic
range is, which is, you know, more down here between around, let's say, 825
nanograms per mL. So when you look at
the pharmacology data as well, you do begin to see the alpha-1 adrenergic
blockade IC-50s occurring at concentrations that are here and above. So, the clinical observation really does fit
with the preclinical pharmacology that at the lower end of the dose range we
wouldn't expect to see any alpha-1 blockade.
And as you go up to higher concentrations, you would then potentially
see some effects consistent with alpha-1 blockade.
The
reason why we don't see first dose syncope, I believe, is because we've never
given a first dose that is sufficiently large to get into the alpha blocking
concentrations.
MEMBER
PICKERING: But what about in the table,
as I said, there are several subjects who appear to be not on large doses.
DR.
WOLFF: Well, I think Professor Camm
reviewed them. And can we see the table,
please? The table that you're asking
about.
MEMBER
HIRSCH: Well, might you overlay the
syncope out of the dose response that you had earlier?
DR.
WOLFF: So, this is part of that
table. I think as we get down to most of
these 11 volunteers that had syncope had a very situational component to it. I think Professor Camm has spoken to
them. You know, they are often with
respect to defecation or urination and so forth and so on.
MEMBER
PICKERING: There's another part to that
table.
DR.
WOLFF: Can we go forward? So, erect vital signs with a single dose of
342 milligrams, that shouldn't have produced very high plasma concentration. So, they do appear in large part, as I have
showed you on the first slide, to be related to dose and plasma
concentration. It's also just not an
uncommon event, and we have observed it at other concentrations. But, I think clearly the incidents do get
higher as you go up on dose.
Here
is another look at this issue. If we can
have this slide, please? Okay. This is a Kaplan-Meier plot of syncope on
1500 milligrams twice a day, 1000 milligrams twice a day, and then placebo and
750 and 500 in the IR doses. And I think
this shows part of why we don't want to use the 1500 milligram twice daily
dose, and also why we recommend not starting at 1000 milligrams. If you are randomized to 1000 milligrams, we
do see a very clear incidence of syncope that is less than on 1500 and
separates away from the other doses.
So,
if you think about the controlled clinical trials 5 cases of syncope occurred
in CARISA in patients who were randomized directly to 1000. The other three were in patients who were,
you know, forced to 1500 as part of the study design. I believe this slide indicates that if you
start dosing at a low dose as we presently propose and then titrate carefully
out this, this is a problem that can largely be avoided.
MEMBER
PICKERING: Do you have any blood
pressure measurements if you start at 500 bid, you know, supine understanding
blood pressures?
DR.
WOLFF: Yes, we do. There is very little change at 500 milligrams
twice a day in blood pressure, neither supine nor erect.
CHAIRMAN
BORER: Ron?
MEMBER
PORTMAN: Can we see Slide CR-5,
please? What I note that is missing from
these comorbidities is chronic kidney disease.
There are about 14 million people with a GFR less than 60 in the
country, and with all the electrolytes and hemodynamic problems that these
patients have, this drug could have some potential benefit for them. So, my question is how many patients with CKD
have you studied so far?
DR.
WOLFF: I'm sorry, how many patients
with?
MEMBER
PORTMAN: With chronic kidney disease.
DR.
WOLFF: The most definitive study was the
Clinical Pharmacology Study which I'm going to ask my colleague, Dr. Markus
Jerling, to describe. We didn't have a
large number of patients with very significant renal disease in MARISA or
CARISA, because, you know, they were excluded.
But we do know that it is important to understand the kinetics and
dynamics in those patients. And so Dr.
Jerling will talk about what we learned there.
DR.
JERLING: Yes, if we can start to look at
the pharmacokinetics in the special PK Study, rural regression plot. So this was a pharmacokinetics study with
mild, moderate, severe renal impairment and matched controls, according to the
guidance by the Agency. And we were
interested here in the steady-state kinetics of ranolazine as a function of
GA4. And this is the outcome of the
study. We see the oral clearance, which
will then be inverse to the concentration you achieve at the specific dose, as
a function on creatinine clearance.
The
boundaries are as defined by the guidance.
And we saw, more or less, linear reduction in oral clearance with a
reduction in creatinine clearance in the study.
And when calculating the difference between the boundary of moderate,
severe up to normal, the increase in concentration is about 80 percent in this
population. We actually looked in the
MARISA and CARISA combined for renal function as predicted by the
Cockcroft-Gault formula.
There
weren't any specific measurements done in a more precise way. And there were patients down to the high 20s
and the low 30s. Not very many, though,
but that's a function of the patient population. So in the pharmacokinetic analysis we did in
a combined way, a PK analysis. We
actually did not find any relationship.
The reason is most probably that the number of patients with more severe
impairment were too few to pick it up.
But I think it is fair to state that the reduction in clearance in
patients was not more pronounced than what you see in this special study.
MEMBER
PORTMAN: Is this data enough to be able
to give dosing guidelines for nephrologists who deal with these patients at the
different degrees of renal impairment?
DR.
JERLING: Yes, we believe so. This is conducted in terms of both design and
number of the patients according to the guidance. And what we have said that when you read
severe impairment, you should start with a lower dose and the dose range should
also be lower.
MEMBER
PORTMAN: And in the few patients in
MARISA and CARISA that you did have, was there any difference in efficacy or
safety issues in the CKD patients?
DR.
JERLING: I can first talk to the
population efficacy analysis. We did not
include renal impairment as a factor.
However, since concentration was the driving factor, if it would only be
related to change in the concentration, then you would predict actually to get
the more efficacy.
DR.
WOLFF: And we don't have a special
analysis of the adverse events divided by patients with some degree of renal
impairment and not. Markus, can you
speak to the tolerability though in these patients in the special study?
DR.
JERLING: Yes. The dose selected for this study was 500
milligrams bid with an initial dose of 875 just to reach a steady-state a bit
faster. We selected a dose at the lower
range, because we didn't, at the time, know to what extent it would be
related. And the adverse event profile
was, I would say, similar to what we have seen at 500 bid in other populations
at similar concentrations.
One
effect that fell out was a slight increase in creatinine by about 10
percent. We have conducted a special
study and found that it seems to be related to the tubular secretion, an
inhibition to the secretion of creatinine that was fully reversible.
MEMBER
PORTMAN: Okay. That's interesting. One last question. What do we --
CHAIRMAN
BORER: Hold on a second.
MEMBER
PORTMAN: What do we know about this drug
for patients on dialysis? Is it
dialyzable? And its protein binding?
DR.
JERLING: We have not conducted a study
on that. We did not include such
patients in that particular study.
Protein binding is around 60 percent.
They test quite wide volume of distribution, so I would expect that
dialysis would not be very efficient in this case.
CHAIRMAN
BORER: Paul and then Doug.
MEMBER
ARMSTRONG: Jeff, I would like to start
off by complementing Dr. Wolff and his colleagues for a very lucid presentation
of a very comprehensive data set. I want
to go from the kidney to the liver, as I'm sure others will. I've seen and heard a lot about mild and moderate
hepatic dysfunction, but I haven't seen those defined. So I would like you to just define those
parameters. And I would like you to help
me with, I can envisage using this drug if it were approved, and certainly
using it in patients who would be on a statin with some degree of hepatic
congestion and heart failure.
And
the issue about the statin effect on the liver and hepatic congestion and then
trying to apply your information to those types of patients would be helpful to
hear some discussion around that point.
DR.
WOLFF: Well, I think to describe more
specifically the clinical characteristics of the patients with mild and
moderate hepatic impairment that we studied, I'm going to ask Dr. Jerling
again, because he was responsible for that part of the program.
DR.
JERLING: Yes. If I may receive the slide with the
pharmacokinetic parameters from the hepatic study, please? So, we conducted a study fairly much the same
design as the renal study, again according to the guidance by the Agency in patients
with mild and moderate hepatic impairment, classified according to the
Childe-Pugh classification. And the
matched controls are included, as well.
These are steady-state data also at the 500 bid dose.
And
we see that patients with mild impairment had pretty much the same PK
parameters as the controls. So it
doesn't seem that mild impairment would really translate into a pharmacokinetic
consequence. Patients with moderate
impairment had an increase by approximately 80 percent in concentration, and
that is true both for peak concentrations and for UC. And given that ranolazine is almost
completely metabolized, it's really compatible with the reduction in functional
mass. Hepatic blood flow wouldn't really
contribute very much. This is not a high
excretion drug. Suggested reduction of
functional mass would explain this finding.
MEMBER
ARMSTRONG: How would I, as a clinician,
identify mild hepatic impairment? What
would you suggest to me in terms of using the drug in that definition?
DR.
JERLING: I believe that's a perfect
question for our expert, Dr. Lee, to respond to.
UNIDENTIFIED
SPEAKER: These patients with clinical
impairments.
DR.
LEE: In this study, all these patients
had clinically evident cirrhosis, so Child Pew A and B, I think, and certainly
anybody in a Child Pew Class B would have either very obvious ascites, jaundice
or encephalopathy, something fairly obvious that the mild impairment the Child
Pew Class A it's undeniable that there will be a very few that have no obvious
clinical detectability, either by symptoms, physical exam or liver chemistry.
Now,
these patients were obvious clinically, but in the "real world" there
are going to be a few people pop up and I would only suggest that a careful
history, standard liver chemistry panel and if any doubt, perhaps an ultrasound
or maybe consultation with your friendly hepatologist might be the way to
go. How did I know a person from
Edmonton would give me a hard time?
Sorry, private joke.
DR.
WOLFF: I think the important point was
that the patients in the trial had clinically evident hepatic disease. They didn't just have elevated transaminases
or something like that. They had clear
liver disease.
CHAIRMAN
BORER: Doug?
DR.
THROCKMORTON: I'll try to remember
"friendly hepatologist" for labeling maybe. That sounds like that would be good. I had a question actually back a couple. One, Dr. Portman, the Agency looked at
whether there was an interaction by creatinine clearance with QT. To ask a sort of question that goes along
with hepatic impairment, is there a by disease interaction there as well? And we didn't identify one, so, in a sense
that is a good thing.
The
second thing though is I want to pick up on is something Dr. Pickering said,
which, I have to say, had not occurred, which is not uncommon from Dr.
Pickering, there were some things I missed.
Alpha blocker interactions. I
mean, we talk about -- this is all the way back to syncope now, Dr. Wolff. We're talking about interaction that at some
higher doses, there is syncope that is mediated by an alpha adrenergic sort of
effect. I'm sure we don't have any
information about concomitant use with other alpha blockers. I don't know.
DR.
WOLFF: Actually, we do and actually, it
was one of the more increased co-therapies among the 37 patients who had
syncope on ranolazine. You can see that
2 percent of the patients overall were taking an alpha-1 blocker, but 14
percent of the patients who had syncope were.
I mentioned these data before, but we can look at them now.
There
was a rough, you know, doubling in the incidents in the patients who had
syncope and the use of long-acting nitrates, of ACE inhibitors, of calcium
channel blockers, including diltiazem.
Maybe a slightly greater percentage of patients on beta blockers and
diuretics. So drugs that are known to be
associated with syncope were more commonly used in the patients who had
syncope. And if we look at the
distribution of the number of drugs among those patients --
CHAIRMAN
BORER: Before you do that, what are
those percentages? Are they percentages
of the total number of people who fainted or the total number of people who
were taking that drug?
DR.
WOLFF: This means, for example, that 30
of 37 of the patients exposed to ranolazine who had syncope were taking
nitrates for a percentage of 81 percent.
And this, over here, would mean that 71 percent of the overall
population. But nitrates is all
nitrates, and so all the patients were taking sublingual nitroglycerin in the
course of the trial. So these are column
percentages based on the N up here, and the N up here.
And
then here is the distribution of the number of these different vasoactive
medications that were being taken by the patients who experienced syncope. This one includes the one on placebo, as
well, and you can see that about a third were taking two vasoactive
medications, and then another third were taking three or more vasoactive
medications. And if we just compare the
incidence of syncope that we have observed on ranolazine to what is reported in
the literature for other known alpha-1 or alpha-1 beta blockers, it's roughly
comparable.
CHAIRMAN
BORER: Okay. I'm going to open the meeting to public
comment now for a moment, if there is any.
For that purpose, let me read this guidance.
"Both
Food and Drug Administration and the public believe in a transparent process
for information gathering and decision making.
To ensure such transparency at the open public hearing session of the
Advisory Committee meeting, FDA believes that it is important to understand the
context of an individual's presentation.
For this reason, FDA encourages you, the open public hearing speaker, at
the beginning of your written or oral statement to advise the Committee of any
financial relationship that you may have with the sponsor, its product and, if
known, its direct competitors.
For
example, this financial information may include the sponsor's payment of your
travel, lodging or other expenses in connection with your attendance at the
meeting. Likewise, FDA encourages you at
the beginning of your statement to advise the Committee if you do not have any
such financial relationships. If you
choose not to address this issue of financial relationships at the beginning of
your statement, it will not preclude you from speaking."
Now,
is there anyone here who wants to make a statement about the matters at hand
today? If not, we'll proceed with the
meeting. Steve?
MEMBER
NISSEN: Okay. First of all, let me add to, I think, several
people's comments that I thought that the presentation today was very lucid and
I really appreciated the care with which the sponsor prepared today. We got really a lot of information succinctly
presented. It made our job a lot
easier. So I don't have as many questions
as I might have. In fact, the Committee
actually asked many of them that I was going to ask, but I have a few.
I
wonder if someone could tell me about 2D6 poor metabolizers. I know this compound is partially metabolized
by 2D6 and we know that some portion of the population is 2D6 poor
metabolizers. What do we know about
those people?
DR.
JERLING: Yes. We have conducted a long interaction study
with paroxetine and that will highlight this, and as shown in what Dr. Wolff
presented previously, the increase in concentrations of ranolazine was 23
percent. And we actually added another
test in that study to confirm what happened.
We didn't genotype, but what we did in the study was to phenotype in the
dextromethorphan test. So it was done on
three occasions. First, at baseline and
these were healthy volunteers. Second,
at steady-state ranolazine and third, at steady-state ranolazine plus
paroxetine. Paroxetine is a potent
CYP2D6 inhibitor. For obvious reasons,
we didn't select quinidine in this study.
And
what we found was that there was a certain shift on ranolazine only, but not to
the extent that anyone turned into poor metabolizer as defined by the
phenotype. But when we added paroxetine,
all but one became a poor metabolizer.
And that means that the situation in this study would mimic a situation
where you have a genotypically poor metabolizer, and then you saw an increase
by 23 percent of the ranolazine concentrations.
MEMBER
NISSEN: Okay. That's actually helpful. You mentioned that, obviously, you didn't do
the study with quinidine, but it was a question actually, my next question on
my list, which is to help you understand where, I think, many of us on the
Committee are at is you have presented preclinical data that tend to be reassuring. The QT prolongation data tend to make us
worry.
And
so we want to explore as much as we can about what you know about what happens
when you give this drug along with other agents. And so, you know, patients with chronic
coronary disease, some of them may be on anti-arrhythmic drugs. And so what I want to try to understand is:
what happens, what happens if you give ranolazine to a patient that is on an
anti-arrhythmic agent that might, in and of itself, have some effect on QTc?
DR.
WOLFF: Well, with respect to Type 1
anti-arrhythmic agents, which I think would be what you're largely concerned
about, we excluded them from the Phase 3 clinical trials, so we didn't really
have the developed understanding of the cellular electrophysiology at the time
we were beginning those trials that we now have due to the efforts of Dr.
Belardinelli and his colleagues.
So
we really don't have direct clinical experience, and then we would have to rely
on the preclinical data. The preclinical
data actually would suggest, for example, that somebody who had a very long QT
on sotalol might experience shortening with ranolazine, but those data don't
exist at this point. And so our proposed
labeling currently would be to caution against the use of one QT prolonging
drug with ranolazine. I don't believe I
have ever seen a study done with any two QT prolonging drugs together to
understand what happens clinically.
MEMBER
NISSEN: Well, but on the other hand, you
have made the case here that the QT prolongation that ranolazine produces is
not clinically important.
DR.
WOLFF: That's our position. That is very different from what is seen with
drugs that cause torsade.
MEMBER
NISSEN: I mean, obviously, you know, we
have to think about the population that's likely to get the drug and, you know,
I must tell you that one of my obvious concerns is that when drugs get out in
the general community, you know, even when you put things in the label, people
have a tendency to give drugs together, anyway, and there are certainly a lot
of people out there on drugs like quinidine.
And
so, you know, it seems to me at least in some sense, it would be reassuring to
know that there isn't some incredibly important interaction that occurs when
you give a patient with coronary heart disease an anti-arrhythmic drug along
with ranolazine. But I take it that
there is no data, so we can't really answer that question.
DR.
TEMPLE: Steve, for other drugs that have
been developed with modest QT prolonging, the labeling all says don't take any
other drugs that prolong the QT interval.
Whether that's remotely realistic or not, I don't know, but they all do
say that.
MEMBER
NISSEN: And nobody ever does, right?
DR.
TEMPLE: But we really don't know. As he said, we don't know whether the effect
is additive, superadditive, inhibitive.
We just don't know.
MEMBER
NISSEN: Right.
DR.
TEMPLE: With any data we have ever seen.
MEMBER
NISSEN: Okay. Fair enough.
Just, you know, again in terms of my understanding of this, I needed to
ask that question.
DR.
TEMPLE: But there is no question that
the use of ranolazine would be very large if it could reverse the bad effects
of dofetilide, sotalol and other drugs, which we could name.
MEMBER
NISSEN: Yes.
DR.
TEMPLE: It's worth --
MEMBER
NISSEN: Yes.
DR.
TEMPLE: Just a little advert, it's worth
taking a look at that.
MEMBER
NISSEN: It did actually occur to
me. It also occurred to me that a drug
that lowers the hemoglobin A1c by 1 percent might have some potential clinical
utility, as well, but we won't go there.
DR.
KOWEY: Steve?
MEMBER
NISSEN: Yes.
DR.
KOWEY: I'm sorry. Peter Kowey.
MEMBER
NISSEN: Yes.
DR.
KOWEY: It's even more complex, because
what we also don't know is if you were to reverse some of the QT prolonging
effects with ranolazine of a drug like dofetilide or sotalol, whether you would
still preserve efficacy of those drugs for the indication you were using
them. So not only do you have to look at
the safety side, you would also have to look at the efficacy side. So, it's a fairly daunting task, but not one
that isn't interesting scientifically.
MEMBER
NISSEN: Yes, and of clinical
relevance. I mean, I think, you know,
the chances that this drug would get out in general use, given the millions of
people we heard have angina, and never have it be given to a patient that's
also on some anti-arrhythmic drug, I mean, the chances are zero. I mean, somebody is going to get this drug
who is on quinidine, and so my argument would be the more we know about that,
the better off we are.
DR.
THROCKMORTON: Yes. And just to follow on that, you will be asked
sort of explicitly to sort of be ready to comment on things like that, but this
might be a case, an argument might be made that this drug is behaving a little
differently than the kinds of drugs that we have typically seen in the past,
places where, as has been pointed, we have typically not seen interaction
studies. Although, there is a study
ongoing as a part of a Phase 4 commitment to, in fact, look at an interaction
with two drugs like this. Peter is
smiling. I'm sure he'll be delighted.
DR.
KOWEY: No, that's exactly what I was
going to say.
DR.
THROCKMORTON: But the issue here is you
have another interaction. You have an
interaction by disease that is unprecedented.
As everyone said, we don't -- we haven't seen that before. We have seen an interaction with gender, with
quinidine. An interaction by disease of
this magnitude, maybe we haven't looked hard enough, something like that. It just hasn't been seen. I don't know what that does to your level of
assuredness. Does that tip the balance
for needing additional interaction studies in this case? And you will help us out with that a bit
later on.
MEMBER
NISSEN: I will indeed. You know, it's interesting. We heard about the term "friendly
hepatologist" and actually, the term "friendly cardiologist" is
actually an oxymoron.
UNIDENTIFIED
SPEAKER: That's harsh.
MEMBER
NISSEN: It's tough, but it's true. I also want to explore with you another
area. I mean, I am very interested in
understanding better the drug-drug interaction potentials here, and so I wonder
if you could put up the slide. There is
a nice slide that shows various doses of diltiazem and the sort of drug-drug
interactions. You got a variety of drugs
on that slide, and I think you know which one.
DR.
WOLFF: From the core presentation?
MEMBER
NISSEN: Yes, from the core presentation,
exactly.
DR.
WOLFF: Here we go.
MEMBER
NISSEN: Okay. Now, you know, it's interesting, because you
did some studies with, I think, diltiazem 180 milligrams. Wasn't that your comparitor in at least one
of your --
DR.
WOLFF: It was the background treatment.
MEMBER
NISSEN: Yes.
DR.
WOLFF: In CARISA.
MEMBER
NISSEN: Yes, that's right. Okay.
But, you know, it's actually interesting and I would be interested in
the other Panel members, but I see a lot of patients on 240 and 360 milligrams
of diltiazem. Now, the 360 milligram
dose of diltiazem increases. Is that
peak concentration? Is that correct?
DR.
WOLFF: I believe it is.
MEMBER
NISSEN: Or AUC?
DR.
WOLFF: Markus, can you?
MEMBER
NISSEN: And what are the numbers on the
right?
DR.
WOLFF: These numbers are the fold
increase compared to ranolazine as monotherapy.
MEMBER
NISSEN: Yes, yes.
DR.
TEMPLE: So they are the same numbers
that are on the bottom, because they are not?
I mean, look, push 1.5 up and it's not where -- and it's where 1.2 is.
MEMBER
NISSEN: Within the limits of
slide-making, I mean, Bob, gee, give them a break here. I mean, I actually know the people who are
making the slides here. They are pretty
good, you know.
DR.
TEMPLE: Well, it has been bothering me
for a half hour.
MEMBER
NISSEN: All right. Well, if I may pursue this a little bit. Okay.
Now, the dose range that you are recommending here is 500 bid up to 1000
bid. Isn't that right?
DR.
WOLFF: Except in patients receiving
doses of diltiazem larger than or equal to 240 milligrams a day or doses of
verapamil at 360.
MEMBER
NISSEN: And what would you recommend for
those?
DR.
WOLFF: Starting at 375 and stopping at
750.
MEMBER
NISSEN: I see. So the formulations you are going to make
available are? What would be the
formulations?
DR.
WOLFF: Tablets of 375 milligrams and 500
milligrams.
MEMBER
NISSEN: I see. So the idea then would be that 375 bid would
be equivalent to 1000 bid in a patient not taking diltiazem. Am I with you? In other words, if you take the AUC,
approximately, you would expect to elevate serum levels to the level of about
1000 bid?
DR.
WOLFF: Well, no. I mean, I think it would be something less
than that. It would be around 750
bid. I mean, there is a rough --
depending on the dose of diltiazem that we're discussing, because the inhibition
of 3A4 by diltiazem is dose related, but at 240 and 360 it's on the order of a
doubling.
MEMBER
NISSEN: Yes.
DR.
WOLFF: So if you started at 375 bid, it
would be like starting at 750 bid.
MEMBER
NISSEN: Yes. I'm just a knuckle-dragging cardiologist, so
I don't do math too well. But if you
take, you know, 375 and multiply it by 2.4, don't you sort of get 1000 more or
less? Isn't that about right?
DR.
WOLFF: You're between 750 and 1000.
MEMBER
NISSEN: Yes. Okay.
DR.
WOLFF: 2.4, yes.
MEMBER
NISSEN: All right. So again, with the dosing that's available
for that patient that comes in -- see, I am imagining how this drug is going to
be used. Patient comes into my
office. They are good, you know, goodly
doses of diltiazem. I have maxed them
out on diltiazem. They still have angina
and I want to give them ranolazine. So
what that means then is that if I give them 375 bid, they are going to get
blood levels very quickly similar to what I might get from another patient that
would get 1000 bid. Is that right?
DR.
WOLFF: Definitely, there would be an
overlap in the range.
MEMBER
NISSEN: All right.
DR.
THROCKMORTON: But, Steve, that's going
to get more complicated. Remember this
drug is very wide inter-subject variability.
I mean, the exact serum concentrations for an individual, hard to draw
from a mean value.
DR.
WOLFF: Yes.
MEMBER
NISSEN: No, but I'm trying to
understand. What I'm trying to
understand is that what is the potential for a patient on concomitant meds to
quickly get out of range, to quickly get to a level that might be potentially
harmful, might produce syncope. You
know, we heard that if you start them at high doses right away, they tend to go
to ground. And so I'm trying to
understand the potential for this drug-drug interaction to get patients into
trouble.
DR.
WOLFF: I think what I said is that if
they are started on high doses right away and they are going to go to ground,
they go earlier, but the incidence is still very, you know, pretty low. It's not like it's a high risk.
MEMBER
NISSEN: Yes.
DR.
WOLFF: But it could be avoided by
starting at lower doses.
MEMBER
NISSEN: Yes. But we obviously do have an important
interaction here and we just, you know, have to make sure we understand that
between a very commonly used anti-anginal agent, diltiazem, and this drug and
that, obviously, is something that would obviously in labeling be dealt with,
but yes.
CHAIRMAN
BORER: Bob?
DR.
TEMPLE: Jeff, tell me if this isn't the
time to raise it, but one of the ways you protect yourself against problems
like that is to not use the highest dose you conceivably could. So, I don't know when the right time to talk
about it is, but you are talking as if 1000 twice a day is the desirable dose,
but that was indistinguishable from 750 in the largest trial you did. So, one question I wanted to ask, at some
point, I don't know if it's the right time, is why did you pick 1000 twice a
day instead of 750 twice a day, because with 750 you're further away from
trouble, presumably, even if somebody took verapamil, diltiazem or any of
those?
DR.
WOLFF: I believe that we did acknowledge
to the Agency in the letter that that's definitely something worth discussing,
is to limit dosing to 750 bid as a maximum dose. We would be willing to consider that.
CHAIRMAN
BORER: I don't think Bob was suggesting
limiting the dose as a maximum, but as a starting dose.
DR.
TEMPLE: No, no, I was suggesting
limiting it as a maximum, just because there is not a lot of dose-response
data, but what you have doesn't give any indication that 750 is --
CHAIRMAN
BORER: Okay.
DR.
TEMPLE: -- inferior to 1000.
CHAIRMAN
BORER: Yes.
DR.
TEMPLE: That was studied directly in a
trough.
CHAIRMAN
BORER: Yes, we will get --
DR.
TEMPLE: It was numerically slightly
better.
CHAIRMAN
BORER: I'm sure we will get to the
dose-response issue and answering your specific question, so this is a very
reasonable time to raise the point.
DR.
TEMPLE: Yes.
MEMBER
NISSEN: So your response to that is why
not 750?
DR.
WOLFF: Well, I think that it would be a
reasonable consideration to stop dosing at 750 if one is concerned about
avoiding higher plasma concentrations. I
think that there will also then be a limitation in efficacy for some
patients. 1000 milligrams twice daily
was relatively well tolerated. It's
certainly comparable to other anti-anginal drugs. But it is true that syncope never occurred on
500 or 750 milligrams twice daily in the controlled trials. It's also true that it only occurred in
patients randomized to 1000, as well.
MEMBER
NISSEN: But Bob's question was well,
there wasn't any greater efficacy at 1000, so why push the drug to the point of
toxicity if you don't have to?
DR.
WOLFF: I think it's a reasonable
consideration. I think that in general,
the efficacy at 1000 -- what we know is that the plasma concentration is a good
determinant of efficacy and that the dose produces a dose relationship for
plasma concentrations. So although, in
the CARISA Study, we didn't see an apparent difference between 750 and 1000,
across our broader experience, patients on 1000 will generally have a higher
plasma concentration than patients on 750, and that would generally predict
greater efficacy. So, there would be an
efficacy limitation, I believe, in keeping some patients from being titrated to
1000.
CHAIRMAN
BORER: All right.
DR.
WOLFF: But it would come at the savings
of a better safety profile for sure.
CHAIRMAN
BORER: Yes. I think although, again, I don't want to
prejudge the discussion that will follow.
I think one of the issues that we will be raising is the adequacy of the
dose-response data in terms of the overall package that we're seeing and what
that implies in terms of label writing and what that implies in terms of
defining a benefit to risk relationship.
But you have presented to us, I think, all the dose-response information
you have, so I don't think we need to belabor that, at this point, but we will
be discussing it. Steve?
MEMBER
NISSEN: I also wanted to pursue some
other drug interaction issues and particularly, I was -- actually, it was
helpful that slide you showed a few minutes ago, that the patients that had
syncope were more likely to be on long-acting nitrates, but you had just so
little data on long-acting nitrates.
And, I guess this is more of a comment than a question, but maybe you
would like to respond to it.
I
find it troubling when you have a drug you're going to add to a therapeutic
armamentarium that currently consists primarily of beta blockers, calcium
channel blockers and nitrates. And you
have given us a fair amount of data on what happens when you give ranolazine
with calcium channel blockers and what happens when you give ranolazine with
beta blockers, but you have given us almost no information about what happens
when you give ranolazine with nitrates.
And
since I know that an awful lot, if not the majority, of patients that get this
agent will be on long-acting nitrates, I am left without an understanding. Are they going to have a lot more
syncope? Are there going to be other
interactions that we need to know about?
So can you help me here at all in understanding the potential interaction
both for AEs and for efficacy with concomitant nitrate administration?
DR.
WOLFF: Well, the data that we have from
the open-label trials are the longest and most experience we have with patients
being treated with long-acting nitrates, and there we don't see any signal that
there is a difficulty in adding the long-acting nitrates to ranolazine, which
is the way it always would have been done, because as they come out of the
open-label study or the double-blind study, they start on ranolazine and then
other medications are added in as necessary after they are titrated to the top
dose. We don't have an indication there
would be a problem there, nor did we see anything that was a pattern that
raised concern in the use of short-acting nitrates, sublingual nitroglycerin,
during the two pivotal studies.
So
there was actually an abundant co-administration of nitrates during the
controlled studies. We, of course,
precluded that just before the exercise test, so it didn't confound those
measurements. But in terms of safety of
administering nitrates with ranolazine, we don't see a problem there. We just see less nitrate use, in fact.
MEMBER
NISSEN: Yes. But there is another, of course, issue and
that is on the efficacy side. I mean, it
seems to me that there is a group of patients that would be very attractive to
treat with this agent and let me describe the patients, and maybe you can help
me understand what we know about the drug in these patients.
Somebody
that has had every effort made to revascularize. They have angioplasty or bypass surgery. They still have angina. They are put on beta blockers. They are put on calcium channel blockers and
they are put on nitrates, so called triple therapy. That is certainly the majority of patients
that I have in my practice that have chronic angina. They are as well treated as they can. And now, I have got a new class of drugs and
I want to add that drug on top of maximal therapy for the refractory patient.
What
do we know about what happens? Does it
retain efficacy in patients on triple therapy?
Does it have reduced efficacy? Is
there anything you can tell me about what happens in that refractory patient
population?
DR.
WOLFF: We don't have any data
specifically in patients that are non-revascularizable and are treated with
maximal medical therapy. What we have is
some data that I presented earlier under conditions of maximal effective
individual drugs where we do see the drug adding efficacy, but in a patient
population as you described, we just don't have that data.
MEMBER
NISSEN: What about a patient population that
can't tolerate any other anti-anginal drug?
Let me tell you why I'm going here, is that we know we have safety
concerns, and so the uniqueness of the drug, its uniqueness and its ability to
provide clinical benefit for patients would mitigate against any safety
concerns. I mean, if I knew I had a drug
that could help the patient who really has unacceptable angina and can't
tolerate other drugs, that that patient would benefit would be very helpful to
me to know that those people can be benefitted by this class of agent. And it might make me lower my safety, you
know, bar a little bit if I knew that.
So can you help me with that?
DR.
WOLFF: Well, these are the best data
that we have going in that direction. I
mean, we haven't selected patients having identified them as being unable to
tolerate any of the other anti-anginal medications. That hasn't been done, nor have we selected
patients who have been previously revascularized or are unrevascularizable and who
are on maximal medical therapy.
We
do have patients that we have discussed earlier that would be difficult in whom
to titrate up hemodynamically acting anti-anginal drugs, because they already
have low blood pressures or slow heart rates or long PR intervals, and you see
the drug working, you know, generally as well on them as it does in the
others. And we have talked about the
data in patients with heart failure who sometimes can be difficult to treat
with some of the current agents and diabetes, reactive airways disease and any
of the above.
The
patients were not selected on the basis of their intolerance, but they all do
have one thing or another that does cause problems, often, with tolerating
current therapy, and we do see that the effect of the drug is maintained in the
sub-population of interest, as well as in those who don't fit into that
sub-population.
MEMBER
NISSEN: Yes. Okay.
I mean, I think you have shown me what you can on that.
DR.
WOLFF: I think that's what there
is. Yes, sir.
MEMBER
NISSEN: Yes. Okay.
Now, can we see the data on the sudden deaths? So, you showed a slide that had the placebo
and the treated patients for sudden death.
DR.
WOLFF: Yes, from the core presentation.
MEMBER
NISSEN: From the core presentation.
DR.
WOLFF: The first slide on mortality. So, here on the top, we looked at events that
were termed as sudden death or where the cause of death was listed as
ventricular fibrillation or tachycardia or cardiac arrest. There were 23 of them, two on placebo, 21 on
ranolazine. Again, one of the things
that makes interpretation of all our safety data problematic is that the
duration of follow-up on placebo is less than a tenth of the experience on
ranolazine.
The
point estimates for sudden death are very similar, numerically slightly lower
on ranolazine, but probably the most valid thing to say is that the 95 percent
confidence interval about this estimate fits entirely within the 95 percent
confidence about the placebo estimate.
MEMBER
NISSEN: Yes. I was actually more interested here in sort
of looking at all-cause mortality, because you have a little more data to work
with there. Here is the issue. You know, we obviously have a drug that has
some potential for adverse effects that may, at least, potentially be
lethal. And so what we have is just no
power here. I mean, I think -- would you
agree that there is virtually no power to try to see a signal?
But
I was troubled when I reviewed all of this that numerically, you know,
cardiovascular death and all-cause mortality was higher with confidence
intervals that are incredibly wide. And
the question is, you know, is this reassuring, not reassuring or is it simply
no information at all? I would tend to
take the position as really no information at all. There just isn't enough exposure
comparatively between the placebo and ranolazine to know if there is any effect
on all-cause mortality.
DR.
WOLFF: Well, the data are few, but the
duration problem at least can be addressed by going to the next slide and
looking at controlled data. Now,
admittedly, that reduces the ranolazine experience even further, because then
there are no data from the long-term open-label follow-up. But at least you're looking at similar
periods of risk for the placebo patients and the ranolazine treatment, and
there you see actually on ranolazine SR and in CARISA, the numeric rate of
mortality is actually lower on ranolazine compared to placebo. It's very similar when IR studies are added
in. But again, the confidence intervals
are wide and they are completely contained on the ranolazine side within the
interval on the placebo side.
MEMBER
NISSEN: Yes, with numbers --
DR.
WOLFF: So there are few data.
MEMBER
NISSEN: Yes, with numbers of three and
four and seven. So, there really isn't
anything here that can either reassure us or not reassure us about the effect
of ranolazine on survival in these patients?
DR.
WOLFF: The data are few, yes.
MEMBER
NISSEN: They are few. Okay.
You know, I think that was my reading, as well, and I wanted to make sure,
you know, that we all agreed.
CHAIRMAN
BORER: Can I ask you to go back to the
previous slide for one second? I want to
understand completely what that final column is telling us. What is the interval over which the incidence
is defined? Is it per year or is it for
total follow-up?
DR.
WOLFF: This is per patient-year.
CHAIRMAN
BORER: Per patient-year? Okay.
DR.
WOLFF: Yes, it is.
CHAIRMAN
BORER: Thank you.
MEMBER
NISSEN: Okay. I think that's all the questions I have,
Jeff.
CHAIRMAN
BORER: Are there any other
questions? Paul?
MEMBER
ARMSTRONG: We have heard a little bit
about hypokalemia. The coexistence of
hypomagnesemia and hypokalemia are pretty powerful substrate for ventricular
arrhythmia in patients with coronary disease.
Any comments about the coexistence of those two metabolic abnormalities
commonly as a function of diuretic therapy and likelihood of problems?
DR.
WOLFF: Yes. We looked at patients receiving
potassium-wasting diuretics in the population analysis of concentration versus
QT change, and the patients taking diuretics had the same slope of the
relationship as did the other patients.
There wasn't that much variability in the plasma or serum potassium
concentrations, as you might imagine, in the controlled trials, so that seemed
like a better way to do it and that's our best data to that point.
MEMBER
ARMSTRONG: A second question is, as you
know, there is concern about the coexistent use of Viagra and nitrates. Any exposure to Viagra in the patient population
on ranolazine?
DR.
WOLFF: Do we have any data from the
long-term open-label studies with patients that received sildenafil? No, we don't.
CHAIRMAN
BORER: Blase and then Steve and Bob?
MEMBER
CARABELLO: One of the assertions is that
the agent prevents angina without a change in heart rate, blood pressure or
contractility, and I saw the blood pressure and heart rate data, but I haven't
seen the contractility data.
DR.
WOLFF: I think the best data that we
have to speak to the effects of ranolazine on contractility are preclinical
data, and I think that I will ask Dr. Belardinelli to come and present them.
DR.
BELARDINELLI: The best piece of data we
have, Dr. Carabello, with ranolazine and contractility is a study done actually
not too long ago, and I have a slide here that I would like to show to
you. This was done in Dr. Thomas
Hintze's laboratory using awake dogs, instrument for measurement of heart rate,
blood pressure, coronary blood flow and, as you see here, left ventricular
systolic pressure and dP/dt.
And
these animals were exposed to ranolazine at concentration of 1, 3, 14
micromolar and 18 micromolar and measurements were made at various times during
a steady-state of this concentration. As
you can see here, there is very little things for me to report to you, because
there is not much decrease, except at 18.
It's about, I think, if my memory doesn't fail me, this is about a 10 percent reduction on the LV dP/dt. And furthermore, we have also done a study in
isolated tissues. This is the rat left
atria and, again, ranolazine did not decrease, did not produce any negative
inotropic effect.
MEMBER
CARABELLO: Actually, since you mentioned
it, you said that Tom also looked at coronary blood flow.
DR.
BELARDINELLI: Yes.
MEMBER
CARABELLO: Do you happen to have those
data?
DR.
BELARDINELLI: Yes, we can show that
slide, as well. Here we go. So, here is the lack of effect of ranolazine
on coronary flow in the resting dogs, either CBF or the resistance, coronary
vascular resistance. So we haven't found
any major effect of ranolazine on flow or contractility or dP/dt, I should say,
in awake dogs.
MEMBER
CARABELLO: Thank you.
CHAIRMAN
BORER: Bob, and then we'll go back to
Steve.
DR.
TEMPLE: Just one thing about the last
discussion. Correct me if I'm
wrong. My impression was that if you
don't see an increase now in the rate-pressure product, there is no basis for
assuming that the mechanism is anything other than hemodynamic. That is, that it has some effect on blood
pressure or heart rate during exercise, you might not see it at rest, and that
that helps you because somehow you can get to the same rate-pressure product
with a little extra exercise. So that is
not evidence of a different mechanism.
But
leaving that, I wanted to ask Steve the following question. If somebody wanted to claim that a drug has
an additive effect to maximum doses of something else, there is no alternative
that we could see other than to study that and that is basically what our
letter said. The other case you talked
about, though, where you were looking at people who couldn't tolerate a beta
blocker, say, because they got depressed on it or something like that or a CCB,
because they had too much heart failure and no one wanted to use it or because
they didn't like the edema, or whatever, would you need to study a drug that
didn't seem to have those problems in that population in order to believe that
it could be used in those populations?
That's
my question or if you thought you did, how much do you have to? Because, isn't it sort of obvious that if it
doesn't cause depression, it won't cause depression in people who get depressed
on a beta blocker? Isn't it obvious that
if it doesn't cause edema, it won't cause edema in people who have edema?
MEMBER
NISSEN: You know, it's interesting, but
we see patients that seem to have trouble tolerating almost any drug you give
them. You know, they are sort of the
"bad actors" and they drive every physician absolutely crazy, because
whatever you give them, something seems to happen. And, so, you do get some reassurance from the
fact that there really is something different about this drug. If you take some people that, you know, can't
tolerate a calcium channel blocker, can't tolerate a beta blocker, but they can
tolerate this drug, then it could actually be used in that population.
And
to me, that would be valuable, because it would tell me that if I have safety
concerns and yet I have a drug that people who are pretty desperate for some relief
could get relief from that drug, it would make me feel better about having that
drug available.
DR.
TEMPLE: Yes. What I'm asking is not whether that's true,
because you said that before.
MEMBER
NISSEN: Yes.
DR.
TEMPLE: I understand.
MEMBER
NISSEN: Yes.
DR.
TEMPLE: But do you actually -- this may
sound like an odd question coming from me.
Do you actually have to study that or do you already know from the
studies in other people that it doesn't cause those things that cause
intolerance to beta blockers, CCBs, because you have got all this data and it
doesn't show those things?
MEMBER
NISSEN: I think --
DR.
TEMPLE: How much, you know, I don't
know. There is a lot of questions. You could ask the same thing about cough and
ACE inhibitors and stuff.
MEMBER
NISSEN: Yes.
DR.
TEMPLE: How much data do you need, if
there is no evidence of cough, to know that it won't cause cough and the people
who cough too much on the ACE inhibitor might be able to use this? Now, we have made people study that.
MEMBER
NISSEN: Yes.
DR.
TEMPLE: But still, it seems worth
discussing.
MEMBER
NISSEN: Yes.
DR.
TEMPLE: Because it's a question of how
much data you actually need.
MEMBER
NISSEN: Yes.
DR.
TEMPLE: To feel comfortable about that
question, which seems quite distinct to me from is there additive effectiveness
in that setting, which I see no alternative but to study.
MEMBER
NISSEN: Your question is very
provocative and I would be interested in other panel members' thoughts about that,
but to me, I'm always more comfortable when I have the data. You know, when the study has been done and,
you know, when you know what happens, it just gives you some added confidence. And frankly, I think it gives the medical
community added confidence. I mean, I
think it tells us hey, look, here is a drug you can give to people that just
can't tolerate anything else and you can help them. And so, I think it would be good marketing
for a company to do such a study.
The
question is is it a regulatory issue?
Well, maybe it still is for me if there is some risk involved in
convincing myself that the benefits that the therapy outweigh the potential
risks to really actually know that that population would be benefitted. I think I would like to see the data.
CHAIRMAN
BORER: Okay. Let me summarize that answer. I will.
I think everybody would be perfectly happy if a drug was shown to be
effective, and we'll get to acceptably safe in a moment, to do the experiment
of trying it in anyone with the relevant condition. The only limitation to attempting that
experiment would be how much you have to pay for it in terms of safety. And the greater your concern, your safety
concern, the greater the need to have more precise information about the
likelihood of efficacy.
But
that is not a specific answer with regard to what's needed with this drug,
which we'll get to. I think in general,
my own opinion is absent particular safety concerns, if the drug is effective,
you can perform the experiment in an individual patient after the drug is
approved. Beverly?
MEMBER
LORELL: Mr. Chairman, could I move to
pick up on an issue that was discussed a little earlier this afternoon, and
that is the alpha blockade issue, and it relates a bit to the issues that you have
been discussing about efficacy. I wanted
to actually ask a little bit more, explore this a little bit more.
We
have heard a bit that the side effect profile, one component of it that we're
concerned about, the episodes of orthostatic hypotension and syncope may be
related in part to an alpha blockage effect.
That implies that some component of the efficacy during exercise and
perhaps reduction in use of nitroglycerin might also be related to this
pharmacologic effect, at least at higher doses.
When
one thinks about that in the larger setting of use of alpha blockers for
cardiovascular indications, one thinks about the experience several years ago
of use of alpha blockers in heart failure, in which efficacy based in part on
their effect, but not all. Their effect
on vasodilation dissipated and was lost over time, and we often called that,
for lack of a better word, tachyphylaxis.
One
of the things that troubled me a bit in hearing the discussion today and the
sponsor's interpretation that side effects are attributable to alpha blockade,
is the issue of whether the anti-anginal effect is, in fact, sustained, because
your control study, CARISA, went out only for 12 weeks. Is that correct?
DR.
WOLFF: Correct.
MEMBER
LORELL: So do you have a database with
something more than, say, use of nitroglycerin, but something like exercise
duration that shows that benefit is sustained for many months and not lost
after use for a few weeks?
DR.
WOLFF: The longest controlled experience
is the three months of the CARISA Study.
MEMBER
LORELL: How about a withdrawal study for
a longer period of time showing a drop in exercise performance?
DR.
WOLFF: We did the withdrawal study, but
we did it right at the very end of CARISA, so that was three months experience,
as well. We also have withdrawal data
with the immediate-release formulation, but if memory serves me correctly, it
was also either six weeks or 12 weeks, I can't recall, of continuous treatment
and then withdrawal. And we did see what
you would expect, which is in the patients that were withdrawn, there was a
decrement in their exercise times back to a baseline level, but we don't have a
longer controlled efficacy experience beyond the three months of CARISA.
MEMBER
LORELL: Could you speculate or comment
for the Panel knowing this earlier experience of a little more than a decade
ago about loss of efficacy with alpha blockers and heart failure as to what
data you might bring to bear or comments about that?
DR.
WOLFF: I think that data on the changes
in rate-pressure product relative to the changes in exercise duration are
probably the most instructive. I
wouldn't disagree that at the very highest doses that we studied in
concentrations, because there are slight decreases in the end exercise systolic
blood pressure, that there may, in fact, be some contribution from an alpha
blocking effect at those doses. It can't
be excluded from these data.
The
only thing that I can say is that alpha-1 blockade, while it could have some
contributory aspect to the overall efficacy of the drug, as we discussed a bit
earlier, it can't underlie it completely, because really in the absence, I
think, of any change at all in blood pressure, heart rate or rate-pressure
product, we still are able to demonstrate statistically significant
improvements in exercise duration. And
again, whatever the mechanism of these small reductions in rate-pressure
product, they happen in this trial to be greater at trough than at peak. They also were at 1000 milligrams twice a day
in the MARISA Study, as well. And yet,
the exercise effects are generally greater, as you would predict, at peak than
at trough.
So,
I would agree. There could well be some
minor contribution, but it can't be the entire explanation for the efficacy of
the drug, because we can demonstrate the efficacy in the absence of any
clinical profile consistent with alpha blockade.
CHAIRMAN
BORER: I think it's worth having a
clarifying statement here and perhaps, Bob or Doug, you will want to comment
before you ask your next question, please.
There never has been a requirement for showing persistence of effect for
more than 12 weeks for an anti-anginal drug, so unless there was an a priori
expectation of lack of effect persistence, one might not have expected the
sponsor to have done such studies. The
12 week standard was set only when nitrates were found to lose their effect at
six weeks and before that, I think it was six weeks that was required. So, it's not an unreasonable question, but we
probably want to be reasonably certain that there was some strong suggestion of
loss of persistence of effect before changing the standard, I think. Bob?
DR.
TEMPLE: What we usually get, usually is
hard to talk about. There are not a lot
of angina drugs being developed lately, but what we usually get is an active
control trial without a placebo, because who would want to be in a placebo for
six months to a year, that shows nothing, obviously, bad. That is not at all satisfactory. What we would like people to do is do a
randomized withdrawal study after this active controlled trial. So, what they did was great. Ideally though, it would have been done after
six months or 12 months of open-label therapy.
Then you would show persistent effect that way and that would be
better. But it wouldn't be true to say
we have required that.
DR.
THROCKMORTON: We have sort of offered up
in other areas, in blood pressure for instance, where you could make exactly
the same criticism where very little long-term controlled data that allow you
to say you know the blood pressure effect persists beyond the controlled trial
expansion period, randomized withdrawals out of six months or something like
that demonstrating persistence of antihypertensive effect. So it seems like an important enough thing
that we would want to be thinking about labeling a product that actually had
that kind of data and brought it to us.
DR.
TEMPLE: And that has been done for so
many hypertensive drugs, but not all, and we have not required it. It has also been done for antidepressants and
things like that. It's very
informative. It tells you about
maintenance.
MEMBER
LORELL: No, I thank you for that
comment. I think the reason I asked that
this afternoon was getting a little fuller feel of the contribution of alpha
adrenergic receptor blockade to the entire profile of the drug.
CHAIRMAN
BORER: Blase?
MEMBER
CARABELLO: In that same line, I noticed
that in combined MARISA and CARISA, there were about 400 or so patients between
the ages of 65 and 75 if I have got that right.
DR.
WOLFF: Ten percent of the study population were older than 75 and yes, so there
is about a third.
MEMBER
CARABELLO: And in --
DR.
WOLFF: So it's on that order, yes.
MEMBER
CARABELLO: And a number of them, about
three quarters of the whole patient population, were men?
DR.
WOLFF: That's correct.
MEMBER
CARABELLO: Yet, I noticed there were no
reports of urinary retention as a side effect.
Is there any evidence that urinary retention actually went down with the
agent, because, I mean, obviously that would be great to have an anti-anginal
drug that also helped you to pee and also might speak to this alpha blockade
issue.
DR.
WOLFF: It wasn't a signal that came
up. Again, I think in the plasma
concentrations that are going to be experienced by the great majority of
patients receiving the drug if it's approved, there really isn't much in the
way of alpha blockade and you really kind of have to get to end exercise to see
anything that we might attribute to it, but no, there was no signal.
MEMBER
NISSEN: It's particularly useful when
you get to be as old as Blase.
CHAIRMAN
BORER: Well, for someone who wasn't born
yet in 1982, I guess you can say that.
Steve, you had another question to raise?
MEMBER
NISSEN: This is really not at all an
approvability issue, but it's a curiosity issue. You know, we know that patients with angina
have both painful ischemia and silent ischemia and I know some of your
consultants are rather expert in this area.
Did you guys do anything looking at Holter monitor or evidence of
changes in evidence of ischemia other than the exercise testing? I'm just curious as to whether there is
evidence of an effect there.
DR.
WOLFF: We didn't do Holter monitoring in
the pivotal studies. We just don't have
that data.
MEMBER
NISSEN: Yes. It would be interesting to see sometime.
DR.
PRITCHETT: But I thought you told us you
did have some Holter data from the early immediate-release data looking at
silent ischemia.
DR.
WOLFF: I believe the Study 1513 actually
did contain Holter data, but the doses in that study were 30, 60 and 120
milligrams.
DR.
PRITCHETT: Oh.
DR.
WOLFF: Three times a day and they
weren't effective, so those data aren't helpful.
CHAIRMAN
BORER: Okay. If there are no other questions that need to
be clarified before we begin discussion, we'll move on to a structure
discussion within the context of the questions we have been given. I want to reiterate to the sponsor that all
of us believe that the presentation has been excellent. It is credible, forthcoming and I think you
have answered our questions as best as you can with the best data that we can
see.
The
FDA has asked for some specific advice and I will read through this rather than
summarizing it. Since I don't believe
there are any formal votes that are requested here, we'll discuss, but I will
ask people around the table to contribute, so that we get a reasonably
representative view of some on these issues and some perhaps can be dispensed
more summarily.
"The
Cardio-Renal Advisory Committee is asked to give an opinion on the next steps
in the Ranexa Development Program.
Ranexa (ranolazine) is under development for use as an anti-anginal
agent. It is unclear which of its
pharmacological properties contribute to clinical efficacy, but the Agency
review concluded that it is an effective anti-anginal drug.
The
letter of October 30, 2003 communicating an "approvable" action
listed the following deficiencies that are the subject of discussion today:
Inadequate
safety experience with the sustained-release formulation and doses in the range
proposed for marketing; inadequate evidence of effectiveness in a setting
commensurate with the risk associated with effects of ranolazine on ventricular
repolarization; inadequate information on dose-response and dosing interval.
The
ICH E1 recommends that drugs intended for chronic use have a safety database
that includes at least 1,500 individuals treated with relevant doses and 100
patients treated for at least one year.
Greater exposure is recommended if there are specific
concerns." And we have a table that
summarizes the available data for ranolazine, which we have all heard and it's
in the questions that most of you had.
This
is a background. We have several
specific questions. First,
"Evaluate the following factors as influencing the need for additional
safety data: 1.1. Availability of other
approved anti-anginals." We're
dealing here specifically with the issue of the need for safety data in light
of the fact that there are other anti-anginals available. Does anybody want to discuss that? Ed?
DR.
PRITCHETT: Well, I'll just comment and
say that in general, I believe in pharmaceutical innovation. We have heard that there aren't a lot of other
drugs for angina being developed today.
This is apparently some form of novel mechanism. Although, I don't think we know exactly what
the mechanism is, but it's not a calcium channel blocker. It's not a beta blocker and it's not a
nitrate. And so I think there is some
merit in a new compound with a new mechanism for this indication.
So,
I think the fact that it is novel in some ways is good. Although, the fact that it has this, you
know, sort of modest QT effect and the fact that it comes from a new class and
a class that we don't have a lot of other experience with, you know, is perhaps
worrisome. So I think it cuts both ways,
but in general, I applaud the development of new, innovative therapies in new
classes.
CHAIRMAN
BORER: Let me push you just a little
bit. I don't think anybody here would
challenge the idea that a new anti-anginal drug that is effective and
acceptably safe for its intended use is a good thing to have. Gene Braunwald laid out the case and we all
believe it.
I
think the issue here is given the fact that angina is a symptom and that the
drug is intended to prevent the development of a symptom, not to make people
live longer, not to make heart attacks less common, but to relieve a
symptom. Do we have sufficient
information now about the safety of this drug, so that we can approve it, given
the fact that there are some other ways to at least partially relieve symptoms,
this might make things better, but there are other drugs available? Do we need more information about safety,
because, in fact, the purpose of the drug is to make people feel better, rather
than to affect additional natural history endpoints?
DR.
PRITCHETT: I guess I'll stick my neck
out here and say I think that there are some things that make us feel good
here. This is a drug that has been in
the hands of investigators, who are cardiologists, who have easy access to
electrocardiography. It's not like a
drug that is being worked up by psychiatrists or allergists or
gastroenterologists who don't routinely do these things.
I
guess the case that I'm coming around to making, the fact that the people who
worked this drug up and never documented a case of torsade, I think, is kind of
encouraging, because I think these are people who could have done it if it occurred,
because they have ECGs available to them and because a lot of ECGs were done
during the course of this study.
Now,
our colleagues from the FDA will tell us that the database presented on behalf
of bepridil dwarfed this and it still turned out to have torsade. So I'm not saying that there won't be a case
of torsade with this drug at some point in time. In fact, I think there will be one, because I
have seen it in placebo-controlled studies, so if patients on placebo can have
it, then patients on ranolazine can have it.
But I think that the QT interval prolongation that we have here is
pretty modest. You know, in my sort of
calculations that I did, I sort of came up with about 8 milliseconds. You know, it's not five or less, but it's not
20 or above. And so I think we can -- I
am reassured by the absence of a documented case of torsade.
There
are some things here that I don't understand.
I don't understand the interaction of hepatic disease and the QT and,
you know, the syncope is a little bit funny, but I am encouraged by the fact
that we have electrocardiograms recorded during syncope and, you know, they
haven't shown an arrhythmia. I think
with respect to the mortality data, somebody asked is this reassuring or is it
no information? It's virtually no
information.
CHAIRMAN
BORER: Bob?
DR.
TEMPLE: I just want to be sure that we
were clear. There are two sets of
questions. One are questions related to
specific concerns like syncope and QT and stuff like that. That's one set of concerns. The other was just the total exposure, which
this is about -- for total exposure, this is about sort of half of what we
would expect. It's not nothing,
obviously, and we don't think there is any deficiency at all, according to
usual standards, in how much exposure there was of more than six months a
year. That is the usual exposure for
better or worse. It's the, you know,
reasonable dose, acute exposure that's a little low. So we're just asking, you know, how do you
feel about that?
DR.
PRITCHETT: Well --
DR.
TEMPLE: Because there is a principle
that if you get more, you can lighten up on the demands.
DR.
PRITCHETT: But I think --
DR.
TEMPLE: Usually, one is thinking of, you
know, survival and stuff, but not only.
DR.
PRITCHETT: But I think, you know, I
agree that the number of patients and the length of exposure is a little bit
and compared with other things that you see.
Part of the reason is is because they have been lucky and nothing very
messy has shown up that has driven them to say well, we need, you know, another
big study. You know, we need another big
Phase 3 study. It's this anxiety, you
know, the sort of background anxiety. So
I agree it's not as big, but, you know, except for the 8 millisecond QT prolongation at the 1000 milligram dose, you
know, not a whole lot has shown up that worries me.
DR.
TEMPLE: I'm not disagreeing with that
thought.
DR.
PRITCHETT: Okay.
DR.
TEMPLE: I'm just trying to make sure
it's clear we were asking one thing about the specific things and the other as
a sort of general matter, this is what you usually do. I should say that bepridil was -- there were
cases of torsade right in the database.
It was a piece of cake to discover that just as it is with sotalol. We don't think this is anything like
that. And the drugs where QT has been a
concern, we don't think the rate is going to be one in 100 or one in 500. It's the one in 5,000, the one in 10,000 that
people are worrying about. So, we would
never say that for a drug with this degree of impairment, you have to do enough
cases to rule out that, you know, there is one in 10,000. That's not doable. There wouldn't be any drugs if you had to do
that.
DR.
PRITCHETT: Well, then we both agree in
innovation.
CHAIRMAN
BORER: Blase and then Steve?
MEMBER
CARABELLO: I suspect with regard to
electrophysiologic safety that the sponsor has, in fact, set a new bar at a
higher level than we have seen. That is
to say that the preclinical data, which are elegant compared to the sort of
blunderbuss approach of the QT interval may give us more reassurance than we
have ever had. Now, unfortunately, we
won't know that until after there has been greater exposure to the agent, but I
must say I was very persuaded by the preclinical data that this agent is
electrophysiologically safe.
DR.
PRITCHETT: I guess I just have to
address that and say I am unmoved by the preclinical data. I think it's nice. I think it's elegant. We have had a beautiful exposition of
it. I am just a country doctor from a
rural state and I am interested in what happens when the drug is given to
patients, and I am far more impressed by the clinical observations than I am by
the elegant electrophysiology, which congratulations to all of you. It's superb work, beautifully presented. I enjoyed it.
CHAIRMAN
BORER: Steve and then Susanna.
MEMBER
NISSEN: Yes. You know, I sort of read these questions
somewhat more literally, so I'm going to see if I can answer a little more
literally. I do think that the
availability of other approved anti-anginals does play into my thinking about
this, and let me see if I can articulate it.
If you have a drug for pulmonary hypertension, as we have considered at
this Panel, where there is very little we can do for these patients. They are desperately ill and we have almost
no oral drug. You know, we set the
safety bar pretty low, you know, for a drug that, you know, bosentan, that had
major safety concerns.
So,
on the other hand, if you have three classes of agents that are available to
treat angina and we have no study where those agents were used maximally that
showed that this agent, in fact, could produce a benefit beyond what we could
achieve with conventional therapy, then that does, in fact, play into my
thinking about how much safety data we need.
So question 1.1., if I understand what
you're asking, is does the availability of other approved anti-anginal agents
play a role on how low we're willing to drop the safety bar and the answer is
yes, it does play a role. And I'm not
saying this drug isn't safe, but in terms of looking at this as in the big
picture, it does play a role. And I have
different answers for the rest of those questions, as well.
CHAIRMAN
BORER: Susanna?
DR.
CUNNINGHAM: Well, when I think about who
will probably be consuming this drug once it's available, I think it will
probably be a fair number of females and some greater ethnic diversity than has
been studied. So I think in terms of
both efficacy and safety data, we need more data on women and we need more data
on diverse populations as regards to ethnicity.
CHAIRMAN
BORER: Okay. And that conclusion is driven in part by the
fact that there are other drugs that you know you could use in the interim for
those people.
DR.
CUNNINGHAM: Even so, we don't know. There are only 23 percent women in CARISA and
MARISA and, if I remember correctly, it was only five percent ethnic minority
and that's not representative of the population of the country.
DR.
THROCKMORTON: Susanna, could I just ask
you a little bit more about that?
Yesterday we talked about how the Agency sort of thought about subgroups
in populations and we have, of course, been tasked with looking at three of
them, in particular, and we hadn't done -- we hadn't looked as carefully as we
do now in the past, obviously. One way
to handle that is through labeling, to say what's known, to say what's not
known, to allow the informed physician and consumer to make a choice.
The
alternative is to sort of say no, you know, this is an important enough
subgroup to say we really do require information. One thing that might play into that would be
if you had a signal, say, that you believe to be credible that one group was
less -- there was less efficacy in one group or the other or you might just say
no, you know, including it in labeling is sufficient, that, you know, what we
have is available, say, at the labeling.
And I'm just curious where you view, I guess, females in particular, but
heart failure and the other sorts of things we have been talking about.
DR.
CUNNINGHAM: Well, in the FDA analysis,
they have indicated it was much less effective, if not not effective in
women. So I think we would like to know
if it's effective in women. I think that
would be a key piece. And since there is
really no data on ethnic minorities, it's difficult to say if there is a signal
or not of there being a problem, because we don't have enough to decide. So I guess you could put it in the labeling,
but that's not serving the population well, because they are going to get it no
matter, one way or the other.
CHAIRMAN
BORER: Beverly?
MEMBER
LORELL: To pick up on Dr. Cunningham's
comments, I think that it might be easy to sort of sweep the issue of efficacy
in women aside a little bit and just say well, yes, yes, this is seen in
multiple classes of anti-anginals. I
think the problem here, as Dr. Pritchett alluded to, is that whereas we saw
absolutely elegant preclinical data about the interpretation of the long QT, it
is still in part hypothesis generating.
And we do know from experiences with other drugs and torsade of an
increased propensity of women.
So,
I guess, I'm a little bit troubled by that interface that we're using, talking
about adding a drug on to treat a symptom.
We're talking about perhaps tolerating its labeling for a group for
which there is minimal evidence of substantive efficacy in women, but also with
a group that we have a heightened concern about safety issues, particularly if
this drug were used very broadly or were used as it was in CARISA, as a number
two layer-on drug to a low dose of a first one.
DR.
THROCKMORTON: So, very similar to the
sort of conversations we had yesterday, I guess, in terms of the gender
interaction there, too.
DR.
TEMPLE: I just wanted to make one
comment about racial mix. We have been
tracking this and there is no question that now that more data are coming from
foreign sources, the fraction of black people in trials is dropping down, and
we don't have an immediate easy answer other than to say, you know, you better
do your studies in the U.S. or someplace else where there is a proper mix. We have not said that so far, but we're
watching it and are troubled by it.
The
relatively small number of women in the trials is consistent with the past, and
I believe it's because there are age limitations and women catch up a little
later. And if you had a large fraction
of elderly populations, you probably have a high fraction of women, but these
don't for the most part. But I don't
know that that's true. That's just my
explanation. Twenty percent is a little
lower than usual. The other factor is
there is not a lot of controlled trials here.
Sometimes you can pull large amounts of data from multiple trials and
get an answer that you couldn't get from the individual trial. You don't really have that opportunity here.
CHAIRMAN
BORER: Steve, go ahead.
MEMBER
NISSEN: Well, you know, it's
interesting. I want to disagree with Ed
on something and agree with Blase. I'm
actually not reassured by the absence of torsade in the clinical exposure to
date. To me, it doesn't influence me one
way or the other, because if you actually make the calculation of what the 95
percent confidence limits would be around, you know, what rate could you have
had and missed? It's so low, as to be
essentially clinically meaningless.
So
we simply don't know whether this drug will produce torsade in man on the basis
of the exposure to date. So I just think
that that's not helpful nor is it likely to be made more helpful by adding
another 1,000 patients, because, in fact, we're not going to know that before
this drug, you know, goes to market.
DR.
TEMPLE: No, that won't help you. How do you feel about the choice of dose with
respect to that? I mean, if you get down
to relatively low doses, you're probably talking about four milliseconds,
usually not considered a problem, except that this is a drug that has very
variable blood levels.
MEMBER
NISSEN: I want to --
DR.
TEMPLE: What do you do with that?
MEMBER
NISSEN: I want to pursue that just a
little bit further and let me just say, Bob, that I was pretty impressed by the
preclinical data, as well. You know, I
thought that, you know, I recognize that it isn't definitive and that we're
going to need several years of additional information and testing of a lot more
drugs, but it sure made me feel a whole lot better about the degree of QT
prolongation that we saw here. And, you
know, now --
DR.
TEMPLE: You were supposed to.
MEMBER
NISSEN: Yes, now, of course, I was
supposed to. Well, but, I mean, you
know, the sponsor did a nice job there.
I mean, you know, your audience was the Committee and you convinced a
lot of us that you had something important to say from the preclinical
data. Having said that, I'm not sure I
want to bet my patient's life on the preclinical data, and that was a very
harsh way of saying it, but it's reality.
And,
so, what is going to have to happen here is that this drug, I think, will
ultimately be approved and I think we'll have to have vigilance and we'll have
to look for these episodes. We're not
going to see it before the drug is actually released, because there is no
amount of safety data that you could reasonably ask, no amount of exposure data
that you could reasonably ask the sponsor to produce that would sufficiently
reassure me that an eight millisecond QT prolongation is of no
consequence. But I do think the
preclinical data went a long way to making me believe that there is a very good
chance that when generally and widely exposed, that the drug is not going to
hurt people, and that makes me a lot more comfortable.
DR.
TEMPLE: But would you comment
specifically though on what effect, if any, the limitation of dose to, say, 750
twice a day would have on your thinking, because the mean effect is much lower
there than on 1000 or 1500?
MEMBER
NISSEN: Well, I don't think that's such
a big deal here, Bob, and I'll tell you the reason why. If there is a liability the drug brings to
the table, it's the kind of drug-drug interaction liability. If you think about the drugs that we have
gotten in trouble with from QT prolongation, they are drugs that prolong the QT
modestly, but then have a 3A4, an interaction with 3A4 inhibitors. I mean, that is the signature of a drug that gets
people -- one of the signatures of drugs that gets people into trouble. And so --
DR.
TEMPLE: Okay.
MEMBER
NISSEN: Yes.
DR.
TEMPLE: That's true.
MEMBER
NISSEN: Yes.
DR.
TEMPLE: But when you interfere with the
metabolism of terfenadine, you multiply the blood level by something like 20.
MEMBER
NISSEN: Yes, yes.
DR.
TEMPLE: 20, not 3.
MEMBER
NISSEN: No, no, I mean, listen, I'm not
telling you that this is --
DR.
TEMPLE: Amounts matter.
MEMBER
NISSEN: Yes, this is not the ugliest 3A4
interaction I have ever seen, but when a drug that is commonly used to treat
the disorder that we're interested in, namely diltiazem, in a dose that is
commonly used, produces a 2.4-fold elevation.
DR.
TEMPLE: Right.
MEMBER
NISSEN: And when I know that my
colleagues don't read product labels that way, you know, they should and maybe
even I don't. You know, I'm sorry to
tell you that, Bob. I know it's
shocking.
DR.
TEMPLE: This is terrible.
MEMBER
NISSEN: But, you know, it gives me cause
for concern and that is why, you know, I actually -- there are some other
questions in here, including the question about this high-dose intravenous
infusion study, I actually think that was very helpful to me, because I could
see what would happen if you went to the point of very serious toxicity. I mean, they pushed this drug about as hard
as I would have been comfortable. I'm
not sure as an investigator, I would have been comfortable doing that, but they
did it and they didn't see anything really ugly on the QT side when they did
that.
And
so now, I ask the question if you give a 3A4 inhibitor, you know, are you
likely to get into that, to get concentration range that is so high that you're
going to see terrible trouble? And the
answer is probably not.
DR.
TEMPLE: Well, they have pretty good data
on the effect of 3A4 inhibitors. It's
sort of two-ish for the weaker ones and up to four for the big guns.
MEMBER
NISSEN: Yes.
DR.
TEMPLE: I guess I just want to press
this a little more, because I'm sure it's going to come up in any
discussions. The further away you get
from the doses that cause problems, the more you have a little buffer against
the inadvertent exposure to a 3A4 inhibitor, the possibility of a little bit of
liver injury and, you know, you move away.
And, so, I'm still interested in hearing what everybody thinks about
whether that's reassuring and if so, how much and what you think about that.
CHAIRMAN
BORER: Tom?
MEMBER
PICKERING: Yes, I would like to return
to a point I made earlier with regard to the other anti-anginals that if we're
administering this medication, the only reason we're doing it is because we
think the patient is going to feel better.
And if you're a cardiologist, you're not going to do a treadmill test,
put the patient on ranolazine and do another treadmill test and say look, you
have got 23 seconds improvement, so you are better. You are going to ask the patient do you feel
better?
And
we really haven't heard any evidence one way or the other whether patients
liked being on this, and I think the fact that it does prolong the exercise
time, which I certainly accept, is not the same thing, because to take the
example of beta blockers, they may make people be able to go longer on a
treadmill, but they may become depressed and feel slowed up.
And
we have heard that this medication also has side effects. So I don't think we have a sort of -- and you
may say it's a soft endpoint and it is, but there are measures for measuring
patient preference and quality of life, and I'm sort of disappointed that we
haven't heard anything about that, because I think it would make a helpful
reference frame for when we're actually using it in real life practice.
CHAIRMAN
BORER: Yes. We have sort of a poor man's index, which
would be reduction in angina attacks per week and reduction in nitroglycerin
use, but there is no quality of life information, I guess. Ed, you had another comment?
DR.
PRITCHETT: Yes. I just want to comment on the question of
what the torsade incidents could be. I
mean, we have zero incidents, zero cases of torsade in a database, you know,
all comers, 2,700 patients. You know,
there is a statistical rule of thumb that tells you that the 99 percent upper
confidence limit of the point estimate is 2,700 divided by three, one out of
900. So, you know --
DR.
TEMPLE: Ninety-five.
DR.
PRITCHETT: Yes, 95 percent, so it's, you
know, it's one out of 1,000 around is what our point estimate could be. That is a whole lot lower than what we see
with a lot of anti-arrhythmic drugs and things that electrophysiologists are
used to using. Now, I understand all the
caveats. I mean, a lot of these patients
--
DR.
THROCKMORTON: Duration counts.
DR.
PRITCHETT: That's right. Duration counts and that sort of thing, but,
I mean, this is in what my college physics professor used to call desperate
physics. You have taken the numbers you
have and trying to do something with them.
But in any event, you know, if you had to use it, if you had to take the
numbers we had and use them, fine. You
can pare it down. Say they only have,
you know, 1,800 relevant patients, you know, then it's one out of 600. You know, but you can come up with a number
that tells you that the point estimate for the rate of torsade per patient
exposed is way less than what a lot of other drugs are that are out there that
cardiologists are using.
MEMBER
NISSEN: So if the rate were really one
in 600, you would not consider that an approvability issue? In other words, I guess, my issue would be is
if the rate were really one in 600, would you approve this drug as an
anti-anginal? And the answer is I
probably wouldn't.
DR.
PRITCHETT: I probably would.
MEMBER
NISSEN: Okay. That's interesting, because, you know, what
was the rate? Let me ask you a
question. What was the rate of torsade
with terfenadine, another drug for symptomatic relief?
DR.
TEMPLE: Zero. You don't get any until you interfere with
this metabolism.
MEMBER
NISSEN: Yes.
DR.
TEMPLE: And it also wasn't discovered
for three years, too.
MEMBER
NISSEN: Yes. You know, to me, Ed, I guess I'm trying to
make the case here that I just don't think we know.
DR.
PRITCHETT: Right.
MEMBER
NISSEN: You know, I am reassured by the
preclinical data, but the true incidence here will not be known for several
years, and it could be high enough that it could ultimately lead to the
withdrawal of the agent within the range of rates that are possible given our
current clinical database.
DR.
PRITCHETT: I think that's always true,
that something will show up after a drug is marketed that will wind up it being
withdrawn. For my money, when I'm trying
to figure that out, I will put my nickel on what was seen in the clinical
program, though, not the preclinical program.
DR.
TEMPLE: The drugs that have caused
torsade while you have the needle in, things like sotalol, bepridil,
dofetilide, there is nothing to it. It's
one percent. It depends on the
dose. But other major drugs that are a
problem, cisapride didn't turn up any, astemizole didn't turn up any, and that
could be because you needed to interact with them or give too much or something
like that. But, you know, they caused
plenty. Nobody thinks this is like
bepridil or something like that.
CHAIRMAN
BORER: Okay. I want to move on from 1.1. here where we
are. I think we have had some wide
ranging answers and maybe we can telescope down just a bit as we move on, but
we began to discuss, and Beverly actually responded to the nature of the
efficacy demonstrated to date as a basis for perhaps impacting on her need for
more safety data to provide an adequate description of this drug for
consideration for approval.
Paul,
do you want to discuss that issue, as well, the nature of the efficacy
demonstrated data and its impact on the need for additional safety data?
MEMBER
ARMSTRONG: Well, for me the efficacy
does begin to level at 750, but I think there is some evidence that 1000 gets
you more, and my principal -- and I am moderately convinced that there is
durability of the effect, but would like to see longer exposure both from the
standpoint of safety and efficacy. So at
this point, I am moderately confident that the dose range that has been
suggested is reasonable and it would be safer at 750 than it would be at 1000,
but not much, and there would be some more efficacy at 1000 that there isn't at
750. So I'm pretty flexible.
CHAIRMAN
BORER: Okay. If there were more efficacy data, that is, if
the dose-response relationship had been worked out a little better than it has
been, if we had two pivotal trials that were clearly demonstrative of efficacy
rather than one that is clearly demonstrative with no clear dose-response
relation and another about which one might raise questions, and perhaps we will
raise the questions later or maybe we won't, if you had more compelling
information about efficacy, about dose-response, about sub-populations, about
drug-drug interaction, well, that's a safety issue, but about the additivity of
this drug on top of other drugs, if we had more of that, would that lower the
bar for requiring more safety information or would it have no impact?
DR.
TEMPLE: You would have the safety data.
CHAIRMAN
BORER: Well, maybe we do.
DR.
TEMPLE: I mean, I guess Ive got to be clear. You're saying if there were additional
studies that did this, because then they would have 400, 500 people and it
wouldn't look so different anymore.
CHAIRMAN
BORER: Right. If the data were available in the current
data set.
DR.
TEMPLE: Okay.
CHAIRMAN
BORER: Okay. Well, we'll come back to that.
MEMBER
NISSEN: Let me actually answer it if I
could. You know, I do think that if we
had more data, I mean, I do think if we had more very elegant, more elegant
dose-response data from CARISA, it would be helpful, because, you know, Bob is
raising this question. He raises a very
good question. You know, why not limit
it to 750, because we don't see any more from 1000? And so the uncertainties about dose do have
an effect on how we interpret safety, because if, in fact, we really did know
that 750 was the top dose that we needed, then it would mitigate a little bit
against some of the safety concerns. We
would know we didn't have to push the dose in order to get efficacy. So, I think that safety and efficacy here are
interwoven. They are interrelated and
the more rigorous and the more useful the efficacy data, the more one can be
comfortable that we know enough to be able to move forward.
CHAIRMAN
BORER: Ed?
DR.
PRITCHETT: Well, I mean, I think
choosing a dose-response, choosing your doses from this data set is really sort
of a charming exercise, because we have the MARISA Study with 500, 1000 and
1500 in it, you know, which has three doses over a threefold dose range, but there
is a study design that has some problems with it. Then we have this very nice parallel design
study that has the 750 and 1000 bid in it, and they are indistinguishable on
all their outcomes.
So
if you believe that 750 and 1000 are indistinguishable, then how do you account
for the fact that 1000 and 1500 show an efficacy difference in MARISA? So, I believe there is a continuum of these
doses and, you know, frankly, I am intrigued with the idea of the 500, you
know, 750 or 375, 750 as doses, but I am also not terribly troubled by 1000,
you know, as the upper limit.
CHAIRMAN
BORER: Ed, do you believe that the
MARISA trial does show a difference between 1000 and 1500? The statistics don't say that. What they say is that there is a difference
between each of the three doses and placebo.
DR.
PRITCHETT: Yes.
CHAIRMAN
BORER: And I would guess, although we
didn't see the data, I would guess that if one did an analysis and accepted --
forget about the study design and the possibility for carry over and what have
you, and the training effect or the learning effect or whatever it is. Forget about all those things. If you look at those numbers, it would appear
that there is a dose-response curve, that there is a dose-response
relationship.
DR.
PRITCHETT: Yes.
CHAIRMAN
BORER: That it's different than
zero. The slope of that line is
different than zero. But remember that
1500 isn't going to be used, so we have two doses and do you believe that the
data are sufficiently robust, not to use that word, so that you can say there
really is a dose-response relationship within the range of the doses that would
be used?
DR.
PRITCHETT: Well, I think that the
exercise of pulling your doses out of a data set like this requires both
statistics and common sense, and I don't think it requires that we have a study
that shows that the doses that we want to use are statistically different from
each other. You know, I think, you know,
we can say that they numerically show something, but I don't think there is either
a regulatory or a common sense requirement that the studies have to be powered
to demonstrate a difference between two adjacent doses.
MEMBER
NISSEN: Even when there are safety
issues.
DR.
PRITCHETT: Yes. Like I said, I think picking doses, you know,
when you have got -- you know, we have got five doses that have been tested
from two different studies using two different study designs, and you can throw
up your hands and say I don't know what to do with that or you can say that's
interesting, that's an interesting problem, let's see what we can do.
CHAIRMAN
BORER: I don't think there are five
different doses from the two studies. I
think there are three different doses and placebo.
DR.
PRITCHETT: They tested 500, 750, 1000
and 1500.
CHAIRMAN
BORER: Four, four, I'm sorry.
DR.
PRITCHETT: Four doses, one of which we
have all decided we want to discard, the 1500.
MEMBER
NISSEN: And can I ask you about
this? Let's suppose this drug didn't
produce syncope, didn't produce dizziness and it didn't prolong QT, didn't do
any of those things, would we be having this discussion about whether it should
be 750 or 1000 or, in fact, does it implicitly have something to do with our
comfort level about safety? That was
what you asked, Bob.
DR.
PRITCHETT: Yes. No, and I think it does.
MEMBER
NISSEN: And my answer is it does.
DR.
PRITCHETT: I think it does have a little
bit to do with that. I mean, I think we
have tossed out the 1500, because the side effects are patient complaints, you
know, but now we're trying to wrestle with the three remaining dose choices,
the 500, 750 and 1000. And, you know, I
don't have strong feelings, but I'm not -- you know, I'm not standing up at the
ramparts ready to discard 1000 either.
MEMBER
ARMSTRONG: Jeff, if I can just defend
the 750, 1000. To the best of my
knowledge, the patient comfort in angina on a weekly basis bears little
relationship to exercise performance on a treadmill. So I was actually impressed, coming back to
what Tom was raising earlier, the issue of nitroglycerin consumption and angina
frequency, which I think does show a dose-response in the CARISA you have
cited, so that was the basis for my flexibility across, not the fact that the
exercise treadmill times were flat. I
think that's important. There is the
same -- there is clearly no dose-response in exercise, but their data appeared
to me to be a clinical dose-response that I think may be meaningful.
CHAIRMAN
BORER: Yes, it may be, it may be, and I
guess we'll have to make a judgment about that.
Often one gets less places, less confidence in the nitroglycerin
consumption data and the ambient angina data, because we really don't know how
much exertion was involved in generating the symptom that caused the use of the
nitroglycerin. Whereas, we do on a
treadmill, but that's a separate issue and we don't have to get into it
now. Beverly?
MEMBER
LORELL: Well, I think there is an
additional dose issue worth exploring and it's related to the safety issue, and
it would be a non-issue if there weren't the angst about QT prolongation. I think that it is likely that, at this point
in the drug's history, we're not thinking about it being used as initial
monotherapy. So it's of great interest
to understand efficacy by whatever measure on the background of something.
So
to me, one of the points that was very interesting about CARISA is we don't
have data, I don't believe, about the lower dose that is proposed as a second
add-on drug to any of the background therapies that were used, so we really
don't know whether it's efficacious in that setting. Is that correct?
DR.
THROCKMORTON: That is correct.
MEMBER
LORELL: Yes.
DR.
TEMPLE: Right, but none of them really
added on to good sized doses.
MEMBER
LORELL: But we don't have data even on
dinky doses.
DR.
TEMPLE: At all.
MEMBER
LORELL: Yes.
DR.
TEMPLE: Yes.
DR.
THROCKMORTON: Jeffrey, I wonder if we
could go back to the 1500. The sponsors
proposed that it would be a dose that would not be used, and I am wondering. It sounds as though at least, Ed, you're
convinced by that and maybe you could help me understand what it is that
convinces you of that. If you look at
the adverse events, about a third of the people reported them in the 1500
milligram twice a day dose. Now, there
is IV data I understand that informs us maybe, but if only a third of people
had adverse events at least in a week, it seems possible that that would be a
dose that whether or not it were approved, we can sort of anticipate dose
creep.
Dose
creep at least is a concept that has occurred in other settings,
obviously. That is only relevant,
because if we were thinking of using choices of doses to limit safety, we're
going to only approve these couple doses, because they give us some sort of
safety margin, that might work less well unless there is another reason for
people not to go higher. And so I just
-- I wonder.
DR.
PRITCHETT: Yes. I think that's a legitimate question. I would like to congratulate the sponsor for
exploring a dose that turned out to be not one that they liked, you know,
having the courage to go up in steps big enough to demonstrate that you got to
the top of the range, including both the 1500 milligram dose and the IV, what
did you call it, super tolerance study or whatever it was, but I think in the
1500 the thing that I was more impressed with was the sort of non-linearity of
the number of side effects that were reported of the ones that we really
thought really were related to the drug, nausea and things like that. And that is not to say that that's
unacceptable, but it looked like a break point in the curve, so I'm willing to
say that 1000 -- you know, I'm willing to say that the 1500 is probably not a
dose that we want labeled, but it's also not a dose that I am alarmed if they
wind up, if a patient winds up creeping up there.
CHAIRMAN
BORER: Let's move on for a moment here
to 1.3. "Available safety data from short-term studies of the IV
formulation." I think everybody who
has spoken has agreed that these data decreased our safety concerns, so that's
a good thing. 1.4. "Available
safety data from the short-term studies using the immediate-release
formulation." How much weight do you
give to the safety data from the short-term studies using immediate-release
formulation? Steve, would you like to?
MEMBER
NISSEN: Sure. I mean, a little bit, but not a huge
amount. For one thing, it's not the dose
formulation that's going to be given to patients. What it does help me with though is that
because the peak-to-trough effects are greater, then it does give me a little
bit more of an idea what happens. If
there are AEs that are occurring during peak exposure, then that's going to get
unmasked with an immediate-release formulation, but I don't think -- I mean,
unfortunately, it really is an unfortunate development program that it started
out as an immediate-release formulation and then moved to a sustained-release,
because it would have been so much more useful for us to have used that
exposure to understand better what was going on with efficacy and safety in the
formulation that would ultimately be the one that would be chosen. So I suspect this occurred for other reasons,
but nonetheless I don't think it's terribly helpful to me.
CHAIRMAN
BORER: The sponsor made a good deal of
and gave us a fair amount of information about the comparable blood levels
achieved with the short-term immediate-release preparation and the
sustained-release preparation, and tried to provide some comfort about safety,
as well as efficacy from those data. Is
that compelling for you at all? Does
that help? Steve, why don't you
continue?
MEMBER
NISSEN: It helps a little bit. I mean, I think having the immediate-release
data here is useful, but not as useful as having exposed the same number of
patients to the sustained-release formulation.
I mean, that is one of the problems here, is that our knowledge base
based upon the sustained-release formulation is somewhat limited. And it's limited in part, because the total
exposure involves two different formulations of the drug, and I don't know the
extent to which that was an issue for the Agency, but it is an issue for me in
that I would like to see exposure at some greater level to the drug as
formulated in the way that it's going to be administered to patients.
CHAIRMAN
BORER: Okay. Does anybody disagree with that? If not, let's move on. 1.5. "The overall safety profile from
the available data with the sustained-release formulation." I think we have discussed that already unless
you want some additional comments.
Doug? 1.6. "Available data
pertaining to cardiac repolarization:
Preclinical data." I think
we have beaten that one down, too, unless you have a specific additional
question. Okay. "Relationship between plasma concentration
and QT interval prolongation. For
example, the steepness, plateau of the effect," etcetera. Does anyone have any specific thoughts that
are different from what we have said?
Steve?
MEMBER
NISSEN: Well, the only comment I would
make is the steepness in hepatic patients is just, you know, it seems like an
extraordinarily unusual finding and one that, obviously, if you think about it,
if it's 7 milliseconds for every 1000, well, if you say the dose range can be
up to 5000, you can get 30, 35 milliseconds in a hepatic patient of QT
prolongation pretty quickly. And so it's
just one of those things that comes up that we need to know maybe a little bit
more about.
CHAIRMAN
BORER: We probably do. I would remind everyone that there were 16
patients, was it, that provided that data set?
We didn't see the raw data, but correct me if I'm wrong, my guess is
they were all over the map. That is that
there was a fair variability. Is that
correct?
UNIDENTIFIED
SPEAKER: Do you want to see it?
CHAIRMAN
BORER: Perhaps if you can just put it
up. We don't need a long
discussion. Just put up the slide.
MEMBER
CARABELLO: But while that's coming up,
it was also pointed out that none of us knew that 50 percent of patients with
hepatic failure had QT prolongations on no drug. I certainly wasn't aware of that. I mean, I think that's maybe an area where we
didn't have a whole lot of expertise.
CHAIRMAN
BORER: A very good point, but I think
Steve's point is that there is a large unknown here and that the fact that the
relationship between the plasma concentration and QT interval prolongation may
be importantly different in people who have disease of the organ that is
metabolizing the drug might cause us to want a little bit more in the way of
safety data.
DR.
JERLING: Yes. Here we have the data points separated by
mild to moderate impairment. And I
should say it's not only one or two.
Half of the patients in each of the two cohorts had a response that was
more than expected. Half did not. But in the totality of the data, we still see
with some confidence that this is entirely different. It's not only noise. It's something else going on.
MEMBER
HIRSCH: So the comment again is I have
been calling for evidence of this change in QTc with structural heart disease,
heart failure and ischemic cardiomyopathy.
This is certainly a patient group that will be receiving the drug.
MEMBER
ARMSTRONG: Over half the patients had
prior infarction in these studies, so there are certainly structural
abnormalities. We have not seen the
data, but we presume that a number of these patients would have left
ventricular scars.
CHAIRMAN
BORER: Doug?
DR.
THROCKMORTON: Yes. This issue about, you know, sort of
populational definition of QT is a little harder than usual here, because there
is this indication that there is at least this one population where there is an
uncommon response as far as slope of the concentration effect. Typically, the advice has been that if a drug
is found to have an effect on repolarization, you do want to characterize it in
the sort of relevant disease populations.
You want to make sure that you don't miss a drug-disease interaction
that we just don't have enough information from the available data to sort of
predict.
So
the questions I'm hearing from your perspective, that has not been adequately
explored. The sponsor has, you know,
made an effort to explore those things and so I'm just trying to make sure,
from your perspective, some relevant disease populations have not been looked
at as much as you might have liked. Is
that what I'm hearing?
CHAIRMAN
BORER: Is that the general
consensus? Alan suggests that there
needs to be more data in patients with ischemic cardiomyopathy and other
cardiac problems. Does everyone feel,
believe that that's true or are we reasonably satisfied that we have seen a
reasonable range of disease here?
UNIDENTIFIED
SPEAKER: Women.
CHAIRMAN
BORER: Yes. Women, we don't consider women a disease.
MEMBER
NISSEN: Oh, don't bet on it.
UNIDENTIFIED
SPEAKER: Absolutely.
MEMBER
NISSEN: You may not.
DR.
KNAPKA: You know, as a heart patient, I
think no matter what disease you have data on, there is always something
else. I mean, this could go on and on
and on. I think sometimes you have to,
you know, look at the data and be reasonably sure that well, yes, there may be
some other disease, people with other diseases and they can't tolerate this
drug, but we're going to have to find that out and deal with that at that time.
CHAIRMAN
BORER: I must say although, there are a
lot of data I would like to have, a wider range of cardiac disease wouldn't
jump out at me personally as one of the key deficiencies of this data set. I think there are other sub-populations we
might want to know about, but as I looked, patients with heart failure of
diverse ideology have been studied. They
look pretty good. There is nothing to
suggest that people with one disease or another form of disease do particularly
poorly or have particular safety issues.
Beverly?
MEMBER
LORELL: I guess one question for the
group, and I'm not sure how I feel about this, is that it was passed on very
quickly today that the heart failure population was skewed toward a very
healthy population in that Class III was excluded from this controlled data set
that we have. So that's a healthy chunk
of heart failure in a "real-world" population, Steve's practice that
we're talking about. So I guess that is
a little nagging concern for me. I'm not
sure it's a showstopper, but it's one thing to exclude end-stage Class IV, but
to exclude Class III is a concern.
CHAIRMAN
BORER: Okay. I mean, there are several ways that could be
dealt with if we had no other problems and, you know, we could make that clear
in labeling, put a black box on it or something.
DR.
THROCKMORTON: Andy, is that true? Is that accurate that, in fact, we don't have
any heart failure data, except in Class I, II or early?
DR.
WOLFF: The MARISA and CARISA trials
excluded patients with Class III and Class IV just because, basically, we
wanted patients that were limited by their angina and coronary disease, and as
they get sicker with heart failure, they wind up being limited by other
things. But there are about 80 patients
with Class III and Class IV congestive heart failure that we studied in a
pharmacokinetic and drug interaction study, and the kinetics of the drug in
congestive heart failure aren't remarkably different from those, and this was
now the more severe patients. So there
wouldn't need to be dosing recommendations just based on plasma levels.
Then
the second thing is the relationship between the QTc and the plasma level, and
the slope of that relationship for patients with heart failure is actually
slightly lower than it was for the general population. And similarly, with regard to structural
heart disease, I mean, that point goes to that.
And then when we looked at the population analysis of the Qtc, the
patients with coronary artery disease also, which was most of the patients, had
a slope that was no different from the healthy volunteers. So it would seem that that may go to Dr.
Hirsch's issue.
MEMBER
HIRSCH: That helps me. I hadn't quite heard that in detail before.
MEMBER
NISSEN: Yes. There is one other thing. I mean, I know you made the case that it
didn't make a difference, but it sure was disproportionate in how few patients
had undergone prior revascularization. I
mean, I do think it's nice when the patient population looks like the patient
population that we're most likely to give the drug to in the United States, and
the fact is that everybody in the United States, most of our patients that have
angina, have undergone some revascularization procedure and only a minority of
those patients were actually included in studies.
And
so while I don't think it's probably an issue, it always bothers me when the
population for which a drug is studied for approval looks significantly
different from the population that we're likely to administer the drug to, and
this was a difference that caught my eye right away.
CHAIRMAN
BORER: Yes. I would like to give a slightly different
response on that particular issue, because we have raised it several
times. I would say that there are
several regions on the Island of Manhattan where the application of angioplasty
may -- I'm not sure it's exactly as rapid, but it may approach the rate of
application of angioplasty in the middle of Cleveland, but there are other
places, in Brooklyn and in Queens and dare I say at the Bronx where that kind
of response to angina isn't quite the same, and my guess is that there is
diversity all around the country.
And
unless there were a biologic plausibility to suggest there should be a
difference in response and the data suggested a difference in response, I just
can't get too excited about that. The
data don't suggest a difference in response.
We saw the breakdown. It was the
same in people who had prior angioplasty and those who didn't, which is
consistent with my prior bias that there shouldn't be much of a difference. So although it would be nice to see more
people, it would be nice to see a lot more people in every area, that one
particular issue isn't a big thing for me.
So you have now the entire range of responses having been --
DR.
KNAPKA: Yes, but isn't this, I guess,
the measure of any good research that your sample should represent the
population that you're, you know, applying the drug or any other experimental
results to. I mean, sampling is the key
to everything. If you don't have the
right sample, I mean, how can you apply it to anything? And I think that comes down to women's issue,
the race issue and everything else, that if you don't have the correct sample,
the data becomes a little suspect I think.
CHAIRMAN
BORER: Yes, that's certainly true and I
think we're hitting that issue. I think
it's just with regard to this one particular issue. It's not clear to me that the proportion of
patients who have angioplasty and the proportion that doesn't has to mirror
precisely the proportions in the United States, whatever those proportions are,
which I don't know, except in Cleveland where I do know.
Okay. We have discussed the lack of torsade. We have discussed a number of other cardiac
adverse effects. Well, maybe we haven't. Does anybody have any comments on other
cardiac adverse effects reported in the database that have an impact on the
adequacy of the safety database? Focus
specifically on that. Beverly?
MEMBER
LORELL: Yes. One of the issues that was raised last spring
when QT prolongation was discussed here was the issue of whether there is
additional or separate information contained in the outliers. So in other words, the notion that I came
away with from that very confusing session was that there might be mean and
median data, but that there was something to be learned from people who were
outliers.
So
in hearing about this database today, I think we heard that about 2.3 percent
of patients would probably be reasonably classified as outliers, and I guess
one of the things that would have helped me a lot with this efficacy safety
issue, knowing that we can't have an enormous study and wouldn't want to
commission such a study to look for torsade in 20,000 people, was whether we
have a strong enough handle on the frequency of outliers of that magnitude
based on this relationship with disease and background therapy.
CHAIRMAN
BORER: That's a good question and maybe
we'll ask for a very short clarification from the sponsor, but my recollection
is that the outliers were almost entirely people whose QTc increased by greater
than or equal to 60 milliseconds, that there were very few people who actually
exceeded 500 milliseconds. And, you
know, the implications of those things are not quite clear, but that's
different from, for example, some of the other outlier sets we have seen
here. If we can just have a short
clarification, please, Andy.
DR.
WOLFF: Okay. If we can just have the slide back from the
core presentation since that's what patients have seen before. There we go.
There was a clearer, and I think this is what was just said, effect of
the drug to increase the QTc from baseline by more than 60 milliseconds than
there was to have absolute values greater than 500 milliseconds.
The
thing I would like to emphasize is that it's really not 2.3 percent of patients
that I think we should refer to as outlier patients. They are patients who ever had an outlier
value over an average of 14 or 15 ECGs obtained during the course of the study. The majority of those patients had a single
outlier value or sometimes two. No
patient has ever had the majority of their electrocardiograms show outlier
values. So they are very sporadic, and I
think they just represent the random variability in the data superimposed upon
the linear increase that we do see of 2.4 milliseconds per 1000 nanograms per
mL.
There
is a large component of regression to the mean that we can see. So in other words, the high absolute outlier
values tend to occur more commonly in patients who begin in the upper half of
the patient population. The large
changes from baseline tend to be somewhat more common in the patients who start
out in the lower half of the patient population.
But
overall, I think what we have seen when we looked at the 3111 data and at the
population analysis is that there is tremendous variability in this
measurement, excuse me, both within patients throughout the course of the day
and between patients. So if you have a
slope of 2.4 milliseconds per 1000 nanograms per mL -- could we show the slope
with the 95 percent confidence prediction?
Yes. Great. Thank you.
I mean, this is our slope and if you pick as a particular value for
outliers 500 milliseconds, well, then as you climb up this slope and as you
continue to oscillate fairly widely however around it, as you get higher up
you're going to bump up against this more of the time. But we would say that, you know, 2.5 percent
of our values at any plasma concentration is likely to be up here and 2.5
percent are likely to be down here, and our database is exactly consistent with
that.
DR.
THROCKMORTON: Sorry, Andy. I have to say I wish I knew enough to agree
with much of what you just said. The
databases that we have, roughly speaking, are like yours where episodic QT prolongation above 500 milliseconds is viewed
as a signal of alarm.
Now,
I'm not saying I know that's, you know, an airtight thing. I would welcome any one of the 17 QT experts
that you have available today, that that is what the data sets we have are, are
intermittent ECGs that are collected and have QTs over 500. It's true that there is rationale for that
perhaps, but that is what has been associated with a potential signal for risk
by, in particular. The European
community is particularly interested in that say.
The
numbers, I mean, the other question is whether the incidence that you have
reported is different, and that is a little harder to get a handle on. I mean, very large data sets that Peter and
you saw recently had smaller absolute incidence of QTs over 500 milliseconds in
shorter term exposures I would say, and so whether or not that is exactly a
comparable thing is hard to say, but it's probably not completely dismissable
by reference to the known vagaries of collecting ECGs and measuring them and
the intermittent, you know, sort of changes of QT.
DR.
WOLFF: I think those other populations
were actually not patients with cardiac disease also, is that not true, and
their QT values were lower at baseline, I think, overall than where our
patients began with coronary heart disease.
DR.
THROCKMORTON: In that you trended
towards 60 millisecond change from baseline and over 500 showing roughly the
same story. I'm not sure where that
takes you, but there may be some differences there.
DR.
WOLFF: Yes.
CHAIRMAN
BORER: Okay. Maybe we can cut this particular discussion
short. I think, Beverly, you have seen
what is available and we'll have to come to a conclusion. Tom?
MEMBER
PICKERING: Yes. I just wanted to make an additional comment
about the syncope. I think I'm not
really concerned about the syncope in the young people. You know, these are vasovagal episodes and
they get up and they are fine, but in the older patients I think it is a
potential concern and I don't care for many of these patients in this situation
myself, but I think the prognosis in older patients for syncope is very
different. You know, they can -- some of
them may have orthostatic hypotension to begin with. They may break bones. They may hit their head. They may develop all sorts of other
complications.
We
have also heard there may be a very wide inter individual variation in plasma
levels. I'm still not clear what the
mechanism is. Is it an alpha blocker or
isn't it? I don't know. So I think there is a sort of concern here
that I feel hasn't really been resolved.
I'm interested to hear what other people in the Panel think about the
frequency of syncope in a population like this.
CHAIRMAN
BORER: So you're suggesting that perhaps
there should be more safety data to help better define the frequency of
syncope? Okay. Let's put a bookmark on that one. Let's move on to Question 2.
DR.
THROCKMORTON: Sorry, Jeff. You left out, at least I didn't hear a lot of
interaction from 1.6.3., which is really a fairly important one for the Agency.
CHAIRMAN
BORER: Okay.
DR.
THROCKMORTON: We really need to have
some comment from you.
CHAIRMAN
BORER: Okay. I'm sorry.
I thought we had hit the hepatic impairment in some of the drug
interactions, but if you would like some more.
DR.
THROCKMORTON: Yes. Well, again, just to sort of focus it
again. The issue here is, typically, we
have not asked for interaction studies with individuals that have multiple risk
factors for well, any sort of safety concern, but let's talk about QT today. Typically, we have asked well, you know, how
bad can you get if you have a maximum inhibition of your 3A4 if you have a 3A4
interaction? How bad can it get if you
have another liability? But we haven't
asked people to pile them on and so the question, the direct question is here
we have a place where, in fact, we have got a very uncommon finding, this
hepatic impairment. It's a thing that we
haven't seen before.
How
does that factor into the decision as to whether or not you need additional,
you would recommend that we seek additional safety information about the
consequence of more than one liability at the same time, so more than one drug
or hepatic impairment plus CYP3A4 inhibition?
Is that a thing that you see as necessary to be able to understand the
effect of QT seen here or not?
CHAIRMAN
BORER: Paul?
MEMBER
ARMSTRONG: Well, I tried to winnow at
this earlier, but I do think that this deserves a flag and I guess I would say
that probably 90 percent of the patients that would be eligible for this drug
would be on a statin, and the frequency with which hepatic enzymes will be
acceptably elevated in those patient populations or just at the upper limit of
normal is probably quite substantial. So
I did feel that that was an important issue.
I raised the specter of the patient with a little heart failure and on a
statin, which is also a common category of patients. I was somewhat reassured by the heart failure
data that has been shown subsequently on that point, but I do think that that's
a very common, going to be, drug-drug situation here that is likely to be
relevant in a broad category of patients.
CHAIRMAN
BORER: Okay. Are there any other combinations that we
think specifically need to be studied to provide reasonable labeling? Steve?
MEMBER NISSEN: You know, I don't think I would raise the bar
too high here, Doug. I mean, I guess the
problem is you can drive yourself absolutely crazy trying to satisfy every
potential drug-drug interaction and the reality here is that the risk that we're
interested in, which is torsade, you're just not going to know until you get
some post marketing exposure. And so,
you know, rather than wring your hands and make them do every imaginable
interaction, I guess I just don't see it.
The
only thing, the one that I would be interested in, and I suspect this is
completely unprecedented, but here is a drug that is going to be used in a
cardiovascular population, a lot of whom are going to get anti-arrhythmic
drugs, and there has been the suggestion that this would not adversely interact
with such drugs. Boy, I would sure like
to know that. I mean, as a clinician who
treats these patients, I would sure like to know that I actually had an agent
like this I could give and not have to worry about whether they are also on a
concomitant anti-arrhythmic drug, but I don't think I would ask that for
approval.
I
just think it would be very useful information to have, and I don't think I
would not recommend driving yourself nuts trying to figure out every imaginable
interaction, because the real question is is it going to cause torsade or not,
and I don't think you're going to answer that question, you know, in the
premarketing database.
DR.
THROCKMORTON: Yes, it is a question of
what you learn, but, you know, just as an argument you put two things together
and all of a sudden the QT prolongs 60 milliseconds mean, and 25 percent of the
people were over 500 on three successive ECGs.
I mean, would that be useful information to you? And I'm not even saying I think that's
likely. But again, with this relatively
uncommon disease interactions, hepatic impairment, does that change the
calculus is the question?
I'm
not interested in driving anyone crazy and I try not to do things that are
unjustified, so I will try not to do either of those things. But is this a case that's unusual? It's different than other drugs that I am
familiar with. Does that change the
safety equation, I guess, is another way of asking it?
MEMBER
HIRSCH: I'll take the bait, because I
keep sort of coming in here at the late moment.
I mean, it does to a certain extent and I think that there is no answer
to this. I always hate when the Panel or
the FDA comes back and says now, we have changed the rules. You have a very representative population. It's very reasonable. I would have designed a trial just like this,
but aha, we have a new molecular entity.
We have a little bit of discomfort despite the preclinical data and, in
fact, the drug-drug interaction here is not random. One of them was diltiazem with a two to
fourfold increase will be expected to occur frequently. Some doctors might even use it with verapamil
and there will be additional structural disease and aha, there is that liver.
So
there is -- I feel and share some of the concern. I just don't know if we can raise the bar at
this time. We're likely to see, I think,
adverse events and no way of testing it other than to see the post marketing
torsade, unfortunately. I think the drug
is less likely to be as well-tolerated as we have seen in these trials, but
that will be a prescription in the physician-patient interaction problem.
CHAIRMAN
BORER: Yes. In considering these responses, you know, the
focus has been on torsade and that is very reasonable, but Tom pointed out that
syncope may, in fact, be a greater concern in this population and if, in fact,
interactions of whatever sort lead to blood levels sufficiently high to promote
the vasomotor instability that seems to occur as preparatory to syncope, then
that might be a concern. So it's
something worth keeping in mind.
Number
2, "Evaluate the following as factors influencing the need for additional
efficacy data: Available data on effects of ranolazine on rate-pressure product
or maximum oxygen utilization."
Let
me try and respond to that and just disagree with me if you disagree, so we can
move on to the rest. I think the issue
of maximum oxygen utilization, rate-pressure product, etcetera, is all very
interesting in that it deals with some inferences we could make about putative
mechanism of action or pharmacological effects of the drug, I should say, and
that would be interesting to know. I
would say it's important only if we believe the safety data are not adequate
relative to the benefit that we have seen, so that we have to be reassured that
there is something new here. And I have
got to tell you, that gets a relatively low bounce with me. I would rather see the body counts. So I don't think that that really impacts in
a major way, my thinking about how much efficacy data is needed. Blase?
MEMBER
CARABELLO: I agree from the standpoint
of efficacy that you don't need those data.
I think you only need those data to make a claim. Well, I don't think we can make any claim
about mechanism here. The agent works. Presumably, it relieves angina without
lowering blood pressure very much or heart rate very much. Past that, I don't think we have a mechanism
of action.
CHAIRMAN
BORER: Nor do we need one in order to --
MEMBER
CARABELLO: Exactly.
CHAIRMAN
BORER: Yes. Okay.
2.2. "Available controlled experience with the sustained-release
formulation and trials of duration greater than one week." Now, you know, this may be a larger
issue. Steve, as the Committee reviewer,
do you want to approach that?
MEMBER
NISSEN: You know, I -- sorry. I don't have a whole lot of trouble with
this. I mean, I guess if I were to
characterize my response to this Question 2 overall, is I think the evidence
for efficacy is pretty compelling. I
think it only becomes an issue when one gets to 2.3. where you start talking
about the dose-response curve. I mean,
you know, I doubt if there is anybody at this table, if there is they should
speak up, that doubts that the drug is an efficacious anti-anginal of
comparable efficacy to other drugs, you know, within the group of
anti-anginals.
Now,
it's only a question of whether we have enough information on the
sustained-release formulation to know exactly how to label the product for our
colleagues, you know, to use to know exactly how to dose it. And that is where I sort of get a little bit
less clear, but I don't think I need much more efficacy information on longer
term exposure.
CHAIRMAN
BORER: Okay. You know, it's impossible to divorce efficacy
from safety, but let me ask you to respond to this. The standard for approval of drugs is the
availability of substantial evidence from well-controlled trials, which is
interpreted as meaning more than one.
Here we have two pivotal trials.
One of them, CARISA, clearly shows that the drug is effective. Forget about dose-response for a minute. The other one, MARISA, may not meet that
standard or it may, and we have to hear about that. If it does, does it meet the standard that we
would set for a second piece of evidence favoring efficacy sufficiently, so
that we can construct a reasonable benefit to risk relation given the safety
database we have? So I would ask you to
respond to that.
MEMBER
NISSEN: Tough question. I mean, I think that you're right. You can't divorce the two. And, you know, what's actually interesting is
I came in here less convinced than I have been during the course of the
meeting. I got to give the sponsor a lot
of credit for having put on, I think, a very convincing case both for efficacy
and for relative safety.
And
so what happened to me here today is that I came in with somewhat higher levels
of concerns about safety and somewhat higher levels of concern about efficacy
and I got reassured on both sides. And
so if you look at the equation, you know, I don't think that this drug is very
far away from having a commencing case that efficacy is good for the safety
concerns that we have.
I
do think there are a lot of issues, a lot of little issues here on
dose-response and on concomitant meds and whether it actually works, you know,
in patients that are maximally treated and all those things we raised. But, you know, I don't think the efficacy
comparison to safety is very far out of balance for what I would expect to see
in an approvable drug. So I think it's
very close.
CHAIRMAN
BORER: Does everybody else agree with
that or are there any other opinions?
Okay. 2.3. "Available
information on the dose-response relationship for exercise
tolerance." We have talked a little
bit about dose-response. We have heard
some opinions. Does anyone have anything
else to say about the adequacy of the description of dose-response?
DR.
PRITCHETT: I'll just make a summary
remark. I think that there are enough
data now available to pick the doses, the marketable doses, without additional
studies.
CHAIRMAN
BORER: And what would they be?
DR.
PRITCHETT: Well, I think -- I don't feel
strongly. I think it could be, the upper
dose could either be 1000 or 750, you know, and it could either be 375 or 500. The sponsor, I think, has proposed, you know,
500, 1000 and I would probably go with their recommendation, but if people were
anxious and wanted to ratchet things down and say well, you know, I want to
move it down a notch, you know, I think you could do that and if that provides
reassuring safety information that made more people comfortable, I wouldn't
object terribly to that.
CHAIRMAN
BORER: Doug?
DR.
THROCKMORTON: I'm interested in a little
more conversation about that from other members of the Committee, please.
CHAIRMAN
BORER: Do we have any other
comments? Beverly?
UNIDENTIFIED
SPEAKER: Sure. You go first.
MEMBER
LORELL: Let me just reiterate. I am concerned that we don't have, I think,
any efficacy data of 500 milligrams, the lower dose, added on to any
anti-anginal. And I would like to echo
Dr. Cunningham's concern that for approval in a United States population, I
think we have strong efficacy data that this works in white men, and I think we
don't have the kind of sense that was talked about earlier. I think all of us probably feel for that
population, this balance of safety, efficacy feels much better than it did
coming in this morning.
I'm
not sure I feel that about black Americans.
We have a very dramatic example last year of a very interesting
antihypertensive agent whose overall safety profile and efficacy looked pretty
reasonable, except for a group and that group happened to be black
Americans. So I would welcome some other
thoughts about that.
CHAIRMAN
BORER: Let me ask you further. I mean, the issue of whether 500 works on top
of something else or not would be really important only if you had particular
safety concerns, I'm going to suggest, because if not, someone could try it and
see and if it works, it works and if it doesn't, it doesn't. And if it doesn't, you can push up the dose a
little bit. So I don't have a concern
about that absent some issue that we may be causing a safety problem here, and
this is a low dose and what have you. I
mean, how would you respond to that?
MEMBER
LORELL: I guess my concern would be I
would be encouraged by even a modest data set showing efficacy at 500
milligrams on top of something. I mean,
I think if there is no evidence of efficacy in that setting, we're not
proposing this as a monotherapy, a new drug for isolated use in angina, then it
seems to me that some modicum of data would be helpful. I think the issue about the black American
population and the risk balance of efficacy and safety is a whole different
issue.
CHAIRMAN
BORER: Alan?
MEMBER
HIRSCH: Let me just accentuate
that. I mean, there is many ways of
picking a dose-response and, you know, the physician in practice can do that. If there is no safety concerns, I don't think
there is any essential reason we have to worry about the 500 milligram
dose. The sponsor can do it by looking
at their experience with the efficacy data and adverse events.
But
for the sake of the Panel, in my opinion, I also was intrigued by -- it seems
to me from CARISA and MARISA, you get most of your bang for your buck somewhere
between the 500 and maybe 750 dose if you measure the treadmill time and
potentially, as well, if you look at use of nitroglycerin and report of
angina. And yet, I can't really say that
with any sense of definitiveness, because I'm not quite sure I have seen enough
data at 500.
If
I were concerned, it's the bait that I think Bob wanted us to take earlier and
I didn't take it, that they wanted to build insurance for safety, I'm not sure
we need that. But if we needed that, I
would expand the 500 milligram database also adding populations, and have a
much potentially more tolerable and safer compound that would give
syncope-free, QT interval-neutral angina relief.
CHAIRMAN
BORER: Steve?
MEMBER
NISSEN: Would we even have this
conversation if in CARISA the 750 and 1000 milligrams showed even a numerical
difference? I mean, the problem we have
is that they were spot on, as I recall, that basically, you know, the effect on
exercise time for 750 and 1000 was indistinguishable, and so we're left with a
vacuum of information and that creates, I'm sure for Doug, some problems that
would not be there if you saw stepwise as you did in MARISA, a stepwise
increase in efficacy as you went from dose to dose.
Now,
we know all the reasons why that occurred, but so now the question is would it
be helpful to have more information around what that relationship looks like in
the population most likely to be treated, which is a population already on some
anti-anginal agents where this is an add-on?
Would it make a difference if we really had better information? I think the answer is it would.
CHAIRMAN
BORER: Okay. Doug?
DR.
THROCKMORTON: Yes. Just sort of by historical perspective for
something, I mean, the rationale has been to make sure the low dose that's
approved has some efficacy as you said, Steve, that clearly there is no
advantage to approving a dose that doesn't work, then obviously you could only
take on safety risk. And so it is sort
of a question of whether or not you're convinced that you know enough about the
additive effects of this when used concomitantly, maybe from the higher doses
something like that, that you don't need that information. Maybe 500 was robust enough that you're
willing to believe that you wouldn't have lost all of that effect even if you
had concomitant medications.
But
then routinely, we sort of get criticized for not identifying appropriately the
dosing and labeling, which is actually the additional part of requirement for
drug approval, is adequate labeling for safe and effective uses is sort of the
thing that we have to do here. So it is
a question of can you describe to a practitioner how to use the product?
Again,
there are other small differences. There
are differences as far as how people got to the upper doses. In some studies, the sponsor suggested a
titration scheme. I'm not sure that we
have data precisely matching that titration scheme. Does that matter to the Panel? Is that a thing that you might see as a
liability, that you would like to understand what happens when you start at 500
and move through 750 and go to 1000 or you're prepared to believe that you
would receive the same effect?
MEMBER
CARABELLO: It's just that the drug
levels seem to be very sporadic and unpredictable among individuals, so that
even the 375 dose is likely to be efficacious in some people. So I think it's very hard to predict other
than to start low and go slow, how it's going to affect individuals.
CHAIRMAN
BORER: If this drug isn't going to be
labeled for monotherapy, which as I understand is not what's being asked for,
what is being asked for is administration in people for whom current
anti-anginal therapy is not providing adequate relief, then, you know, I think
you do have to know that it's going to give some additional benefit, which is
the point that Beverly is making.
But
having said that, I really don't care whether I know that from a high dose, and
prudence tells me I can start at a low dose, which I know may be effective in
some people and studies in which monotherapy was employed, I wouldn't
care. I would titrate up, because it's
prudent. And if I didn't have a safety
concern, I really wouldn't be worried about doing that. Now, if I did have a safety concern, I would
have a safety concern throughout the entire dose range. But to answer specifically your question, I
don't care that they didn't study the titration scheme.
2.4.
"Effects of ranolazine on hemodynamic parameters, vital signs,
rate-pressure product," etcetera.
Well, we have talked a little bit about that, but, Tom, can I ask you to
respond to that, because I think this is specifically relevant to the
particular safety issue you were raising, even though it's being raised in the
context here of efficacy.
MEMBER PICKERING: Yes. I
guess the concern again is this issue of whether it unpredictably lowers blood
pressure. I mean, we have heard that in
large doses in young people it may do this.
In older people, there is the syncope, but we haven't really had much in
the way of systematic blood pressure data in the old people, except during the
stress testing. So I think this is
something where it would be helpful to have more systematic blood pressures
both lying and standing, I might add.
CHAIRMAN
BORER: I would add, and then we'll go on
to Paul, that the issue that I think Tom has raised and is continuing to raise
is one of safety and predictability of a drop in blood pressure. In terms of specifically buttressing efficacy
with blood pressure and rate-pressure product, I personally don't think that
that's an issue. If the drug prevents
angina and does so with evidence of reduction in ischemia, so that it's not a
safety concern, that is the patient isn't masking ischemia and going onto a
potentially dangerous level of exercise, then I don't really care what it does
to rate-pressure product and to blood pressure.
As a safety issue though, the predictability and the potential for
syncope and whatever, that would be an issue for me. Paul?
MEMBER
ARMSTRONG: Jeff, knowing what I know, if
I were prescribing this to a 78 year-old in my practice, I would certainly
check fastidiously for postural hypotension before I prescribed it and I'm not
clear. I presume all the blood pressures
we're seeing, except for the IV study, were standing blood pressures, and that
we have no information on the effect on posturally modulated blood pressure,
and I think this is a good point relative to the safe application and the issue
of syncope, which is on our minds, and I think Tom has made some effective
points that I agree with in the older population. So it might be worth pausing on that point.
CHAIRMAN
BORER: Just a yes or no. Do you have systematic data on lying and --
DR.
WOLFF: Yes. Yes, we do.
CHAIRMAN
BORER: Okay. Just in a short response, please.
DR.
WOLFF: There is little change seen in
the postural change in blood pressure until we do get up to doses above 1000
milligrams twice a day. And then in the
healthy volunteers we do see, and I did show in response to a question, some
data on the postural change. It's about
8 or 10 millimeters of mercury when you're at 1500 and 2000 milligrams twice a
day, both of which are doses beyond which what we think should be used. But at 500, 750 and 1000, there is very
little change. I don't think we have
that tabulated. The best data comes from
the SR studies.
CHAIRMAN
BORER: Is that responsive to the point
you were making, Paul?
MEMBER
ARMSTRONG: Yes, I think it is. I just would like to have seen it in the
elderly or in the population that might be at risk of syncope, but it sounds as
though there might be something there worth looking at a little more carefully
and worth pursuing.
MEMBER
PICKERING: I wasn't sure. Do they have data in the patients, because,
you know, young people have good bare receptive reflexes and they can
adjust. Older patients can't.
CHAIRMAN
BORER: Andy?
DR.
WOLFF: Yes.
CHAIRMAN
BORER: I'm sorry. Repeat the question, Tom.
MEMBER
PICKERING: Do you have postural blood pressure
data in the patient population as opposed to the young, healthy volunteers?
DR.
WOLFF: We don't have anything currently
summarized on slides that we can show, but we did measure the data in MARISA
and CARISA, so there are supine and standing measurements. They are not remarkably different from what
we saw in the healthy volunteers. I'm
sorry I don't have it to present.
CHAIRMAN
BORER: Okay. 2.5. "The magnitude of the effect of
ranolazine on exercise tolerance."
We have heard that the magnitude on treadmill exercise tolerance is,
approximately, in the range of what we have seen with other anti-anginal
drugs. Is anybody bothered by that? Do we need more efficacy data because of
that?
DR.
THROCKMORTON: And it could go the other
way. I mean, any one of these could be
so overwhelming, the effect that was seen was so remarkable as to obviate the
need for additional information in some sense or the other. I mean, you could potentially look at them as
good things, too, I mean, more than usually good things.
CHAIRMAN
BORER: Did anybody look at it in a more
than unusually good thing or is that as an inadequacy in the data set? I'm not seeing any responses. I think nobody thinks that's a
showstopper. 2.6 "Accumulated data
on the use of ranolazine together with other anti-anginals." And we have had several comments about that,
about the possible inadequacy of that information.
Beverly,
do you want to make a summary statement about that, about the accumulated data
on the use of ranolazine together with other anti-anginals?
MEMBER
LORELL: Yes. I think this is a point we have discussed at
some depth. I take Steve's point earlier
today, particularly in light of the issue of syncope, that it would have been
desirable or would be desirable to have more data on the use of the drug over a
dose range with long-acting nitrates. So
I see that as a bit of a gap in the database.
CHAIRMAN
BORER: How about with beta
blockers? I mean, again, I think the
requested indication, and correct me if I'm wrong, but the requested indication
is to give this drug on top of other drugs and not as monotherapy, and if
that's true, do we have enough information to say that that's a reasonable
recommendation if the background is beta blocker, for example?
DR.
THROCKMORTON: Yes. Sorry.
There is even a bit more than that.
I mean, the language could say one of two things. Either like most antihypertensives, use in
concomitant with other antihypertensive therapy or you could say we work in
patients that are resistant to other therapies, the bepridil sort of example,
and the latter typically has sort of required studies that have studied
patients resistant to maximal approved or tolerated doses.
The
sponsors made an argument that they have similar evidence from the accumulated
exposure data they have from the variety of studies that they have. And so part of this is a question of is that
convincing to you or if they were seeking a claim for treatment in resistant
populations, treatment in patients who weren't otherwise responsive to
therapies that, in fact, additional data, additional formal studies might be
needed.
MEMBER
LORELL: I think those are two quite
different questions. I think for the
first question as an add-on to background therapy, the data set we have is
close with the exception of the gap of long-acting nitrates, as well as perhaps
data in the population I mentioned earlier of black Americans for whom we have
virtually no data. On the other hand, I
would argue that we don't have sufficient data here at all to tell doctors how
to use this drug in a resistant population, because I don't think that is who
has been studied here.
CHAIRMAN
BORER: Steve?
MEMBER
NISSEN: Yes. I was also, you know, bothered by that
because, in fact, that is how the drug is most likely to, at least initially,
be used in people who are in maximal therapy or intolerant of increases in
therapy. And so, you know, 50 milligrams
a day of atenolol is not maximum therapy nor is 180 milligrams of
diltiazem. And so to me, it would be
useful in labeling, but also to clinicians who want to use the drug, to find
out what happens if you take one, two or more classes of anti-anginal agents,
push them to levels that are fully efficacious, you can try to get people up to
maximal doses, and if they still have angina, then you add this drug on.
And
if you could show that, then I would urge the FDA to give you a label of
showing efficacy in patients who are maximally treated with other anti-anginal
agents, which I think would be a very valuable label for you to have and for me
as a clinician, it would be a very valuable therapeutic indication, because
those are the people we really need help with, are the people we can't make
better. If I can make them better by
taking their dose of atenolol from 50 to 100 milligrams, I'm going to do that
before I'm going to add another agent in, but I don't know that. I don't have any information about that at
this point.
MEMBER
HIRSCH: Just being clear, that's exactly
what we don't know and that's likely a population for which the drug will be
used. So exactly, for the two and three
sort of drug using, well, anti-anginal medication using patient with angina, we
don't really know if there is superimposed efficacy. There may be a plateau beyond which you don't
get additional benefit, and that also hasn't been well-examined.
I
want to also share the concern, I think, that both Tom and Beverly had
mentioned. I still consider the syncope
issue to be potentially concerning in this particular population that will be
elderly and using between five and seven global medications. I actually think there has been a wonderful
database. I think this has actually been
a generally well-tolerated drug, which will be used, but not having data with
superimposed nitrates in a potentially syncope prone population, I think, is a
concern. I would have liked to have seen
that filled in.
CHAIRMAN
BORER: Blase?
MEMBER
CARABELLO: Yes. I think we couldn't possibly recommend it for
patients on maximum therapy, because we don't have any -- we could really be
covered with mud if we did that. We
don't have any idea that those patients would get any better on this
agent. So I think that in that group of
patients, we just haven't seen those data.
The people who did have syncope, two thirds of them were on one or more
vasoactive agents besides ranolazine. So
I think that certainly can be added into the label.
CHAIRMAN
BORER: Okay. 2.7. "The effects of ranolazine on
'hard' clinical outcomes." Let me
make a statement and, again, just respond if you disagree. This is an efficacy question. I don't think it's relevant here. This is the drug is being proposed as an
anti-anginal. Nobody has suggested it
prevented death or myocardial infarction.
And on the safety side, which is not this question, there were
relatively few data, but there was certainly nothing that suggested a major red
flag and I don't think we have a reason to be concerned about that any
further. Doug?
DR.
THROCKMORTON: And just on the other
side, you saw nothing here that made you -- no efficacy here that suggested to
you a benefit above the sort of symptomatic claims that we have been
discussing?
CHAIRMAN
BORER: No. It hasn't been studied and there are no data
to inform us about that. Question 3
"What additional data, if any, are needed for ranolazine to obtain a claim
for use in an unrestricted population with angina?" I have a feeling that we have given you a
great deal of information about that.
DR.
THROCKMORTON: Yes, but this is an important
question to us, Jeff. In this particular
case, I guess I'm going to ask that each member be asked to discuss this
question to the extent that they feel necessary. Again, it's sort of a regulator's sort of
question. The sponsor is interested in an
approval, obviously, and the approval could be of different flavors, if you
will, and the flavors are outlined in the bullets, sorry, in the numbers and in
the bullets there, and the Agency is interested in some discussion that has
gone already, but discussion from each of the members about whether the current
data set sort of meet any of those standards, whether they view that there is
sufficient data available to give one of those claims or the other. And if not, what additional data would be
needed? Again, we have had some
conversation already to support one or more of these particular claims. Is that clear?
CHAIRMAN
BORER: Yes.
DR.
THROCKMORTON: But I would ask that each
of the members be asked to give an opportunity to speak.
CHAIRMAN
BORER: Okay. Why don't we take Question 3 in its entirety
and everyone can give whatever opinions he or she thinks are appropriate. We'll start with Steve, who is the Committee
reviewer, and go around the table that way.
Steve?
MEMBER
NISSEN: Very tough question, Doug,
probably the crux of it all, because it really all depends on to what extent
you're worried about the QTc prolongation effect. If it's really a non-issue, then you have
another class of drugs that's arguably equally effective to the other classes
and, therefore, should be able to be used in an unrestricted population. The difficulty is we have got, you know, only
about 1,700 patient-years of exposure.
We have preclinical data, which is interesting, but we don't have a lot
of precedent for knowing what that means, so that there are several strategies
for dealing with this.
The
problem is I don't see any way out of the box, because if you say well, to use
it in an unrestricted population, you have got to have very good evidence that
you're not going to cause torsade. Well,
you are not going to find that out until the drug has been out there for a fair
amount of time. And so if that's the
standard you want to apply, you're not going to be able to apply it
premarketing. There is no way to know
that.
DR.
THROCKMORTON: Okay. That might be true. You can think of lots of sort of possible
ways out of the box, I guess, but I guess I'll just provide one and the one
possibility that has been discussed, obviously, is a resistant population claim
that would allow marketing and then follow-up.
You know, you would follow and see and, at some point in the future, the
claim would be expanded. That's a fairly
standard way for the Agency to handle uncertainty, let's say, or a place where
you have got to benefit a resistant population that you view or might be viewed
as offsetting this potential safety, and you get additional information that
would allow you to broaden it later, I guess.
That's at least one possible way.
There
may be other ways, the proposal the sponsor has made about an outcome
study. Is that a thing that moves
you? I mean, there are other sort of
strategies that you could think about.
MEMBER
NISSEN: I don't think there are, you
know, and the real -- for me there are not, and the real question is does the
level of concern about QTc rise to the level where you would want to restrict
this drug to a resistant population, and I am pretty much on the border about
that. I mean, I know the problem is
there. I am reassured by the preclinical
data.
You
could argue that letting the drug out there in an unrestricted population is
probably the fastest way to find out.
You know, you get enough exposure, you're going to find out pretty
quickly whether there's a problem or not, and I know that's not something a
regulator would like, but, you know.
DR.
THROCKMORTON: Could you name who would
like that just so I could talk with them?
MEMBER
NISSEN: Yes. I don't know.
You know, I guess the argument for giving it to a restricted population
only is that we do have other anti-anginals.
If we didn't, I think it would be a harder case. And so I think you could arguably say let's
limit it to a very restricted population, get it out there and if we don't see
any additional safety concerns emerge, take away that restriction at some time
in the future. I just wouldn't want that
to be years and years and years if the drug were really effective and safe.
DR.
THROCKMORTON: So just to complete that
thought, you previously said that if a resistant population was what the
sponsor was looking for, the available data were not sufficient for you, so
then would you -- again, without putting words into your mouth, can you tell me
what additional data you would want?
MEMBER
NISSEN: Yes.
DR.
THROCKMORTON: And that goes to 3.2.1.
MEMBER
NISSEN: Yes. I mean, I would do a study in patients that
are maximally treated with conventional anti-anginal agents or intolerable of
them, and demonstrate both safety and efficacy in that population. I think that would be a very useful, you
know, piece of data to allow you to say this drug works in a resistant
population.
So
now, you know, how many drugs and all of that is, you know, hard to say,
because it's going to be very tricky, because sometimes if you push the beta
blocker up you get certain dose limiting toxicities. You push up nitrates, you push up calcium
channel blockers, some patients will reach maximum tolerance with one
drug. Some will reach it with two and
some will reach it with three. So I can't
write the script for that very easily.
Although, somebody would obviously have to be able to do that.
DR.
THROCKMORTON: No, I would like you to
try for us and there is two things.
Remember, you helped write the script for omapatrilat.
MEMBER
NISSEN: Yes.
DR.
THROCKMORTON: So you do have, you know,
sort of experience with the writing of these sorts of things. Two sort of possible things. Typically, what we have told sponsors is in
anti-anginals, although not in resistant antihypertensive populations, is that
demonstrating benefit on top of one anti-anginal at maximal labeled or
tolerated dose, that was sufficient to sort of demonstrate a resistant
population claim.
Now,
you have raised another possibility.
Well, so I don't tolerate nitrates very well, but maybe I tolerate, you
know, calcium channel blockers, you know, without any edema, without any
trouble, so if the one drug rule was what you were interested in, would I be
obligated, would the sponsor be obligated to switch between, say, the three
typically ordered anti-anginal classes before saying intolerance or is an
arbitrary choice of one or the other?
Although,
I mean, you can imagine some populations are almost predictably less tolerant
of one class or the other. And then the
add-on, is the advice we have been giving people reasonable, that is a single
drug sufficient to test the question of resistance or should we be asking
sponsors to look for -- put people on more than one drug? Again, as you say, with the uncertainty of
this agent, you have two other drugs, three other classes out there. So it's a complicated question, but it does
matter as far as sort of development.
MEMBER
NISSEN: It's much harder, Doug, here,
because the dose limiting toxicities for each of these three agents that are
currently available is different. You
know, some patients you give a smidgen of isosorbide dinitrate to and they get
the worst headache of their life and they say don't ever give that drug to me
again, I don't want to ever see you again, you know, and other people who get
pretty profound responses to beta blockers.
So you know, it's just not that simple.
When
we talked about omapatrilat we got blood pressure, right? And we said all right, you throw one drug
after another at them and if their blood pressure is still above X, Y or Z,
then they are resistant. I don't think
with anti-anginals it's nearly that simple to design a trial to actually do
that. So I'm not sure I can write that
script as easily for you.
CHAIRMAN
BORER: Alan?
MEMBER
HIRSCH: I wish you had gone the other
way around the table. It is very
challenging. I'm not going to have an
answer for this one. Though I have been
a critical voice, I find the development program to have been enticing and it
has actually been convincing to me that we have an effective agent that
probably could be useful in either a resistant population or in a general
population in individuals with angina.
Let
me first start where Steve left us. I
don't think it's easy to define, though I called for it, for a study that looks
for one, two and three drug resistance.
Though I would like to see it, I would like to see it more in a broad
based, large population, sort of an interventional trial of individuals with
angina where that naturally might be part of the background treatment. And then I would post hoc evaluate that. I think it's very hard to pre hoc define
resistance. So I'm not sure.
Alternatively,
maybe just to go the other direction to an unrestricted population, one more
pivotal trial. I think that if we sort
of are reassured. I have been reassured
by the QT prolongation, torsade issues a bit to this point. One could jettison the approach, at this
point, to look for resistance and attempt to gain approval for a first line
therapy.
CHAIRMAN
BORER: Who should be -- what population
should be studied in that trial?
MEMBER
HIRSCH: That would be individuals with
angina.
CHAIRMAN
BORER: Okay. So you --
MEMBER
HIRSCH: Broad based population.
CHAIRMAN
BORER: You have no concerns about
sub-populations that haven't been studied?
MEMBER
HIRSCH: They would be answered, as sort
of Bev called earlier, by their inclusion in the next trial.
CHAIRMAN
BORER: Tom?
MEMBER
PICKERING: Well, this is being compared
against three classes of anti-anginal agents, all of which are effective and on
all of which we have huge amounts of long-term data, so we know they are
safe. In the case of beta blockers, they
do other good things. So I would be very
concerned about its unrestricted use. I
think potentially it does have a place in patients who have failed or who are
still symptomatic while being treated with the three conventional agents, but I
don't think -- I mean, we haven't heard anything about how effective it is on
patients already taking long-acting nitrates.
So
I personally would like to see more data in patients who have been tried on
maximal doses of the more conventional agents to see if this really does have a
beneficial effect, which I would define not only by doing treadmill tests, but
also by talking to the patient, which nobody seems to have done.
CHAIRMAN
BORER: Beverly?
DR.
THROCKMORTON: Sorry. One drug, two drugs for your resistant
population?
MEMBER
PICKERING: Well, I think they should
have been exposed to three drugs. I
mean, maybe not. They couldn't
necessarily tolerate them all, but I think that would be the conventional way
to try those three other drugs first.
MEMBER
HIRSCH: Can I ask him to follow-up? Do you mean this in a deliberate, prospective
manner or in a more broad, "real-world" population where some will be
treated with one, two or three?
MEMBER
PICKERING: I'm not sure I'm going to
design the study, but I do think the question has not adequately been answered
whether the patients that we have heard about could have been controlled by
increasing the dose, say, of the beta blocker or the amlodipine or the
diltiazem and the nitrate stories.
CHAIRMAN
BORER: Beverly?
MEMBER
LORELL: I think the safety issues that
we have discussed today have been modified by the beautiful preclinical data we
heard, but have not completely gone away.
To my mind, the preclinical data is elegant and is hypothesis
generating, but doesn't allow us to say with surety to any of our patients that
there is no increased risk of torsade or excess syncope with this agent
compared to other available drugs.
That
being said, I personally would be very comfortable with what I would think
would be a very modest label of restriction.
To me it's formidable to think about how one might do this complex
matrix of perhaps patients who remain symptomatic despite treatment on one or
more other anti-anginal drugs. Remember
that what will inform doctors in the "real-world" about how to use
this agent is a single trial, which is CARISA, and that's what that trial did.
However,
not to beat a point, but I would like to see for its use in the United States a
modest trial with that kind of permissive restriction, if you would, in black
Americans, because otherwise, I think we don't have either safety or efficacy
data on a big chunk of the United States population who has refractory angina
or difficult-to-manage angina.
CHAIRMAN
BORER: Dr. Knapka?
DR.
KNAPKA: Yes, thank you. Well, first I want to commend the
sponsor. I was very impressed with the
data. Usually, those of you who know me,
I am real critical of statistics and I didn't have anything to really criticize
this time. As I said before, I think
certainly from a patient's perspective, and I have been one that had angina,
and I do know when the pain goes away you feel better, Tom.
But
I would probably vote that there be some marketing of this drug to a restricted
population, which we know, and at the same time probably be another clinical
trial, another trial done that includes actually a sample that represents the
population where the drug is going to be sold.
Now, that may mean folks taking two to three of the drugs, different
ethnic backgrounds, races, gender, but I just think the weakest point in the
core study is that the sample used does not represent the American population.
DR.
THROCKMORTON: Sorry. Just to clarify. So from your perspective, you believe there
is currently available data sufficient to give the sponsor a claim in a
resistant population or do you think that additional data are required before
that would be possible?
DR.
KNAPKA: I think they should be done
concurrently. I think that --
DR.
THROCKMORTON: Right. So "concurrently" means available
data are sufficient to allow approval in a resistant population?
DR.
KNAPKA: Right, and then do this other
study.
DR.
THROCKMORTON: Okay.
CHAIRMAN
BORER: Blase?
MEMBER
CARABELLO: I have been persuaded that
this is a safe, effective agent. I mean,
we say that the current agents that we have available are safe. That is only because we have learned how to
use them. Certainly, we were all there
when beta blockers almost killed a bunch of folks or when calcium channel
blockers almost did the same thing. We
have simply learned how to use those drugs in a safe fashion.
CHAIRMAN
BORER: Steve wasn't here. He wasn't born yet.
MEMBER
CARABELLO: Well, I know, he wasn't born
yet, but that doesn't mean those specific agents were any safer than this
one. We simply learned how to use them
safely. I don't think we have any
evidence that this agent is going to be any more effective in a resistant
population, depending on how you define that, and I don't see limiting it to
use there. In fact, I think that's the
area where we know the least about its efficacy. So I wouldn't get excited about calling it
for use in a resistant population.
I
do think Beverly's concern is one we can't gloss over. It has been used in preciously few black
Americans, and I don't know how you get around that. We just don't know what its safety is there,
but I guess I would vote for, you know, it's unrestricted use. And I don't know, have we ever labeled an
agent? We label agents as not proven
safe in pregnant women, etcetera, etcetera.
Have we ever labeled an agent as not proven safe in a race or in another
category of patients?
DR.
THROCKMORTON: In fact, we're fairly
standard issue asked to reflect the available data at a minimum, which is so in
this case it would be -- well, I mean, so you would look at the data and say we
don't have any information as to safety and efficacy, whatever that is, unless
you thought there was a signal that, in fact, there was diminished efficacy or
safety concerns, something like that, like the LIFE trial, like might be the
case for women here or something like that.
So
just to be clear, your recommendation is approval in an unrestricted population
based on the available data?
MEMBER
CARABELLO: Yes, with the appropriate
labeling caveat.
DR.
THROCKMORTON: Right.
MEMBER
CARABELLO: About vasoactive agents, etcetera, etcetera.
DR.
THROCKMORTON: Sorry. Vasoactive agents?
MEMBER
CARABELLO: Well, I mean, I think you
would urge caution in patients taking other or taking vasoactive agents since
that's where two thirds of the syncope occur.
DR.
THROCKMORTON: I see. Okay.
CHAIRMAN
BORER: Ed?
DR.
PRITCHETT: Well, as a principal of drug
labeling, my sort of first principle is that the drug should be labeled for the
population that was included in the clinical trials, and I think so, and I'm
actually quite persuaded by the efficacy and safety data that we have seen here
today. And so the population that I like
would be the CARISA population, you know, where I think we have the most data. You know, and that's a population that
included people who were on, you know, one other drug at least. It excluded patients with Class III and Class
IV angina, you know, but I would craft, you know, the target population around
the CARISA population.
I
think that the concept of defining a resistant population and doing some kind
of study in that population or labeling that population is one of those ideas
where the devil is really in the details, and I think that to go out and try
and write a protocol that recruited patients with resistant something or
patients who were on maximally tolerated something, I think would be very
difficult. And in addition to that, I
think if you took that protocol around to angina clinics, that all the
investigators would say I got thousands of those patients in my clinic, and
then when you gave them the protocol they wouldn't be able to recruit any of
them. It looks like a very difficult
concept.
So
in addition to that, I am troubled by the fact, by the notion of saying that
based on the current data set that we should restrict the drug to use in some
population that essentially wasn't studied.
So I am much more comfortable with saying I like the CARISA population
as the population.
DR.
THROCKMORTON: Okay. So let me just ask you a little more about that. The basis of that conclusion would be that
you have adequate safety information?
DR.
PRITCHETT: Yes.
DR.
THROCKMORTON: That the reason to choose
a resistant population is that that's a benefit above and beyond a general
population. It's a therapy when no other
therapies are available that gives you additional ability to tolerate
uncertainty and safety. I just want to
make sure that that's the basis for your thinking.
DR.
PRITCHETT: Well, no, what I'm saying is
that I am uncomfortable with saying here is a new drug and let's use it in a
resistant population when, in fact, it hasn't been tested in a resistant
population.
DR.
THROCKMORTON: Right, and I know that's
right.
DR.
PRITCHETT: At least about efficacy and
safety in a resistant population.
DR.
THROCKMORTON: Right. So I hear that loud and clear. You don't believe that efficacy has been
demonstrated in a resistant population.
But again, that the trials have been done, of course, is true. We have done resistant trials, resistant population
trials. You know, sort of without any
difficulty, obviously, bepridil was able to do theirs with -- I mean, that's
not an insoluble problem if you believe it's necessary, and so it's back to
that necessary part. Your assertion,
it's difficult, is not the same thing as saying and it's necessary? So you're saying it's not necessary?
DR.
PRITCHETT: It's not necessary.
DR.
THROCKMORTON: Okay.
DR.
PRITCHETT: Okay. I believe it's not necessary.
CHAIRMAN
BORER: Ron?
MEMBER
PORTMAN: I agree with Ed in large
part. First, I again want to compliment
the sponsors on a terrific job of presenting their data. I am convinced, as a nephrologist, of the
effectiveness of the drug in the population studied. I also think that the safety is reasonable,
particularly in the lower maximal dose, and I would certainly favor that. I mean, clinicians will raise the dose if
they can and if they would see that it's going to be more effective on their
own, but if you look at the data, there is at least a twofold increase in some
of the side effects when you get to 1000 compared to 750 where the efficacy,
you know, seems to be pretty good at that level.
So
I would label this, I think, for a resistant group, but again, similar to the
CARISA Study. If we were looking at the
bullets under 3.2.1., I think the first bullet and the third bullet look
reasonable to me. For those who are
symptomatic maximally tolerated, of course, we haven't studied maximally
tolerated, of one other anginal drug or in those patients where just for some
other reason, those other drugs can't be used, and I think that would be
reasonable. The second bullet would
require further study.
So
I think, again, concomitantly we could have that approval, but I still urge, as
Beverly has suggested, that we go forward, the company go forward with
additional studies, particularly looking at the African-Americans, studying the
hepatic group in more detail, the renal group.
And whatever they do, I hope the company will look at trough levels on
population kinetics, particularly with all the different concomitant
medications that can effect 34A, just to see what effect these multi drugs will
have on the levels.
CHAIRMAN
BORER: Ron, if I understand, you're
saying that it's approvable. You believe
it's approvable right now for unrestricted use?
MEMBER
PORTMAN: No.
CHAIRMAN
BORER: No? Okay.
MEMBER
PORTMAN: For restricted use.
CHAIRMAN
BORER: It's approvable for restricted
use?
MEMBER
PORTMAN: Right.
DR.
THROCKMORTON: Ron, say more about the
third bullet. How would you identify
those patients? I'm asking that only
because --
MEMBER
PORTMAN: Yes.
DR.
THROCKMORTON: -- we haven't had a chance
to talk a lot about that.
MEMBER
PORTMAN: It's fine. I mean, look, to be honest, it's imaginary
for me. I mean, I don't treat patients
with angina. Okay. But, you know, just from a logic sense, I
mean, I could see that you could come up with a patient, you know, who for some
reason can't take a beta blocker, can't take a calcium channel blocker or not
higher doses.
DR.
THROCKMORTON: Right.
MEMBER
PORTMAN: And thus --
DR.
THROCKMORTON: The sponsor has made a
number of proposals in that.
MEMBER
PORTMAN: Right.
DR.
THROCKMORTON: Along those lines, and I
wanted to ask one, if you found that credible, and then I will return to
something that Bob Temple asked earlier, argued that some blood pressures, some
individuals' resting blood pressures might be so low that let's suppose that
the other blood pressure lowering agents that were also anti-anginals, you
wouldn't want to try that. I wondered if
you had a cutpoint in mind in that regard or if anyone had a cutpoint in mind
in that regard.
The
question is whether it's an a priori demographic, a bench mark, or whether it
needs individual determination. So if
the sponsors propose that the bench mark of anyone below, well, I don't want to
get it wrong, correct, 60 beats per minute would be at risk for the diltiazem,
that no reasonable physician would ever give them diltiazem because of the
concerns over the AV block, that that identifies a population that shouldn't
get diltiazem. So it's not that they are
not resistant. It's just that they
shouldn't get it. I mean, I'm seeing a
nodding head, so I'm taking that resonates with you.
MEMBER
PORTMAN: Yes, it does, it does. And I think it's obvious that it's very
complicated not just with other levels and all the different concomitant
medications, but, you know, even in the -- we're talking about lowering blood
pressure and yet, Paul was showing me that in the renal group, the diastolic
blood pressure went up 10 millimeters of mercury. So I think it's a very complex issue.
DR.
THROCKMORTON: Right. And certainly, it's a complicated issue,
excuse me, given the variability of the patients.
MEMBER
PORTMAN: Right.
DR.
THROCKMORTON: Pharmacokinetics and
things like that, but you believe, again, a sort of line in the sand approach
is something that would be approachable here?
MEMBER
PORTMAN: I do, yes.
DR.
THROCKMORTON: Steve, I'm sorry, I see
other --
MEMBER
NISSEN: You know, it just isn't that
easy, Doug, because we see patients, sometimes heart failure patients, I know
Bev probably sees them, that walk around with blood pressures under 100 that
are asymptomatic and that you could give them nitrates and you wouldn't have
any trouble at all. I mean, and we
actually do sometimes push beta blockers in those patients and we work our way
up to high doses sometimes over a period of time.
And
so the notion that there is some line in the sand that defines such patients is
not realistic. That is why this is so
hard, is that it is really a difficult judgment about what is a medically
refractory patient. In this particular
arena, it's extremely difficult, and so it's very hard for me to actually
answer that question for you in a way that would allow you to design a
trial. I am really struggling with it.
DR.
THROCKMORTON: Yes. Well, the bepridil experience was fairly
clear cut and, again, we haven't talked a lot about that. That was patients demonstrated to be
resistant to diltiazem, then re-randomized to either diltiazem or to
bepridil. Now, that was a superiority
trial. Again, that isn't the sort of
thing that we would be talking about here, but that was a trial of, I don't
know, 50 people or something like that.
It was not a huge number. So, I
mean, that is at least one way to approach it.
But I am interested in more conversation around the sort of other
population, this intolerant population, when we get to the end, but let's go to
the end of the group here first if we could.
CHAIRMAN
BORER: Paul?
MEMBER
ARMSTRONG: Starting from 3.2.2. then, I
would favor a broader population, more background medical therapy, longer
duration and incorporation of silent ischemia with the added benefit of QT
being able to be measured on Holters out further. For me approval with limitation to one prior
anti-anginal, I actually bring a different approach to this. That is to say, I mean, I think they should
all be on beta blockers, and I think many of us translate the evidence on beta
blockers on hard endpoints to the anginal population. So my view would be that that would be a
minimum.
Like
Blase, I think the calcium antagonists, many of them are not all that safe and
there are some problems, but of course if one were concerned about AV block
with diltiazem, one would use amlodipine or dihydropyridine, so that the issue
of selection, vis-a-vis a calcium antagonist in this situation is moot. But I would certainly be prepared to consider
ranolazine in a patient who is on beta blockers and still having angina.
The
nitrates have tolerance and windows of vulnerability notwithstanding their
venerability, and I do think on the third bullet that there are a significant
proportion of patients that either are asthmatic or have significant AV
block. The low heart rate at rest again,
many of us would put a beta blocker since the exercise heart rate is a far
better marker than the resting heart rate of beta blocker. So I think these are complicated issues, but
I would make the additional pitch that the patient, unless intolerant, should
be on a beta blocker, and that would be my opinion.
DR.
THROCKMORTON: So, Paul, sorry, just to
-- if I understand then, you believe additional data are needed in a resistant
population, and you have talked now about the way that resistant population
looked. Does that capture what you're
saying? I just want to make sure I'm not
--
MEMBER
ARMSTRONG: Well, it was resistant, but
also I said broader and also background therapy. So I think to touch on the other --
DR.
THROCKMORTON: Issues like what Dr.
Pickering and Dr. Lorell raised with nitrates and things like that.
MEMBER
ARMSTRONG: Yes, yes.
DR.
THROCKMORTON: Okay. And I also heard some sympathy for the
intolerant population, but I wasn't sure how well you thought that population
or how best to define an intolerant population.
MEMBER
ARMSTRONG: I think that you lay out some
general parameters. I don't think that
you lay out numbers. I think that you
say symptomatic intolerable hypotension or bradycardia and you leave that to
the physician and the patient.
DR.
THROCKMORTON: Okay.
CHAIRMAN
BORER: Paul, just to clarify, I didn't
hear. 3.1, you didn't specifically
respond. Do you think additional data
needed for ranolazine to obtain a claim for use in an unrestricted population
and if so, what do they need?
MEMBER
ARMSTRONG: I'm sorry, I implied that I
thought the label should be in a resistant population that was taking one
anti-anginal that was a beta blocker or if intolerant another, and I suggested
that the further characterization --
CHAIRMAN
BORER: Not if they wanted an
unrestricted claim. What kind of data
did they need?
MEMBER
ARMSTRONG: More patients, longer period
of time and broader population and better background therapy.
CHAIRMAN
BORER: Susanna?
DR.
CUNNINGHAM: Yes, I think the only
population currently now that they could be approved for are white males, so I
think to be approved -- okay, once again, we're at the same place where we seem
to always end up. So I think that's an
ongoing problem. I think to get approval
we need a representative population that is representative by gender, is
representative by ethnicity and that's not just African-American, that is
Hispanic and that is Asian-American, Pacific Islander population.
I
think the population to be approved should be identical to the population that
has angina in the United States. So I
think we just need the epidemiology data of who has angina and that's the
population we should look at. I think,
Tom is right on that we should talk to these patients. It is key that they feel better. If they don't feel better, it's not really
getting us very far. So I think that's
the other piece. And I will defer to my
cardiologist colleagues in terms of other medications.
CHAIRMAN
BORER: Okay.
DR.
THROCKMORTON: Jeff, sorry, I need to
press just a little bit more on this one.
I apologize. What I heard around
the table and I'll ask for people just to clarify is that at least five of you
saw a way to get -- and oh, you haven't even given yours yet. I better be -- how old are you?
CHAIRMAN
BORER: I'm getting older every day. Okay.
I was very impressed with the presentation and I'm really much less
concerned about the QT issue than I was when I came in or that I might have
been. And I agree with Steve that there
is no reasonable single study that is going to resolve any lingering concerns,
even though I have lingering concerns.
So I have some lingering concerns that can't be resolved, but that
doesn't mean that the drug can never be approved.
I
have a somewhat greater concern about the syncope issue, because I don't quite
understand it yet and I don't understand it, particularly. I don't understand how much I should worry,
particularly, in the context of nitrates being administered, because we have so
little information about that. In
addition, although it isn't the show stopper issue specifically for approvability,
at the first instance, I am concerned that we don't have sufficient
dose-response information to adequately write a label.
But
in terms of approval for an unrestricted population, forgetting about all those
things, I have to agree with everyone who said that we haven't seen a
representative and a varied enough population to give unrestricted approval for
this drug. And I think that in order for
that to be done, we do need to see some data.
It doesn't have to be from a well-controlled trial on angina. It can be from an experience in 50 patients
who are on both.
We
need some information about the concomitant administration of nitrates and this
drug, specifically with reference to what happens to blood pressure, whether
any syncope occurs. There just needs to
be some experience that is greater than what we have. I think that we need a study that involves
women and some representation from sub-populations that are important in the
United States numerically, so that we can have some sense that all those groups
are reasonably likely to respond to the drug.
And
in the context of doing that, I would like to get some more information about
those response. So I think that an
additional study would be helpful, would be necessary or additional data would
be necessary for approval in an unrestricted population with angina. Along the way, we would get more information,
of course, about QTc and torsade, but not enough to resolve that issue. As I've said, however, I don't think that
that's a show stopper for any approval.
If
one doesn't want to do the additional study that I think is necessary to
confirm efficacy and acceptable safety for unrestricted approval, if one didn't
want to do that and didn't want to get the additional information about drug
combinations and what have you, and one wanted to go the route of a restricted
label for a restricted population, then I don't think we have the data to allow
us to provide an approval or to write a label for such patients.
And
if you ask me what population should be studied, well, I'll tell you what I
think could be done and should be done for restricted population. I would say that it is reasonable to study
patients who still have angina on a maximally tolerated dose of at least one
other anti-anginal drug. It could be
more than one. It could be three. It could be two. It could be one. It doesn't matter to me, because my
expectation is that within a study that would be done, the entire range would
be involved, that would be my expectation, and that we could look for internal
consistency within such a study.
And
in that population, I would also allow to be included people who have
conditions that would make them necessarily inappropriate candidates for one or
another of the current classes of anti-anginal, specifically people with major
conduction blocks, patients with asthma, maybe I could add on a few more. So I would be perfectly happy with a
relatively heterogenous group to be studied for restricted label with the
proviso that there be reasonable consistency in the results in that group for a
restricted label, if that's what the sponsor wants.
You
know, so I could see a study that could be designed to give approval for
restricted labeling. If unrestricted
approval is what is wanted, then I would want to see more data the way I've
outlined it.
DR.
THROCKMORTON: I'm fairly certain
unrestricted approval would be what they would be most interested in, and you
don't see that as -- you see that as possible is what I'm hearing. Is that right?
CHAIRMAN
BORER: I see it as possible, but I would
like to see the data that I said should be obtained before I would suggest that
that should be done. Okay. Are there any additional questions you want
to ask before we get to 4?
DR.
THROCKMORTON: I just wanted to ask if
anyone wanted to comment about we've had a fair amount of comment about how
well people do or do not believe they understand the dose-response of the
agent. I don't know if anyone has any
need to say anything else. I think we've
had a fair discussion about that from the two studies.
CHAIRMAN
BORER: What about the issue of duration
of controlled exposure? I mean, that
came up and, you know, we haven't required long duration, that is longer than
the three months controlled exposure. Do
you want comments about that?
DR.
THROCKMORTON: Well, no, sorry, I think
you're missing -- the thrust of the question is not that. The thrust of the question is you have a
single study that exposes patients for more than one week, as far as testing
anti-anginal efficacy. Again, that would
be short of what we have required in the past for other anti-anginal
development projects, at least that I'm familiar with. Maybe there is a good rational for that. It was just a question whether or not you
believe we should, in fact, relax that typical requirement.
CHAIRMAN
BORER: For a second study?
DR.
THROCKMORTON: A second --
CHAIRMAN
BORER: Like CARISA?
DR.
THROCKMORTON: -- longer study would give
you more safety information. It would
provide you additional information. I
mean, it has to do with all of the stuff we've been talking about, but are you
satisfied that one study going longer than a week, in fact, adequately bounders
what you need to know about this drug?
This is sort of another way of asking the question.
CHAIRMAN
BORER: Yes, I would be satisfied with
that. Are there any other
responses? Beverly?
MEMBER
LORELL: Yes. As I said earlier, I also would be satisfied
with that for a restricted population, and I would probably use the word
persistently symptomatic as opposed to refractory, which I think has slightly
different meanings. But I would not be
comfortable seeing this drug for unrestricted use as monotherapy, since we only
have one week of experience as monotherapy in a controlled trial at each of the
doses. And I don't think one week of
experience is sufficient.
CHAIRMAN
BORER: Can I just make a point about
that? I mean, the current guidelines
would allow that. If there is one week
and it shows clear effectiveness and you are satisfied with the effectiveness,
I don't know if you would be from the data we have here from MARISA, but if you
were satisfied with one week of monotherapy placebo-controlled data, if you
were, then all the rest of the development program does not have to have
prolonged monotherapy. And, in fact, a
very reasonable alternative would be to have a placebo-controlled trial on
background therapy that runs for three months.
I mean, you could do that.
MEMBER
LORELL: Just to restate with the current
data, I personally would not be comfortable with unrestricted monotherapy use.
CHAIRMAN
BORER: And what would you want in
addition?
MEMBER
LORELL: I would want to see, I think,
some of the parameters, Jeff, that you brought up. I would want to see a longer experience and
in a much wider database, more typical of United States anginal population.
CHAIRMAN
BORER: Doug, have we exhausted this or
do you want deeper probing?
DR.
THROCKMORTON: No, I think I have
probably heard what I need to hear, unless other people have comments about
that. The demographics, I guess, a great
number of people have made a lot of different comments again, unless there is
things people need to say about that. I
probably have heard enough as well.
CHAIRMAN
BORER: Okay.
DR.
THROCKMORTON: So no, I think, we're
quite happy with that.
CHAIRMAN
BORER: Let me summarize, because I
understand that a short summary is desirable.
I believe that what we collectively have said is that, in general with
some exceptions, and it's not unanimous, the group would not be happy with
approval of this drug for unrestricted use in patients with angina, based on
the current data set. That wider
experience, perhaps with some longer duration with some associated use with
other drugs that are anti-anginal, so at least we have some way of
understanding the potential problems, and some more experience to give us a
better handle on the magnitude of syncope risk, perhaps that this would be
appropriate before considering this drug for unrestricted approval.
That
it could be approved with a restricted label only if studies were done,
appropriate studies, in a population defined as we have given you some
definitions of that could be accepted as being resistant to current therapy or
highly likely to be resistant to currently available therapy. So if an unrestricted label is desired, more
data are needed. If a restricted label
is desired, more data are needed. I
think that's basically what we, as a group, came down to, although there are
some variations that you can read in the transcript.
Does
everybody subscribe to that? I'll take
that as a yes.
DR.
THROCKMORTON: My thanks to the Committee
for two days of heroic endeavor. The
Agency very much appreciates your assistance.
Thank you very much.
CHAIRMAN
BORER: The meeting is concluded.
(Whereupon,
at 4:04 p.m. the meeting was concluded.)