UNITED STATES OF
AMERICA
+ + + + +
FOOD AND DRUG
ADMINISTRATION
MEDICAL DEVICES ADVISORY
COMMITTEE
+ + + + +
OPHTHALMIC DEVICES
ADVISORY PANEL
106TH
MEETING
+ + + + +
FRIDAY,
OCTOBER 3, 2003
The panel met at 8:30 a.m. in the Gaithersburg Marriott Washingtonian Center, 9751 Washingtonian Boulevard, Gaithersburg, Maryland, Dr. Jayne S. Weiss, Chair, presiding.
PRESENT:
JAYNE S. WEISS, MD., Chair
ARTHUR BRADLEY, Ph.D., Member
MICHAEL R. GRIMMETT, M.D., Member
ALICE Y. MATOBA, M.D., Member
TIMOTHY T. McMAHON, O.D., Member
ALLEN C. HO, M.D., Member
ANNE L. COLEMAN, M.D., Ph.D, Member
KAREN BANDEEN-ROCHE, Ph.D, Consultant,
deputized to vote
WILLIAM D. MATHERS, M.D., Consultant,
deputized to vote
JOEL SUGAR, M.D., Consultant, deputized to vote
MARIAN S. MACSAI-KAPLAN, M.D., Consultant,
deputized to vote
JAMES P. McCULLEY, M.D., Consultant
OLIVER D. SCHEIN, M.D., Consultant,
deputized to vote
GLENDA V. SUCH, M.Ed., Consumer Representative
R. MICHAEL CROMPTON, J.D., M.P.H., R.A.C.
Acting Industry Representative
SPONSOR'S PRESENTERS:
HENRY F. EDELHAUSER, Ph.D
HELENE LAMIELLE, M.D.
DONALD R. SANDERS, M.D., Ph.D.
STEVEN G. SLADE, M.D.
JOHN A. VUKICH, M.D.
FDA PARTICIPANTS:
A. RALPH ROSENTHAL, M..D.
GERRY W. GRAY, Ph.D.
DONNA R. LOCHNER
MALVINA B. EYDELMAN, M.D.
SARA THORNTON
OPEN PUBLIC HEARING SPEAKER:
CAPT. STEVEN C. SCHALLHORN, M.D.
C-O-N-T-E-N-T-S
Call to order................................... 5
Introductory Remarks............................ 5
FDA Presentation............................... 13
Open Public Hearing............................ 15
Open Committee Session......................... 26
Division Update................................ 26
Branch Updates................................. 31
PMA P030016
Sponsor
Presentation
Helene
Lamielle, M.D..................... 32
Steven
Slade, M.D........................ 34
John
Vukich, M.D......................... 44
Henry
Edelhauser, Ph.D................... 55
Panel
Questions for Sponsor.............. 69
FDA
Presentation
Donna
Lochner........................... 120
Malvina
Eydelman, M.D................... 128
Gerry
Gray, Ph.D........................ 138
Panel Questions for FDA....................... 154
Additional Comments from the Sponsor.......... 169
Committee Deliberations
Primary
Panel Reviewers
Dr.
Marian S. Macsai‑Kaplan............. 174
Dr.
Joel Sugar.......................... 187
Dr.
Michael R. Grimmett................. 192
Panel Discussion of PMA P030016............... 219
to Include FDA Questions to the Panel
C-O-N-T-E-N-T-S
FDA ‑ Closing Comments........................ 374
SPONSOR ‑ Closing Comments.................... 374
Voting Options Read........................... 384
Panel Recommendation Takes by Vote............ 422
Polling of Panel Votes........................ 426
Meeting Adjourned............................. 432
P-R-O-C-E-E-D-I-N-G-S
(8:34
a.m.)
DR.
WEISS: Would everyone please take their
seats? We will be beginning in a
moment. I would like to call this
meeting of the Ophthalmic Devices Panel to order. We will have introductory remarks by Sally Thornton and for the
record, I would like to note that there is a quorum present.
MS.
THORNTON: Good morning. I'd like to
introduce myself. I am Sara Thornton,
and I am the Executive Secretary of the Ophthalmic Devices Panel. On behalf of the FDA, I would like to welcome
you to the 106th meeting of the Ophthalmic Devices Panel. Before we proceed with today's agenda, I
have a few short announcements to make.
I'd like to remind everyone to please sign in our at the registration
table. There are sheets there for you
to fill out, just your name and whether you're from industry or the panel or
FDA or the public. Please, we do like
to have that filled out.
All
public handouts for today's meeting are available at the registration
table. There are two new additions to our
usual group of handouts. We've put out
there information on public participation in open public hearings and copies of
a guidance document for FDA and industry on quality system information for
certain pre-market application reviews.
Messages
for panel members and FDA participants, information or special needs should be
directed through Ms. AnnMarie Williams, who is available at the registration
table. The phone number to call for the
meeting area is 301-590-0044. In
consideration of the panel, the sponsor and the Agency we ask that those of you
with cell phones and pagers either turn them off or put them on vibration mode
while in this room and to make your calls outside the meeting area, please.
Lastly,
will all meeting participants please speak into the microphone and give your
name clearly so the transcriber will have an accurate recording of your
comments? Now, at this time, I'd like
to extend a special welcome and introduce to the public the panel and the FDA
staff a new panel consultant who is with us at the table for the first time
today, Dr. Oliver Schein, to my left, who comes to us from Johns Hopkins
University where he holds a joint appointment as the Grossman Professor of
Opthamology in the School of Medicine and as a Professor of Epidemiology in the
School of Public Health and Hygiene.
His
clinical expertise is in the medical and surgical management of patients with
corneal disease and problems involving the interior segment of the eye. I'd also like to welcome our acting industry
rep, Mr. Michael Crompton, Vice President for Regulatory and Clinical Affairs
and Quality Assurance for Carl Zeiss Meditec, Inc. Mr. Crompton is sitting in for Mr. Ronald McCarley, who will not
participate in today's proceedings at the request of the PMA sponsor.
Will
the remaining panel members please introduce themselves beginning with Glenda?
MS.
SUCH: Glenda Such, Consumer
Representative.
DR.
SUGAR: Joel Sugar, University of
Illinois at Chicago.
DR.
BANDEEN-ROCHE: Karen Bandeen-Rhodes,
Johns Hopkins University.
DR.
McMAHON: Tim McMahon, Department of
Ophthalmology, University of Illinois at Chicago.
DR.
MATOBA: Alice Matoba, Cullen Eye
Institute, Baylor College of Medicine.
DR.
BRADLEY: Arthur Bradley, Professor of
Vision Science, Indiana University.
DR.
WEISS: Jayne Weiss, Kresge Eye
Institute, Wayne State University, School of Medicine.
DR.
MATHERS: Bill Mathers, Oregon Health
Sciences University.
DR.
HO: Allen Ho, Wills Eye Hospital,
Philadelphia.
DR.
GRIMMETT: Michael Grimmett, West Palm
Beach Florida.
DR.
MACSAI: Marian Macsai, Northwestern
University, Chicago.
DR.
McCULLEY: Jim McCulley, University of
Texas, Southwestern Medical School, Dallas.
DR.
COLEMAN: Anne Coleman, UCLA.
DR.
ROSENTHAL: Ralph Rosenthal, FDA.
MS.
THORNTON: Thank you, panel. I'd like to read now the conflict of
interest statement for this meeting of October 3rd, 2003. The following announcement addresses
conflict of interest issues associated with this meeting and is made part of the
record to preclude even the appearance of an impropriety. To determine if any conflict existed, the
Agency reviewed the submitted data for this meeting and all financial interest
reported by the committee participants.
The conflict of interest statutes prohibit special government employees
from participating in matters that could effect their or their employer's
financial interest.
The
Agency has determined, however, that the participation of certain members and
consultants, the need for whose services outweigh the potential conflict of
interest involved is in the best interest of the government. Therefore, a waiver has been granted for Dr.
Oliver Schein for his interest in firms that could potentially be effected by
the panel's recommendations. The waiver
which allows him to participate fully in today's deliberations involves a
pending consulting relationship on a competitor's unrelated product for which
he has not received any compensation and also consulting with a competitor on
unrelated matters for which he receives between $10,001.00 and $50,000.00
yearly.
Dr.
James McCulley has been granted a limited waiver which allows him to
participate in the review and discussion but excludes him from voting on the
application. Dr. McCulley's waiver
involves three consulting arrangements with competing firms. For these consulting services he received
greater than $50,000.00 within the past year.
Copies of these waivers may be obtained from the Agency's Freedom of
Information Office, Room 12A-15 of the Park Loan Building.
We
would like to note for the record that the Agency took into consideration other
matters regarding Drs. Bradley, Schein and Coleman, Michael Grimmett, Allen Ho
and Jayne Weiss. Each of these
panelists reported past or current interest involving firms at issue but in
matters that are not related to today's agenda. The Agency has determined, therefore, that the panelists may
participate fully in the deliberations with the exception of Dr. McCulley, as
noted previously.
We
would also like to note that the Acting Industry Representative for this
meeting, Mr. Michael Crompton, reported that his employer has numerous business
relationships with firms at issue. In
the event that the discussions involve any other products or firms not already
on the agenda for which an FDA participant has a financial interest, the
participant should excuse him or herself from such involvement and the
exclusion will be noted for the record.
With
respect to all other participants, we ask in the interest of fairness that all
persons making statements or presentations disclose any current or previous
financial involvement with any firm whose products they may wish to comment
upon. Thank you.
I'd
like to read not at this time the appointment to temporary voting status for
this meeting. Pursuant to the authority
granted under the Medical Devices Advisory Committee Charter dated October
27th, 1990, and as amended August 18th, 1999, I appoint the following
individuals as voting members of the Ophthalmic Devices Panel for this meeting
on October 3rd, 2003. Drs. William
Mathers, Karen Bandeen-Roche, Joel Sugar, Marian Macsai-Kaplan and Oliver
Schein. For the record, these individuals
are special government employees and consultants to this panel or other panels
under the Medical Devices Advisory Committee.
They
have undergone the customary conflict of interest review and have reviewed the
materials to be considered at this meeting.
Signed, David W. Feigal, Jr. MD, MPH, Director of the Center for Devices
and Radiological Health dated September 26th.
Thank you. Dr. Weiss.
DR.
WEISS: Thank you, Sally. We will now begin the open public
hearing. Captain Steven Schallhorn --
I'm sorry, I'm just going to have him approach the podium and then I have a
statement. But, I'm sorry, you have a
presentation to make to Dr. Matoba. I
apologize.
DR.
ROSENTHAL: I do thank you very much.
DR.
WEISS: That's very important.
DR.
ROSENTHAL: I will come over and stand
next to her.
MS.
THORNTON: Give him a microphone. This is important.
DR.
ROSENTHAL: Hi. I get two kisses this time. I'd like to give this presentation to Alice
Matoba and read the Associate Commissioner for External Relations'
comments. "Dear Dr. Matoba, I
would like to express my deepest appreciation for your efforts and guidance
during your term member -- your term as a member of the Ophthalmic Devices Panel
of the Medical Devices Advisory Committee.
The success of this committee's work reinforces our conviction that
responsible regulation of consumer products depends greatly on the experience,
knowledge and various backgrounds and viewpoints that are represented on the
committee.
In
recognition of your distinguished service to the Food and Drug Administration,
I am pleased to present you with the enclosed plaque". And I am pleased to express my thanks. Alice and I go back a long time.
(Applause)
DR.
MATOBA: Well, thank you, Dr.
Rosenthal. It was a great honor for me
to be asked to serve as a member of the FDA Ophthalmic Devices Panel and it's
been such a great pleasure for me to work with the excellent FDA staff and
fellow panel members and with you and especially with Sally Thornton, who has
done such a great job.
I
have been so impressed with the thoroughness and the very high standard of
scrutiny that you give to all of the protocols that we have seen and I look
forward to continuing to work with you as a consultant in the future. Thank you.
DR.
WEISS: Thank you, Alice. Thank you, Dr. Rosenthal. We will now begin the Open Public Hearing
but first, I wanted to read a statement that was requested by the FDA.
"Both the Food and Drug Administration and the public believe in a
transparent process for information gathering and decision making. To insure such transparency of the open
public hearing session of the Advisory Committee, 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
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.
Dr.
Schallhorn, we have your presentation, we have up to a half hour for the open
public hearing, but you have 10 minutes at this point.
DR.
SCHALLHORN: Well, good morning, and
thank you for allowing me to address the panel. My name is Steve Schallhorn.
I'm an opthamologist, the Director of Cornea and Refractive Surgery at
the Navy Medical Center, San Diego. I
have no financial interest in STAAR.
I'm not a paid consultant. I've
self-funded my travel to come here to address the panel. I am a clinical investigator in the Toric
ICL Study, which is ongoing but treatments at our center have not begun.
I'd
like to also add that I'm an active duty U.S. Navy Ophthalmologist but the
views that I express are not necessarily those of the U.S. Navy.
The
reason I'm here is just to address an important issue, I believe and that is
that we need options. We need surgical
options, surgical options beyond what we can do with keratorefractive surgery
in particular, excimer laser ablative procedures, especially to correct high
myopia. There are many issues here and
they deal with issues such as thin corneas.
There are patients who are not good candidates for refractive surgery
because of high refractive errors.
Patients
with high refractive errors may not be good candidates anyway because current
technology induces a number of aberrations on the cornea which can result in
visual symptoms. And there are patients
or subject that we want to treat that have critical visual demands, especially
those again with high refractive error.
Now,
my area of expertise and what we've studied to a great extent, deals with the
quality of vision after refractive surgery and that's really what I'd like to
spend the rest of the time talking about.
The -- what I'd like to talk about is a study that we've conducted
looking at a 105 consecutive LASIK
subjects that we had visual acuities measurement on, questionnaires and
a special test, a night-driving simulator.
I'll talk more about that.
This
was LASIK performed with multiple laser platforms with a six and a half
millimeter optical zone size with a transition zone, so it's the latest
technology for high myopia. This was
also conventional and not customer wavefront-guided. The average preop refraction was relatively high, it was minus
six, a little over minus six diopters and it ranged up to minus 11. At six months the results were good and the
uncorrected visual acuity results were satisfactory with about three-quarters
of the patients achieving 20/20 uncorrected.
The
night-driving simulator that we used was a derivative of the simulator that Dr.
Ginsberg developed that I believe was required in some earlier investigational
studies conducted for intraocular lenses.
This test, and it's shown here, you can see the -- it doesn't show up
very well, but on the right side, it's looking over the shoulder of a subject
in best corrected trial frames right here, looking at a rural night driving
scene at 55 mile per hour. It's done in
best corrected vision. Each eye is
tested independently. There were
numerous conditions at that the subject were tested on; that was business
signs, traffic signs, pedestrian hazards, et cetera.
Six
thresholds were made for each one of those conditions for both detection and
identifying what that was and it was conducted with and without a glare source
simulating driving which led to 144 measurements that were made, threshold measurements,
per patient and so in these 105 subjects that we tested each eye independently,
with this unique test, the data represents thousands and thousands of man-hours
because it's extremely labor intensive.
They're very, very specialized tests, but nonetheless, it's a
performance-based task and that's what I'm going to start with.
It
is a performance-based task, whereas, other tests, I should say of visual
acuity such as contrast sensitivity, you can ask yourself, I certainly pondered
this, you know, what does it mean if somebody has a subtle loss of
contrast? What does that really mean
and that's a very good question? What
does that really mean and we're trying to get an answer to that, what does that
really mean, but a performance based task built in has some of those answers
addressed. This is a task that we are
now looking at.
We
look at that. Under all conditions, in
this population of 105 subjects, we find a decrement in night driving
performance. How much of a decrement? A little bit. This is the data shown another way and this shows the seconds
improvement or the seconds decreased in the detection or identification
distance, preop to post-op, so it's a paired analysis and zero represents no
change post-op compared to preop and you can see most patients had no
change. But the trend and the
significant -- and it is significant that there was a loss. About 40 percent of patients had one second
or longer increase in their detection distance.
Now,
you could ask also, what does one second mean?
Is that significant? We've
worked with the National Traffic Safety Administration on the meaning of this
and they've conducted studies which have shown that one second is a significant
decrement in night driving performance
at 55 miles per hour under similar but different circumstances. So it's a
-- we're seeing a significant loss in a significant portion of patients
treated with LASIK for relatively high levels of myopia.
Now,
let's look at the vision. This is best
corrected and five percent contrast acuity shown on the same chart. In orange, it's best corrected and this is
lines gained or lost and you can see most patients had no change but the curve
has shifted to the right meaning more patients had improvement than a
decrement, consistent with what we see and that's, perhaps, partly due to
reduction in minification from the act of putting that correction on the
cornea.
In
contrast to what we see with high contrast acuity, we see a shift to the left
or worse with five percent contrast acuity, five percent low contrast
acuity. It's an ETDRS eye chart, that
five percent level and it's backlit. We
see a loss, in fact, 25 percent of patients having measurable loss of contrast
acuity with this. How about the
symptomatology, most patients have no change in their symptomatology, preop to
post-op. However, the curve is shifted
slighted toward worse. Again, this is a
paired analysis. We're looking at all
patients and the difference between post-op and preop. It's slightly shifted worse, meaning
patients have symptoms. In fact, a
subset of patients can have relatively significant symptoms after the
surgery.
Now,
we tried to find out, okay, what are the factors that now are related to their
driving performance decrement, what are those factors and we've done
correlation analysis. And we find
surprisingly that pupil size placed no factor whatsoever and I'll talk more
about the briefly. Pupil size placed no
factor in their night driving performance.
Where we see a significant decrement pupil size has no effect. One of the strongest effects we see, though,
is the level of preop myopia. The
higher level of preop myopia, the worse the night driving symptoms. I'll talk, again, more about that.
We
also get correlations with symptomatology in night driving performance. We get correlations with the contrast. People who have worse contrast, don't do as
well in night driving. That all makes
sense. Here's, just quickly, shows the
low-light pupil diameter and you can see we had patients that were eight
millimeters or larger. We had a wide
range of pupils. We did not exclude
patients who had large pupils in this study.
Just to repeat, we did not exclude patients who had large pupils from
the study. We had a broad distribution
of pupil size. We found no correlation
with pupil size.
And
all of the analysis that we've done, other types of analysis with many, many
other data sets have shown no correlation with pupil size. However, we do find a significant
correlation again, as I mentioned, with preop myopia. Patients who have high levels of preop myopia had a significant
decrease in the night-driving performance.
You can see on a scatter plot of all the data that there is significant
spread. However, there is a significant
relationship also.
Now,
what are the causes of this, what are the causes of these problems after LASIK
and the answer is, I think, has to do with higher order aberrations, the
induction of higher order aberrations.
This is looking at preop, a distribution of the higher order RMS preop
and looking at it post-op in yellow and we see a significant increase in the
higher order aberrations.
We
do correlation analysis with those higher order aberrations and we find that
the level of preop myopia is significantly correlated to induced or an increase
in spherical aberration. And again, a
lot of scatter, but a significant relationship. Likewise, we find that increase in higher order aberrations,
higher order RMS, change in higher order RMS vertically versus change in five-percent
contrast horizontally that there also a significant relationship. Patients who have increase in higher order
aberrations have an increase or a decrease in their contrast acuity.
Anyway,
in conclusion, conventional LASIK works well.
Most patients have no symptoms, but in some patients, it can induce
visual symptoms, it can reduce low contrast acuity, it can increase higher
order aberrations and it can decrease night driving visual performance. Preop myopia is the strongest risk
factor. Patients who are especially
above six diopters have the greatest risk and, of course, that's also the range
where improved algorithms, improved ways to do LASIK, such as wavefront-guided
surgery, is not yet -- is not available.
And
lastly, we need these kind of surgical options. Surgical options are needed especially to correct higher orders
of myopia. Thank you.
DR.
WEISS: Thank you, Dr. Schallhorn.
(Applause)
DR.
WEISS: We don't usually have questions
at this point, but if anyone had any pressing questions for Dr. Schallhorn, we
could limit them to a few, otherwise, we'll -- Dr. Bradley does, Dr.
Schallhorn.
DR.
BRADLEY: Thanks for the presentation,
Dr. Schallhorn. One question, you made
an emphatic statement that pupil size was not critical. You then inferred from your data that these
driving problems were related to higher order aberrations. Well, the one thing we know for use is that
as pupil size gets bigger, aberrations get worse. So how can there be a correlation with higher order aberrations
but not with pupil size?
DR.
SCHALLHORN: Well, aberrations can
increase as the pupil size increases.
But its effect on visual performance is what I'm saying we don't see
that effect on visual performance. For
instance, there may be -- I think there are things we really don't understand
about the visual system and this comes to the heart of several of them. You can have a very aberrated eye that might
have aberrations at seven or eight millimeters but it may not effect visual
performance. You can measure it on an
aberrometer, but if it doesn't effect visual performance, I'm not sure.
You
know, I think the central four, five, six maybe larger than that, millimeters,
of the visual system is critical for high quality vision but it may not be that
the eye has to be that perfect beyond that range, even though we can measure
aberrations in that range.
DR.
WEISS: Thank you very much. We are going to move onto the open committee
session with the Division update by Dr. Rosenthal, followed by a Branch update
by Donna Lochner.
DR.
ROSENTHAL: Thank you, Dr. Weiss. This year we are pleased to announce the
addition of several members to the staff of our Division and I'd like to
introduce them to you. There are
actually two from the Ear, Nose and Throat Branch but I will not introduce
them. They're not here and probably
will not be playing much of a role, though I will comment on them at the end on
their -- who they are.
First,
I'd like to introduce Lori Austin-Hanberry, who has joined our Division in the
position of Project Manager. Amongst
her duties will be insuring that the Division meets MDUFA (ph) product review
goals. She's a Lieutenant Commander in
the Public Health Service, has over 14 years experience as a registered nurse
with clinical, instructional and management background. Prior to joining FDA she managed various
clinical and administrative operations for the Montgomery County Department of
Health and Human Services, most recently managing the Childhood Lead Poisoning
and Prevention Program.
She
was also a Captain in the Air Force Reserves for 11 years. She obtained her nursing degree from Howard
University and her Masters Degree in Health Care Administration from Central
Michigan University. Lori?
Dr.
Joseph Blustein is a shared hire with the Office of Surveillance and Biometrics
and will be working on post-market issues relating to ophthalmic and ENT
devices. He is a Board certified
ophthalmologist and former Medical Director of the Wisconsin Peer Review
Organization. He has two Masters
degrees, one in epidemiology and one in food science. He serves on the Wisconsin Public Health Advisory Committee and
we welcome Dr. Blustein.
Clay
Buttemere went to Virginia Tech to pursue his engineering studies. In 2000 he received his BS in engineering
science and mechanic from Virginia Tech.
He and his wife, after living in Macedonia, moved to Nashville,
Tennessee where he enrolled in graduate studies in the Biomedical Engineering
Department at Vanderbilt University.
His research in the biomedical optics lab at Vanderbilt involved using
optical spectroscopy to assess tissue thermal damage in vivo. In May of 2003, he received an MS degree in
Biomedical Engineering from Vanderbilt and in August of this year he joined the
FDA as a Biomedical Engineer.
Brad
Cunningham is also a Biomedical Engineer, who was hired to work in Donna
Lochner's Intraocular and Corneal Implants Branch. He received his undergraduate degree from the University of
Maryland in Bioengineering focusing on biomedical instrumentation. After graduation, he is employed full time
at Walter Reed Army Institute of Research in the Department of
Neuropharmacology in the Division of Neuroscience. Whilst there, he co-authored three papers, two recently published
articles focusing on studying the therapeutic intervention window following
transient cerebral ischemia and the delayed gene response and he's also in the
Public Health Service as you can tell from his uniform.
I'd
like to announce that the Office of Science and Technology has brought Dr.
Ethan Cohen to work as a staff fellow in the Electrophysiology Branch of the
Division of Physical Sciences. This is
also a shared hire with OST. He will be
working in our Division as well. Dr.
Cohen's area of expertise is electrophysiology of the retina and Dr. Saviola
usurped me. His position is a shared
high with the Office of Device Evaluation.
Dr.
Cohn comes to CDRH from Harvard University where he was a visiting professor in
the Department of Molecular and Cell Biology.
Prior to working at Harvard, Ethan was an assistant professor in the
Department of Ophthalmology and Visual Sciences at Yale Medical School. His PhD is in anatomy from the University of
Pennsylvania Medical School. As an OST
staff fellow, he will continue to research synaptic interactions of retinal
cells. His review work with ODE will be
in the area of retinal prosthetic devices that are reviewed in the
Vitreoretinal and Extraocular Devices Branch of DOED. Dr. Cohen.
And
the final two are from ENT. The first
is Dr. Nandkumar, who is an electrical engineer with an MS in EE from Tulane
University receiving his PhD from Duke in Electrical Engineering. He is an authority on acoustical issues and
will be working in the ENT Branch and the final individual is Dr. Antonio
Periera, who is a Board certified otolaryngologist, head and neck surgeon who
was trained at the University of Puerto Rico and subsequently came to work in
private practice in Washington, D.C.
He
has been in the Center for Biologics since 1995 and where he had assisted in
formulating regulations for the human tissue program and we pinched him from
them and I must say we're delighted to have him join our staff, although there
may not -- they probably will not be working on ophthalmic issues, they might
be if we have issues that relate to their expertise.
So
we welcome all seven new people and I hope you will all get a chance to work
with them and enjoy their company.
Thank you.
DR.
WEISS: Thank you. Donna?
MS.
LOCHNER: In the spirit of keeping the
panel apprised of PMAs that have come before the panel previously, I'd like to
discuss two such PMAs. First, P010059
is a PMA for the Morcher endocapsular tension ring used for capsular bag
stabilization in patients with pseudo exfoliation syndrome or other situations
of compromised zonulas.
This
PMA was reviewed by the panel in January of 2002. The panel recommended that the PMA was approvable with requests
for essentially a complete reanalysis of the clinical data to resolve
discrepancies in the PMA and to clarify information that was presented at the
panel meeting. We are in the final
stages of review and we expect a decision in the near future.
The
second PMA is P030002 for the C&C Vision CrystalLens Accommodating
Intraocular Lens. This PMA was reviewed
by the panel in May of 2003. The panel
recommended that the PMA was approvable with requests that the patient
satisfaction data be stratified by pupil size and that certain labeling
revisions be made. The panel recommended
that the lens provides accommodative amplitude of about one diopter. Again, we are in the final stages of review
and expect a decision in the near future.
Thank you.
DR.
WEISS: Thank you, Donna. I will ask the sponsor to come to the
podium. We are going to begin the
presentation of PMA P030016. The
sponsor has one hour for their presentation.
I would request that each presenter speak into the microphone, initially
identify yourself and your relationship with the sponsor and any potential financial
conflicts.
DR.
LAMIELLE: Good morning. My name is Helene Lamielle and I'm Chief
Scientific Officer for STAAR Surgical.
We are pleased to present you today PMA P030016 for the Collamer
Implantable Contact Lens for the correction of myopia. Presenting on behalf of STAAR Surgical today
will be Dr. Steven Slade, from Houston, Texas, Dr. John Vukich, a medical monitor
from Madison, Wisconsin and Dr. Henry Edelhauser, Director of Ophthalmic
Research at Emory University an Director of Specular Microscopy Reading
Center.
Dr.
Vukich has a financial interest in STAAR Surgical while Dr. Slade and
Edelhauser are paid consultants with no financial interest other than
compensation for their time. Dr. Donald
Sanders will participate in the discussions that follow our presentation. Dr. Sanders has a financial interest in
STAAR Surgical.
The
STAAR Myopic Implantable Contact Lens is the subject of today's panel meeting,
is indicated for the correction of moderate to high myopia between minus three
to minus 20 diopters and is intended for placement behind the iris in the
posterior chamber of the phakic eye.
The design of the ICL is very similar to that of standard plate haptic
intraocular lenses used for cataract surgery.
However, the ICL has been designed with forward vault to minimize
contact with the central anterior capsule of the crystalline lens. The lens material is a hydrophilic
biocompatible polymer known as Collamer and has a history of safe use in
approved standard posterior chamber intraocular lenses.
Here
is a photograph of the ICL in the vault of the crystalline lens. The footplates are approximately 100 microns
thick and are intended to rest in the sulcus.
At this time, I would like to introduce Dr. Steven Slade, who will
present the surgical procedure, study method for the PMA clinical trial and
effectiveness outcome.
DR.
SLADE: Okay, thank you, Helene. Good morning. My name is Steven Slade and I certainly appreciate the
opportunity to present for you today.
I'd like to begin my presentation by describing the procedure used to
implant the STAAR ICL. The ICL is
shipped to the surgeon in a sterile glass vial and hydrated in saline
solution. The lens is removed from the
vial with forceps. The lens is then
loaded by the surgeon into a sterile disposal injector cartridge for insertion
into the eye and this injection system is just like the ones we commonly use
for small incision cataract surgery.
The
injector is specifically designed to minimize surgical manipulation associated with
the ICL insertion. Iridotomies are
performed up to two weeks before the ICL surgery. The pupil is dilated and the entire surgery is performed under
topical anesthesia. Viscoelastic is
placed in the anterior chamber. The
lens is injected through a spornia (ph) cataract-style incision.
Now,
the surgery is completed then by positioning the lens haptics beneath the iris
and rinsing out the Viscoelastic. The
lens centers extremely well and no sutures were necessary in virtually all
cases. The STAAR ICL is specifically
designed to vault over the anterior capsule of the human crystalline lens. This vault should be approximately 500
microns or one corneal thickness. This
shine through (ph) photograph demonstrates an average vault with the STAAR ICL.
The
clinical study of the STAAR ICL described in this PMA was a prospective
multi-center clinical trial designed to evaluate the safety and effectiveness
of this lens for the correction of moderate to high myopia. Patients with myopia of minus three to minus
20 were enrolled and followed for three years.
The study was originally planned for a two-year follow-up under the IDE
which was approved in 1995.
During
the study, follow up was extended to three years at the FDA's recommendation to
be consistent with more recent guidance for studies of phakic refractive
intraocular lenses. Our patients were
required to be between 21 and 45 years of age and of note, their best corrected
vision pre-optively could be as poor as 2100, and they were allowed to enroll
with as much as two and a half diopters of refractive cylinder, since moderate
to high myopia is associated with lower levels of best corrected visual acuity,
and higher amounts of cylinder. Our
effective parameters included a decrease in refractive myopia, improvement in
uncorrected visual acuity, predictability of the refractive outcomes,
refractive stability and patient satisfaction.
Safety
parameters included a preservation of best corrected visual acuity. Slit lamp findings, intraocular pressure,
contrast sensitivity with and without glare, reports of complications in
adverse events. Specular microscopy was
also performed and we'll present the results in detail of those studies. Accountability; 539 eyes of 305 patients
were implanted with the ICL. Thirteen
eyes of 11 subjects did not meet the entry criteria and were excluded from the
safety and effectiveness cohort.
This
accountability was well within FDA guidance of no more than 10 percent loss per
year of follow up. Even though the study
was originally planned for only two years of follow up, accountability at three
years was 77.2 percent, exceeding the target of 70 percent identified in the
FDA's draft guidance for refractive implants.
Again, even though the FDA guidance requires a minimum of 80 percent
accountability at two years, we had follow up on 91 percent of our cohort and
at three years, we were well above the minimum follow up of 70 percent of
patients.
The
demographics of the study population were fairly unremarkable but it is worth
noting that the average mean myopia preoperatively in this population was over
10 diopters, minus 10.1 diopters. Now,
I'd like to show you uncorrected visual acuity for the entire study cohort and
then uncorrected visual acuity for the eyes that had the potential preoptively
to achieve 20/20 uncorrected vision as well as then the eyes that had the
potential and were actually able to be targeted to emmetropia or 20/20.
Because
we enroll patients with up to 20 diopters of myopia, not all eyes had the
potential for 20/20 nor were all eyes able to be targeted to emmetropia. In part, this was the result of limits on
the range of lens powers available during this study. If we look at the entire
cohort of study patients, the uncorrected visual acuity over time 20/40 or
better, excellent uncorrected distance visual was achieved rapidly, 80 percent
at one week, 20/40 or better and had excellent stability, 81 percent 20/40 or
better uncorrected at the three-year visit.
Again,
looking at the entire study cohort, but at the 20/20 level, we see again, a
rapid improvement in uncorrected acuity and excellent stability. It should be noted that the total cohort of
eyes, this slide, includes those eyes that were not able to be targeted for
emmetropia, eyes with preoperative best spectacle corrected visual acuity worse
than 20/20 and eyes that had up two and a half diopters of refractive
cylinder.
Here's
the breakout for uncorrected visual acuity for the entire study cohort at three
years showing the 20/20, 20/25, 20/30 and 20/40 levels. Now, if you take that same format, I'd like
to show you the results for eyes that had the potential for 20/20 uncorrected
vision. In this group, 89 percent, of
250, 89 percent reached 20/40 or better at the three-year visit and 52 percent
were 20/20 or better, the eyes that had the potential preoperatively to reach
20/20, and the results get even better if we look at the patients who had both
the potential to achieve 20/20 and were able to be targeted to emmetropia. In this population, good visual potential,
59 percent were 20/20 or better at the three-year visit and 95 percent were
20/40 or better uncorrected at their three-year visit. If we take the population and stratify it by
preoperative myopia as in this slide, with less than 7, 7 to 10, 10 to 15 and
over 15, it's apparent that the uncorrected visual acuity of 20/40 or better
and of 20/20 or better was achieved by a lower portion of the eyes with
preoperative myopia greater than minus 15.
It's
not unexpected given that the majority of these eyes could not be targeted for
emmetropia and the lens powers were not available to allow for full correction
of all eyes in this group. Further, in
this group of the highest myopes, only four eyes had best corrected visual
acuity of 20/20 or better preoperatively.
In fact, if we look at the patients again stratified by myopia, who had
the potential for 20/20 and were targets of emmetropia, we see excellent
results at both the 20/40 and the 20/20 levels of uncorrected vision.
But
indeed, none of the patients who were in the over 15 group actually even had
the potential for 20/20 at the same time they were able to be targeted to
emmetropia. We'll have more to say
about this group of higher myopes, over 15, later in the presentation since it
certainly is a unique population.
From
a patient's perspective, this efficacy ratio slide comparing the post-operative
uncorrected visual acuity to the preoperative best corrected visual acuity may
be the most important data in this part of our presentation, since this is what
patients are seeking, uncorrected vision, better than or equal to what they
were able to see before surgery with their best spectacle correction. The efficacy ratio for the ICL was excellent
with upwards of 60 percent of patients seeing as well or better after surgery
with nothing, no correction, than they were able to see before surgery with
their very best spectacle correction.
We
examined the standard metrics of predictability of refractive outcome as well
as refractive stability. As indicated
on this slide, our achieved levels of plus or minus a half and plus or minus
one attempted versus achieved, were excellent and did exceed FDA targets for
both phakic IOLs and refractive lasers were greater than minus seven diopters
of myopia. Accuracy of the attempted
refractive change was excellent in eyes of pre-operative myopia looking at the
cohort stratified by myopia up to minus 15 and then did, indeed, decrease for the myopes with a baseline myopia
greater than 15 as you can see in this slide, again, three years looked at the
entire cohort stratified by myopia.
This
slide pretty much speaks for itself.
This is our stability slide. The
achieved refractive change was again, both rapid, one week, and sustainable
throughout the follow up minus a half, minus a half at 36 months. These outcomes do exceed FDA guidance for
stability of manifest spherical equivalent refraction.
A
patient survey was administered to all study subjects and I will share the
three-year results of that survey with you.
Ninety-nine percent of our patients reported very extremely or
moderately satisfied. When asked to
rate their quality of vision, 77 percent reported very good or excellent
quality of vision as compared to 55 percent of patients before the
surgery. Indeed, 97 percent of the
study patients expressed a willingness to have the ICL surgery again. The unwilling included eyes with refractive
errors, hyperopia (ph), myopia, vomiting right after surgery, and one patient
who questioned why repeat the surgery when they had already had the surgery and
were doing fine.
To
summarize, our uncorrected distance visual acuity at three years all eyes in
the yellow was excellent. Eighty-one
percent of the entire cohort achieved 20/40 or better and 95 percent of the
entire cohort stratified now for those people that had the potential to see
20/20 and were able to be targeted for 20/20, 95 -- that group, 95 percent of
those patients achieved 20/40 or better uncorrected visual acuity.
Predictability
of refractive outcome was also excellent, exceeding FDA targets with a
significantly -- a very small amount of patients winding up over-corrected or
under-corrected, particularly in view of the very broad range of high to
moderate myopia treated and this does, again, exceed FDA targets.
And
now I would like to introduce Dr. John Vukich, who was the medical monitor for
the ICL clinical trial. Dr. Vukich will
present safety outcomes and he'll be followed by Dr. Henry Edelhauser who will
discuss the specular microscopy outcomes for the ICL study. Thank you.
DR.
VUKICH: Good morning. My name is Dr. John Vukich and I am the
medical monitor of the STAAR Surgical Implantable Contact Lens Clinical Trials. I have a financial interest in STARR
Surgical. I will be presenting the
safety outcomes for the study cohort.
Key
safety parameters that were analyzed and will be presented include preservation
of best spectacle corrected acuity, complications and adverse events, lens
opacities, inflammation, patient symptoms, contrast sensitivity and endothelial
cell analysis. There was a rapid and
sustained return of best spectacle corrected visual acuity in the study
population beginning at one week and continuing through every follow up
interval through the three-year period.
At every follow up visit the proportion of eyes with 20/40 best
corrected acuity was improved over the baseline preoperative level of 97 percent. When we break out the best spectacle
corrected acuity at three years, the improvement experienced by the study
population is even more notable particularly with regard to the improvement in
spectacle correction of 20/20 and 20/25.
Thus,
these patients have the potential to benefit not only with regards to
uncorrected acuity, but also in terms of best spectacle corrected acuity. This study population is quite different
from other populations that have undergone refractive surgery evaluations in
that only 69 percent of the preop cohort could be corrected to 20/20 or
better. We believe this is a unique
feature of this cohort and reflects the high level of myopia and the unique
challenges these patients face.
When
we stratify postoperative best corrected acuity by baseline myopia, at every
level of myopia, the ICL cohort experienced an improvement in best corrected
acuity at 20/20 or better as compared to baseline. The highest myopes, those with preoperative myopia greater than
15 diopters, also experienced a substantial improvement at the 20/40
level. The most dramatic increase was
observed in those patients with the highest level of myopia. While we acknowledge the contribution of
magnification in this group of very highly myopic patients, the visual results
are real and are enjoyed by the patients.
When
we look at the changes in lines of best spectacle corrected acuity, 49 percent
of eyes gained one or more lines of acuity at three years. This contrasts with only eight percent of
eyes that lost one or more lines of best corrected acuity. Complications and adverse events are an
important aspect of the evaluation of the ICL and we examined this from several
perspectives. Perioperative
complications were reported for 17 eyes, the most common of which was removal
and reinsertion on the day of surgery.
A
small number of other perioperative complications was also reported and these
included reformation of the anterior chamber, a peripheral iridectomy and
repair of iris prolapse. Postoperative
complications other than intraocular pressure rises, lens opacities or secondary
surgical procedures were reported in five of the 526 eyes in the study cohort
for an incidence of less than one percent.
Since there were so few of these cases in this category, I think it is useful to describe each of these
individually.
One
eye experienced a macular hemorrhage at one week and this result without
sequelae. An asymptomatic subretinal
hemorrhage was observed as an incidental finding at the three-month visit and
best corrected visual acuity remained unchanged from baseline in this eye. Three retinal detachments were reported
during the three years of follow up in this ICL clinical trial. One eye had a retinal detachment with a
macula off. This required repair with
silicon oil and a subsequent nuclear pacification was noted with loss of best
corrected acuity to count fingers. This
patient represents the only case in the study cohort with irreversible loss of
acuity to worse than 20/40. This
patient had 16 diopters of myopia preoperatively.
Two
other retinal detachments were reported during the course of the clinical
trial. Both cases were successfully
repaired such that the final best corrected visual acuity remained within one
line of the preoperative spectacle correction.
Based on published reports, and incidents of retinal detachment of .68
percent per year might have been anticipated and we might have anticipated as
many as nine retinal detachments in
this study cohort that is following 526 eyes over three years. That fact that we had only three retinal
detachments in this study suggests that the ICL had limited or no impact on the
incidents of this adverse event.
Intraocular
pressure rises occurred in 20 eyes or 3.8 percent of the study cohort. The majority of the acture pressure rises
occurred during the first one to two days after surgery. Preoperative iridotomies were performed on
all study eyes as a routine part of the ICL surgery. Seventeen eyes required additional YAG iridotomy or enlargement
of an existing iridotomy for control of intraocular pressure. Irrigation of the anterior chamber for
removal of retain viscoelastic was performed in three eyes. Late intraocular pressure rises occurred in
five eyes or less than one percent of the cohort. This was defined as a single reading intraocular pressure of 25
millimeters or greater or an increase over baseline of 10 millimeters of
mercury at three months or later.
In
three of these eyes the intraocular pressures are being monitored without
intervention and the most recent pressures are shown on this slide. Two eyes are currently being treated with a
topical beta blocker. The most recent
intraocular pressure for these patients are 20 millimeters of mercury or
less. Secondary surgical procedures
were performed in three percent of the study cohort. The most common procedure was removal and replacement as a result
of sizing issues.
Repositioning
was performed in four study eyes. One
ICL was replaced for a power miscalculation.
In the entire study cohort only three eyes underwent ICL removal and
cataract extraction representing .6 percent of the entire study
population. This summary slide shows
all of the secondary ICL surgeries. I'd
like to point out that only a single eye lost best corrected acuity and this
loss was only one line occurring in one eye that underwent and ICL
repositioning. It is particularly
noteworthy that those patients who underwent cataract extraction maintained their
best spectacle corrected acuity relative to their preoperative level prior to
insertion of the ICL.
Assessment
of the crystalline lens was an area of significant concern and this was
monitored carefully throughout the course of the study. Nuclear opacities were observed in five eyes
of three patients. In a patient who
was previously described, a nuclear opacification occurred following retinal
detachment which was repaired with silicon oil. Both eyes of two patients developed simultaneous bilateral
nuclear opacities between two and three years postoperatively and one of these
four eyes required cataract extraction.
Once again, it should be noted that all of these eyes were very highly
myopic ranging from minus 14 to minus 17 diopters.
Lens
clarity was graded at all patient visits using the LOCS 3 Scale. This scale ranges from zero to 5.9 and under
this system a Grade 1 was best described as a trace opacity. Given here is the photographic standard for
Grade 1. I'd like you to keep this
photograph in mind since over half of the anterior subcapsular opacities we are
going to describe were no greater than this clinical standard. In fact only one eye in the study had an
anterior subcapsular change at Grade 2 or higher.
Anterior
subcapsular opacities were observed in 14 eyes of 13 patients. It is important to note that 12 of these 14
cases were asymptomatic and visually insignificant at the most recent follow up
visit. We believe that many of these
cases were surgically related and this is supported by the fact that 11 of
these cases occurred within the first six months of surgery.
Clinically
significant anterior subcapsular opacities were observed in only two eyes. These were defined as LOCS score of less
than -- greater than .5 with a loss of two or more lines of best spectacle
corrected acuity or an increase in glare or a opacity requiring ICL removal
with cataract extraction. One of these
cases was a surgical mishap in which a preservative containing topical miotic
was inadvertently injected into the anterior chamber.
The
second case was an eye in which an opacity was observed six months postoperatively. Cataract surgery was performed and
post-cataract best corrected acuity was unchanged from the pre-ICL
baseline. To summarize our findings on
lens opacities, only three cataract extractions were performed in the study
population of 526 eyes.
One
was related to the inadvertent injection of a topical preserve miotic into the
eye. One was a nuclear cataract and the
third case was an anterior subcapsular opacity that did progress to the level
of clinical significance. Best
corrected visual acuity was unchanged or improved following cataract extraction
in all three eyes compared to pre-UCL treatment. Safety may be best summarized in eye -- by examining the eyes
with persistent loss of best corrected acuity of two or more lines. There are only five of these eyes and you
have seen all of these cases previously in our presentation on safety.
Here
is the retinal detachment repaired with silicone oil and the eye irrigated
intracamerally with preserve miotic
agent. Additionally, three of the
nuclear opacities had a persistent loss of two or more lines of best corrected
acuity. One of these we've just
described had cataract extraction. In
the entire clinical trial, these are the only eyes that had a persistent loss
of two lines or more of best corrected acuity.
Next
I would like to present our findings related to inflammation. Slit lamp examination was performed in all
study eyes at all visits and a laser
cell-flare meter was used to evaluate information in a sub-study of
patients. No inflammatory response was
observed after the first week postoperatively either clinically or by the more
sensitive laser cell-flare meter. Laser
flare measurements following ICL implantation were within the normal range for the
first post-operative week, and remained normal throughout the course of the
entire clinical trial.
A
subjective questionnaire was administered to all study patients preoperatively
and at follow up examinations. Patients
were asked to rate each of the symptoms listed on this slide as either absent,
mild, moderate, marked or severe. When
comparing preoperative responses to those attained at three years, there were
no significant changes in symptoms rated as absent or mild.
Equally
importantly is the fact that there were no significant changes from baseline to
three years in symptoms rated as moderate, marked or severe. Contrast sensitivity and glare were
evaluated in a sub-group study. Well
established techniques were used in our contrast sensitivity testing. After 10 minutes of dark adaptation,
measurements were made both with and without a glare source. There was no loss of contrast sensitivity at
any spacial frequency when compared to baseline to postoperative results. In fact, at two frequencies there was a
significant increase in log units of contrast sensitivity. When contrast sensitivity was repeated in
the presence of a glare source, there was a significant improvement at all four
spacial frequencies starting at three cycles per degree up to 18 cycles per
degree.
I
would now like to introduce Dr. Henry Edelhauser who will be presenting the
Specular Microscopy Substudy.
DR.
EDELHAUSER: Thank you, John. Good morning. I'm Dr. Henry Edelhauser, Director of ophthalmic research at
Emory University. I have no financial
interest in STAAR Surgical. I serve as
Director of the Specular Microscopy Reading Center for the ICL clinical trial
and will be presenting the results of a sub-study conducted by STAAR Surgical
to evaluate the effects of the ICL implantation on the corneal endothelium. I would like to emphasize the importance of
the methods used at the Specular Microscopy Reading Center. Images were received from 12 investigators
at nine clinical sites and a signal masked reader analyzed all the images. The images were then scanned and analyzed
with the Konan KSS-300 Software.
Approximately 1300 images were analyzed in this study and the mean
number of cells per image that was
counted was 93. This slide shows how
the images were handled and that the images were taken with a Konan. They were then sent to us in the reading
center as hard copy. We then scanned
them. We then resized them and
formatted the images. We then
calibrated and analyzed, put it in a spreadsheet and then sent the data back
for statistical analysis at STARR.
I
think it's important when we talk about specular microscopy to review what a
good image is because not all specular microscope and reading centers and
photographers are able to take good images and this is the real challenge in
undertaking specular microscopy. One,
it's important to have distinct cells as illustrated on the right. In the specular micrograph one can identify
100 cells and even more in that's essentially what we do at the reading center
is to identify as many cells as possible because when you analyze this, it's
done by putting a dot in each one of the cells and then the analysis software
is the nearest neighbor analysis. So
cells in the periphery that don't have a nearest neighbor are not counted.
Cells
need to be grouped into form in a contiguous area and then after you have
dotted all the cells, it's extremely important that the evaluator or the reader
check to see that the cells haven't been double-dotted or cells missing because
if you miss three cells, you have a significant change in the end of field cell
density because what you see from this specular micrograph is multiplied by 106.
Precision of the readings is an important factor in the analysis of any
endothelium. We have estimated that the
precision to be two percent in the ideal situation which was published in our
study of LASIK patients. In this
particular case we had one single clinical site, photographer and one single
reader. When you undertake multi-center
study where you have numerous photographers and then you then send this to a
reading center and one single reader, the precision is somewhere between eight
to 10 percent.
The
outcomes of our analysis of the corneal endothelium are shown in this slide and
include endothelial cell density, percent hexagonality, or pleomorphism and
coefficient of variation or polymegathism.
Studies indicate that stress corneas present -- have a percent
hexagonality of less than 45 and a coefficient of variation greater than 45.
Published
studies and studies from my own laboratory have shown that morphology is the
best indicator of corneal endothelial stress and instability. I would now like
to share with you some examples where endothelial morphology has been
demonstrated to be the most sensitive measure of corneal endothelium
stability. These examples are
pseudophakic bullous, diabetes, and contact lens wear.
In
this seminal paper, published by Rao and Aquavella in 1984, they studied
patients implanted with iris fixated lenses in patients whose corneas made
clear shown in the yellow bars, were compared to patients who ultimately
developed corneal edema in the blue bars.
Interesting, these authors found no difference between the two groups
with regard to percent endothelial cell loss.
However, there was a marked difference in coefficient of variation
indicating that morphology is a more sensitive indicator for the development of
bullous keratopathy.
In
the second illustration, the corneal endothelium is illustrated in diabetes and
this was published from one of our papers in 1984 where we reviewed the
endothelium of both Type 1 and Type 2 diabetics. In this study we showed there was no significant difference in
endothelial cell density but there was a significant difference -- decrease in
percent hexagonality and a significant increase in coefficient of variation.
The
next example that shows the importance of morphology is related to endothelial
cell density is provided in a study by McRae and Matsuda, et al, and they
compared patients who used contact lenses for more than 20 years and compared
to age-match controls. Again there was
no significant difference in endothelial cell density, a significant decrease
in hexagonality and a significant increase in the coefficient of
variation.
The
three examples I've shown demonstrate the corneal endothelial morphometric
changes are the first indicators of endothelial stress. The percent hexagonality and coefficient of
variation are more sensitive indicators of endothelial stability than
endothelial cell density.
I
would now like to review the ICL STAAR PMA data on endothelial morphology. This graph is a scattergram of all pre and
post-operative data points. In general,
the majority of the points were between 2,000 and 3,000 cells per millimeter
square with a small number our outlyers.
The dark bars in the center of the scattergram illustrate the mean plus
or minus 90 percent of the confidence interval. This slide shows a similar scattergram but with data points for a
consistent cohort of 37 eyes with specular microscopic data in all visits from
preop to four years.
This
slide does show that the endothelial cell density remains unchanged from three
to four years.
DR.
GRIMMETT: Do you know the confidence
intervals at the last visit?
DR.
EDELHAUSER: Yes, I have it. It's coming up in the next slide.
DR.
GRIMMETT: Thank you.
DR.
EDELHAUSER: The table shows the
pair-wide comparison of endothelial cell density at consecutive intervals
beginning with the preop to three months a minus .2 was measured and cell loss
was observed and from three months to one year a minus .9 percent
observed. Between three and four years,
a plus .1 percent and a narrow confidence limits of 1.4 percent to plus 1.6
percent. The percent hexagonality data
shows no change over the course of study in this cohort of patients.
For
comparative purposes, a percent hexagonality of 45 would be an indication of a
stressed corneal endothelium. The
coefficient of variation data also shows no increase over the course of study
of this cohort. Again, for comparative
purposes, a coefficient of variation of 45 would be an indication of a stressed
corneal endothelium. In summary, the
specular microscopic data show a cumulative or a total mean endothelial cell
loss of 8.4 percent to 9.7 percent over a course of four-year follow up with
stabilization suggested at the four years.
It should be noted that there is no apparent mechanism for chronic cell
loss due to the ICL. This is supported
by the absence of changes in the percent hexagonality and coefficient of
variation, which do not indicate chronic endothelial cell stress in this study
population. This conclusion is
supported by the previous reported data on pseudophakic loss, diabetics and
contact lens wear.
We
don't have a long-term study of endothelium in high myopes in the peer review
literature. But we know that
extrapolating endothelial cell densities over time is complex. It should be noted that the endothelium is
not a homogenous population of cells from central to peripheral and migration
of endothelial cells must be considered in any long term modeling of the
endothelial cell density.
Recent
data published from my laboratory in March of this year in the AJO, addressed
the issue of peripheral corneal endothelial cells. In this study we found that if, indeed, you measure the corneal
endothelium here and then you go two millimeters off in the paracentral region,
there's a five percent increase in the corneal endothelium. And if you go four millimeters off center,
there is a 10 percent increase in endothelial cell density.
Now,
let's put this into perspective with this.
The cell density within a four millimeter button is roughly 34,740. The paracentral region has a cell density of
119,845. And four millimeters off center
in this area where we have a high cell density, the cell density is calculated
out to be 264,632 cells per millimeter square.
Now, this is not a study that doesn't have backup because it had first
been identified by Bert Chimifane (ph) in 1984 and subsequently two papers in
the German literature in `89 and `90, all showing an increase in the peripheral
corneal endothelium. I do want to say
that in this study we measured the corneal endothelial cells in four different
ways; non-contact specular microscopy, contact specular microscopy, alizarin
red staining of corneas we received from the eye bank, and also fixed corneas
where we developed the nomogram to correlate with the pathologist the number of
corneal endothelial cells as measured by the nuclei in high power field
correlated to a nomogram of endothelial cell density.
The
higher the endothelial cell density found in the paracentral and peripheral
cornea affords an additional reassurance of safety for the endothelium in the
patients implanted with the ICL. In
summary, stability appears to be achieved between three years and four years in
the ICL population. This data -- these
data are consistent with endothelial remodeling and stabilization. The absence of any effect on the percent
hexagonality, coefficient of variation support the absence of stress on the
corneal endothelium. This would be consistent
with an implant placed behind the iris and suggests that the endothelial cell
loss observed in the ICL clinical trial is related to the initial surgical
procedure and not a chronic phenomena.
Ongoing
surveillance of the corneal endothelium will be critical to establishing the
continual safety of the ICL and the study sponsor is committed to collecting
the additional four-year follow up patients.
Patients will also be asked to return for five-year specular microscopic
exams and the same rigor and precision will be used to evaluate that corneal
endothelium by the reading center. I
would now like to turn the podium over to Dr. John Vukich.
DR.
VUKICH: Once again, I am Dr. John
Vukich. A unique group in our clinical
trials represented by the patients with more than 15 diopters of myopia. This group deserves special attention since
concerns have been expressed by both the FDA and panel reviewers regarding
acceptability of study outcomes in this population. I think we all understand the unique challenges represented by
this group of extremely myopic patients.
These include significant variability in simply determining the end
point of the manifest refraction. Many
of these patients have poor visual acuity even with their best spectacle
corrected acuity. In spite of this, the
mean post-operative spherical equivalent was reduced from minus 17.3 diopters
to minus 2.2 diopters with the implantable contact lens for an average
correction of 88 percent of the pre-existing myopia. At the time of the ICL clinical trial, lens powers were not
available to achieve full correction to emmetropia in all cases. Even with this limitation, 39 percent of
eyes with greater than 15 diopters of myopia achieved an uncorrected acuity of
20/40 or better.
Substantial
improvement was observed in the proportion of eyes with best corrected acuity
of 20/40 or better. The proportion of
eyes with best corrected acuity of 20/20 or better increased from 13 percent at
baseline to 42 percent at three years.
We acknowledge that magnification contributes to the observed
improvement in best corrected acuity but continue to believe that this
improvement in best corrected vision is an important benefit to the
patient.
Any
analysis of complications and adverse events in this population of high myopes
must be viewed relative to their baseline risk. A body of published literature has established that the risk of
spontaneous complications such as retinal detachment and nuclear opacities is
significantly increased in high myopes.
For example, the risk of detachment of the retina is 26 times higher in
myopes above minus 6 diopters. A
significantly increased risk has also been established for the incidents of
nuclear opacities in highly myoptic patients.
These complications must be viewed in the context of the increased risk
of the population. Given the additional
risk it should not be surprising that a higher rate of complications was
observed in the subset of highly myopic patients.
Review
of these complications which have already been presented as part of the safety
data for the total study population revealed that two retinal detachments and
four nuclear opacities were observed in six eyes. Only the eye with complicated detachment requiring silicone oil
has had an irreversible loss of vision.
In fact, this is the only eye in the entire clinical trial in this
category.
With
the exception of the eye with retinal detachment requiring silicone oil, all of
these patients were satisfied with the outcome of ICL implantation and would be
willing to undergo surgery again. We
have shown that these patients had a substantial improvement uncorrected visual
acuity and over half of these eyes experienced a gain in best corrected
acuity. We believe that these are the
very patients that stand to gain the most from implantation of an ICL
particularly in the absence of alternative devices or surgeries for the
correction or reduction of their myopia.
In
summary, the data presented to you on the outcomes in this PMA serve to
establish the safety and effectiveness of the myopic ICL for its intended use
in myopia from minus 3 to minus 20 diopters.
We believe that the concerns raised by the FDA and panel reviewers can
and should be addressed. To this end,
we are committed to long-term surveillance of the study population with regard
to endothelial cell analysis. We also
believe that a comprehensive training program is an essential part of achieving
successful outcomes with the ICL and plan to require formal training and
certification for all surgeons who use this device.
Finally,
we believe that labeling can be developed to adequately communicate the risks
as well as the benefits of the ICL and we welcome labeling recommendations from
both FDA and panel. This will allow
surgeons and patients to make informed decisions on the use of the ICL and the
appropriateness of this device for each individual patient. We believe that the data presented to you
today and the safeguards we are proposing in terms of long-term patient
surveillance, surgeon training and adequate labeling support a panel
recommendation for approval of the ICL as an important option in the management
of myopia. Thank you and this concludes
the formal presentation by the sponsor.
DR.
WEISS: I'd like to thank the sponsor
for their presentation and if they'd remain at the podium, we will begin for
questions from the panel to sponsor on their presentation. Dr. Macsai?
DR.
MACSAI: My question is directed at Dr.
Edelhauser. The slide you showed of the
37 patients, the standard cohort of endothelial cells changing, on the next
slide you said you would address the coefficient variation confidence intervals
and that slide was not for that 37 patient cohort. This is new information and I think that data would help us
figure out more information about the endothelial cells.
DR.
EDELHAUSER: Yes, I'd like to turn this
-- this was data that came back to us.
DR.
WEISS: Please, would you be able to
identify yourself each time you speak in the mike for the transcription.
DR.
EDELHAUSER: I'm Dr. Edelhauser. This data came from Dr. Gray, the
statistician from the FDA when he sent his review back to STAAR where he then
broke out and calculated this cohort of patients from the start or the pre-op
all the way to four years.
DR.
MACSAI: But what is the -- this is Dr.
Macsai.
DR.
SANDERS: Dr. Gray did not include that
in --
DR.
WEISS: Please identify yourself.
DR.
SANDERS: Dr. Sanders. We used the analysis that Dr. Gray provided
us on the Internet and it did not include the confidence intervals.
DR.
MACSAI: Dr. Macsai speaking. But does STAAR have the same patients
followed from pre-op all the way through to four years, those 37 patients? Do you have that information, can you
provide that information to us?
DR.
VUKICH: We do have those patients and
again, this is an analysis -- I'm sorry, Dr. John Vukich. We do have that analysis available and can
provide that to the panel.
DR.
MACSAI: Thank you.
DR.
WEISS: Dr. Grimmett?
DR.
GRIMMETT: Sure, Dr. Michael
Grimmett. I have a number of questions
as you can well imagine. The first one
to Dr. Edelhauser; I really appreciated your review of the endothelial morphology
data and I would just like to ask you regarding that data of endothelial
stress, has it ever been stratisfied (sic) by corneal age, that is do younger
corneas have a blunted endothelial morphometric alteration as compared to old
corneas with less endothelial cushion or reserve?
DR.
EDELHAUSER: Dr. Edelhauser. The best data stratification that I can
think of to answer the question is the
data that we published in `84 on the diabetic corneas. In there we broke it down in terms of
decades. And indeed, if you look at the
bar graph that is published in that paper, you will find that there is -- as
one ages, there is both a progressive decreased in percent hexagonality and an
increase in coefficient of variation, so they -- as the cornea does age, you
know, you see these changes and that's in a diabetic population, you know,
compared to controls.
DR.
GRIMMETT: Okay, Dr. Grimmett
again. Then can you infer that a
younger cornea, because if its higher reserve, higher cushion, will have a
blunted response in terms of hexagonality and coefficient of variation?
DR.
EDELHAUSER: Yes, I think you can. I think the corneal endothelial cells are
certainly more robust in a younger population and I certainly have seen this in
laboratory studies where for example, if calcium free solution is placed on a
corneal endothelium and you break the endothelial junctions, the -- in an older
cornea, you know, about 40 or so, those junctions won't come back in an in
vitro situation but they certainly will with younger tissue.
DR.
GRIMMETT: Okay. Dr. Grimmett again, just as a reminder, this
study ranged to age 21 or so up to 45 and an average age in the 30s I believe. So from the discussion we've just had, this
particular cohort may not show as much change in morphometric parameters as a
60, 70-year old cornea, something like that.
DR.
EDELHAUSER: Dr. Edelhauser, that's
true.
DR.
WEISS: I just had a follow-up question
as far as that goes. For a patient
who's destined to develop corneal edema from continued cell loss, would you say
100 percent of the time they're going have the first sign as a change in the
percent hexagonality or coefficient of variation? Is that always the first sign?
DR.
EDELHAUSER: From our experience, yes,
you see this and let me just illustrate it in terms of patients who undergo
cataract surgery for example, the -- when the percent hexagonality and the
coefficient of variation start to come back or the cells become more regular,
the chances of that cornea going onto a post-operative corneal edema are very
much less, so you do see that once stability is established, you do have a
normal functioning corneal endothelium
DR.
WEISS: But just in relationship to Dr.
Grimmett's point, in a younger patient, it would be -- those changes might be
more subtle but would they always be able to be picked up, do you think, as a
first sign?
DR.
EDELHAUSER: They might, but don't
forget, this would have to be done with specular microscopy and when you are
sampling the cornea, you are taking central corneal endothelial cells in a
very, very small population, small area.
I mean, you're roughly counting 100, 150 cells and are looking at the
endothelium of that out of a population say of 450,000 cells. So you may not pick it up and certainly our
past studies have shown that you do see changes in the superior region if you
do cataract surgery there. You'll pick
that up in the peripheral area very readily where you have damaged the
endothelium.
DR.
WEISS: So it's possible in a younger
patient there might be a subtle change in these -- in the coefficient of
variation of the percent hexagonality which might not initially be picked up
but then later on as things developed got picked up and that could lead to
corneal edema.
DR.
EDELHAUSER: Possibly, yeah, and I mean,
it goes in hand in hand with total cell analysis, too, because you know that
corneal decompensation is going to occur somewhere between 500 and 800 cells
per millimeter square.
DR.
WEISS: Thank you. Dr. Sugar, Dr. Bandeen-Roche, Dr. Matoba and
then Dr. Mathers.
DR.
SUGAR: Two things. One is a comment on what Dr. Edelhauser said
and what he said in his presentation.
Certainly, you didn't measure the peripheral corneal endothelial cell
densities in any of these patients and presumably the trauma was greatest in
the periphery, so that it's conceivable that the central measurements are a
distant reflection of what really counts.
And I agree that the increased hexagonality and the decreased
coefficient of variation over time implies that the endothelial cells in the
center are doing better, but you don't -- your reassurance from the data on the
periphery is not specifically appropo of this study because you didn't look at
it, correct?
DR.
EDELHAUSER: Yes.
DR.
SUGAR: The other issue is, I guess for
John Vukich. In terms of the powers of
the lenses -- I assume we can ask about anything just stick with endothelium.
DR.
WEISS: Dr. Sugar, you can ask about
anything you want.
DR.
SUGAR: I'll limit myself.
DR.
WEISS: And that applies to everyone
else on the panel.
DR.
SUGAR: Okay. When you started this study, did you know that the powers of the
lenses that you had were insufficient for totally correcting the patient
population that you were investigating?
And is -- if that is so, is there an engineering reason or a reason why
you didn't have lenses of higher power to correct what you wanted to, that is
are there thickness limitations, optic size limitations that keep you from
having a higher power?
DR.
VUKICH: At the time of the initiation
of the study, we had anticipated that we would be able to correct the full
range. It became clear that at the
higher powers the effective power within the eye was less than the engineering
estimates and at that point. Due to
manufacturing limitations we found that we could only manufacture at that time
up to a minus 20 lens but the effective power within the eye was approximately
16 to 16-1/2 diopters.
At
this point those manufacturing limitations are not longer applicable but, of
course, that wasn't germane to this clinical trial.
DR.
SUGAR: And one other, you said
anything?
DR.
WEISS: Yes.
DR.
SUGAR: You talk about repositioning
lenses and you talk about sizing.
Repositioning lenses was for haptics that went in front of the iris, for
lenses that propellered, what was that and the sizing, are you talking about
vaulting or are you talking about something that doesn't go -- that isn't
sufficiently long to be stable or so long that it causes iris pombe (ph) or
some other problem?
DR.
VUKICH: There were four eyes that
underwent repositioning. Two of these
were for a haptic that was malpositioned, not anterior to the iris but appeared
to be folded without flap presentation.
One of these was a rotation or actually a decentration, a slight
decentration that was recentered without removal and then finally there was one
eye that had an edge and one side that captured the pupil in the perioperative
area, periopterative period that was readjusted.
DR.
SUGAR: Did any lenses ever propeller? Were they ever small enough that they
rotated?
DR.
VUKICH: No, we did not observe
rotational changes in any of our patients throughout the course of the trial.
DR.
WEISS: Dr. Bandeen-Roche?
DR.
BANDEEN-ROCHE: Karen Bandeen-Roche, and
I have a few questions about the specular microscopy. First is a clarification question, so there were 67 eyes followed
to four years. As Dr. Grimmett pointed
out, two separate 57 patient cohorts preop to four year and three year to four
year, and so by my calculations that leads to 47 patients at baseline three
years and four years and then two 10-patient cohorts that missed either
baseline or three years.
And
I just want to make sure, by my calculations, the -- and you may need to get
somebody to check on this, the mean cell density in that 47 patient group was
2496, in the group that did not have the three-year visit, 1779 and in the
group that did not have the baseline visit 2269 or I guess rounding up to
2270. And so can someone check whether
that's correct or --
DR.
VUKICH: We will look into that and
have an answer for you.
DR.
BANDEEN-ROCHE: Okay, now, three quick
other questions. First, regarding the
plot that Dr. Macsai asked for, what would also be very useful would be to have
a plot just like you showed for the 37 patient cohort along with overlaid on
the same plot, the patients who had
three-year data to just compare. Do you
know if it's possible to show the panel something like that?
DR.
VUKICH: We do have that available and
can give that to the panel as well.
DR.
BANDEEN-ROCHE: Okay. I'm interested in how representative the
patients with four-year data are of the entire cohort. So that's part of what the first two
questions were getting at. Could you
tell us the number of investigators who contributed to the 67-patient cohort
and anything else that would help us about how representative they are besides
the anterior chamber depth which we already know about?
DR.
VUKICH: These eyes were done as a
sub-study and the number of investigators that actually contributed again, I'll
have to look up that particular number for you. There were 12 sites that did participate in the entire trial,
however. Nine actually did the specular
microscopy.
DR.
BANDEEN-ROCHE: Right, and so the number
who actually had four-year data, that would be helpful.
DR.
VUKICH: Four-year data and we'll get
that information. I'm sorry, I don't
have that with me.
DR.
BANDEEN-ROCHE: Okay, thank you. And finally, I guess a question for Dr.
Edelhauser. Certainly an unlimited
amount of cell loss would not be benign.
I mean, could you give me an idea for the degree of cell loss that would
be of concern and that would be expected to cause stress independently of hexagonal
cells or CV?
DR.
EDELHAUSER: Well, if we go back and
look at the literature, the data that we have in the literature, for example,
says that in a normal population, not a high myopic population, the cell loss
per year is .6 percent, and that seems to be consistent, say .6 to 1 percent per
year, which goes. The only other
comparative data that I can think about as we -- and this is not really the
best comparative data, is the data published from Bill Bourne, and this is
10-year data that he has published with various types of intraocular
lenses. He's used three different types
of lenses. The only trouble with this
is that his average age population was 70 at that particular time and he used a
medallion iris suture lens. He used a
trans-iridectomy clip lens and he used a posterior chamber lens. He could show no difference in cell loss in
any one of those three and the cell loss ranged from 2.8, 2.6 and 2.9
percent. So that's kind of the upper
level where we do know that if you have that type of cell loss that you still
have clear cornea in a 70-year old population.
DR.
BANDEEN-ROCHE: Thank you.
DR.
WEISS: Dr. Matoba?
DR.
MATOBA: Alice Matoba. My question goes back to the age issue
raised by Dr. Grimmett. You enrolled
patients, ages 21 to 45. Could you tell
us how you selected 45 as the cutoff point?
DR.
VUKICH: That was the recommendation and
guidance of the FDA for enrollment and I believe this was primarily to look at
issues of aging as a compounding variable in the formation of lens opacities.
DR.
MATOBA: And then in your labeling, I
notice that the patient information states that you must be 21 to 45 to receive
this implant. Does that mean that you
intend to limit the use of the implant to patients 45 years or younger?
DR.
VUKICH: That is the only age range on which
we have data to support the safety of this product and would be consistent with
our labeling.
DR.
MATOBA: Okay, and then as the patient
ages, what do you think happens to the vaulting, amount of clearance that you
have as the lens becomes more nuclear sclerotic with age.
DR.
VUKICH: Well, we do know that over time
we can anticipate an increase in the anterior, posterior dimension of the
crystalline lens. We do have
information internationally with up to 10 years of experience that suggests that
there doesn't seem to be a significant change in the vaulting characteristics
which is somewhat counter-intuitive. We
believe that there is also an age related change in the ciliary sulcus diameter
as well. And so there may be several
things going on at once that can influence the characteristics that fit within
the eye over time.
Nevertheless,
we simply have to accept that as an unknowable piece of information until those
time periods have been observed in greater quantities and greater patients have
been observed.
DR.
MATOBA: But you're saying the
information you do have indicates that the clearance doesn't change
significantly over time.
DR.
VUKICH: Throughout the course of our
trial, which clearly is the best controlled, we have no evidence but again,
this is only three years but at this point, we've been carefully monitoring
this internationally where there has been longer data follow-up but at this
point, we have not seen that as a trend.
DR.
WEISS: Dr. Mathers, Dr. Schein, Dr.
McMahon and Dr. Grimmett.
DR.
MATHERS: I have a question for Dr.
Edelhauser. If the morphologic change
in the endothelium is so sensitive, why doesn't it show something when we know
that the endothelial cell count is actually falling by these measurements?
DR.
EDELHAUSER: Well, I think that you're
dealing with essentially a stable -- Dr. Edelhauser -- a stable endothelium and
the way cells in a normal population that you would see. For instance, we do know we lose cells over
a lifetime that if we say .6 to 1 percent.
We don't see marked changed there either because one, it's an apoptotic
change that usually occurs. You're
losing a cell. The adjacent cell then
slides into then cover up the area and I think that what we're seeing here is
just a distribution over the whole surface of the cornea.
I
can say that we -- I have seen this and we've published papers on this where if
you look at the regional areas of corneas.
For example, in cataract surgery, if you look superiorly, centrally and
inferiorly, you can see these changes markedly and don't forget, in this study,
these -- as these were specular micrographs that were taken.
DR.
MATHERS: Is your explanation
inconsistent with the concept that you could have progressive stable loss rate
of one, two, three percent and have a maintenance of a hexagonality as it would
be, because the process is essentially just an accelerated but similar to a
normal loss rate. It's just faster, so
you'd still maintain hexagonality.
DR.
EDELHAUSER: You could. I mean, again, it's going to depend upon the
-- you're expecting a change to occur over the total corneal endothelium and
that may not be the specific case that we're seeing.
DR.
MATHERS: Do you think it would be
helpful in understanding what's happening to the endothelium to have images
that incorporated more than 93 cells on a given patient? It seems to me that when you're looking at
the snapshot of the endothelium and as you pointed out, this is a very small
area that you're trying to extrapolate then to the entire cornea. Did you only -- for these readings, did you
use the single image for each patient time point or do you use five?
DR.
EDELHAUSER: We use single image, single
image and to answer your question, yes, it would be but the only way that you
can get large field or wide field specular micrographs is either with contact
specular microscopy and there's no algorithm to go ahead and automatically
digitize that other than tracing cells and putting it into a computer, or more
recently, there is the possibility of using the confocal and that's certainly a
possibility. That gives you a wonderful
wide field.
DR.
MATHERS: You mentioned that you -- with
Bourne's study on endothelium loss in iris fixed lenses, that sort of thing,
that he found a loss rate of 2.7 and it was consistent or that -- and also a
clear cornea. You're not maintaining
that a loss rate of 2.7 would be able to sustain a clear cornea over a long
period of time, I would think. I mean,
you're not suggesting that.
DR.
EDELHAUSER: Well, if you make the
assumption that there's not a possibility of some mechanism to produce more
corneal endothelial cells, and I think recent evidence has been shown that ARVO
-- that we're seeing is that there is the potential that the peripheral corneal
endothelial cells have adult stem cells there.
This hasn't been confirmed.
There's leading indication that you can measure telomerase activity out
there which show -- with telomerase activity you only find in cancer cells and
stem cells.
You
can see that cells do stain with BrdU which is -- and so I think this is a
world of research that is developing about the potential of endothelial cells
to be replenished.
DR.
MATHERS: But there is a loss rate at
which eventually you will run out of endothelial cells, I'm sure, you maintain.
DR.
EDELHAUSER: Yes, uh-huh, right.
DR.
MATHERS: Thank you.
DR.
WEISS: Dr. Schein?
DR.
SCHEIN: This is Oliver Schein. I'm going to limit questions or comments to
the endothelial area at this time. I
remember in 1995 when the first data was presented to the panel on photo
refractive keratotectomy there was endothelial cell counts and morphology was
performed and the sponsor was pleased and amused to see a large and
statistically significant improvement in the morphology from pre-PRK to two
years.
And
this was explained that the majority of individuals before PRK were chronic
contact lens users which effected not the cell count but the morphology and the
removal of the contact lens allowed the remodeling that appeared favorable over
time. Can you please give us some
summary of the contact lens wear in this patient population before the surgery
and perhaps speculate on how that might impact your estimates of stabilization
in the morphology.
DR.
VUKICH: Let me lead off by saying that
contact lens wear was common in our patient population. However, we do not have an exact number of
contact lens wearers pre-operatively.
That was not recorded as pre-operative entry criteria other than they
had to be out of their lenses for six weeks prior to the entry exam. So we have to make the assumption the
majority were. We believe that to be
true but we can't give you the percent.
We
do know that these patients actually showed stability not improvement over
time. And so that when we look at the
morphometric analysis through time, we did not see a worsening with improvement
of a simpler stable population.
DR.
SCHEIN: But if you're presenting
comparison of means, you can't actually determine that. You have to look within subgroups to arrive
at such a conclusion. Across an entire
population if there is an improvement, that would balance worsening and appear
as if there were stabilization.
That
gets at a second issue. If a majority
of the population were wearing contact lenses, that's the acuity that I'd be
most interested in as a baseline comparison.
It's kind of a habitual vision. It's the vision the patient enters the
trial with. The second issue related to
endothelial cell count that struck me was not so much the concern about
progressive cell loss but of absolute cell loss when you look at the entire
cohort. And again, if you simply
present a mean, it doesn't get at the safety issues that we're concerned with.
So
I interpreted one table as showing that about a third, slightly more than a
third of individuals lost 10 percent or more of the central endothelial cell
count comparing baseline to three years.
Tell me if I've done that correctly.
And about 20 percent lost 15 percent or more. Is that correct?
DR.
EDELHAUSER: I'd have to -- Dr.
Edelhauser. Don, you'll have to --
DR.
SLADE: Steve Slade. While they're getting that, I might just
address, Oliver, your point about the contact lens being the habitual vision,
that's a good point. On the other hand,
this was developed with best spectical visual acuity as a target with FDA
guidance and, of course, as a standard for refractive surgery and if you look
at the patient's satisfaction rates, they were very high and if they were
comparing their post-operative vision to what they were used to in contact
lenses, and if that were markedly better and we had reduced them, I don't think
the satisfaction rates would have been quite so high.
DR.
SCHEIN: You've got me now on digression
which I wasn't going to raise now. The
satisfaction scale that you use appeared to only have three options which
doesn't give a lot of room a very strong ceiling and floor effect with only
three options for a response. And there
are at least two well validated, available, three kinds of visual function
questionnaires directed towards populations like this that I think could be
used to get more detail.
DR.
WEISS: I would ask -- I would have the
sponsor just given the advantage of not having to identify themselves any more
because I'm told the transcriptist knows your voice. I would also ask the panel members if we could limit our
questions because now we're over. So if
we could just get to the cogent points quickly and give the sponsor the ability
to answer those. Are there any other
questions you have Dr. Schein?
DR.
SCHEIN: I'm just waiting for the -- was
I correct on the endothelial cell count?
DR.
SANDERS: Yeah, I believe you were
correct on the numbers. I think one has
to remember that that was the cumulative -- you were talking the cumulative
loss between pre-op to three years.
DR.
SCHEIN: Correct.
DR.
SANDERS: Yes. And again, I think we have to also keep in mind that some of that
-- given that the counting variability is eight to 10 percent, that that enters
into the equation, the numbers you did give us are very similar to what we
would calculate.
DR.
WEISS: Dr. McMahon, Dr. Grimmett, Dr.
Coleman, Dr. Ho, then Dr. Macsai and Dr. McCulley.
DR.
McMAHON: Dr. McMahon. This is a question for Dr. Vukich. I believe two and a half percent of
implanted lenses were implanted initially
up side down. And the majority
of those, I believe occurred in the first 10 cases, though in Dr. Grimmett's
review he pointed out that a number of them occurred downstream. The question I have, is this an issue of
surgical training or is this an issue where the device needs to be more clearly
labeled as to which is right, left, to minimize those sorts of things?
DR.
VUKICH: There's clearly a learning
curve in this, in that half of these did occur early in the experience, within
the first eight cases of any individual surgeon. This technique is an important part of our training program. We've identified that if this lens is loaded
properly and carefully under the microscope in the cartridge, that we can
significantly minimize the risk of an uncontrolled entry into the anterior
chamber. And so I believe firmly that
this is something that can be controlled and in fact, in my personal experience
of having put 90 of the lenses in at our site, not a single one went in up side
down. I'm also in charge of the
training to address this issue. So I
think it is something that clearly is a concern but we believe it's an issue
that isn't a matter of identifying the right side up. It's just a matter of doing it properly in the first place.
DR.
WEISS: Dr. Grimmett.
DR.
GRIMMETT: Michael Grimmett. Dr. Slade mentioned that this study was
IDE-approved in 1995. What was the
first date of the V4 lens implantation?
Quite a bit later?
DR.
SLADE: All of the -- Steve Slade. I believe all of this data was before.
DR.
GRIMMETT: Correct, `89, `99 something
like that?
DR.
SLADE: `98.
DR.
GRIMMETT: `98, okay. Was gonioscopy performed on any patient in
this study?
DR.
SLADE: Gonioscopy was performed on all
patients preoperatively in this study.
DR.
GRIMMETT: Preop, okay. I didn't note it on the clinical study
report form or in the PMA materials.
You have that somewhere then. We
just didn't see it; is that correct?
DR.
VUKICH: Dr. Vukich. It was on the preoperative checklist for
inclusion in the study and gonioscopy was required for every patient as an
entry criteria.
DR.
GRIMMETT: Okay, good, but just to
confirm it was not performed post-op on any patient.
DR.
SLADE: It was not a required
examination.
DR.
GRIMMETT: Okay, was angle anatomy
viewed with ultrasound in the ultrasound sub-study?
DR.
VUKICH: Yes, it was.
DR.
GRIMMETT: It was, good. Was the data in the PMA somewhere?
DR.
VUKICH: It was not.
DR.
GRIMMETT: It was not, okay. Of the up side down lens insertions that we
just heard about from Dr. McMahon, were they related at all to using the
plunger versus the screw injector style, like 13 used plunger and 3 used the
screw injector?
DR.
VUKICH: We did look at that as a
variable and we are unable to look at any evidence that the screw -- that the
actual injection mechanism itself was a factor. Again, we firmly believe that it was how the lens was loaded in
the cartridge as opposed to how it is pushed through the cartridge.
DR.
GRIMMETT: Okay.
DR.
SLADE: It might be worthwhile -- the
lens, it's very apparent, the lens because of the vault, because of the
markings before you load is which is right side and which is not. And the cartridge is the same whether you
use it with the screw type injector or the plunger.
DR.
GRIMMETT: Okay, all right. Your materials indicate your white-to-white
measurements had an accuracy of a tenth of a millimeter. My Castroviejo's calipers in the OR have an
accuracy in one millimeter increments.
What calipers were you using to get .1?
DR.
VUKICH: The same ones you are.
DR.
GRIMMETT: Oh, okay.
DR.
VUKICH: Calibrate them against the
steel rule under a microscope.
DR.
GRIMMETT: But they're only one millimeter
increments. So any unit underneath one
millimeter is a shear guess; isn't that correct?
DR.
VUKICH: There would be an estimate,
yes, below that level, correct.
DR.
GRIMMETT: Okay, I've used them and,
boy, when I want them at 3.3, it's awful hard to set it at that. And I guess my last question I'll make it,
I'll just skip some of these, we'll get to it later, in your materials you
stated that your version 4 lens has an additional .13 to .21 millimeters of
vault compared to version 3. And I was just
curious, did you substantiate that by in vivo measurements or was this a design
parameter and you postulated it or how do you know that?
DR.
VUKICH: It was a manufacturing and
design parameter. This is an
engineering issue. External to the eye, this would be the vault that was designed.
DR.
GRIMMETT: Okay, thank you very much.
DR.
WEISS: Dr. Coleman?
DR.
COLEMAN: This is Dr. Coleman and I have
a question about two of your subjects developed glaucoma in this study and I
was questioning how you define glaucoma.
Was that based on optic nerve changes or visual field loss?
DR.
VUKICH: Actually, two of our patients
were treated with beta blockers, neither of which showed optic nerve changes or
visual field changes. So I think they
would be best categorized as ocular hypertensive so there was not the diagnosis
of visual field loss or glaucoma as we would classically define it.
DR.
COLEMAN: You might want to change
that. In addition, you said that you
did do angle morphology via ultrasound but that's not available in the
PMA. Is that --
DR.
VUKICH: That angle was observed. There was a sub-study of forty patients that
were observed with a P40 unit, a
Paradigm unit and we did look at angle morphology. There is within the PMA a description, pictures as well as a
commentary of the results of that study.
DR.
COLEMAN: Okay, and then in terms of
post-operative gonioscopy was not done, not even in the subjects who were
diagnosed with glaucoma or is that not available or --
DR.
VUKICH: That information was not a
required part of the post-operative follow up and I do not have that
information as part of the PMA.
DR.
WEISS: Dr. Macsai?
DR.
MACSAI: My questions are mostly to Dr.
Edelhauser again. Sorry, Hank.
DR.
EDELHAUSER: No problem.
DR.
MACSAI: When this lens is inserted, the
most damage to the endothelium should occur in the periphery. If the surgeon is following the technique,
they're not supposed to go anywhere near the central cornea. It's defined as a no-touch zone. The manipulation of the haptics is done way
at the periphery and they're tucked under the iris with a little lens
manipulator, haptic manipulator device as Dr. Slade showed us in his slide. So given that and the presentation you've
said about how the peripheral endothelial cell counts is greater than the
central in your well-established published articles, and the fact that we're
talking about implanting this in 22-year old patients, I have some level of
confusion I'm asking you to help me with.
In
a guidance draft from a meeting in 10/02 accepted endothelial cell loss rate
was 1.5 percent, yet in an ANSI document that I think is also a draft, it was
set at two percent. So let me ask this
question to you. In your 22-year old
child that is being implanted with this intraocular lens because they are minus
13 and too thin for LASIK and contact lens intolerant, what is an acceptable
cell loss rate, not coefficient of variation, so that when they are 82 they
still have a functioning endothelium?
What
is the number? Is it .9? Is it .6?
Is it 1.5? Is it 2?
DR.
EDELHAUSER: Good question and it's hard
to come up with a number because the thing that I think would be ideal to
answer that question would be is that if we had a longitudinal study of high
myopes and looked and actually measured the cell loss, I think this would be
very important. Unfortunately, this is
not in the literature. So the -- what
you -- in order to answer that question, you know, it has jumped around between
1 to 2 percent as to where we stand with it.
One can do all kinds of mathematical calculations to see, you know, how
many years would the endothelial cells be depleted, half percent, one percent,
two percent, and this all assumes a linear decline which I don't think is
completely accurate at this particular stage based on the new information.
So
to answer your question, I don't know what the exact level would be with this
without some good longitudinal data to be able to make an absolute judgment
on. And I think one of the things that
all of the endothelial studies suffer from is that we don't have good
epidemiological data on various populations for the corneal endothelium with
regard to aging and various types of subsets like high myopia for example.
DR.
MACSAI: Well, given that lack of
security and an absolute number, you know, I'm wary of creating another closed
loop anterior chamber IOL disaster that I think most of the cornea surgeons in
this room experienced. So what do you
think -- I mean, is there a problem with vault and does that correlate with
endothelial cell damage? We saw laser
flare meter data, not fluoroscopy data, and it looked good but I've posed to
the sponsors and I continue to have this concern, vault is good because
cataracts are bad but does vault cause posterior chamber -- I mean, posterior
iris chafing? Does it release
pigment? We don't know. We haven't looked for sample EC lines on
gonioscopy.
Does
that cause some chronic inflammation that over the 60-year life expectancy of
this 22-year old, may effect their endothelial cells. Someone needs to, you know, provide some data from the sponsor
regarding this concern.
DR.
VUKICH: Well, there's two things that I
think we are putting together. One
would be the initial -- that could account for some initial cell loss
DR.
MACSAI: And then to propose there's an
increased rate of loss, there has to be some ongoing irritation to accelerate
above baseline. That ongoing
accelerated rate, we believe, would be consistent with the morphometric analysis. If we're going to see some sort of insult,
whether it be inflammation of which we detected none, whether it would be a
mechanical of which again, we would have to postulate some contact with the
cornea that we simply have not observed.
These chambers have remained well-formed and we have, again, not seen a
mechanism by which we can take a posterior chamber lens and equate this into
ongoing corneal endothelial trauma. We
would really have to propose a new mechanism for a chronic ongoing accelerated
loss of endothelial cells that takes into account normal morphology and no
other known cause of this accelerated loss.
We believe a lot of what we're seeing here is just an extended
remodeling period. We have some insult
similar to what we'd expect in clear corneal cataract surgery and there is
remodeling that stabilizes the population back to its, again, normal
redistribution and that, we believe takes as long as three years and we simply
can't see an accelerated rate. So I
think projecting is difficult but we've certainly accepted the limitations of
the data we have and are committed to long-term follow up. It's an important issue and I think it needs
monitoring.
DR.
MACSAI: Have -- you know, when you talk
about long-term insult, my concern is not lens corneal touch. My concern is lens iris touch. My concern is that you know, pigment release
and has the sponsor in some way separated those with the good high vault,
segregate those out, look at their flare meter, look at their angles, look at
their transillumination defects, and look at their endothelial cell loss, that
particular group, because I think that would help answer the question.
DR.
SANDERS: Well, we do have data on three
lenses were replaced because they were too long, which were the highest vault
and if you look at the final endothelial cell densities, 3300, 2400, 2700. They were the highest cell densities at the
later time periods so it appears that these cases are not the ones that
demonstrate cell loss with time.
DR.
MACSAI: But they were replaced.
DR.
SANDERS: Yes, but they were replaced
after a fairly long period in the eye.
DR.
SUGAR: Can I ask a clarification from
Marian? Are you implying that pigment
release causes endothelial cell loss
because I'm not aware of that?
DR.
MACSAI: I'm not implying pigment
release causes endothelial cell loss.
I'm implying pigment release implies touch. Touch may insight chronic inflammation and may have some role in
this. I don't know. I ask the questions of the sponsor because I
don't know.
DR.
WEISS: Dr. McCulley and then Dr. Ho.
DR.
McCULLEY: I've been around -- Jim
McCulley. I've been around since prior
to the beginning of clinical specular microscopy. Been through decades of frustrations of trying to listen to
people make sense out of and make points based on cell density. And having listened to -- read everything
that was provided, having listened to what everyone has said, quite honestly,
I'm at a point where it seems to me that what you've presented at least my
interpretation of it, would be that we have surgical trauma, endothelial cell
loss, and no evidence for anything except continued remodeling. And no evidence for any other mechanism for
continued endothelial cell loss or death other than the normal apoptotic
death. So I'm not sure where, you know,
one could go further with this or what we would ask you to do other than the
surveillance that you're doing except to ask is there some other more sensitive
way of looking for inflammation which wasn't a part of your PMA. So I'm not even sure how fair that question
is.
DR.
SANDERS: With regard to the
inflammation, ocular inflammation was the subject of my PhD thesis so I did
quite a bit of work in this area and that's why we included in the PMA five --
I mean, the laser cell flare meter has been basically thought to be too
sensitive a measure of inflammation and it's not even allowed for inflammatory
studies because it's too easy to show a decrease in inflammation between
groups, and five separate studies in the published literature have shown no
inflammatory response after the early post-operative period with this
implantable contact lens.
DR.
McCULLEY: Well, then I guess what I
would hope is I envision potential hours of discussion about small points
relative to endothelial cell loss and cell density in something that is less
than an ideal science. So I would hope
that the panel would really press Hank, who is the world's expert in my
experience on endothelial specular microscopy with any other issues rather than
us trying to figure out what's what among ourselves. If we can have -- so I guess my plea is -- to the panel is,
please press Hank while he's here to give us the information that will be more
expert than we're at to be able to generate amongst ourselves and hopefully
have a more efficient discussion of this because to me this is surgical trauma
remodeling.
DR.
WEISS: Dr. Ho.
DR.
HO: Allen Ho. But is there any evidence that this sub-clinical inflammation has
a deleterious effect on the cornea?
DR.
VUKICH: We have not demonstrated any
subclinical information, no.
DR.
HO: Is there anything in the
literature?
DR.
McCULLEY: I think -- Jim McCulley. They have no evidence for subclinical
inflammation and depending on how you define subclinical which presumably would
be what we see at the slip lamp, they've gone another step forward, don't have
any. What we could do would be again,
intuition. My intuition tells me what
I've said. It would be intuitively to
go back to some of the closed-loop AC IOLs that actually didn't have
sub-clinical, they had clinical inflammation that led to loss of endothelium,
so I'm not sure that maybe in some of those eyes some of us didn't see the cell
and flare that was going along with those AC IOLs but I think if you have
chronic inflammation or chronic rise in intraocular pressure, there is data
that suggests there is endothelial cell damage over time.
But
we don't have any of that there and that's one of the things that intuitively
leads me to my conclusion, we have no proposed -- we have no support for any
mechanism for any continued endothelial cell loss beyond the apoptotic aging.
DR.
WEISS: Yeah, I would prefer if we could
keep the panel discussion in the panel discussion portion and keep the
questions while the sponsor is up there because we have limited time. Do you have any other questions specifically
for the sponsor?
DR.
HO: I do. The only patient that had == Allen Ho -- that had severe
sustainable loss of vision in this trial was a patient who had a retinal
detachment and in a group of very high myopes we would expect perhaps without
intervention by natural history that you might see retinal detachment.
However,
one of the predisposing factors to retinal detachment in high myopes is clearly
retinal breaks and lattice degeneration.
Do you have any data about number one, lattice degeneration retinal
breaks pre-operatively and was indirect ophthalmoscopy part of the study
procedures pre and post-operatively?
DR.
VUKICH: A dilated funduscopic
examination was required at several intervals throughout the follow-up period
and detailed information was collected by the investigators specific to
peripheral retinal findings. We don't
have that collated specifically but also entry criteria did require a stable
retinal exam. Any pre-existing holes or
tears or retinal changes that would be considered high risk, of course, were
excluded.
DR.
HO: They were excluded. Stable retinal breaks were included in this
or were they treated preoperatively with laser, for example?
DR.
VUKICH: We do have a patient, I
believe, who had -- we had one patient was treated for an acute retinal
break.
DR.
HO: Yeah, I think that's really
important to flesh out for a potential consumer of this kind of technology
because, you know, that's where you're losing an eye. However, you may not lose that eye based on your
intervention. It simply may be natural
history. So I think that's -- I would
like to see that information. Thank
you.
DR.
WEISS: Do you think the optic size of
4.65 had any impact on visual acuity in younger patients who had larger pupils
or is this something you didn't look at?
DR.
VUKICH: Well, visual acuity and quality
were two different things. The visual
acuity didn't seem to have an impact in terms of the improvement in best
spectacle corrected acuity. Those were
the patients who actually had the most improvement quality of vision by subject
of symptoms. We can stratify that by
level and can provide that, yes.
DR.
WEISS: So you would be able to look at
the size of the pupils to see if it had any adverse effect. Dr. --
DR.
VUKICH: Well, excuse me, let me qualify
that by saying, pupil size measurement was not a part of this clinical exam,
either preoperatively or during the course of the trial, so we could only
stratify it by level of myopia, not by pupil size.
DR.
WEISS: Okay, so that's an unknown
factor.
DR.
VUKICH: Correct.
DR.
WEISS: Dr. Grimmett?
DR.
GRIMMETT: A quick one for Dr.
Sanders. Campbell estimated that
pigment particles can be as small as one micrometer in size. Does that laser cell meter detect particles
that small?
DR.
SANDERS: Yes, it does. The standards that are used are in the two
micron range and those are meant to be certainly large enough. One micron sized particles should be
detected by the Kowan machine.
DR.
GRIMMETT: You had about 20 patients
after the three-month period or so, 25 or something like that up to two years,
something like that.
DR.
SANDERS: Correct, and the cell measurements
were essentially below one per area that was seen on average.
DR.
GRIMMETT: In those 20, okay, thank you.
DR.
SANDERS: Yes.
DR.
SLADE: Yeah, Steve Slade, one quick
point to address Dr. Macsai's concern about the vaulting, I just want to make
it clear that while angle examination, gonioscopy, was not part of the exam, we
certainly did slit lamp exams at multiple intervals and at no point did we ever
find peripheral touch, so we were looking at grading angles in that fashion and
at no point was the vaulting such that it actually caused touch or PAS.
DR.
WEISS: Thank you. Dr. Mathers?
DR.
MATHERS: For Dr. Edelhauser, if you're
going to postulate that remodeling is the process, it might be helpful to know
-- to see these cells and watch them remodel because they're not being created. They've got to be out there. Could you help us by letting us know how
many cells you like to see on a cornea to understand the remodeling process. You're looking at 93 here. What would you recommend that we try to look
at if we're going to actually understand if remodeling is the issue versus cell
loss on a given patient?
DR.
EDELHAUSER: I think that one, it's
important to do more than -- if you want right now the information, more than
just central specular microscopy.
Obviously, if we have these pooled cells out in the periphery, it would
be interesting to see what's happening with those. I mean, and to get a larger cell number, now the -- most of the
instruments that we used in specular microscopy you're limited to pretty much
about four millimeters in the center, unless you really encourage the patient
you can get out to maybe four millimeters off center to look at the
periphery. It's not an easy
measurement to obtain.
DR.
MATHERS: But there's a half a
million cells in that area, so --
DR.
EDELHAUSER: Yeah, so I mean, one -- if
one had to say predict the ideal way to really evaluate it, is I think some of
the ways that we -- that article we published in the AJO is that we did take
eight or nine readings across the cornea; one central, four paracentral and for
far peripheral and then if you do that, you can -- and then the interesting
thing when you do that, Bill, is that you find out that there's a higher
percentage of corneal endothelial cells in the superior region. And similarly the German Daus all found the
same thing. So you have a 16-percent
increase in peripheral endothelial cells in the superior region.
DR.
MATHERS: Would you recommend that --
matching that against controls as a means to obtain this understanding?
DR.
EDELHAUSER: Well, if we're going to
really map out what's happening in the cornea, with any type of surgical
situation with remodeling one would have to do that.
DR.
WEISS: Dr. Bradley has one brief
question. I will ask a question and
then we're going to have a 10-minute break.
DR.
BRADLEY: You might need a 10-minute
break after my question. I'm bringing
-- I'd like to just go back to the issue that Dr. Weiss raised a few minutes
ago about pupil size. There seems to be
a certain irony here. I mean, one of
the motivations for the product is that there are certain people out there
whose myopia level is too high although cornea too thin to perform LASIK simply
because -- perform LASIK and have the standard 6.5 millimeter diameter optical
zone.
The
replacement product is only having potentially a 4.65 millimeter optical
zone. And one of the reasons why we
have a large optical zone with LASIK is because we are concerned about pupil
size issues. And I'm a bit concerned
that we have so little information about pupil sizes of these patients even --
we would anticipate for example, with young adults mesopic light levels that at
least half of the light would be passing into the eye outside of the optical
zone of the ICL.
Under
those circumstances, one can only imagine that the image quality would be very
poor. Having said all that, the data
seems to point that the patients are quite happy with their nighttime driving,
your mesopic contrast sensitivity test with a glare source showed perfectly
good results and I'm completed confused by that. I wonder if the sponsor could clarify how that could possibly
happen with such a small pupil size.
DR.
VUKICH: Well, we'll start by looking at
pupil size. Certainly, when we
developed the protocol in 1995, I don't believe that the interest or the
understanding of how these pupil sizes could interact with optical quality were
fully understood. That said, pupil size
we neither an entry criteria nor a parameter that was measured throughout the
course of the trial. I think the only
way that we can answer that is to go back to the patient's satisfaction surveys
and the quality of vision that they report inasmuch as the patients, in fact,
didn't seem to be bothered by the theoretical concerns of an optic size smaller
than their pupil. Of course, they
didn't know this but what they saw they seemed satisfied with.
I
understand and appreciate the concerns even with pupil size. However, there seems to be some variability
in the response or the effect of the pupil size that we're understanding now
with LASIK where it may not be as much of a correlation as we perhaps,
intuitively may expect. So we don't
understand the mechanism why a smaller optical size at the level of the lens
inside the eye may not have as much influence but yet, we simply have to go
back to the results and I believe that
they are consistent with patient satisfaction and with the use of this device.
To
speak to vision quality, there was a subset in a published report looking at
vision quality in patients looking at induced aberrations and we found
post-LASIK versus ICL, that the ICL patients had one-third as much spherical
aberration and half as much coma. And
so we certainly believe that it's at least in comparison to LASIK, probably
better in that regard at least.
DR.
WEISS: One last question and this is
sort of a bottom line question for Dr. Edelhauser because it seems that the
main concern of the panel is the impact on the endothelium. Would you be surprised if this lens was a
contributory factor in causing corneal edema in any of the patients on whom it
was implanted?
DR.
EDELHAUSER: At this stage, no, because
the cell density of these patients were well above, you know, 23, 2400.
DR.
WEISS: I should say eventually. If any of these patients eventually
developed corneal edema, in conjunction with having this placed, would that
surprise you or do you think that would be totally independent of having this
lens placed?
DR.
EDELHAUSER: Well, when you think about
having a lens behind the iris and not rubbing onto the corneal endothelium,
it's hard to imagine, you know, the mechanism of what would cause this -- a
marked decrease in corneal endothelial cells.
DR.
WEISS: So you would be -- that as a
complication would be surprising to you even 20 years down the line.
DR.
EDELHAUSER: Yeah.
DR.
WEISS: Okay.
DR.
SLADE: Just one quick thing, this lens
has been implanted outside the U.S., tens of thousands of cases over 10 years
and while reporting that experience is not FDA quality, I do believe we would
know if this lens ever created a corneal decompensation if the patient had to
have a graft and we know of none in that experience.
DR.
WEISS: Thank you. We're going to take a 10-minute break and
I'd ask you to be back here promptly and then we're going to go onto the FDA
presentation.
(A
brief recess was taken.)
DR.
WEISS: Donna Lochner will be
introducing the FDA presentation.
MS.
LOCHNER: Thank you, Dr. Weiss. Because this is the first phakic IOL to be
brought before the panel, I would like to briefly present how FDA's guidance to
industry on the design of phakic IOL studies has evolved beginning with the
October `98 panel meeting. In 1999 ANSI
standards and later the ISO meetings began and they currently are held every
six months or so. Both the ANSI and
ISO standards are expected to be submitted for voting in 2004.
Today
I'll provide just the highlights of the three panel discussions and then
summarize the current ANSI and ISO standards which have incorporated all the
major recommendations of the panel with some minor exceptions. FDA issued a draft guidance document in 2000
and expects to issue a final guidance when the ANSI standards are
finalized. So this first slide -- I
think I went -- this first slide is for the October 23rd, 1998 meeting which,
as I said was the first discussion by the panel and at that meeting, the panel
recommended that effectiveness criteria generally followed the refractive laser
guidance. For example, with respect to
the uncorrected VA loss of BSCVA, and also recommended that adverse events in
the first year should generally follow the IOL grid for aphakia as a starting
point for the study design.
The
panel recommended a sample size of 500 subjects and this was primarily because
they felt that as a new indication, new technology, they should take a more
conservative approach and the 500 subjects was consistent with what was
originally done with IOL aphakia studies.
Further, they recommended mesopic contrast and sensitivity testing be
done and mesopic pupil size measurements be done. That a questionnaire for visual complaints be administered and
that pachymetry, dilated lens and fundus evaluations, topography, keratometry
and gonioscopy evaluations be performed.
With
regards to specular microscopy, the panel recommended a sample size to allow
detection of 2.5 percent per year and they obtained this figure from the Bourne
article that was referred earlier in the discussion this morning. There was a suggestion that all patients be
tested but they felt that FDA should try to power the studies to detect the 2.5
percent per year. They felt PMA data
was needed to three years and if there was a loss or the loss was progressing,
a five-year study should be performed.
With respect to lens opacities, the panel recommended a clinical grading
system and three-year data be collected.
The
May 12th meeting was held to receive the panel's input prior to publication of
FDA's draft guide and at that meeting, the panel generally endorsed our
proposals to power the studies to be able to detect a 1.5 percent loss in the
specular microscopy study per year and the 1.5 percent figure came after
iterating several hypothetical annual losses from a phakic IOL taking an
average endothelial cell densities at different age ranges from the literature
and determining the age at which the hypothetical annual loss would result in
corneal decompensation for the various age groupings. From there we assigned a standard deviation of five percent and
sort of arrived at -- which was sort of arrived at as being a reasonable loss
so that even young adults would be in their 70s prior to decompensation and
that the sample size would still remain reasonable for these studies.
The
panel endorsed this approach and also asked for data analysis to include a
stratification by age. And they further
recommended that the analysis look at the mean rate of loss and a frequency
analysis to show the percent of patients losing greater than 10 percent over
the course of the study. With respect
to lens opacities, the panel again recommended a preoperative and
post-operative clinical grading system and at this meeting they also -- there
was quite a bit of discussion about control group and felt that that was
recommended. The panel also again
emphasized gonioscopy and dilated fundus exam.
After
another two years of meetings with ANSI and ISO we brought a composite of the
standards to the panel but with a focused review of endothelial cell density,
lens opacity and the contra-sensitivity
study. We assigned primary
reviewers for each of these three topics and also invited speakers to address
endothelial cell design and lens opacity clinical study design issues. The panel recommended that the cell density
studies be able to detect the 1.5 percent annual loss and this, again, was
based upon entry criteria on cell density and acceptable density for the life
of the patient. Depending upon the
standard deviation, they commented that this will equate to about 200 to 300
eyes. They recommended use of a central
reading center or other methods with similar precision and validity. They recommended the three-year data was needed
for the PMA and also that an intermediate measure between the two and
three-year point might be needed to help to establish linearity.
Depending
upon the three-year data, the panel recommended that additional two years
post-marketing study may be needed. And
finally, again, the frequency analysis was requested. With respect to lens opacities, again, the panel recommended a
clinical rating system and the three-year data also was needed to address the
issue of lens opacity and that consideration will be given to longer term at
least a five-year post-marketing study.
Once a PMA has been reviewed,
the panel felt it was useful to look at laser flare and high resolution
ultrasound for source of any opacities.
And they felt that two or more lines loss with glare or one line without
glare would be the level that would be considered clinically significant for
any opacity.
They
further recommended that contrast sensitivity testing be done on all patients
to document the severity of any future opacity. With respect to the contrast sensitivity discussion, the major
recommendation that came out of that was that the panel felt a clinically
significant decrease in contrast sensitivity should be set at .3 log units and
again, the panel emphasized gonioscopy and further stated at this meeting that
consideration should be given to collection of data post-market depending upon
how the PMA data looked.
Again,
as I said, all of this culminated in the current draft ANSI and ISO standards
with recommendations for a three-year, 300-subject preoperative control
study. Safety end points from the FDA's
aphakic IOL grid are also used as control data in these standards and now I'll
just briefly go through the current recommendations and the most current
versions of these standards and that is that the following evaluations be
performed; in corrected CVA, distance and near, BSCVA distance and near,
manifest and cycloplegic refractions, a subject questionnaire, a slit lamp exam
including aqueous cell and flare, gonioscopic exam, corneal edema, pupillary
irregularities, iris atrophy and pigment dispersion.
These
standards recommended a dilated fundus exam, that IOP testing be performed,
mesopic pupil size be measured and that pachymetry, preoperative axial length,
anterior chamber duct measurement and kerotometry be performed. With respect to specular microscopy, the
standards assume a 10 percent surgical loss and recommend that the studies be
able to deduct a two-percent loss per year.
The standards recommend that all 300 subjects be tested so that at least
200 good images would be obtained.
They
recommend use of a central reading center and they recommend that 100 to 150
cells be counted. With respect to lens
opacities, again the standards recommend a clinical grading system and they
recommend that a change in contrast sensitivity performance from preop to each
post-op visit at which an opacity is observed be performed to document any
significance to the opacity. The
standards recommend contrast sensitivity be performed under mesop and mesopic
with glare and the sample size recommended is 61 subjects.
Now,
I'd like to thank and acknowledge the
PMA review team for this application.
Dr. Alexander, who is the lead reviewer for the PMA, Dr. Eydelman, the
clinical reviewer, Dr. Gray who performed the statistical review, Don Calogero,
our jack of all trades who performed engineering, contrast sensitivity and
specular microscopy reviews. Susanna
Jones reviewed the toxicology. Susan
Gouge, microbiology, Charles Sawyer, patient labeling, Pam Reynolds performed
the bio-research monitoring review and Vertleen Covington on the quality
systems or good manufacturing practices review. And last but not least, I have to give a special thanks to Sally
Thornton, who due to the expedited nature of this PMA really had to do above
and beyond the amount of normal running
around and we couldn't have gotten here today without her excellent
support.
Now,
Dr. Eydelman will present the clinical questions.
DR.
EYDELMAN: Good morning. This PMA is truly precedent setting and I
wanted you to be aware of it for several reasons. First of all, there are currently no phakic intraocular lenses
approved in the U.S. There are also no
currently approved devices requiring intraocular surgery for correction of
refractive error. Thirdly, there are no
current FDA approved devices for the correction of myopia greater than 15
diopters. In addition, FDA approved
IOLs for use only in adults 60 years of age and older until this year.
Currently,
responses may require lowering age for indication to all adults by reference to
our recent publication. This is the
first time, therefore, that you're going to be considering a PMA for an IOL
intended solely for implantation in young adults. As you heard, this PMA received an expedited review status. That truly meant much shorter turnaround
time for both the sponsor and us. To
make a point of it, I want you to be aware that the last major clinical
amendment wasn't received by FDA till September 3rd.
As
a result of all this, I haven't been able to receive the sponsor's final panel
presentation until today, so please forgive any redundancies that I might have
in my presentation. As you have all
seen, this was a very large PMA with numerous analysis and I will not try to
summarize all of it. I'm merely trying
to bring your attention to some information which is relevant to the questions
that we ask for your consideration.
Regarding
lens opacification, there were five eyes in the whole PMA that developed
nuclear opacities of two plus at the LOCS scale at two to three years. There were 14 cases of ASC opacities of
trace or more. Eleven of them occurred
at or before the six months and three cases at one year to 26 months
post-op. In view of these, do you
believe that the three-year follow up is sufficient to establish a lens opacification
profile associated with this device? If
not, what is your recommendation?
Eleven
out of the 14 cases of ASC appeared at or before the six-month visit suggesting
surgical trauma. Combining surgical
experience with V3 and V4 models, 50 percent of 87.5 percent if you exclude the
problematic site number 15, of early ASC cases occurred within the first eight
surgical cases. In the Canadian trial
performed by three inexperienced surgeons, 22.5 percent of cases developed ASC
opacification.
The
Dominican Republic study which was performed under supervision of a surgical
proctor, demonstrated a rate of 4.8 percent.
In light of these findings, do you believe surgeon experience to be an
important factor in ASC development, secondary to surgical trauma? If yes, do you believe that future users of
this lens should be required to undergo special training?
Vault
measurements in the study were clinical estimates comparing the slit lamp
appearance of the corneal thickness to the interval centrally between the
crystalline lens and the ICL. Five
hundred micron corneal thickness was assumed for conversion from a percentage
of corneal thickness to microns. All
measurements in an individual case at every visit were averaged to derive at a
vault measurement. So as you can see,
it was not a very precise measurement estimate. However, it was done.
Patients
were graded as having poor vault if
investigators consistently graded the space between ICL and crystalline
lens as less than 10 percent of the central corneal thickness and that equated
to about 50 microns. Twenty-four cases
of the V4 cohort with this technique were determined to have poor vault, 16.7
percent of them or four out of 24 V4 cases with poor vault, subsequently
developed ASC opacification in contrast only two percent of cases with good
vault had ASC.
All
three cases of significant ASC opacification of late onset defined as greater
than six months in V4 cohort were in the eyes with poor vault. In V3 cohort, 41 percent of cases with poor
vault developed ASC versus nine percent of cases with good vault. Gonvers, et al, in his recent publication
further supported the relationship of vaulting to cataract information. In the PMA the sponsor recommended
replacement of the ICL only in cases of poor vault that exhibited early ASC in
areas of ICL touch in subjects with UCVA worse than 20/50. Do you agree with this recommendation? If not, what would you recommend?
In
the clinical trial, sizing was determined by the horizontal white-to-white and
ACD, anterior chamber depth measurements.
Inherent measurement error associated with caliper measurements was
judged by the sponsor to be plus or minus .1 millimeter. Anterior chamber depths in the study was
measured by ultrasound, Orbscan and IOL master. From the literature review, the sponsor concluded that results
may differ by as much as .3 millimeters between different measurement
methods.
Our
own literature review revealed lack of correlation of white-to-white
measurements and the sulcus-to-sulcus dimension. We also believed that the literature shows that none of the
external measurements, including anterior chamber depth and axial length, have
been able to accurately predict internal ocular dimensions. The sponsor believes that this literature
evidence currently available is
anecdotal and they further point out that all the safety and efficacy
data available were obtained with a current sizing algorithm based on
white-to-white and ACD measurements.
It's
interesting to note that looking at the distribution of the ICL implanted, 50
percent were performed with 12.5 millimeters, versus 7.6 percent was 11.5
millimeter lens. In the overall PMA
cohort, 1.5 percent of the lenses were
replaced due to inappropriate sizing.
Do you believe that the method currently recommended by the sponsor for
determination of the overall diameter of the ICL to be inserted is appropriate? If not, what do you recommend?
As
you heard previously, we asked the sponsor to break up their cohort into four
refractive groups. Fifteen to 20
diopter group contained 31 eyes at three years. I want to make sure that you're aware that while preliminary
discussion for refractive laser guidance for myopia greater than seven diopters
was held a the `97 panel meeting. There
was no consensus reached on several issues and therefore, there is no currently
available guidance for acceptable safety and efficacy outcomes for high myopes
after refractive surgery. For eyes with
MRSE greater than 15 diopters, in the ICL cohort, there were 3.8 percent or two
eyes that lost greater than two lines, 3.8 percent that lost 2 lines and 17.3
percent that lost 1 line. If you
calculate it out, it turns out that at 15 diopters of myopia, magnification factor
account for a one-line loss being equivalent to a two-line loss. Therefore, we ask the sponsor to include
that in the analysis of their high myopia group.
Thus,
if you add it up, total loss of one line or greater was 25 percent for the
small cohort.
Some additional safety outcomes for these eyes
were retinal detachment at 3.8 percent, ASC opacification of 5.8 percent and as
of 9/15, only -- the sponsor informed us that only one eye of these was
clinically -- had clinically significant ASC and that is 1.9 percent. Clinically significant nuclear cataract in
7.7 percent, ICL removal/cataract extraction performed in 3.8 percent and
again, 3.8 percent had an increase of greater than two diopter cylinder.
As
you heard, currently limitation of ICL power is minus 20 diopters. Inadvertently a lot of eyes with MRSE
greater than 15 diopters were targeted for under-correction. Eleven point five percent of them were
targeted for greater than three diopters, 28.8 for greater than two and 65.4
for greater than one. Looking at predictability, 23.3 percent had
accuracy within half diopter, 53.3 was within one diopter. Combining the targeted under-correction was
a predictability that you saw resulted in rather large range for resultant MRSE
for this group at three years. As you
can see, it ranged from minus .85 diopters to plus .5 with 10 percent of the
eyes ending up greater than four diopter myopia, 26.6 greater than three
diopters.
Looking
at all eyes with preop MRSE greater than 15 diopters 38.7 percent of them were
able to achieve 20/40 or better. There
were no eyes available that were targeted for emmetropia and had preop of 20/20
or better. While all eyes in this
sub-group were -- while there were no eyes that were -- there were no patients
that were unsatisfied, looking at very extremely satisfied patients, you see
that for the group of greater than 15 diopters, the satisfaction percentage
drops somewhat to 75 percent.
Does
the safety and efficacy data for eyes with preoperative myopia of greater than
15 to 20 diopters support approval of this refractive range? If approval for eyes with preoperative MRSE
greater than 15 to 20 is recommended, is the term "correction of" as
it relates to this refractive range, appropriate in the indication
statement? If not, what alternative
term do you recommend?
Any
time we at FDA consider risk benefit analysis for each of the refractive
groups, we have to consider two factors.
First, is a safety and efficacy profile for each refractive group with
the device in question. In addition, we
look at safety and efficacy profile for the currently approved or alternate
devices available; in this case, glasses, contacts, LASIK, for each of the
refractive groups? With this in mind,
does the safety and effectiveness outcomes support approval of STAAR ICL for the
eyes with the following preoperative MRSE, minus 3 to minus 7, greater than 7
to 10, and from greater from 10 to 15 diopters? Twenty patients in overall PMA cohort required treatment other
than IOP-lowering meds in the early post-op period. Seventeen of them requiring additional irodotomies, and three
requiring additional irrigation/aspiration procedure. In these 20 eyes, IOP ranged as high as 65, with IOP spikes
observed between one and 21 days post-op. Most of them, however, were seen in
one to two days post-op.
Incidents
of early post-op spikes was stratified by study site and was shown to range
between zero to 20 percent. The
differences were not found to be statistically significant. Do you believe that specific recommendations
regarding early post-op follow up are needed in the labeling? I want to bring your attention to the fact
that the labeling you currently have is not -- did not undergo final FDA's
review. We always correct all the
inconsistencies. Patient symptoms and
quality of vision assessment stratified by refractive groups would
automatically be included. Demographics
is always included.
What
we are asking your input on is issues unique to ICL that need to be
communicated in physician and patient labeling, possibly as a warning or
precaution. In addition, we're asking
you to consider issues that will be common to all phakic IOLs, such as possible
requirement for exclusion of subjects with low endothelial cell density as a
function of age. This would be
consistent with ANSI PIOL draft standards recommendation for clinical
studies. It would, however, imply
access to specular microscope for all implanting surgeons.
In
addition, recommendations for gonioscopy and mesopic pupil size assessment
preop and post-op in all patients. This
is consistent, once again, with our standards recommendation for all clinical
studies. Overall, we want to know what
additional labeling recommendations do you have. Now, I would like to introduce Dr. Gerry Gray who will review all
of the endothelial cell data analysis and when the Chair is ready, I'll be
happy to project all questions as they appear in your handout.
DR.
GRAY: Good morning. My name is Gerry Gray. I'm the team leader for cardiovascular and
ophthalmic statistics and I was the statistical reviewer for this PMA. My comments are going to be restricted to
the specular microscopy sub-study. This
is an overview of the design. We've
heard it several times. We're talking
about endothelial cell counts and measurements on endothelial cells based on
photographs from a specular microscope and all the images were read at a core
center with one reader.
The
study was originally designed to have a preoperative and then three-month,
one-year, two-year follow up. During
the course of the study it was modified to add three and four-year visits. And the purpose was to investigate the
effects on endothelial cells. There
were a total of 306 eyes that were enrolled in this sub-study and it had at
least one count. I'm just going to go
through a little bit about the accountability of the eyes because it gets a
little confusing here.
The
pattern of missing is not quite standard where everyone has a preop visit and
then people start to drop off after that.
It's a fair amount different. In fact, there were -- 94 of the 306
patients had no preoperative visit. Six
people had preop and one subsequent.
Thirty-four had preop, two subsequent and 172 had preop and then three
of them were after that, and the small numbers after that tell you where the
person's last visit was.
And
all this accountability information is based on a data set that was submitted
to me by the sponsor for analysis. So
actually, I think it was a SAS formatted data set. A couple of more accountability combinations; 154 patients had
preop and three-year visits, 57 comes up a couple of times. It's not the same
57 patients but 57 had three and four-year visits, 57 had preop and four-year
visits. A total of 67 people had all
the visits up to three years and a total of 37 had all visits up to four
years. So there's 37 patients out of
these 306 that had all the visits.
So
here's a plot that we've seen before.
It's the raw results from the data -- from the study, excuse me. The year or the time has been jittered a
little bit to show the distribution there.
There are preop measurements and then three months, one year, two years,
three years and four years. The dashed
blue line here just simply connects the means at those time points. And when we look at this, there's really two
questions that are key here. The first
one is how -- at what point in time can we say that any effect of the actual
surgical procedure, whether it would be just lost due to surgical trauma and/or
some amount of remodeling, at what point in time would we say that is
negligible and we can ignore it and use the data after that to get some
estimate of what long-term loss might be?
So that's the first key question that we need to think about.
And
then the second thing is what happens off to the right-hand side of this graph,
what happens after five, 10, 20 years down the road? Just to set the stage a little bit, this is -- these numbers here
are the mean cell counts for various cohorts of patients that you might think
about using in this study. The first
cohort is all eyes. That's just all 306
eyes that were measured whenever, the baseline preoperative measurement, the
mean was 2657 and it steadily declined after that to 2355 at the four-year
point.
The
next cohort, I couldn't fit it in very well, so I call it pre and two
plus. Those are all the patients that
have a preoperative measurement and then they had at least two measurements
after that. So that's 206 of the 306
patients and you can see there, it's fairly similar actually to what we get
with all eyes. The next two cohorts are
somewhat different. The cohort that
only has three and four-year measurements and this is a cohort that in the
analysis presented to us by the sponsor for the three to four-year loss they
used. You'll note that the main
difference here is at the three-year point that measurement of 2355 is somewhat
lower and it's actually in fact, lower than the average measurement they got at
four years for those 57 patients.
And
then finally, an even smaller subset was everyone who had all the visits and
that shows a similar pattern to the three and four-year one, and I presume
these are the numbers that were used to make that plot that came up in the
sponsor's presentation. So over the
duration of the study, over the three and four years we're talking about here,
the estimates of cell loss are fairly stable regardless of how you calculate
them. At three years, the range of
estimates is 8.5 to 8.9 percent. If you
use the 154 patients who had preoperative and then three-year -- a three-year
visit, the estimate is 8.7 percent. And
the competence interval for that is anywhere between a 10.3 and 7.1 percent
loss. In raw numbers that's 220, 235
cells per millimeter square and that calculation includes anything that
happened to the patients between preop and the three-year point which would be
any initial operational loss, any kind of remodeling, any normal loss due to
aging over that period.
And
at four years, we've added on a little bit here and it's anywhere from 8.4 to
9.7 percent loss. Okay, now the big
question, of course, is what's the steady-state long-term loss that we can
expect to see. What's the long-term
rate of change in the endothelial cell density we might think we would
see? And it turns out that this
estimate depends mostly on those -- on the question of how long we believe the
effects of the implantation persist, at what time point can we say whatever
remodeling or operative loss we have seen in negligible at this point. And that translates into which of the
cohorts we actually used to do that estimation. As you saw in the previous slide, the table of cell densities,
the two cohorts on the bottom that only had -- that had three and four-year
measurements had a markedly lower three-year cell count than the others and
that's the main difference in terms of what you get out in the estimates.
The
analysis that was presented to us by the sponsor in this PMA was basically
using the percent change between the three and four-year time points, using
only those patients who had both three and four-year measurements. That's the 57-patient cohort and it properly
did some statistics to account for a correlation within a patient between eyes.
And the net result there is an estimated percent change of .07 percent, that is
a slight gain. In fact, it was one cell
per millimeter squared with a confidence interval between minus 1.4 and
positive 1.6 percent.
Now
other cohorts you'll recall, have relatively higher three-year counts and you
can do a lot of different kinds of analyses but the bottom line is that the
various analyses using those other cohorts and using all time points or time
points other than just the three and four-year, produce a change of around
minus two percent per year. If you go
the fancy statistics route and do random coefficients regression, you get a
loss of minus 1.9 percent per year. If
you believe that whatever -- that the time cutoff for the operational and/or
remodeling change is three months and just use the data after three months, and
go through an analysis, it's exactly like the one done by the sponsor, in other
words, just use the changes from time point T to T plus one, you get an
estimate of minus two percent per year.
If
you believe that any trauma or remodeling is done after two years and you use
the two to three-year difference plus the three to four-year differences, you
get an estimate of minus 1.8 percent.
And the confidence intervals change a little bit. The one for the -- using the regression is
probably the smallest because it has a model to help it make the balance
smaller, but those are fairly consistent estimates compared to the difference
between them and the one that only uses the three and four-year data.
So
the key question, of course, is where is that cutoff between operative and/or
remodeling loss and whatever you might call steady-state, long-term loss. And all I can do is statistics, right? I don't have the clinical knowledge but I
have the data, so using the data that we do have, the question here from the
statistical point of view is we see that there's some amount -- in many of the
cohorts, there's some amount of leveling off after the three-year point between
three and four years and the question is, is that statistically significantly
different than whatever the slope we saw between three months and one year, one
year and two years, two years and three years.
And the answer to that is no. If
you'll recall the previous plot, it showed the dotted line that connected the
means, it looked pretty much like a straight line and the statistics confirm
that. There's no strong evidence that
the rate of endothelial cell loss between three and four years is any different
than the rate -- the annual rate before that.
So in the data we have, there's not strong evidence that it's
different. Of course, we only have 57
people at four years and that could be do to just random fluctuation or we just
don't have a big enough sample at four years to have much statistical power but
that's what we have.
And
just in case you care about the details, this was all based on a piecewise
linear model that assumes there's a preoperative loss between zero and three
months and then after that, it's steady decline either to three years and then
a change to four years or it's straight from three months on. But the implication of all this from the
data we have is that is that the steady
state loss should be estimated using all the data after three months. And if you'll recall from a previous slide,
even if we want to go to two years, it doesn't make that much difference
here.
And
so my best guess is due to long-term loss would be that we have -- first of
all, there's a mean preoperative measure of 2651 and with the first three
months, the absolute loss is about 1.9 percent, so about a two-percent loss
over the first three months, and then after that, the rate of loss per year is
about 1.9 percent.
If
we extend this model a little bit to include a three and four-year slope, which
again was not warranted by the statistics probably, you do get a pretty similar
estimate to what the sponsor had between three and four years of an actual
slight gain. So here's the results from
the two different fits, the two main different kinds of fit that I'm talking
about. First of all, there's a blue line
here that's just like the one you saw in the previous plot that's pretty much
overlaid by the black line. The black
line is the fit that I was describing where we had a linear drop at the three
months and then a straight line after that.
And the green line out at the end is the analysis that was presented to
us by the sponsor which is just using the patients who have three and four-year
data. And you look at this plot and you
say, well, that's not that much different because you know, the only thing different
is maybe the difference between the mean at three years there, but the problem
is that we don't really care that much at the four-year point. What we care is what happens after 10, 20,
30 years and when you make the plot -- when you show the time span we're
talking about those are quite a bit different results.
And
if you believe the three to four -- using the three to four-year data, we're
basically a flat line, slight increase over time on the endothelial cell
density. If you believe that the loss
is going to continue linearly at 1.9 percent per year forever, then after about
20 years you're at the 1500 cells per millimeter squared and somewhere around
35 years you're down to 800. I don't
have any -- I don't show any errors around these lines, in the error bars. If you know much -- if you know about errors
for regression the errors go, they move outward the further away you get from
the center of the data and if I put them on here, they would -- these estimates
are pretty much meaningless I think after 15 to 20 years. You don't have very much confidence at all
in them.
And
that brings me to, of course, the caveats that the statisticians always give
about extrapolation. It's always a
questionable exercise to extrapolate beyond the range of the data we have and
especially when we're talking about the range we have here. It's highly -- any extrapolation you would
make would be highly dependent on the model we use and the assumptions we want
to make and both those lines that you saw previously assume that whatever
linear trend you saw between three and four years is going to continue forever
beyond that.
And
it's probably in this case a lot more important to think about if it's
necessary to obtain good long-term data and if so, how to go about doing
that. Okay, now, I'm going to switch
gears a little bit and talk about individual patients because maybe more
important than the average cell loss through time which is described by the
linear fits are questions like what proportions of patients will show a cell
loss greater than some critical amount.
In other words, what proportion of patients will have cell densities
less than 1500 or 800 cells per millimeter squared in 10, 20 or 30 years.
And
from my point of view, the problem is you can't really answer this with much
confidence using the data we have here.
But let me just summarize what we do have here. If you'll recall one of the previous -- the
fancy statistical model I used previously actually gives me an estimate for
each eye of what the post-operative ECD change for that eye is and then after
that, what's the annual change through time, and so you have a distribution of
those estimates for each eye.
And
using that, you can get -- you can create tables like this that tell you
something like in this case four and a half -- excuse me, 10 percent of the
patients will have an initial loss of four and a half percent or more and 10
percent of the patients will have an annual loss of 2.9 percent or more. Now, that's based on again, I'm making some
assumption that whatever we've seen in the first three or four years is going
to continue however far in the future you want to go. Okay, and finally, there were some co-variants that seemed to be
significant predictors of endothelial cell loss, notably is the anterior
chamber depth which was a statistically significant predictor of cell loss
regardless of how you analyze it really.
The sponsor presented analysis in the PMA that showed the used binned
data, in other words, they broke the ACD into four different groups based on
three, three and a half, four millimeter cuts and then presented the cell loss
for each of those groups.
A
bunch of other co-periods didn't appear to be significant predictors of cell
loss. Just to help put the ACD effect
into context, I created this graph here that takes -- for each eye, you take
all the possible annual differences that you got for that eye and calculate
from those the percentage loss for that eye and then average those for that one
eye. So on the Y axis is for each eye
now an annual percentage ECD change that we see in the four years -- after
three months. I threw out the first few
months because that seemed to be somewhat different. And then platted on the X axis is the ACD measurement for that
eye.
And
the point is that, remember the average ACD is around 3.5 and the average cell
-- annual cell loss was right here,
it's around two percent and down here it says estimated slope is 1.6, so you
know that the difference between -- if this right here is about two percent
loss, and someone that's a half a unit to the left is going to have a loss
that's about 0.8 percent more, 2.8 percent, and someone who is a half a unit to
the right is going to have about 0.8 percent, less cell loss. They're loss is going to be about 1.2
percent per year. This is just an
attempt to kind of put the -- take the statistical significance of the ACD
effects and try to put it in some terms that might be hopefully relevant.
So
after all that, there's two main questions here for the panel. The first one is that the mean change
between three and four years in that 57-patient cohort that had both of those
was an actual gain of .1 percent in endothelial cell density, so is there sufficient
data to support the conclusion that the losses in the first three years are
reflective of surgical trauma with some prolonged remodeling period that
culminates in a stabilization after three years and if not, what minimum eyes
in follow up would you try to make a recommendation that we might need to make
that assessment?
The
second question relating to the anterior chamber depth eyes with the smaller
anterior depth of 2.8 to 3 had a greater loss of endothelial cells than the
eyes with a greater than 3 millimeter ACD.
So the question is, do the outcomes of the ACD analysis provide some
assurance of safety in this device for eyes in the lower end and then the upper
end of the ACD spectrum? Thank you very
much for your attention.
DR.
WEISS: Thank you. We will now have questions for the FDA from
the panel. I'm just going to start off,
just to clarify for myself about the endothelial cell loss in terms of
determination whether it levels off or increases between three to four years
versus whether it continues dropping.
From what I understood you to say, if you look at the cohort of 57 which
is what the sponsor was looking at between three to four years, you could
possibly say that it was going to level off, but if you look at the other
cohorts, it does not show that. Am I
misinterpreting it or is that basically --
DR.
GRAY: That's correct. Your estimated amount of endothelial cell
loss depends primarily on which cohort you use and the one cohort -- the cohort
that has either the three and four-year measurement that has three and
four-year measurements has a lower three-year count and therefore, you get
basically a flat line after that.
DR.
WEISS: So we have a choice of basically
looking at the cohort of 306 and if we look at the cohort of 306, it does not
support leveling off between three to four years. If we look at the cohort of 206, it does not support leveling off
at three to four years. And if we look
at the cohort of 37?
DR.
GRAY: Well, when you say
"support" it might mean a different thing to you than to me. When you get down to the 57 or 37 patients,
there is more of a leveling off but on the other hand, there's more air because
you have fewer patients. So I didn't
actually do the test with the 37 patient cohort, but my guess is that you
couldn't say statistically that there was a difference, but I didn't actually
do that.
DR.
WEISS: But certainly for the larger
groups, which would have more statistical strength, it shows no leveling off.
DR.
GRAY: That's correct. I personally used -- concentrated on the
group that had a preoperative measurement and then two or more measurements
after that because that was the one that I -- in order to do these tests you
have to be able to fit a model of some sort.
DR.
WEISS: So we're talking about if you
look at the group of 206, which had the preoperative measurement and
measurements at each of these time points, or at some of these time points, at
least on two.
DR.
GRAY: Two or more, yes.
DR.
WEISS: At two or more of those time
points. If you looked at that group,
this did not support leveling off between three to four years.
DR.
GRAY: From a statistical point of view
doing the test for leveling, that's correct, it did not support it.
DR.
WEISS: Okay, thank you. Dr. Grimmett?
DR.
GRIMMETT: Michael Grimmett. Dr. Gray, I appreciate your comments. On the group of 37, you may not have run the
analysis at the end but did you calculate the rates of or the confidence
intervals for the endothelial cell loss, what it ranges between for the 37 eyes
at year four? Did you show that? I mean, I know for the 57 it was a 90
percent confidence interval was 1.4 something.
Did you do the same thing for the 37 eyes? It's probably wider, right?
DR.
GRAY: No, I didn't do that. It would most likely be wider because of the
sample size is three-quarters. So that
would increase it by some amount, yes.
DR.
GRIMMETT: Okay, thank you.
DR.
WEISS: Dr. Bradley?
DR.
BRADLEY: Dr. Gray, on one of your last
slides there you showed us the relationship between anterior chamber depth and
cell loss and you did a linear regression that 1.6 percent per millimeter.
DR.
GRAY: Yes.
DR.
BRADLEY: Did you do the analysis to
find out how much of the variance was explained by the linear model? That becomes quite an important number for
us.
DR.
GRAY: Well, that was part of the
analysis but I don't have that number here on me. The reason I -- I guess their point is that there is a
statistically -- when you ask how much of the variation is explained, there is
a statistically significant -- that slope is significantly different than zero,
okay, so from a statistical point of view there is -- that's a significant
slope. And what I was trying to get at
was that what's the clinical relevance of that and that's where -- why I made
the plot that calculated the 1.6 percent per year. But I don't have that number on me.
DR.
BRADLEY: Yeah, but it's the clinical
significance that's driving my question here in a sense that the linear
regression might be highly significant but it may explain a very tiny amount of
the variance and thus making policy based upon a parameter which explains only
a tiny amount of the variance is really meaningless. So if we had that number or after the meeting somehow that number
could be available, that might help policy.
DR.
WEISS: Dr. Bandeen-Roche, Dr. McCulley
and then Dr. Mathers.
DR.
BANDEEN-ROCHE: Thank you for your
presentation. I just have a brief
clarification question which is that the numbers that you cited for the
four-year mean cell counts differ from the calculations that I cited
earlier. And so for instance the three,
four-year mean that you cited three years and four years is 2355 and 2356 and
reading from Volume 4 of 4, page MD19, those numbers are cited as 2455 and
2456. Now, this in a way sounds like a
little point but it goes to the representativeness, the relative
representativeness of the various cohorts.
So I don't know whether it's clear which one of those is right.
DR.
GRAY: I'm not, those all differ by
exactly 100?
DR.
BANDEEN-ROCHE: Yes, yes.
DR.
GRAY: So my first guess is somebody has
a typo because that's probably not just a coincidence that they're both exactly
100 off. These calculations that you
see here, the mean cell, the sponsor sent me a data set at the end of July,
July 25th, that has the endothelial cell counts that I later discovered they
were rounded -- these are mean so they were rounded off to the nearest cell,
the one I got. And that -- the numbers
you see here are what I calculated using the data set that I was sent.
Now,
if the three and four years -- if the two-year number is correct of 2428, then
I would say 2455 and 2456 are probably
not correct, because that would mean that there was an increase between two
years and three years as well.
DR.
BANDEEN-ROCHE: Okay, thank you.
DR.
WEISS: Dr. McCulley?
DR.
McCULLEY: Yeah, I've already expressed
a little bit of skepticism about the emphasis being put on cell density but I
know those are the numbers you had when you did your analysis, but from a
clinical standpoint just over the years, I'm a little skeptical about putting
too terribly much weight on something that can vary depending on where you take
the count and the variability over time, the reproducibility, so I remain a
little skeptical in that regard based on my clinical experience and what I've
seen in reviewing papers and hearing presentations over many years.
So
I guess then my question is, did you do any statistical analysis assessing the
size and shape variation over time of the cells?
DR.
GRAY: No, I did not do that. I used the results that we were submitted to
us by the sponsor which seemed to indicate there was really not an issue.
So I didn't --
DR.
McCULLEY: Not, an issue, I'm sorry,
meaning what, that there wasn't a change over time?
DR.
GRAY: There did not seem to be a change
through time for either the percent hexagonal or the CV and I didn't dig into
that further. I used the same thing
that you got in the submission, which is the analysis that the sponsor did.
DR.
McCULLEY: Yeah, I mean, in the absence
of data, I don't really know for sure what's right here and your extrapolation
caveats, I think, are good and it would be nice to have the very long-term
data, but at least from a cell density standpoint, my impression is that the
critical cell density for corneal edema is 800 plus/minus 400 roughly
tremendous range and tremendous variability.
And that these other factors seem to play a very critical role and it
would be more comforting for me to know that we had more data to support the
size and shape didn't change over time.
The numbers just aren't -- or the density isn't the only thing and
there's tremendous variability in the measurement methodologies.
DR.
WEISS: One thing, and I hope that we
can pull this perhaps on the lunch break is one difficult item is for the
August 2002 panel meeting when we had some of the people who were working with
sponsor actually consult and guide the panel as far as what the requirements
should be for such a study, I do not recall any such emphasis on hexagonality
and coefficient of variation. The
number -- the cell density is what was emphasized. Dr. Grimmett can comment in terms if your recollection is any
different.
DR.
GRIMMETT: Yeah, Mike Grimmett. I was the assigned primary reviewer for
endothelial analysis at that meeting in August of `02 and in the presentation I
made and included in the outline were the references that Dr. Edelhauser was
citing regarding the sensitivity of pleomorphism and polymegathism so it was
covered. I don't think the sponsor
emphasized it or the presenters emphasized it but I did cover it in my
presentation, making very similar comments to what Dr. Edelhauser said.
DR.
WEISS: Dr. Mathers?
DR.
MATHERS: Thank you for the clarity of
your presentation. I thought it was
very helpful. In the written work that
we were given beforehand, you note that the -- by your model one you had an
endothelial cell density loss in absolute numbers of about 49 cells per year
and 20 percent of the population actually had a cell loss of 100 cells per
year. That's what you're saying. Am I correct in assuming then that that 20
percent of the population in this population would then have an endothelial
cell loss rate of about 3.8 percent per year by that calculation? If the 4.9 is average and the average is 1.9
by your model 1, it seems to me that would give a 20 percent of this group that
were having a loss of 3.8 percent per year.
I mean, that's the logical conclusion.
DR.
GRAY: That is a conclusion that I
didn't actually calculate. It's very
difficult -- the problem is it's hard enough to estimate the mean function here
and now we're trying to estimate the line below which only 10 percent of the
people are going to be. And that
actually is not -- is even harder statistically.
DR.
MATHERS: Right, okay.
DR.
GRAY: The best estimate I can do right
now, based on the data we have are what I gave in the presentation, which is
that 25 percent of the people will have 2.3 percent or more. Now, if I understand your confidence limits
on that, it would be pretty wide.
DR.
MATHERS: Right.
DR.
GRAY: I'm not sure exactly what they
are. I haven't -- I don't have them on
me.
DR.
WEISS: Seeing no other -- Dr. Macsai?
DR.
MACSAI: I have three brief comments and
I thought all your presentations were great, thank you. The first, they all revolve around
endothelium but the first is to Donna.
In all your presentations about ANSI and the guidance documents, nowhere
did you mention a history of contact lens work and in light of all this
discussion about endothelial cell remodeling, I would ask the agency to
consider adding that so that that -- I think it's a critical piece of
information to help us in the future on any intraocular device.
So
I didn't see it. Maybe it's there.
MS.
LOCHNER: It was discussed at some of
the earlier panel meetings and the end result was that I think given considerations to the
population you're treating and that there is going to be contact lens wear and
what's the practical thing to impose on a clinical study, in the end the panel
didn't give that emphasis, but I do hear what you're saying and I appreciate
the comment.
DR.
MACSAI: I'm simply asking for history
so that you could segregate out --
MS.
LOCHNER: Oh, yes, yes.
DR.
MACSAI: -- who wore lenses and who
didn't preoperatively. It helps analyze
this endothelial cell data.
MS.
LOCHNER: Yes, and I think many studies
will be able to do that.
DR.
MACSAI: Okay, the second two questions
are for Dr. Gray. In this data set you
received from the sponsor, do you know if patients who had exchanges at the
time of implantation or subsequent to the time of implantation were excluded
because that would skew this data, I think significantly?
DR.
EYDELMAN: I think I actually touched on
this in my review. I believe there were
two different analysis. In the overall
analysis by the sponsor, the data for the eyes that underwent secondary
procedure were included, but they were excluded in the analysis where they were
determining ACD significance.
DR.
MACSAI: But were they excluded in
measuring endothelial cell density long term?
DR.
EYDELMAN: They weren't excluded from
continuation of collection of data if that's what you're asking. We don't have the analysis for those eyes
separated out.
DR.
MACSAI: Well, do we have an analysis of
the eyes that had the lens put in once and only once and never touched again
and what happened to the endothelial cells?
DR.
EYDELMAN: I believe that would be the
analysis where the tables for the ACD depth significance were performed.
DR.
MACSAI: And then I would ask Dr. Gray,
looking at those tables, does your slope still hold to the green versus the
black slide number 15 or whatever it was, 13, sorry?
DR.
GRAY: I guess I'm -- first of all, I'm
not entirely sure because I don't recall the exact -- I didn't actually do that
analysis both ways to compare but the key difference between the estimates that we saw was the fact that the 37 or the
57 patients had a lower, a much lower count at the three-year time point than
the other group and that's what is driving most of the difference. All the other methods of analysis and
different groups of patients that you include, if you get beyond just the three
and four-year data, you have a switch and so all of a sudden, it's about two
percent, 1.8, 1.9, 2 and so it really comes down to a question of what time
point you think the remodeling is over or whatever happens during the surgery
is done with and beyond that, we can consider steady state. And then you get into the whole issue of
what does that even mean and how can we extrapolate 20 years down the road
which is sort of unanswerable, I think, with the data we have.
DR.
MACSAI: Maybe I'm not getting something
here.
DR.
EYDELMAN: Let me just try to add, we
don't have exactly what you're asking for, Dr. Macsai. We don't have the analysis of just the eyes
that had secondary intervention, the endothelial cell separated out. What I do want to point out were that there
were few eyes to start out with and chances are some of them did not have the
analysis all together. As far as I'm
aware, PMA did not contain breakdown for the -- on this issue. Certainly your recommendation can look upon
it after the panel.
DR.
WEISS: Since we're running 40 minutes
behind and we haven't gotten into a discussion, I'm going to have one brief
comment by Dr. McCulley, and then we're going to go to five minutes of
questions for the sponsor and then break for a 45-minute lunch.
DR.
McCULLEY: Okay, a critical question
seems to be in humans, how long does it take for the endothelium to remodel
after an injury and is it degree of injury dependent, is it age dependent? I don't know the answers to those questions
but that seems to be absolutely -- the answer to that seems to be absolutely
critical in knowing how to interpret the cell density and the cell shape and
size change. Do we know that? Do we know how long it takes to -- and maybe
when the sponsor comes back, Hank will know.
But that's a key question to all of this.
DR.
WEISS: I want to thank FDA for an
excellent analysis and presentation.
Sponsor, would you be able to answer or address some of these issues?
So you have five minutes to answer all our
questions. While the sponsor is setting
up, when we break for lunch, I'll just point out, this will be
abbreviated. It will be 45 minutes, not
an hour as listed in deference to the fact that we are running over
significantly at this early point in time.
MS.
THORNTON: Are you ready, Dr. Vukich?
DR.
VUKICH: Pardon me?
MS.
THORNTON: Are you ready?
DR.
VUKICH: I believe so. For some reason, I believe the projector was
changed out from underneath us. Okay. We would like to just take a moment to
respond to a couple of the questions that were requested of the sponsor. For the number of sites that were
contributing to the four-year analysis, this data was collected at eight of the
nine sites that were collecting specular micrographs. We were able to calculate the confidence interval for the 37-eye
consistent cohort of eyes at all of the intervals and that will be the graph
that follows.
There
was clarification that we will need from Dr. Bandeen-Roche on her request for
information on an overlie of one of our cohorts, but it may take a little more
time than we have available and a little more clarification on exactly what we
would like to provide. This is the
90-percent confidence interval of the mean for the 37-eye cohort and at four
years, which I think is the point of interest.
It was 2244 to 2509. I see we're
taking notes here. Okay, good. This is the entire cohort then for the
endothelial cell density. For a point
of clarification, this cohort did include all patients and these were also --
who were examined and did include patients who had secondary procedures so in
some essence it does look at a worse case scenario.
A
separate analysis of the data, subtracting those patients out has been
done. We can tell you that it shows no
difference in our estimation. We were
hoping it would, but it didn't.
There
was one final question that we'd like to address and that was from Dr.
Bradley. There was a question
concerning pupil size and quality of vision.
We wanted to point out that our contrast sensitivities were all done
under mesopic illumination at 3 candelas per meter squared. Although we did not have pupil size to
correlate with that, there would be some assumption that the pupils would be at
least smaller than under photopic conditions and that with and without glare
there was no demonstrable difference at post-operative contrast sensitivity and
in fact, at four of the five measured intervals, there was actually an
improvement in contrast sensitivity so we hope that speaks to the quality of
vision at least under mesopic conditions.
Finally,
we'd like to thank the members of the FDA panel for their thoughtful and
thorough review of all of this information.
Thank you.
DR.
WEISS: Thank you for making it brief.
DR.
McCULLEY: Does Hank have an answer to
my question?
DR.
WEISS: We'll find out. Can you make it -- can you give a brief
answer and if the answer is, we don't have the information, then that is the
answer.
DR.
EDELHAUSER: I think that is the
answer. We don't really have the
information. The only really data that
we can rely on is probably the keratoplasty data from Bill Bourne which showed
a market drop-off, you know, and that's not really the data we're after. So we don't have the data.
DR.
WEISS: No data. Forty-five minutes for lunch and then we'll
be starting promptly.
(Whereupon,
the proceedings in the above‑entitled matter went off the record at 12:22
p.m. and went back on the record at 1:14 p.m.)
DR.
WEISS: Can everyone from the panel take
their seat, please. We're going to
continue the Committee deliberations on this PMA with presentations from
Primary Panel Reviewers, beginning with Dr. Marian Macsai‑Kaplan. I will remind Panel Members and Sponsor, and
FDA, et cetera, that we are now about an hour behind, so I would suggest or
request that all comments be short, to the point, and have the purpose of
moving this PMA ahead.
DR.
MACSAI: I'm done.
DR.
WEISS: With that non‑intimidating
introduction, I have Dr. Macsai.
DR.
MACSAI: I would like to first
acknowledge a few things. One is, that
the Sponsors did an amazing job on a really fast track PMA, and that the FDA
did an outstanding job in getting us this information as fast as it could be
gotten. And I want to really thank
Sally for being in such close communication.
This was a difficult PMA to review I think for all of the reviewers.
The
Sponsor has gone through a lot, and so has the FDA, so I'm going to try and
limit my comments, but I have a few things I just feel obliged to say.
First
of all, you saw in the distribution of the patients enrolled in the study, that
the vast majority were Caucasian. And
from previous devices we looked at, we realized that we do need to look at the
affects in non‑Caucasian patients.
The Sponsor did supply data from the Dominican Republic data set, and I
think it would be important for that to be included in anything made available
to the public, segregated by refractive error, to help the non‑Caucasian
population with their expectations.
Second
of all, exclusion criteria were included, and 65 eyes with pre‑existing
conditions were included in the study.
The results of what happened to those 65 eyes should also be made
available by the Sponsor to the Agency, because from those 65 eyes, we may
glean information that would help patients who might be treated in an off‑label
manner.
In
addition, in the exclusion criteria, limbal pathology was not included, and
must be included if a white‑to‑white measurement is required to
size this IOL.
Another
additional criteria that must be included for exclusion is what the lower limit
of endothelial cell counts are per age group.
And I would reference Dr. Grimmett's excellent review for that.
I'm
going to now address efficacy, and then the questions put forward by the
Agency. Efficacy of this device is
really good, very good. And I'm going
to just limit by comments by saying that I was happy to see the efficacy of
this data in the 3 to 7, 7 to 10, and 10 to 15 diopter groups, and leave the
over 15 diopter group for later in my discussion.
I
would have some questions why a refractive surgeon might use this in a minus 3
diopter group, and until I personally see data that this is superior to
refractive surgery already out there, I would personally wonder about that
issue.
Regarding
the specular microscopy data, which was my question 1 in the original questions
provided by Dr. Eydelman to us, I feel uncomfortable, plain and simple. I feel uncomfortable because we haven't set
a limit of what is the minimal number of endothelial cells that a patient needs
to have. We're talking about implanting
a device in a 22 year old patient, taking worse case scenario, as the Sponsor
said earlier.
We've
segregated out the patients that had complications, replacements, removal, and
if you take a 22 year old and assume that they don't become in need of a
cataract until they're 62, assuming they're myopic, they have a higher
prevalence of nuclear sclerotic cataracts, you're talking about the device
remaining in place for 40 years. And at
40 years, according to Dr. Gray's chart, they're going to drop to a dangerous
limit. And so my discomfort comes from
the fact that the surgeons who participated in this trial are the best of the
best. They have the best hands, they
have the best experience. I've had the
privilege of being taught by some, and observing them, and they are really the
best there is, so we're taking a device and releasing it to Joe Q. Average
surgeon, and this device will be seen as sort of a drive‑ through
procedure, I'm afraid, where you drive in, you get your IOL, you drive out, you
move to Outer Mongolia, and we don't know what happens to you. And we don't know what's going to happen in
10, 20, 30, 40 years to the endothelium.
So I, of course, having experienced the closed‑loop AC IOL induced
pseudo phakic bullous keratopathy, am concerned about this device and its
effect on the endothelium. And that, to
me, is the biggest issue with this PMA.
Everything else is really pretty small in comparison to that.
Along
those lines, we were asked to look at the anterior chamber depths. And I think the Sponsor has shown, Dr. Gray
has shown, everyone has shown that in the hands of the best, with an anterior
chamber depth less than 3, this device induces a 50 percent higher endothelial
cell loss. So at this time, my
recommendation would be that this device not be labeled to be used in an eye
under 3 millimeters anterior chamber depth.
And that if the Sponsor has further data, that can, of course, be looked
at in the future.
Question
2 is the nuclear opacities. Nuclear
opacities in this population developed at two time courses, early‑on,
probably surgically‑related.
Later on, probably nuclear sclerosis developing in these high myopes.
I
didn't have a big problem with this, but it brings very much to the surface the
training of surgeons who are going to use this device. If you look at the Canadian data in those
three inexperienced surgeons, there was a 22.5 incidence of anterior
subcapsular opacities, while the surgeons that were proctored in the Dominican
Republic only had a 4.8 percent incidence of anterior subcapsular opacity
development. So clearly, that technique
used in the Dominican Republic has some effect, so the Sponsors are now left
with a huge challenge; how do you take Joe Q. Average surgeon and make him good
enough to use this device?
And
some of my suggestions would be that this device, this Collamer ICL is very
similar to the Collamer posterior chamber intraocular lens and Toric
intraocular lens that is currently available, and has been for years, for
cataract surgery. And that any surgeon
who wants to implant this device must first become proficient using that
intraocular lens and loading it in the shooter, which is the exact same, and
implanting it in the eye. And only
after they're proficient with that device, should they then be able to use this
device. And they should be proctored
one‑ on‑one in the use of this device.
But
it brings to mind another concern, which is, if you look at the analysis of the
investigational sites, one surgeon at one site had a significantly higher
number of complications, and a significantly higher number of IOL removals and
exchanges. And remember, we're dealing
with the best of the best, so I raise this question to the Sponsor, pending
release to the general public, how is the Sponsor going to monitor this? If the Sponsor has to supply these IOLs to
someone who's exchanging them too often, or repositioning them too often, the
Sponsor seemingly should have some kind of tracking method for this, and
further training required prior to the release of this device. And it's a big, onerous task, but we're
talking about putting this in young people with clear lenses, so I think that
there's a degree of responsibility the Sponsor will have on this post‑approval.
Regarding
the Agency's question about removal, and if there's areas of touch, and if the
uncorrected vision is worse than 20/50, I thought these were fine caveats, but
I would also raise the question to both the Agency and the Sponsor, if there is
an anterior subcapsular cataract in the visual pathway, should that also be
added as a reason for removal?
Question
3 regarded the use of the horizontal white‑to‑white in the anterior
chamber depth measurements to determine the sizing of the ICL. I too, like Dr. Grimmett, went back to my
operating room and looked at what I had available to measure white‑to‑white,
and it's just a little, I think, Castroviejo caliper, and mine goes by 1
millimeter increments.
I,
like Dr. Vukich and Dr. Slade, was trained in a time that we did extra caps, we
measured white‑to‑white. I
think my residents have done five extra caps in their entire training. I don't think they know how to measure white‑to‑white. I think the Sponsor is going to either have
a huge task of teaching them how to do it, or find a better technique. And for that, I would recommend
consideration of the Orbscan, which we now know has been shown in the Wang
article from the Development of Ophthalmology Journal to be reproducible. It also supplies your anterior chamber
depth.
I'm
not endorsing that product. I hold no
interest in that product, but it's out there, and it would give a reliable
reproducible measurement for the
beginning surgeon. Regardless
though, if the patient has limbal pathology, you cannot ascertain a white‑to‑white
measurement; therefore, that is an exclusion criteria in my mind for this device.
Question
4. There are currently no devices
approved in the U.S. for correction of myopia greater than 15 diopters. True.
So I feel once again very uncomfortable here.
First
of all, clearly this device in that population does not correct myopia, it only
reduces it. So in light of Dr.
Eydelman's question, we have to change "correction of" to
"reduction of". But I worry
that we, as a panel, are going to arbitrarily set a standard by approving this
in this age range.
I
look to the Agency, and ANSI in their wisdom for guidance, and my feeling is
once a guidance document is developed in this population, minus 15 to minus 20,
and the Sponsor has this engineering thing worked out, that at that time, once
the guidance document is set, if the device meets the guidance document
criteria, approval is a no‑brainer.
But at this time, we have no guidance, and I'm uncomfortable with
arbitrary approval, which would set a standard, because I am certain there will
be more phakic IOLs to come in the future.
Question
5, does safety and effectiveness data support approval of the STAAR ICL for the
eyes with the following pre‑operative MRSE, minus 3 to minus 7, minus 7
to minus 10, minus 10 to minus 15. And
in general, my response to this question is yes. However, there remains this outstanding issue regarding endothelial
cell loss, sizing of the IOL, cataract information. I'm not uncomfortable with the cataract formation, sizing of the
IOL is fixable. And I guess I feel if
Dr. Edelhauser doesn't have the answer for endothelial cell loss, I don't know
who will. And so, we're functioning in
a big old gray zone. And maybe a
warning that might be appropriate is that endothelial cell count must be done
on these patients pre‑operatively, and should be done on these patients
post‑operatively for a very long time.
And if there is a decrease long‑term in endothelial cell count,
not from an otherwise obvious condition, such as a high fema, trauma, iritis,
that perhaps this device should be explanted to protect these patients from
pseudo phakic bullous ‑‑ from bullous keratopathy at some time in
the future.
The
Sponsor Question 6, management of acute intraocular pressure rises in post‑operative
period. Well, I'm disappointed that
gonioscopy was not performed post‑operatively in these patients, and I
think that Dr. Lochner's presentation has addressed this issue. A mistake was made in the development of
this PMA protocol, and it will have to be rectified in the future. But perhaps if the PIs were made farther in
advance ‑ I don't know, one week seems awfully early to me ‑ the PI
would have healed, and not of them might have been included. And there wouldn't be a need for reopening
in the future.
In
addition, I think the Sponsor must mandate that the surgeon check the pressure
within 4 to 6 hours after placement of the device, and again in 24 hours, so
that if it's the viscoelastic, this can be addressed.
Question
7, Sponsors have reported that a number of patients noted glare and/or halos
post‑operatively. Again, I'm
disappointed because though Dr. Schallhorn might feel pupil does not make a
difference, and I know this lens is much farther inside the eye, I think we
could have learned a great deal from that information. And I would ask the Agency to mandate pupil
measurements in the future, so that our patients can have a better idea of what
to expect from a device. Without it, we
can't answer the question, so we're kind of left ‑‑ we need to
include the data about glare and halos, what patients experienced. We need to include the data about the
quality of vision pre‑operatively.
It was poor at 11.6 percent of patients pre‑operatively, but at 36
months, it was still poor in 5.8 percent of patients. And that's a little disconcerting, because if you read the
recently published paper where they compared an eye with an ICL and an eye with
LASIK, those patients were doing great.
And I have no doubt that the refractive quality with this device for
patients will be better than a minus 10 LASIK.
And that the higher order aberrations will be less with this device than
a minus 10 LASIK. But I'm still
wondering why 5.8 percent of the patients rated their vision poor. Who were they, and why was it poor? So that concludes my presentation. Thank you.
DR.
WEISS: Thank you very much, Dr.
Macsai. We're going to have Dr. Joel
Sugar, who's the second primary reviewer.
DR.
SUGAR: Thank you. I'm going to just skip through various parts
of my review. Of course, I want to
thank and compliment the Sponsor and the FDA reviewers for the excellent job
they did in both putting the data together, and then analyzing the information.
The
accountability was good in the study.
The efficacy was good up to the minus 15 diopter range, and beyond that
range, certainly reduction of myopia should be the indication, or the labeling
should be for reduction of myopia, not for correction of myopia. The stability was good.
In
terms of safety, the loss of lines of best corrected visual acuity, I thought
was very acceptable. I think that you
can play games about the fact that the minification has changed and, therefore,
you should lose less lines, but what matters to the patient is how well they
see. And if they don't lose lines of
vision, even though they should have theoretically gained a line of vision, I
think they're still benefitted.
I
was concerned about the patients who required enlargement of their laser
iridotomies post‑operatively because of elevated interocular
pressures. In my review, I had the
wrong time periods because I measured from the baseline examination, not from
the day of treatment. I'm concerned
about the Sponsor developing a better means of assessing the iridotomies, both
their spacing and their size, so that these patients won't have the pressure
elevations as high as 65, as were noted in the presentations.
The
retinal detachments, I think were acceptable given the population that was
being assessed. The cataracts, I think,
were acceptable given the population that was being assessed. Although I have concern about the
recommendation for removing the lens when anterior subcapsular cataract is seen
at an acuity of 20/50 or greater, I would be more concerned about removing it
when there's progression of cataract.
If, however, I had the data that I don't have, which is, is going in and
taking the IOL out, putting a new one cause more progression of the ASC or not,
and I don't think we've been presented with any information to tell us whether
that does or does not happen.
I'm
also concerned in terms of the issue of cataracts, since these are patients who
will develop cataracts in the long run, like all of us. Is axial length measurable through the IOL
easily or not? Does a new algorithm
have to be developed for ultrasonic, or whatever technique is used for
measuring axial length?
People
who have their axial length measured, their anterior chamber depth measured
ultrasonically could presumably have that data, their axial length captured
concurrently and presented to the patient.
And it would, I think, make sense, since this is an implant, that the
patients be given a card with the data on the lens implanted. But also, if there's data on their axial
length, that that be captured, unless it's easy to measure their axial length
with the IOL in place, and it would be nice to know that from the Sponsor. It would also be nice to know whether
exchanging the lens in and of itself induces another order of complications.
Endothelial
cell loss has, I think, been very well discussed, and I guess I do feel that,
contrary to what I wrote in my review, that anterior chamber depth less than 3
should probably be contraindicated for this lens.
There
are a few other minor issues. There's
some in the labeling that I mentioned in my review. For example, in the brochure it says that surgeons should never
touch the center of the optic with instruments when it's in the eye. I don't know if that's because of concern
about leaving imprints on the lens, or it's because pushing the lens, pushing
the IOL into the crystalline lens could induce cataract. It would be worth having a statement in
the brochure saying why that's an
issue.
The
statements made, again, in the labeling, that this device has "been shown
to improve the overall quality of vision", I think that's too broad a
brush to paint this with. I think you
need specific data saying that some patients have overall vision improvement,
some don't, and give data.
The
brochure should also, I think, have a picture of the device, and a picture of
the positioning so that even if someone's taking a course, they will have some
hard copy information, should a question arise about lens positioning; although
it seems pretty obvious.
In
terms of the specific questions, is there sufficient data to suggest that
there's remodeling? I think that there
is. I'm concerned that we capture more
data in four years, and definitely capture data at five years on endothelial
cell loss. I don't think that we should
wait for that information to approve the product.
I
already talked about the anterior chamber depth. Do I believe surgeon experience is an issue? Absolutely, and that's been addressed by the
Sponsor, saying that there will be mandated training. I also talked about the anterior subcapsular cataract, that we
need more information on what secondary interventions do.
Do
I believe the method for determination of overall diameter is appropriate? I think that it is. I think that white‑to‑white is
not as difficult to measure as has been implied. While Orbscan gives it a .1 millimeter on a standard printout, it
gives you the white‑to‑white up to .1 millimeter, I don't think
that that ‑‑ and that's been shown to be reproducible, I don't know
that it's been shown to be any better than manual white‑to‑white
measurements. And certainly, hasn't
been shown with this device to provide any advantages. And it's a substantial expense for the
average practitioner, who may not have the Orbscan.
We
talked about the greater than 15. I
think that the device should be approved for correction of myopia up to minus
15 diopters, and for reduction of myopia beyond that level. And I think that ends my review. Thank you.
DR.
WEISS: Thank you very much, Dr.
Sugar. The last reviewer, Dr. Grimmett.
DR.
GRIMMETT: I'm pleased to have the
privilege to make a few comments about the application. I apologize for any redundancy. I didn't have any of the talks before during
the preparation of my talk.
Additionally, part of my purpose and mission is to get the information
in the public record, so that interested patients in the future can search relevant
issues regarding this device.
You've
obviously all read my review, the cure for insomnia, and I will try to
highlight just a few of those issues, but will not go over the data in
excruciating detail. You can be happy
about that.
Before
I dig into the PMA, I'd like to go over a few background issues regarding the
application to help us in our overall analysis. First, I want to review a few issues related to phakic IOL lens
vault. Proper lens vaulting is clearly
critical to the success of this phakic IOL.
Excessive vault over the crystalline lens will push the iris forward,
and has the following potential complications; angle closure, angle synechiae,
iris chafing with potential complications of pigment dispersion and pigmentary
glaucoma, iris sphincter erosion, iris translumination defects, and alteration
of the normal aqueous dynamics that is pupilary block.
On
the flip side, a poor vault in the ‑‑ over the crystalline lens has
the potential to induce cataracts due to IOL crystalline lens contact. Moreover, if the IOL is too short, it's
theoretically possible for it to be mobile, with possible rotation or
anteroposterior movement. Clearly, the
vault has to be just right to minimize complications, and the tolerances are
expected to be low.
With
an older version of the ICL, Version 3, the Sponsor believes that poor lens
vault led to a higher right of anterior subcapsular opacities, quoting results
from Sanders, in the Journal of Refractive Surgery in 2002. The current application states that Version
4 has an additional .13 to .21 millimeters of anterior vault, as compared to
Version 3. And while I didn't find data
in the PMA to substantiate that, the Sponsor clarified today that's a design
issue.
In
the literature, Gonvers & Associates examined central vaulting with
digitized slit lamp photographs in 75 eyes.
They had 24 V3s and 51 V4s. At
three months, the central vaulting of the 24 V3s was slightly less than the
central vault of the 51 V4s, but the difference in their study was not
statistically different. And they
concluded, "The change in design between models V3 and V4 did not achieve
its goal, which was an increase in vaulting." I just bring that up because I didn't see any data in this
application to substantiate the assertion in vivo. Certainly, it's important to keep in mind that increased vaulting
may reduce cataractogenesis at the
expense of iris and angle complications.
In
the application, when looking at vaulting, one gets the impression that the
phakic IOL vault is a static situation, but I don't ‑‑ this
couldn't be further from the truth.
Stable phakic IOL vaulting on a day‑to‑day basis is probably
not achievable for numerous reasons.
Number one, accommodation has been shown to decrease anterior chamber
depth by about a quarter of a millimeter, increase the lens thickness by .28
millimeters, and it decreases the radius or curvature of the anterior surface
of the crystalline lens.
Number
two, lens vaulting may differ, depending on whether the patient is supine or
prone; that is, gravitational effects.
And number three, the light reflex has been shown to cause a reduction
in the phakic IOL anterior capsular distance.
Therefore, on a day‑ to‑day basis, the actual lens vault is
probably a dynamic variable.
Here's
an ultrasonic image from Kim and colleagues in AJO in 1998. The third image on the top shows
accommodation on a 30 centimeter target, and displays a decreased distance
between the IOL and the crystalline lens right there, due to changes in lens
thickness and radius of curvature.
The
fourth image shows a relationship of the phakic IOL to the crystalline lens in
total darkness right here. And then the
relevant change when shining a penlight on this eye. In this particular case, there's IOL lens contact with simply a
light reflex. Based upon these data,
perfectly static phakic IOL crystalline lens relationships on a day‑to‑day
basis are improbable.
Moreover,
stable IOL vault over the lifetime of the eye is probably not achievable either
for numerous reasons. One, the soft IOL
material may flatten with time. Dr.
Vukich, I believe, mentioned European or outside the United States data over 10
years, that it may not. There is an
article in the literature that indicates that it may. I believe it's from Arne.
Number
two, aging has been shown to increase the lens thickness by 1.24 millimeters
from age 40 to age 65. Number three,
plate phakic IOLs may rotate or have mobility.
And number four, the ciliary sulcus diameter has been shown to decrease
by approximately 1 millimeter in diameter from age 40 to 80.
All
of these day‑to‑day and lifetime issues may lead to intermittent or
permanent IOL crystalline lens contact, and may lead to cataractogenesis,
pigment dispersion, subclinical inflammation, and/or disruption of the normal
aqueous humer dynamics. Given these factors,
I can't imagine that ICL positioning will be stable and problem‑free for
the lifetime of a given patient, especially since this device is intended for
young recipients.
Let's
talk about issues related to the sizing of these IOLs. The sizing of the ICL myopic lenses was
determined by the horizontal white‑to‑white and the anterior
chamber depth measurements in the following fashion. For anterior chamber depths 2.8 to 3‑1/2, they added half
millimeter to the white‑to‑white, and for anterior chambers greater
than 3‑1/2, they added 1 millimeter to the white‑ to‑white. For in‑between sizes, there was a
rounding down and rounding up protocol.
Hence,
STAAR's sizing methodology is based upon white‑to‑white
measurements. However, valid scientific
evidence exists saying that white‑to‑white measurement do not
correlate to the sulcus dimension. So
white‑to‑white measurement does not ‑‑ is not a good
surrogate marker of the variable of interest, the sulcus diameter.
Here
is just one piece of information from Reinstein's study, in which he examined
white‑to‑white values with calibrated photographs and sulcus‑to‑sulcus
dimensions with high frequency ultrasound.
All this information is in the public domain. It's right off the Internet.
The
top value shows that of myopic eyes, plotting white‑to‑white on the
X axis, and sulcus‑to‑sulcus on the Y axis, that there's no
correlation for myopic eyes. The same
was true for hyperopic eyes.
These
data imply that a one‑size fits all phakic IOL would seemingly have just
a good chance of success or failure as basing the ICL upon the horizontal
corneal diameter.
Let's
go ahead and look at a few examples of basing the ICL on white‑to‑white
measurements to display this fact.
Here's a case where white‑to‑white is 11‑1/2 OU. Put the ICL based on that, bravo, it looks
pretty good ‑ adequate lens vault in both eyes, left and right, so we're
pleased with ourselves on this case.
The
next one we have an asymmetric white‑to‑white, 11‑1/2 on the
right, and 12 on the left. However,
despite differing white‑to‑ white measurements, the lenses were
over‑sized in both by about the same amount, rather than an asymmetric
amount, and the vault is excessive, causing angle closure, as you can probably
see.
Here's
a case where the same white‑to‑white existed on both sides, but the
vault was excessive on the right, and non‑existent on the left, with lens
IOL touch. I simply would say that
because there's valid scientific evidence indicating there's a lack of
correlation between white‑to‑white and sulcus‑to‑sulcus,
that physician labeling should include relevant material facts indicating the
lack of the correlation. In fact, in knowing this data now, it's amazing to me
that the vault data within the application is as good as it looks.
We'll
review a few issues related to glaucoma.
And please pardon me, Dr. Coleman.
I will defer to your judgment on these issues. I'm just the cornea guy.
Projected glaucoma risks for this device include pigment dispersion
syndrome, angle narrowing, and angle closure.
Regarding
pigment dispersion syndrome, it's important to realize that STAAR's study
cohort fit squarely within the known risk factors for pigment dispersion
syndrome; that is, myopia young age in Caucasian race. Pigment dispersion syndrome is at least as
common in women as in men.
One
study quoted about a 2‑1/2 percent incidence of pigment dispersion in
Caucasians. Simply using this figure
based on the number of Caucasians in the STAAR PMA, we'd expect six in this
study to have pigment dispersion. The
Sponsor reports zero, both before and after ICL implantation. Let's look to the literature.
A
published study found pigment dispersion in the angle in 9 of 58 eyes, or 15‑1/2
percent at 18 months. The authors
postulated that the STAAR ICL pushes the iris anteriorly, and optic iris
chafing leads to pigment dispersion syndrome in a subset of patients.
A
1998 study, using ultrasound after ICL implantation, found angle narrowing in
all eyes, and peripheral anterior synechiae in 2 out of 9 eyes, or 22
percent. The ICL was in wide contact
with the iris in all eyes.
For
this study, I reviewed the submitted
PMA materials, and reviewed both the pre‑op and post‑op
clinical study report forms. I didn't
find any gonioscopy data, which I was shocked to see that. I also didn't find any ultrasound data
presented to determine angle anatomy alterations following the ICL. It's my opinion that the lack of these data
is a disservice to present and future patients with the STAAR ICL, and
represents a major study design error.
Gonioscopy
can assess angle pigment deposition, a sensitive and common finding in pigment
dispersion syndrome. Perhaps no patient
was diagnosed with pigment dispersion syndrome because no one looked at the
angle post‑op.
Moreover,
gonioscopy can determine angle narrowing and synechiae. Further, if no gonioscopy examinations were
performed, other relevant features could be missed, vascularization and other
preoperative abnormalities.
The
theoretical risk to the angle can be easily surmised given the design and
intended use of this phakic IOL, and it's my belief that the initial study
design should have included gonioscopy, whether or not it was mandated by the
FDA.
Let's
review issues related to pupil diameter and the lens optic diameter. It's well known that dim illumination
mydriasis can be robust in the young.
Dr. Vukich indicated that when this study was designed, that those
parameters were not well known. Being
an old guy, I beg to differ. Back in
about 1993‑94, I reviewed issues related to pupil diameter with small
optical zone radial keratotomy. My
literature review at that time revealed that the mydriasis being robust in the
young was documented, well know, and in the literature at that time. I believe that predates the design of this
particular study.
STAAR's
study cohort ranged from 22 to 45 years of age, and we've heard that the lens
optic diameter is 465 to 55. Given the
young age of the cohort, as Dr. Bradley already noted, it's reasonable to
expect that some patients will have dim illumination pupil diameters that
exceed the lens optic diameter. We,
therefore, have an expectation that some patients may experience halos and dim
illumination, or have nighttime visual aberrations.
Looking
to the literature, Arne found a higher frequency of halos with small optic
diameter ICLs. The rate of halos
correlated to the difference between the scotopic pupil diameter and the
optical zone size. Due to these halos,
these authors recommended intentional under‑correction for high myopia;
that is, using a larger optic diameter lens followed by LASIK.
Hence,
another study design error in this PMA is the absence of pupil size
measurements. Relevant analysis should
have included the rate of visual aberrations with increasing optic pupil
mismatch. Regrettably, this was not
performed for our review.
In
the absence of this pupil size information, the best we can do is stratify the
patient's symptoms by the lens optic diameter.
I couldn't find this information in the materials given to me, but it
should be required for later FDA review.
Also, each symptom category should be reported separately; that is,
separately none and mild, rather than lumping the categories in the current
tables. Of course, this information
presumes that the small lens optic patients do not have skewed pupil sizes one
way or the other. We'll simply never
know.
Let's
go on to endothelial cell loss. The
threshold analyses that I presented in Appendix 1 of my written review show
maximum rates of annual cell loss to reach various target levels at the time of
death. Clearly, there's many
assumptions that are made, including an annual instantaneous cell loss, and
that it's linear, and it doesn't include information regarding stem cell
repopulation. However, using these
figures, if we desire a 1500 cell for millimeter square density at death, a .9
percent annual loss rate is the maximum, inclusive of all age ranges; that is,
the 20 to 30 year old range. And if we
desire an 800 cell per millimeter square density at death, a 1.9 percent annual
loss is the maximum.
It's
important to remind ourselves that 50 percent of patients will have endothelial
cell densities that fall below the normal mean cut‑off values; and,
therefore, younger patients, that 20 to 30 age group, have a significantly
higher risk of running out of endothelial cells during their lifetime if these
rates are continuous. And now to the
PMA itself.
Regarding
the study population, the total eyes show with the blue bars indicate very good
follow‑up. I certainly recognize
the difficulty of carrying out such a large study for an extended period of
time, and commend the Sponsor for their efforts. The purple bars show endothelial data on approximately 200 eyes,
with a large drop‑off at the 48 month interval shown out here as 67 eyes.
I
find it ironic, some studies we reveal at panel only have 6 and 12 month data,
and we're always wrestling with not enough data. And here a Sponsor has run a 3 and 4 year study, and we're still
wrestling with not enough data. I just
found that amazing.
Unfortunately,
the endothelial data in the written PMA have varying ends, and there's no
consistent cohort of eyes followed through each and every examination
interval. The data we've seen today
with that 37 eye consistent cohort was not provided to me in the materials that
I reviewed. That made the evaluation
difficult.
Just
one housekeeping item, and I believe Malvina already alluded to this. The inclusion criteria had a stable
refraction within a half diopter over the prior year. The indications for use statement had a 1 diopter over the prior
year, obviously, needs to be matched or reconciled.
Regarding
the exclusion criteria, we know that phakic IOLs can alter the corneal
endothelial. Dr. Macsai alluded to
this. The corneal endothelial status
was omitted from the exclusion criteria, and given the young age of these
patients, I believe it would be a relevant material fact to be considered prior
to implantation of this device.
Certainly,
if a young patient had an abnormal endothelial layer, I would not recommend
this device as a clinician. There is no
question that I wanted pre‑op specular endothelial analysis for this
cosmetic elective procedure, where the alternative is glasses or contact
lenses.
On
to some safety issues. Let's discuss
the learning curve associated with phakic IOL implantation. I believe we're all in agreement that the
labeling should include relevant learning curve issues. Of the 13 upside down lens insertions, 11
occurred within the investigator's first 22 procedures, 6 out of 13 developed
in AST in the early post‑op period.
Of the 14 eyes that developed anterior subcapsular cataracts, most
occurred within each investigator's first 8 surgical cases. One investigator accounted for a disproportionate
share of the ASCs, a 9.4 percent rate, and that same investigator accounted for
both cataract extractions in the study.
To lessen the impact of learning curve issues for the patient, I'd favor
specialized course training or case supervision by an experienced surgeon for
early cases.
On
to change in best spectacle corrected visual acuity. As compared to the lower dioptic groups, there are larger post‑op
gains of best corrected visual acuity, 20/20 or better, in the high myopia
group. For the less than 7 diopter
group shown in the orange, there is an 8.3 percent gain pre‑op among
36. For the 7 to 10 diopter group shown
in the maroon, there's a 15.6 gain pre‑op among 36, and for the greater
than 10 diopter group shown down here in the blue, there's about a 20.4 percent
gain pre‑op among 36. These are
findings strongly argued for an induced magnification effect as a result of the
surgery.
In
looking at greater than or equal to one line of best corrected visual acuity
loss, high myopes have an increased rate of vision loss with time as compared
to lower myopes. And we've already
heard that for this particular group, a one line loss is the equivalent of a
two line loss due to induced magnification as a result of the surgery.
The
rate of greater than one line loss goes up to about 16 percent. I'm not sure why that would exactly be. I don't know if that has to do with lens
optic pupil mismatch or other issues, but I'm not sure it's well
delineated. It's certainly not clear in
my mind as the ultimate etiology of that.
Another
way to look at the same issue, the mean improvement in lines of vision, high
myopes with time decline in improvement starting at 6 months, one line
improvement down to .4, two line improvement at 36 months. Certainly, appropriate labeling should
mention this trend.
On
to interocular pressure, 20 of 526 eyes, or 3.8 percent had pressure spikes in
the early post‑op period, 11 reached 40 to 50, 4 reached 55 to 58, and 1
reached a whopping 65 millimeters of mercury.
Most of the spikes occurred by day one or two, 17 needed additional YAG,
3 required AC washout for retained viscoelastic. Clearly, these pressure elevations are not trivial. Myopic disks are perhaps slightly more
susceptible to damage from elevation of IOP than ametropic or hyperopic disks.
Patient
and physician labeling should highlight the issue in order to appropriately
plan early post‑op exams. As a
clinician, I might consider the use of Diamox on a case‑by‑case
basis.
With
regard to chronic pressure elevation, the overall cohort shows an increasing
trend for patients to experience an increase in pressure greater than 5,
looking at the graph, at 6 months about a little under 3 percent, and at 36
months something over 6 percent, 6‑1/2 percent had a change in baseline
pressure.
Pre‑op,
looking at patients with a pressure greater than 21, about 3 percent had
pressures greater than 21, and at 36 months about 6 percent had pressures
greater than 21. Two patients were
diagnosed with glaucoma and treated topically.
Given
the potential for the STAAR lens to alter pressure regulation for the factors
previously mentioned, I'm concerned about this finding. We must recognize these recipients are
young, expected to live many future years.
At a minimum, labeling should emphasize this particular issue. I again note that the STAAR study omitted
gonioscopy for a device that affects the angle. Gonioscopy can assess pigment deposition, a sensitive and common
progressive finding in pigment dispersion syndrome. Angle grade and synechiae formation are also relevant
findings. Inexplicably, gonioscopy
wasn't done. If I were a clinician, I
would be doing gonioscopy.
The
corneal endothelial data ‑ in the materials provide there was no true
consistent cohort data for each and every examination interval. There was fluctuating denominators at the
various examination intervals, and this made our analysis difficult. We've seen data today on 37 eyes that had
consistent cohort data, but the remainder of the application does not.
While
this is not a consistent cohort of eyes, there appears to be progressive
endothelial cell loss over time. The
total at four years is insufficient to make conclusive statements, but the cell
loss does not stabilize over the study period.
These cell loss rates, if continuous, constitute a serious safety issue
that may jeopardize approval of this device.
Looking
at the 154 eye consistent cohort at year 3, pre‑op to 36 months, 8.9
percent loss, that was higher than the table we just looked at with 8.4
percent. It took me a long time to
figure out that there were two disparate groups that had an "N" of
57, and both reported 4 year loss rates, and both were called the consistent
cohort. Two groups, pre‑op to 48
months, there was a 9‑ 1/2 percent endothelial loss. Three year to four year there was a .041
percent endothelial gain, with the upper limit of the 90 percent confidence
interval at 1.43 percent loss per year.
It's
this one isolated group, as we've heard, which the Sponsor is making the
argument for stability in conjunction with the morphometric data that Dr.
Edelhauser reviewed.
Let's
look closer at this 57 eye cohort. This
is a histogram that was in the material somewhere, that outlines where these
eyes fell in terms of cells gained or cells lost. The mean cell density increased by one cell. Overall, just looking on the number of eyes
on either side as zero, 31 eyes lost cell density, and 26 eyes gained. More eyes lost zero to five here at 21, than
gained zero to five. It's about even on
either side of 5 to 10, 8 versus 7.
This is the group that had me wondering.
Here's
a group out here gaining 10 to 15 percent of cells, versus only one eye losing
10 to 15 percent. Of these 7 histogram analyses in the
application, this is the only one that had more eyes gaining 10 to 15, than
losing 10 to 15. Certainly, I'm willing
to accept random measurement error that leads to an evenly matched set of gains
and losses. That is a true bell curve
due to precision errors measuring endothelial cell loss, but I can't come up
with a physiologic reason that five eyes have truly gained a sizeable
percentage of endothelial cells in 12 months.
I'm wondering whether these big ticket outliers up here at 10 to 15
percent skewed the mean data and falsely elevated it, leading us to a
conclusion of stability.
We've
heard from Dr. Gray, and his comments were greatly appreciated by me. I place
great emphasis on statistical analysis of the data. He noted that simple comparison of the two to three year loss
versus the three to four year loss is not appropriate due to the likelihood of
producing negatively correlated observations.
And he mentioned that multiple ways by saying that the three year loss
was lower than the other data points.
He
also noted there was not strong statistical evidence that the cell loss levels
off after year three. Additionally, of
the 57 eye cohort with both three and four year data, 10 out of 57, or 17‑1/2
percent had more than 5 percent cell loss over 12 months. Those are pretty big numbers if those are
true for a young cohort.
Based
upon these data, I remain scientifically unconvinced that this procedure
provides a reasonable assurance of safety for the corneal endothelium in the
long run. The preponderance of evidence
that we were offered was weighted toward an unsafe level of endothelial cell
loss, that if continuous, would jeopardize the safety of a future interocular
procedure or cause corneal edema during the patient's lifetime, or both. I think we're all in agreement, we need a
larger four year sample size. I would
agree that ongoing endothelial surveillance to year five would be desirable,
given the youth of the cohort.
I'll
talk briefly about anterior chamber cell depth. We see that the endothelial loss in eyes with shallow anterior
chambers was 12.2 percent over three years, while the loss was 8.4 percent for
eyes with anterior chambers greater than three. As Dr. Macsai noted, a 50 percent increase in shallow
chambers. I would not necessarily
disagree with an abundance of caution approach to limit the device to eyes with
anterior chambers greater than 3.
It's
worthwhile noting that only 5‑1/2 percent of the total study cohort would
be excluded by this limitation. And,
therefore, I don't believe it's an onerous limitation that would exclude large
numbers of patients. I think it's
reasonable to do that.
Something
interesting in this 57 eye cohort, in addition to looking at the histogram, if
we look at the anterior chamber depths for 50 of these eyes in that cohort with
three to four year data, 50 eyes had an anterior chamber depth greater than 3
millimeters. They gained .3 ‑
excuse me ‑ they lost .3 percent in endothelial cell loss from year three
to four, and there were 7 eyes with an anterior chamber depth that was shallow,
and they had a 2.9 percent gain in endothelial cells between years three to
four.
From
my vantage point, that didn't make sense.
That was a counter‑intuitive result that contradicts the
generalized study results of a higher rate of loss in the shallow AC
group. From my vantage point, something
smells wrong with that 57 eye cohort. I
would love for that four year cohort to be larger so that it would even it all,
so that we'd have a better statistical sense of what's going on.
On
to effectiveness, and at this point I'm going to stipulate to Dr. Slade's
excellent presentation on effectiveness, and we're not going to go over all
this data, so yadda‑yadda‑yadda, the procedure seems
effective. That's enough of that.
In
terms of willingness to have the ICL again, 5.6 percent less than 7 diopters
were not willing to undergo it again.
And in the greater than 15 diopter group, all patients were willing to
undergo it again, despite poor effectiveness and high rate of complications. I interpret this finding just to mean that
low myopes are less desperate for the surgery, as compared to high myopes who
appreciate help of any kind, even though it may not be perfect.
And
in conclusion, this does appear to be an effective device to reduce
myopia. We must be reasonably sure that
the endothelial cell loss does indeed stabilize following ICL
implantation. It's critical to
recognize that these devices are intended for a young population with 50 plus
years to go. We can't afford an
epidemic of bullous keratopathy for a cosmetic elective procedure.
I'm
also concerned that while the morphometric data show that we don't have a
change in pleomorphism or polymegathism, what I'm concerned about is that
there's evidence to suggest that younger corneas may blunt our ability to see
those changes. I'm just wondering whether we're not seeing much of a change for
chronic stress simply due to the fact that the cohort is a bunch of young
corneas.
Dr.
Edelhauser, I believe, was in general agreement that younger corneas are
robust, and may not show stress factors as readily as an older cornea, so I'm
concerned that the data does not have statistical evidence to show that it
tapers off for sure, and I'm concerned that the younger corneas may blunt our
ordinary morphometric data that would ordinarily tell us there's stress.
I
certainly need convincing with a larger "N" for the four year
endothelial data one way or another. I
think that number needs to be bigger.
Thank you very much for your attention, and I apologize if it was
redundant.
DR.
WEISS: Thank you, Dr. Grimmett, for
your usual detailed, insightful reviews.
We're
going to now go on with panel discussion of this PMA. I'm going to ask the FDA if they'd be so kind to come to the
podium. And I would also request that
we go out of order of your questions.
There's a method to my madness, so I'd like to start with question 3,
which is a discussion of how to decide what size to put in the eye. And in terms of whether the currently
recommended method measuring the white‑to‑white, which was
recommended by the sponsor is an appropriate way to do it. And if not, what does the panel recommend.
I
will remind you just in terms of what we've heard from our reviewers, Dr.
Macsai was recommending using the Orbscan or something similar, because the
white‑to‑white is not very accurate. And Dr. Grimmett also agreed, the white‑to‑white was
not very accurate. But I'd like us as a
panel to determine whether we're going to recommend that the labeling include
the way the panel ‑‑ the way the sponsor did the study, which is
measuring white‑to‑ white, or do we want something else. Dr. Sugar.
DR.
SUGAR: I'd like to recommend that we
recommend no changes from the Sponsor has recommended, given that we don't have
anything better that I'm aware of.
Certainly we don't ‑‑ while the white‑ to‑white
doesn't correlate with sulcus‑to‑sulcus dimensions, it is highly
impractical to do ultrasound
biomycrospy as 20 or 50 megahertz.
It's very unwieldy. At 50
megahertz you almost can't do it. You
have to make a collage of the pictures in order to measure it, and I don't
think we have anything better. If
something better becomes available, it may be worth recommending in the future.
DR.
WEISS: Dr. Macsai.
DR.
MACSAI: I respectfully disagree with
Dr. Sugar, not about ultrasound biomicroscopy, just about the
irreproducibility, if that's a word, of the caliper method. And that since you need an anterior chamber
depth measurement from the back of the cornea to the front of the lens, you're
getting two for one there with Orbscan.
That's been validated reproducible.
DR.
SUGAR: I said measure white‑to‑white. You're talking about measuring white‑to‑white
in terms of what instrument? I didn't
say what instrument to use.
DR.
MACSAI: Well, I did.
DR.
SUGAR: That is, you're saying ‑‑
I understand ‑ that Orbscan is a better way to measure white‑to‑white. And again, I don't ‑‑ I'm not
aware of validation of that information apropos of this device.
DR.
MACSAI: Well, then I guess we need to
ask the Sponsor if they used that technique, because I thought the Sponsor used
many techniques. I don't know if I'm
allowed to do that at this time, Madam Chairperson.
DR.
WEISS: Not at this time. We can have them address it in the proper
time point, but not at this point. Does
anyone else have any opinions on that?
We're going to get some musical accompaniment at the same time by Dr.
Bradley which is quite kind. Anyone
else have any opinions on this particular point? No, so I think that is ‑‑ does anyone have any
concerns about measuring it with calipers, aside from those that have been
expressed? So we will move on. I guess for the FDA, I think what's been
expressed is if the Sponsor has shown that Orbscan is any more accurate than
calipers, we would go with that, but I doubt that's what they've shown, because
if they did, that would have been clearly presented. Malvina.
DR.
EYDELMAN: The nature of the question
wasn't to try to determine the instrumentation that's best to perform the
measurement with. The question ‑‑
during the study, the white‑to‑ white was only measured with
calipers. The Orbscan was used for
ACD. What this question intends to get
at is whether the white‑to‑ white measurement is appropriate for
sizing of the ICL.
DR.
WEISS: Well, I think the panel would
probably agree that it may not be great, but we don't have another option. And nothing else was done in the study, so
we don't have a choice. Would anyone
disagree with me, any of the primary reviewers disagree with that spin? So the answer is, we think it's just great,
since we have nothing else. We will go
to question 4.
DR.
EYDELMAN: Did you want me to read it,
or do you want me to just project the question part?
DR.
WEISS: Why don't we ‑‑ can
you read the question part of the question?
DR.
EYDELMAN: Question 4(a), "Does the
safety and efficacy data for eyes with preoperative myopia of greater than 15
to 20 diopters support this range"?
DR.
WEISS: From what I understood from all
of the primary reviewers, everyone seemed to be in agreement that it supported
this refractive range if the labeling was changed to reduction of myopia, as
opposed to correction. Dr. Macsai.
DR.
MACSAI: Maybe I misled you. I didn't mean that. I think that this is something the Agency
has to provide a guidance document on.
I think when the Agency tells us what are acceptable outcomes in the
minus 15 to minus 20 range, then we can approve it. But right now, we're throwing the dice. It's arbitrary.
DR.
WEISS: Dr. McCulley.
DR.
McCULLEY: I have to ask a question of
what the Agency expects of us. If they
bring something to us for an opinion, and they have a guidance document, then
we would apply our opinion, or use that in our decision making. If they bring something to us and ask us an
opinion where there's not a guidance, then I think my impression would be the
FDA would be asking us to provide our best opinion based on what's provided to
us.
DR.
WEISS: You're entirely correct. And also guidance documents are just that,
you don't have to adhere to guidance documents. They're just meant as guidance.
So with that in mind, Dr. Macsai, what is your opinion sans guidance
document?
DR.
MACSAI: My opinion from history is once
approved, guidance or no, it's set as a standard for those that follow. And I urge the panel to proceed with
caution. I think it's arbitrary. I think the numbers are limited, and I have
trouble with it in this range of myopia because once this is approved, every
other device will be measured compared to this. Whether appropriate or not, the comparison will be made.
DR.
WEISS: I see Dr. Rosenthal shaking his
head, and I think really what we have to do ‑ this is not a
guidance. This is, we have to decide on
the efficacy and safety of this particular device. And you can have the labeling reflect. So, for example, as has been suggested by Dr. Sugar, you could
say that this does not ‑‑ this is not for correction of entire
myopia in above minus 15, but it's for reduction of myopia in this group. Dr. Rosenthal.
DR.
ROSENTHAL: May I just clarify, Dr.
Macsai, that in fact, each Class 3 PMA must stand on its own, and a decision
should be made without comparison to data from any other PMA. And I think that's the way ‑‑
we've been pretty consistent about that over the past 7 or 8 years. So hopefully, what decision you make on this
will not bear on another decision made on another device.
DR.
WEISS: Dr. McCulley.
DR.
McCULLEY: My impression is that often
despite guidance to industry, they will try to use prior PMAs and compare,
despite the fact that they're advised not to do that. We don't have any control over that. But it really should not set anything that can be legitimately
used in the future in a PMA application or presentation.
DR.
WEISS: And also, we've just been, you know, guided by Dr. Rosenthal, is that we
should not be ‑‑ that should not reflect what your opinion is at
this particular point. Your opinion
should stand alone for the devices being brought forward to you. So with that in mind, without thinking of
the future or the past, just the moment, is this efficacious for reducing
myopia in patients who have more than a minus 15? Dr. Schein, then Dr. McMahon.
DR.
SCHEIN: Jayne, I hope I don't throw too
much of a wrench in the works, but it seems to me there's one overriding
question that needs to be addressed before getting into the sub‑levels. So assuming that there's some consensus that
there is efficacy, which I think I've heard some consensus, there also seems to
be some consensus of concern about certain adverse events.
DR.
WEISS: Which we will get into, so this
is ‑‑
DR.
SCHEIN: Which you cannot separate this
tension between having an appearance of safety during a short time period, and
uncertainty in a long time period. You
can analyze this all day long, and that uncertainty will still be there. So my entire focus on these questions has to
do with the level of rigor and detail that one can request in a post market
setting. Everything else depends upon
that.
DR.
WEISS: Because these are going to be
very ‑‑ this is going to be, obviously, a much longer discussion
and much more detailed, I'm trying to get some of the housekeeping out of the
way. I understand this is not
scientific, but on the other hand, I think it'll work, so I'd ask you to bear
with me.
DR.
SCHEIN: Okay.
DR.
WEISS: We may not get to the bottom
line on all these questions, but certainly, once we start getting involved in
the question of what are the endothelial cell specular microscopy data mean,
are we talking about post‑market studies, this is going to be a more
lengthy discussion, and I want to delay that lengthy discussion.
DR.
SCHEIN: Okay. So to answer, I'd say efficacy, yes ‑ safety, unknown.
DR.
WEISS: Fine. That's good enough. Dr.
Matoba.
DR.
MATOBA: Then maybe we should do the
first of those questions first, and then come back to this.
DR.
WEISS: Well, I'm actually mostly
interested in efficacy, so I think if the answer is it shows efficacy for
reduction, then we have an answer. And
then I think for the question of safety, that's going to be going across the
refractive ranges. Is there any other
discussion on this particular question?
We may need to come back to it.
SPEAKER: Can you get a sense of the panel for us?
DR.
WEISS: I'm just going to have a hand
show, a brief vote. What ‑‑
if the members of the panel could raise their hand if they believe that this
device is efficacious for reduction of myopia in patients with refractive
errors greater than minus 15. Those of
you who believe it's efficacious, we're not discussing safety at this moment,
can you please raise your hand.
(Vote
taken.)
DR.
WEISS: So I think that's ‑‑
SPEAKER: Is this a reduction, Jayne?
DR.
WEISS: Reduction, yes. I think that's consensus, so that would
answer for efficacy. I'm going to skip
then to Question 6 on IOP rise, if we could.
DR.
EYDELMAN: There was a 4(b), but I was
instructed to skip it.
DR.
WEISS: What was 4(b)? I'm sorry.
DR.
SUGAR: Corrections to treatment.
DR.
WEISS: Well, we did say reduction. We said reduction of myopia. Question 6 relates to IOP increase. Would you be able to read that?
DR.
EYDELMAN: Certainly. "Do you believe that specific
recommendations regarding early post‑operative follow‑up are needed
in the labeling"?
DR.
WEISS: So Dr. Macsai has suggested in
relationship to the IOP rise that it be suggested that the pressure be checked
4 to 6 hours later. Dr. Sugar suggested
that there should be ‑‑ the Sponsor should indicate a better way to
assess the size of the iridotomies when they're too small. Could I have some discussion on these
particular recommendations? Dr. Macsai.
DR.
MACSAI: I would also ask maybe Dr.
Coleman to help us with the question of timing of the iridotomies, if 7 days in
advance is the appropriate amount of time to ensure patency. And then the second part is, which I forgot
to mention in my verbal review, I did in my written review, is whether or not
irrigation and aspiration of the viscoelastic would be recommended by the
Sponsor, because that's what was used when the pressure rise was thought to be
due to retained viscoelastic in those problematic cases.
DR.
WEISS: Dr. Coleman.
DR.
COLEMAN: This is Dr. Coleman. In terms of the timing, it's really hard to
tell from their data whether or not the problems that they had with the
iridotomies closing in the post‑op period was because the iridotomies
were done within 7 days of the surgery.
They were still on steroids when you look at the PMA at the time of
surgery, so it would be recommended that they actually had done the iridotomies
at least two to three weeks prior to surgery, confirmed the patency of the
iridotomies prior to placing the implant.
And then also having the patients off of steroids, because that would
reduce their steroid responders, because they also had problems in the PMA of
individuals that they identified as having interocular pressure elevations due
to steroid response.
And
in their labeling, they do have that irrigating with a 27‑ gauge cannula
to the wound is sufficient to flush viscoelastic from the eye. I would say that's not true. Their own data shows that it's not
sufficient, and so you would ‑‑ they would need to change that
wording, and also to show in the labeling that if you don't flush the
viscoelastic from the eye, you can have some major problems with interocular
pressure spikes. So as Dr. Grimmett had
mentioned, IV Diamox may be beneficial in preventing these.
In
terms of checking the interocular pressure afterwards, that would need to be
within like 4 to 6 hours of a procedure, and then the following day they would
also need to check it within 24 hours, and also 48 hours, because they had
spikes up to two days. And it's well
known that viscoelastic can remain in the anterior chamber from 48 to 72 hours,
if it's not flushed out.
DR.
WEISS: Let me just clarify. You would then suggest in labeling that it
be indicated to check pressure 4 to 6 hours, and 48 hours. And what are your time points?
DR.
MACSAI: I would say 4 to 6, 24, and 48
hours.
DR.
WEISS: Is that not onerous? We don't do that with cataract
extractions. Dr. McCulley.
DR.
McCULLEY: The issue is ‑‑ I
mean, if you're going to irrigate, as I understand it, the way the viscoelastic
was removed, it's a cohesive viscoelastic.
You tried to irrigate it out with a 27‑gauge cannula. Why not use something like a Simcoe needle
for I&A? I mean, I think that's the
point. Then there would be less concern. I still would go with the 4 to 6 hours, and
the 24 hours, but I would think that would be a better approach.
DR.
COLEMAN: Because one of the problems is
you get ‑‑ this is Dr. Coleman.
You get viscoelastic in the trabecular meshwork, and even sometimes even
irrigating it out, you don't get all the viscoelastic out in certain eyes. And some of these eyes are going to be
predisposed to having interocular pressure spikes. Because of the study design, they were already on steroids, and
so that's predisposing them, in addition to their being myopic.
DR.
WEISS: How many procedures do we do
that we require patients to come back 4 to 6 hours later to check if we still
have viscoelastic in them? I mean, I
think that's not ‑‑ that's fairly burdensome in my book.
DR.
COLEMAN: Well, there may ‑‑
I think one of the issues is that if you take eyes that run and spike pressures
up to 55 or 65, and these eyes are, you know, very painful and stuff, it's an
issue in terms of in the orange study when Dr. Grimmett had pointed out, where
they looked at those 50 eyes. They
actually gave people IV Diamox on the table, and the 4 hours later post‑operatively,
and they didn't report any of those acute IOP pressure spikes.
DR.
WEISS: But if we're talking about such
a small percentage of eyes that are ‑‑ in which that's happening,
wouldn't it ‑‑
DR.
COLEMAN: You don't know the long‑term
ramifications of elevated interocular pressure spikes to 65 for 24, 48, 72
hours, even in a young person.
DR.
WEISS: Dr. Mathers, and then Dr.
McCulley.
DR.
MATHERS: In common sense terms, I don't
see that this is terribly difficult from filling an eye with viscoelastic when
you do cataract surgery, measure pressure the next day, and if there's a
problem, you continue to measure it. It
sounds to me like this would work if you did that, but I certainly think it's
necessary to measure it the next day.
And if you treat promptly, you perhaps will tolerate, like cataract
surgery patients do, a brief pressure rise.
DR.
COLEMAN: This is Dr. Coleman. It's debatable how brief is 24 hours with a
pressure up to 65. And even if you
potentially irrigate it, they can re‑spike again. I mean, it's ‑‑ we see it in
terms of the management of individuals with cataract surgery, where we have to
go for 48 hours, sometimes managing pressure spikes. Now these are eyes with compromised angles, but you don't know
how many of these individuals do have already potentially compromised angles
because we don't really have the gonioscopy on it. And so it's some ‑‑ unfortunately, the issue is
muddied with the viscoelastic, the closed iridotomies, and then potential
problems with the angle due to the placement of the phakic lens.
DR.
WEISS: You know, I think on this
particular issue, since it's ‑‑ we can agree to disagree on this
particular one, so that has ‑‑ the idea of perhaps suggesting an
IOP check in 4 to 6 hours, and 24 hours, and also putting in labeling that the
IOP rise may occur if viscoelastic is not rinsed. Those have both been suggested.
Can you elaborate, Dr. Sugar, about the labeling advice you would want
as far as the iridotomies go?
DR.
SUGAR: I will ‑‑ well, I
need to back up a little bit. I think
that there were only 2 or 3 patients that required re‑ irrigation of
viscoelastic out of 20 that had pressure elevations that were substantial. I don't think that's sufficient to mandate a
change in the way you get rid of the viscoelastic.
There's
a cost issue if you're going to have to have a machine to do I&A , and
having tubing and stuff, or even a Simcoe.
I don't think there's sufficient evidence to suggest that the techniques
suggested by the Sponsor should be altered.
Your question was?
DR.
WEISS: You had mentioned having a
better way to assess the size of the iridotomy when it's too small.
DR.
SUGAR: I just wonder if the Sponsors
had from those 17 patients that needed their iridotomies enlarged, if there was
‑‑ you know, if the distance between them was insufficient and,
therefore, they were covered, or if there was something about them that would
suggest a different approach to doing the irridotomies to make that less likely
to happen. I certainly think that
Anne's suggestion that you do it longer in advance, and you look and see that
they're patent makes perfect sense.
DR.
WEISS: So basically, if the Sponsor could
provide information of what they've learned for those iridotomies that had to
be enlarged, what was done incorrectly the first time around?
DR.
SUGAR: If they have such information.
DR.
WEISS: I think unless anyone has more
comments on this question, we'll go to Question number 1.
DR.
McCULLEY: You've skipped 5. Jayne, you skipped 5.
DR.
WEISS: I know. Intentionally.
DR.
McCULLEY: Okay.
DR.
WEISS: Because I was afraid that Dr.
Schein was going to be getting out another wrench.
DR.
McCULLEY: You pretty much rusted his
wrench.
DR.
WEISS: I have a feeling it was going to
be headed in my direction, so we'll go to 1.
One is the question which has been sort of the most emphasized point
during the discussion, is about the significance of the specular microscopy
data. And I'm going to hit a couple of
things concerning this question that maybe we can reach consensus on before we
get to the more contentious issue.
Dr.
Grimmett and Dr. Macsai both suggested that a minimal number of cells, specular
microscopy be performed pre‑op, and that patients have a minimal number
of endothelial cells before consideration is made for having this
procedure. I'd like to have some
discussion on that by the panel. Is
that something that people agree with or not?
Dr. McCulley.
DR.
McCULLEY: Oh, I was just nodding to
myself.
DR.
WEISS: That's dangerous around here.
DR.
McCULLEY: I see. I think that's reasonable. I think that to screen patients to be
certain that they have normal endothelium for age prior to the procedure is
wise and prudent.
DR.
WEISS: Dr. Mathers, and then Dr.
Grimmett.
DR.
MATHERS: Some of the subjects had very
little endothelial counts to begin with, and that's going to be part of this
population if you do any sizeable number.
I think it would be very unwise to not have some lower cut‑off for
endothelium. And I think it's
appropriate to look at endothelial cell counts.
DR.
WEISS: Dr. Grimmett.
DR.
GRIMMETT: I agree with Dr. McCulley,
but I would ask Dr. McCulley, would you set your lower threshold at like one
standard deviation, or two standard deviations lower than a normal mean value
for that given age range, or how would you set your threshold?
DR.
McCULLEY: I suppose I'd need ‑‑
you, again, have more confidence in these counting things than I do. I guess I'd want to look at the data for
normal, and for age, and one and two standard deviations before I would answer
that. I would just leave it loose and
for right now that it be normal for age.
And I would think that would add additional comfort to all of us, and
those who are really concerned about the accuracy and reproducibility of the
density. But I think that would be a
reasonable thing to add, that should give us all more comfort with this whole
issue.
DR.
GRIMMETT: Dr. Grimmett again. I agree with Dr. McCulley. I had suggested a year ago to use age
stratified normal means, plus or minus one standard deviation. But I think that's debatable exactly where
you draw the line. Normal for 20 to 30,
for example, is about 2950 plus or minus 150 or so, something like that.
DR.
WEISS: Dr. Macsai had also suggested in
line with this that post‑op endothelial cell counts be done, and
consideration of explantation be made if the cell count is dropping. Is that ‑‑ what does the panel ‑‑
Dr. McCulley. You're shaking your head
again.
DR.
McCULLEY: Again, we don't know ‑‑
we're missing so much information. We
need to know what the remodeling process of the endothelial is over time based
on degree of initial injury, surgical injury, and age of the patient that has
incurred the injury. So I'm not sure
that I would know what to say in terms of when to do it, when not to. I think it ends up being surgeon judgment to
make those decisions. I don't think we
can dictate anything because we just simply don't know.
DR.
WEISS: Dr. Sugar, then Dr. Schein.
DR.
SUGAR: I agree that we don't know, and
that we have no data, you know ‑‑ having no reason to postulate a
source of progressive endothelial cell loss, and having no data on what that
second intervention would do to progressive endothelial cell loss, I would
think that that would be actually the opposite of the recommendation that I
would want to make.
DR.
WEISS: Dr. Schein.
DR.
SCHEIN: We can make a distinction
between recommending doing a monitoring test and the timing of an
intervention. So by analogy, one might
recommend in a glaucoma setting, visual fields at a certain frequency without
recommending when a trabeculectomy be done.
And I think that there is a concern about long‑term endothelial
attrition, it makes sense to recommend that the only test that we have be
performed on some schedule.
DR.
SUGAR: But we don't know what
intervention.
DR.
SCHEIN: Well, no, but we have an
opportunity to, one, learn the natural history. And the other is to describe to a patient that over the last five
years, you've had a 25 percent loss of density.
DR.
WEISS: Dr. Sugar.
DR.
SUGAR: There's a difference between
recommending that the Sponsor get post‑marketing data on that, and
recommending that the practitioner do that, because we don't get that
data. And presumably, the Sponsor
doesn't get that data.
DR.
WEISS: Dr. Sugar's point is very
important, and we're going to be getting into whether there should be any post‑market
studies, is data that is interesting shouldn't be put in labeling. That's up to any of us here or outside to do
a study. But data that would be
important, we feel, for patient care, should be put in the labeling. So is the specular microscopy post‑operatively
important for patient care? And Dr.
Sugar would disagree. Dr. Mathers.
DR.
MATHERS: I would agree that it is
important to patient care. There are
some patients here that had very substantial loss in cell count, and you would
want to pick those up. And it would be
important for that patient's well‑being that you do so at some not short
interval after surgery, perhaps a year or something like that.
DR.
WEISS: So if you're going to give
guidance as far as when repeat specular microscopy would be done, what would
you suggest?
DR.
MATHERS: As early as three months,
possibly six, and at latest, one year.
DR.
WEISS: Somewhere between six months and
a year. Dr. Macsai.
DR.
MACSAI: That's not what I intended by
my comment.
DR.
WEISS: What did you intend?
DR.
MACSAI: My intention was that in my
hands and my practice, if I was to implant this device, which appears to be an
efficacious device, we don't have an answer about the long‑term
endothelial damage. And I, as alluded
to by both Dr. Sugar, Schein and Mathers, would want to know if my patient was
getting into trouble. And if they go
from 28 to 2000, there's trouble right here in River City, and it's time to
decide if that thing is safer in or out.
And I don't want to wait until there's microcystic edema and we're
transplanting that cornea in a 4 year old.
DR.
WEISS: What do you recommend for
labeling though? This is what you do
when ‑‑
DR.
MACSAI: I want to suggest ‑‑
DR.
WEISS: You suggest, okay.
DR.
MACSAI: ‑‑ that the
practitioner follow their patients with endothelial cell counts, because that's
all we have.
SPEAKER: For what time?
DR.
MACSAI: Well, my personal opinion, I
would say five years. And when we got
all this long‑term data that comes in, and it shows that I'm off the
wall, I'll be the first to stand up and say thank you. I'm wrong, and then we can change the
labeling on the device, and that will be a wonderful thing.
DR.
WEISS: Well, actually, you know, we
don't even have to ‑‑
DR.
MACSAI: Annually for five years.
SPEAKER: Oh, annually.
DR.
MACSAI: Is that what you want?
DR.
WEISS: And actually, we don't even have
to ‑‑ and I'll defer to Dr. Rosenthal. We could just say if this was what we're trying to ‑‑
everything is a suggestion here. Even
our vote is a suggestion. We could say
that ‑‑
DR.
ROSENTHAL: If you suggest that you put
it in labeling as a suggestion, you put doctors in liability risk if they don't
do it. So if it's in the labeling, and
it's not done, even as a suggestion, I think it holds greater water than a
suggestion.
DR.
WEISS: So you might be suggesting to
the malpractice attorney to take that case.
DR.
ROSENTHAL: Did I make myself clear?
DR.
WEISS: Malvina.
SPEAKER: You put people at medical legal risk.
DR.
WEISS: Yeah. Did you want to comment?
No. Dr. Sugar and Dr. McMahon.
DR.
ROSENTHAL: Excuse me. So therefore, I think what you put in as a
suggestion will be done.
SPEAKER: That will just be a suggestion, maybe wrong.
DR.
WEISS: Dr. Sugar and then ‑‑
DR.
SUGAR: To use Mike Grimmett's term
arguendo, to play devil's advocate, we don't know what to do with that
information. I think that it is
appropriate in the labeling to suggest that practitioners monitor corneal
health subsequent to the procedure, period, and to deal with however you see
fit. We do not have any information
that I am aware of that suggests that knowing that the cell count is now 1200,
and it was 2000 eight months ago, that any intervention that we're going to do
is going to alter that state. So how
could we make a recommendation that you gather that information so that you can
alter that state, when you don't know how to do it? That's ‑‑ my point is that if you go in and take the
IOL out, my suspicion is you're going to lose more endothelial cells. You're not going to help the situation.
DR.
WEISS: Well, you could say that
physicians should monitor the corneal health with such means as A, B, C, or D,
and include this as the possibilities.
DR. SUGAR: I think that as Ralph suggested, the more specific we get, the
more we constrain the practitioner.
DR.
WEISS: Dr. Ho.
DR.
HO: Furthermore, just as a retinal
surgeon, give me a sense for what percentage of anterior segment surgeons have
or do specular microscopy. Is this
something that is routine?
SPEAKER: Yes.
Routine.
SPEAKER: yeah.
DR.
HO: Routine for all cataract
surgeons? Okay.
DR.
SUGAR: No, it is not. No, he's talking about the average doctor ‑‑
DR.
WEISS: Dr. Macsai.
DR.
MACSAI: When it was reimbursable ‑‑
DR.
WEISS: Dr. Macsai.
DR.
MACSAI: I'm going to tell you when it
was reimbursable it was routine, so that the access to it, I think, remains.
DR.
HO: Furthermore ‑‑
DR.
WEISS: How about let's tell you who ‑‑
Dr. Ho. Yes.
DR.
HO: But I suspect that this procedure,
were it to be approved, would be something that would be done by comprehensive
ophthalmologists, as well.
DR.
WEISS: Dr. McCulley.
DR.
McCULLEY: From a practical standpoint,
there are a couple of issues here. One,
we've already said we thought that a person should have pre‑op specular
microscopy. Number two, most people who
are active in these areas are going to have a specular microscope then to do it
post‑op. And if not, it's
available in the community, so I don't think we'll be limiting the market scope
or the number of people doing this if we require specular microscopy. On the other hand we did, we required high
frequency ultrasonography, we might.
But with specular microscopy, I don't think it's going to have a
negative impact or be unfair to have it pre‑op. But whether we do make a specific suggestion about it post‑op
or not, I feel less strongly about. I
kind of lean toward Joel, that we need to ‑‑ if I interpreted Joel
correctly, we need to leave that to the judgment of the physician. And then if we want a post‑market
study, then rather than suggesting that every ophthalmologist do it, that we
request a post‑market surveillance study on endothelial cell count.
DR.
WEISS: So I'd just like a poll at this
point in terms of how the panel views this question. Those who would be in favor of suggesting or mandating, or
indicating in the labeling that endothelial cell counts not only be performed
preoperatively, but also be performed post‑operatively, and we don't even
have to indicate at what time point.
Those of you who would like them performed post‑operatively in the
labeling, could you please raise your hand.
(Vote
taken.)
DR.
WEISS: So we're almost split down the
middle on that, so that issue is not decided at this moment. Yes, Dr. McMahon.
DR.
McMAHON: We're getting into a circular
argument here. And we don't have the
data to know what's happening with the endothelium, so making suggestions to
the Sponsors and practitioners is not ‑‑ it's more emotional than
logical. And my suggestion is, is that
we get the information from the sponsor so that you can then address the
labeling question, which goes to a post‑market study, which goes to Dr.
Grimmett's seeing year four and year five data. And actually, directing to this question, the answer is have we
showed stability? The answer, I think,
is no, they haven't shown anything yet.
The second part of the question is, is how many eyes and for how
long? And I think we should decide.
DR.
WEISS: We will in a moment. I want to get to the more difficult stuff,
and just get the simpler things out of the way. The anterior chamber depth cut‑off of 3, should this ‑‑
would you be able to read that portion of the question?
DR.
EYDELMAN: "Do the outcomes of the
endothelial cell density analysis provide reasonable assurance of safety for
this device for eyes with 1 ACD of 2.8 to 3, and 2 ACD of greater than 3
millimeters."
DR.
WEISS: And all the primary reviewers,
Dr. Sugar, Dr. Macsai, Dr. Grimmett, all suggested that this not be implanted
in ACDs less than 3. Is there any
discussion on that from the panel? Dr.
Bradley.
DR.
BRADLEY: Dr. Gray, in his statistical
presentation, showed no evidence that there was a dichotomizing of the
data. You did a linear model to fit all
of the data, and I queried Dr. Gray on how much of the variance is explained by
this linear model. It looked to me like
not much of it. And, therefore, I
wonder about making judgments about a certain threshold level of anterior
chamber depth based upon that study. It
didn't seem to me that that was warranted.
I wondered why one of the proponents of this dichotomy would argue this
case, and maybe Dr. Gray could comment on it.
DR.
WEISS: Any proponents want to argue
this case? Dr. Sugar.
DR.
SUGAR: Your point is, you know, the
data, I think, does show that there is a linear, an apparent linear
relationship between anterior chamber depth and endothelial cell loss. And the only question is, is there a point
where we should cut it off because there is no obvious dichotomy, an obvious
point to cut it off. Is that correct?
DR.
BRADLEY: Two points, yeah. One is that there is no dichotomy in the
data themselves. And the other point is
that this is a mean linear regression, and the data were highly variable around
that point. And it looked like some
other factor was the ‑‑ or factors were the primary determiner of
cell death, or cell loss, not the anterior chamber depth.
DR.
WEISS: Dr. Eydelman, I think, has a
comment.
DR.
EYDELMAN: We actually ‑‑
well, the Sponsor has actually ran several analyses, and there were no apparent
other factors associated other than anterior chamber depth. And if I may comment on your earlier
statement; yes, you're correct, from Dr. Gray's model, it is a linear
association.
One
must keep in mind, however, that as we progress up that line, the percentage of
the overall population was that ACD depth is going to increase, i.e., we know
that below 3 there's only 5.5 percent of the overall cohort. And when we get up to 3.5, we're close to 50
percent of the cohort. So while it's
possible that this line could be drawn somewhere higher, just keep in mind that
then you would be excluding a higher percentage of patients from having the
surgery.
DR.
WEISS: Dr. Bradley.
DR.
BRADLEY: Just an interpretational
point. What you said is correct. It's important though to realize that with
such an exclusionary criterion, you would be excluding candidates from the
procedure who would have a much smaller level of cell loss. And you would be including patients who
would have a much larger level of cell loss, simply because of the variability
in that population. And that was the
question I was asking Dr. Gray about, because it seemed there was so much
variability in that regression analysis.
He's nodding his head there, so perhaps he could ‑‑
DR.
WEISS: Dr. Gray, did you want to
address this?
DR.
GRAY: Well, the question you asked me
was how much of the variability was explainable by ACD. And unfortunately, I don't have that with
me. But you are correct, the
relationship appeared to be linear without an obvious break, and there is a
fair amount of spread around the line.
But the decision about where, if at all, to put a cut point on the ACD
is purely a judgment call at this point, I'd say.
DR.
WEISS: Dr. Grimmett.
DR.
GRIMMETT: I was in agreement with
making the cut‑off 2.8 to 3 for three reasons. One, the data on that arbitrary break point showed 50 percent
higher loss with a shallow depth.
Number two, the cut‑off would not be overly onerous, only 5‑1/2
percent of the cohort would be taken out.
Number three, my review of the literature back last year at our guidance
discussion showed that the closer that phakic IOLs are ‑‑ the
closer they are to the endothelium, the greater risk to the endothelium with
angle supported having a higher risk than high risk clip versus posterior
chamber. So I was using all three in
combination just to make that determination.
DR.
WEISS: Aside from Dr. Bradley, does anyone else have any concerns
about limiting it? Dr. Bandeen‑Roche
and then Dr. McCulley.
DR.
BANDEEN‑ROCHE: Yes. I have two comments. First, I agree with Dr. McMahon that the
primary point, as far as I'm concerned, is whether stability has, in fact, been
achieved. And, you know, I am not at
all convinced that it has been, so at that point, the distinction between 2.8
to 3, versus 3 and above, I think is totally arbitrary.
The
second point just goes back to a point that Dr. Bradley was making about what
else might have explained the variance.
And I wanted to ask Dr. Gray were you able to reproduce, or did you even
try to reproduce the sponsor's analysis of what were the factors related to
cell loss, and finding only ACD being the only thing that was related?
DR.
GRAY: Well, that's a hard question to
answer.
DR.
BANDEEN‑ROCHE: Sorry.
DR.
GRAY: There's a ‑‑ we had a
fairly complicated situation in terms of the data because we had multiple
measurements per person over time. We
have baselines, and there's a lot of missing data. It's difficult to know how to actually model it. The
Sponsor went through a particular procedure where they cut up ‑‑
they binned the data into categories, and they checked quite a number of
potential co‑variates, and the only one that ended up to be significant
was the anterior chamber depth.
If
you do some alternative analyses using things like the percent of hexagonal
cells at baseline, or the endothelial cell density at baseline, sometimes those
show up to be significant predictors.
It's not obvious how to, for an individual patient though, say whether
they are at high or low risk of having a high rate of endothelial cell
loss. That's a very difficult procedure
which we didn't go through, and that would take some amount of effort on
everyone's part to do that.
DR.
BANDEEN‑ROCHE: Thank you.
DR.
WEISS: Dr. McCulley.
DR.
McCULLEY: My comment was with
Mike. I don't think it's so much the distance, necessarily, as how you're
fixating it. So you're taking AC
versus, you know, a posterior chamber.
I think it's apt to be more influenced by the way you're fixating than
the distance, except for possibly surgical trauma. If you've got a bigger space to work in, less problems ‑
smaller space to work in, more damage.
But I'm not convinced that just the distance ‑‑ if you start
throwing in, and try to extrapolate that, the AC to iris to PC, that that holds
up. It's apples and oranges, and
grapefruits.
DR.
GRIMMETT: Mike Grimmett. Certainly with the angle supported lens
data, there were some minimum distances that had some very unacceptable rates
of endothelial cell loss for the angle supported data in and of itself. And grant it, some patients are eye‑
rubbers, which would deform the cornea, touch the edge of the IOL. So certainly for the anterior chamber at the
angle supported phakic IOLs, I think there's a very strong argument that the
closer that the optic is to the endothelium, the higher the rate of endothelial
cell loss.
Now,
obviously, trying to translate that to all three groups with some meta‑analysis,
obviously, you get fairly sticky in that.
But at least in that one group, I think the data is fairly strong.
DR.
WEISS: Dr. McCulley.
DR.
McCULLEY: You'd have to keep it within
the category of lens type, fixation type.
DR.
GRIMMETT: Anyway, enough.
DR.
WEISS: Just a ‑‑ I think
we're at the point that panel members are calling for time out. That definitely means we've belabored that
one. But I'm not sure we have a
consensus on that, but I guess we will go to ‑‑
DR.
ROSENTHAL: Vote.
DR.
WEISS: It doesn't actually really
matter if we have a consensus on it or not.
DR.
ROSENTHAL: It helps the FDA. It helps us a lot.
DR.
WEISS: At this point?
DR.
ROSENTHAL: It depends what you
ultimately say, but we need ‑ ‑
DR.
WEISS: Well, do you want the consensus
right now?
DR.
ROSENTHAL: Yeah.
DR.
WEISS: Fine. Let's have ‑‑ okay.
For those of you who want to limit it, please vote that you'd like to
limit it to 3 and above anterior chamber depth.
DR.
EYDELMAN: It's actually above 3.
DR.
WEISS: Above 3.
(Vote
taken.)
DR.
WEISS: Okay. So I guess we do have a fairly good consensus. We're going to ‑‑ if you could
read Question 1(a).
DR.
EYDELMAN: I guess I'll read the whole
thing. "The main change between 3
and 4 years in 57 eyes was a gain of .1.
A decrease in co‑efficient variation and increasing percentage of
hexagonality were observed. Is there
sufficient data to support the Sponsor's conclusion that the losses in the
first three years are reflective of the surgical trauma was a prolonged
remodeling culminating in stabilization of cell loss after three years."
DR.
WEISS: And I'm going to just cut the
question off there. We spent quite a
bit of time having the data presented to us in different formats, showing us
the impressions of this, so I don't know that we have to discuss this. But I would like to get an impression of the
panel's opinion on this particular one by vote. And for those of you who agree there's sufficient data to support
the Sponsor's conclusion that there is stabilization of cell loss after three
years, for those of you who agree with that statement, can you raise your hand.
(Vote
taken.)
DR.
WEISS: So what I can see is that no one
on the panel believes that there is a stabilization of cell loss ‑‑
that the data support that there is necessarily ‑‑ well, why don't
you phrase it, Dr. McCulley.
DR.
McCULLEY: Well, I mean, your question
was ‑‑ we don't know. The
question was, do we agree the Sponsor has presented data that assures us that
there's stabilization after three years.
We don't have that data.
DR.
WEISS: Fine.
DR.
McCULLEY: We have an opinion, but it's
opinion based on things, not based on data.
I like to base it on data.
DR.
WEISS: That's fine.
DR.
McCULLEY: We don't have data to support
that.
DR.
WEISS: So we do not have any data ‑‑
DR.
McCULLEY: Up to three years, and then
we can argue the three to four years.
DR.
WEISS: Okay. We do not have data showing that there is stabilization at that
period of time.
DR.
EYDELMAN: So what is the minimum number
of eyes, and the minimum length of follow‑up that you recommend for this
assessment?
DR.
WEISS: And what this is getting to, I
think is, in order to get this information, are we talking about any ‑‑
DR.
BRADLEY: Let Karen answer that.
DR.
WEISS: Well, are we talking about any
further studies, longer studies? Dr.
Bandeen‑Roche.
DR.
BANDEEN‑ROCHE: Yeah. I mean, I would consider it entirely a
question of a minimum number. I mean,
if you're looking for a number to establish a power, I mean, I would hope that
you would at least try to establish power to ensure a rate of decline less than
something, or a precision to establish what the post three year rate of decline
is.
I
would also encourage you not to only focus on the mean, as Dr. Grimmett has
raised; that it's also important to think about what are the proportion who are
declining at an unacceptable rate. And
so one could do power calculations or precision calculations to establish a
number sufficient for that quantity.
But it does also go to representativeness of the cohort, you know. And so that's certainly unlaying my question
about how many providers was it. You
know, I would be totally less convinced about the quality of the data if it was
the one or two best surgeons who had provided the 67 eyes. It sounds like it was not, that that was not
the case. But I don't have any feel for
how representative the 67 eyes that we have are. And, moreover, if I look at Dr. Gray's data, one thing that I
have been worried about was regression to the mean. And so, for instance, if the eyes that are contributing to that 3
to 4 year, the 57 eyes, I guess, 3 to 4 year interval were those who had
declined, you know, particularly far from 2 to 3, or were particularly
low. Then one could expect somewhat of
an improvement just due to regression to the mean, let alone things like
contact lenses and issues like that.
And so, indeed, according to Dr. Gray's table, all visits, the cohort of
37 has a mean cell count, 100 cells less than all of the other eyes at three
years. So that is in the direction of
that concern.
And
I guess a final point that I would make would be everyone has been commenting
that we're in a gray zone, that the physicians who participated in this study
were the best of the best. And so I
would not at all just settle for a 95 percent confidence found, you know, just
barely squeaking in there at a level of a 95 percent confidence found. I think that I would recommend a bit more
assurance than that, taking into account the fact that this is a precedent,
that these are the best physicians who participated in this study.
DR.
WEISS: I think we have to be careful
about this best physicians talking about lack of data. I'm sure these were good docs and good
surgeons, but creating this extra god‑like category, I think we should
take out of the discussion.
DR.
BANDEEN‑ROCHE: That's a point
well‑taken. That's a point well‑taken. Nonetheless, I mean, we hardly expect better
performance in the field than we do in a clinical trial.
DR.
McCULLEY: You don't have data to
support that statement, do you? Do you
have data to support that statement? You
do. Okay.
DR.
ROSENTHAL: With all kinds of devices.
DR.
McCULLEY: All right.
DR.
WEISS: What I would then like to lead
to is since there's agreement ‑‑
DR.
ROSENTHAL: Wait.
DR.
WEISS: Yes.
DR.
ROSENTHAL: I want to make sure I said
the right thing. Once they go out in
the field, they tend to have more problems than they do within the clinical
trial.
DR.
McCULLEY: But you don't have data to
support that the people who do the trials are the best of the best.
DR.
ROSENTHAL: No.
DR.
McCULLEY: I think that is opinion ‑‑
DR.
MACSAI: That's my opinion.
DR.
McCULLEY: That is Marian's opinion, and
it should not be in our discussions.
DR.
WEISS: So we're going to take out the
"god" factor out of the discussion.
(Laughter.)
DR.
WEISS: But what I would like to
introduce into the discussion is the fact that since there is consensus that
there's no data demonstrating stabilization of cell loss between 3 and 4 years,
what would please the panel to do perhaps to demonstrate that the issue of
endothelial cell damage is not present here?
Dr. McCulley.
DR.
McCULLEY: Yeah. My impression that we ‑‑ I could
not argue the point and present data to absolutely support that we have
stabilization. My impression of
everything presented is I would lean toward we probably do. At least ‑‑ or that we probably
will. At least to the point where I
would be comfortable not voting on this, that if the panel recommended
approvable, that I would be comfortable with that, with some form of continued
surveillance or gathering of data about the stability or lack thereof of the endothelium.
DR.
WEISS: Okay. So if we're talking about post‑market study, would we be
talking about a post‑market study following the initial cohort, or would
we be talking about ‑‑ and would we require those patients who have
had preoperative endothelial cell counts, or would we be talking about getting
a new cohort with specified time points at which they've had endothelial cell
counts? Dr. Schein, and then Dr. Sugar,
then Dr. Mathers.
DR.
SCHEIN: I would argue that one needs
both, but for different reasons. So on
the specific question of the data related to the endothelial cell count, the
existing cohort will tell us a lot more about the natural history. I mean, if there's a three year lead time on
any new cases that come along.
On
the other hand, when I use the word "post‑market surveillance",
it doesn't at all mean a continuation of a pre‑ market cohort, because
the question from a public health perspective is very different. And what you're worried about is a
situation, which I think we have here, where you've got reasonable short‑term
safety, and some ‑‑ an inclination ‑ if I could speak
generally, you know, to approve based on that, but concern about longer‑term
issues which cannot be addressed from this particular pre‑market cohort.
It's
an analogous situation with the extended wear contact lenses, which is
currently undergoing a 5,000 person study looking just for ulcerative
keratitis. So the concerns here are not
just adequate length of follow‑up for endothelial cell count, but the
representativeness. We don't have to
get into the glorified surgical skill, but there are means of examples where
you go from an efficacy study pre‑market, to an effectiveness evaluation,
which is how the product is actually used once it's approved. And it never performs as well. So one needs some kind of way to sample cases
from a post‑market setting, from surgeons and different kinds of
patients, to look at big outcomes; corneal failure, new treatment for glaucoma,
retinal detachment, and cataract, because there has been some concern in my
mind about some of these other complications, which have all been reported on a
per‑eye basis; whereas, obviously, retinal detachment is a per‑patient
issue.
DR.
WEISS: Can you tell me the study ‑‑
the number of patients, numbers of years that you would suggest if we're just
actually going to make it concrete?
What would you like?
DR.
McCULLEY: For which purpose?
DR.
WEISS: For both.
DR.
McCULLEY: No, I'd have to do some
sample size calculations.
DR.
WEISS: So you would like ‑‑
DR.
McCULLEY: But even this is, you know,
done in a few hours.
DR.
WEISS: But you would like, basically,
both types of studies getting a new cohort of patients with specular microscopy
prior to the procedure, and then following them through, as well as following
these patients?
DR.
McCULLEY: No. No. So for the specular
microscopy, I would go with the existing group, because in a post‑market
surveillance study that I'm more concerned about, I want to know about corneal
graft. I want to know about retinal
detachment, because the absence of a control group here is a major deficiency. And, you know, using control groups based on
other case series is inadequate, so I would like to know on a much larger
sample, with less defined testing, less onerous testing, about major outcomes;
cataract surgery, new treatment for glaucoma, retinal detachment.
DR.
WEISS: And how long out would you
follow those patients?
DR.
McCULLEY: Probably ‑‑
initially about probably 3 to 5 years.
DR.
WEISS: Do you think for ‑‑
I mean, say those posterior keratotomy took 20 years for them to get corneal
edema, so will that ‑‑
DR.
McCULLEY: Well, each one of these
things is different, so ones that
occurred in my lifetime, professional lifetime. One example would be extended wear contact lenses, approved for
30 days in 1981. They were reduced in
1989, so about 8 years later, with a very, very inefficient way of making that
determination. Anterior chamber lenses
was even more inefficient. There was no
surveillance mechanism. There was a lot
of controversy about what we're seeing.
The literature is a very inefficient way to do post‑ market
surveillance. There are many, many
patients who have rigid anterior chamber lenses with no clinical inclination
that one could see as one followed them.
DR.
WEISS: Well, we're going to make this
efficient.
DR.
McCULLEY: Right.
DR.
WEISS: So for this particular efficient
way of doing it, how long of a follow‑up would you recommend? Would you still say 3 to 5 years?
DR.
McCULLEY: Yes.
DR.
WEISS: Okay. Dr. Mathers.
DR.
MATHERS: In terms of modeling,
addressing what Karen Bandeen‑Roche said, I think we could reasonably
have an objective as we model this, that we would like to stay above. And I think from our various analyses here,
that it is reasonable to propose that at the end of the expected use of the
device, that we end up with an endothelial cell count of 1500 or greater,
because this is still far less than the normal cell loss.
Normal
cell loss is quoted here as being .6, but if you do the numbers on the data
from Dr. Grimmett, the normal is really like .4 percent per year. And if we have a loss rate that you're
calculating of 1, 1.1, we are still like three times greater than the
normal. So if we do our projections and
model this to keep above 1500 by the end of the device use, I think we will be
serving the public reasonably well. And
it's still a relatively conservative approach.
DR.
WEISS: So are you saying take the
original cohort and if the cell count kept on dropping off, at what point, how
many years they would take ‑‑
DR.
MATHERS: As this gets modeled and we
have more data, the model is going to get better. The projections are going to get better, and the width of ‑‑
or the data is going to get more accurate.
And as we can determine this, when we know how accurate it is, if we set
the parameter to keep the end point at greater than 1500, which we will be able
to do as you continue to model it.
DR.
WEISS: So you're basically saying to
the FDA that statistically they should try to predict into the future, and that
will tell them how long that they would be able to do the study. And if that's ‑‑ if I'm correct,
I'm being told at the same time that that can't be done.
DR.
MATHERS: Well, as we get more data, we
don't know how good the data is going to be when it comes in, and it may be
possible in a year or two to determine what the rate of this loss is.
DR.
WEISS: I think we probably have to tell
them up front what we want, as opposed to let this go on for as long as we see
fit. Dr. Macsai.
DR.
MACSAI: I'm a little lost here in this
conversation, and I just want to ‑‑ reel me back in here. I'm listening to what Dr. Schein is saying,
and I'm in no way disagreeing with you, that it would be interesting to know
this information from a public health perspective. I'm not sure it's the Sponsor's responsibility to get that
data. It would require a National
Registry akin to the Australian Graft Registry, and I don't know that we have
that set up in the United States.
I
think it's a wonderful concept if we could do it. We have to register every patient that has this device, and
follow them forever, and I'd love to know.
And I just don't know that it's reasonable to know. So to the second thing, though ‑‑
DR.
WEISS: Actually, he was saying 3 to 5
years.
DR.
MACSAI: Well, we'd look at them for 3
to 5 years.
DR.
WEISS: Okay. So you would prefer not to have a new cohort ‑ ‑
DR.
MACSAI: I know about the cataracts, and
I know about the retinal detachments.
Okay. But I thought we were
supposed to be talking about the endothelium here. And I thought the question was how many patients do we have to
follow and for how long to establish stability of the endothelial cell change,
because we're all setting around not raising our hands, because we don't know
if the endothelial cells are decreasing to a stable level, so the question is
how many.
My
answer to you in my review was, I am not a biostatistician. Dr. Gray is a biostatistician. Dr. Edelhauser is an expert in endothelium,
you know. Put those two in a room,
figure it out, tell us the answer, we're done.
DR.
WEISS: Dr. Edelhauser is about to tell
us the answer. Sometimes you get what
you want.
DR.
EYDELMAN: If you're not ready to give
us the exact number, maybe you can give us the parameters on which to base the
calculation, so we can certainly perform the calculations. But if you tell us the rate that you'd like
to ascertain, and with which predictability, or with which ‑‑ what
statistical parameters you want us to include, we can certainly perform the
calculations.
DR.
WEISS: Well, let me just get one thing
from the panel, just in terms of following the initial cohort. Whether it's those 200 ‑ ‑ one
question for the panel. For this cohort
that would be looked at with specular microscopy, does the panel want these
patients to have had pre‑operative specular microscopy done? Those of you who would like to have at least
pre‑operative specular microscopy, could you raise your hand.
(Vote
taken.)
DR.
WEISS: So I think there's ‑‑
Dr. McMahon. There's a majority that
would like pre‑operative specular microscopy. So from what I recall from the FDA's presentation, there were 206
patients who had pre‑operative specular microscopy, and at least two time
points afterwards. Correct me if I'm
wrong. So of those 206 patients,
perhaps we're starting out that with ‑‑ that's the maximum
number. And then we could ‑‑
we'll probably go down from that.
Does
the panel think that 206 would, starting out, be too low? Would it be feasible to tap into that
population? Anyone have an opinion on
that? Dr. Macsai.
DR.
MACSAI: I think that's the only
population we have. I think we expect a
10 percent loss to follow‑up. You
know, unfortunately those 206 weren't told you've got to come back every year
for five years. So the Sponsor, I'm
sure, will do their best to track them down and reel them in, and look at their
endothelium. And whether or not it's
statistically significant, Dr. Gray will tell us.
DR.
WEISS: So then I would propose that
that 206 could be at least the cohort that we're looking at for a post‑market
study. Then the second question that
the FDA has asked us and I will ask the panel, is there guidance for number of
years that you would like these people followed? Dr. McCulley.
DR.
McCULLEY: I think five is reasonable.
DR.
WEISS: An additional five years?
DR.
McCULLEY: No.
DR.
WEISS: Total of five years.
DR.
McCULLEY: Total of five years.
DR.
WEISS: So that you want one more time
line at one year down the line.
DR.
McCULLEY: No. What I want ‑‑ what I would ideally like to see,
again, I have a sense that all we've done is shift the things to the right or
left, however you're looking at it. But
I would like to see yearly up to five years for as many years as possible. We've already missed some years for that
cohort of 206.
DR.
WEISS: Okay. Well, those ‑‑ okay.
Dr. Sugar.
DR.
SUGAR: I was going to say the same
thing. The last patient ‑‑
the first patient should reach the five year time window next month. And the last patient would reach that time
in December of 2007, so I think as many patients as possible should get ‑‑
of those 306, not 206. There are 306
that had baseline specular microscopy.
As many of those as possible should get annual data for as long as ‑‑
up to as many ‑‑
DR.
WEISS: Dr. Eydelman, would that answer
1(a)?
DR.
EYDELMAN: So you want all eyes in the
PMA cohort that had pre‑operative endothelial cell counts to be followed
for five years. Is that correct?
DR.
SUGAR: With specular microscopy.
DR.
WEISS: Dr. Sugar, is that correct?
DR.
SUGAR: That's what I'm suggesting. Yes.
DR.
WEISS: That's correct. Dr. McCulley, you concur?
DR.
McCULLEY: I think that's reasonable,
annually for five years.
DR.
WEISS: Is that ‑‑ Dr.
Rosenthal, is that burdensome?
DR.
ROSENTHAL: No, but we need to know
whether you want it done in the pre‑market arena, or in the post‑market
arena.
DR.
McCULLEY: Post.
DR.
WEISS: Post‑market arena is what
Dr. McCulley.
DR.
McCULLEY: It depends on whether you
approve it now or not.
DR.
WEISS: Dr. Sugar, post‑market
arena?
DR.
SUGAR: Yes. I mean ‑‑
DR.
WEISS: Post‑market.
DR.
SUGAR: That's assuming that we're going
to approve the product now, which I presume, and that we shouldn't ‑‑
DR.
ROSENTHAL: No. We can't presume what we're going to do,
because we haven't voted it for it yet.
DR.
SUGAR: No, but I can tell you what I
presume. And my presumption is that we
will approve it, and that we should not hold up approval of the product based
on acquisition of this data.
DR.
WEISS: Dr. McCulley, and then Dr.
Macsai.
DR.
McCULLEY: I would agree with Joel, but
to put it back more broadly for Ralph, I mean, if it's not approved, then we
would request that ‑‑ or recommended for approvable, that they be
followed annually. If we do recommend
approvable, which I too would ‑ not being a voting ‑ not going to
get to vote, but I would. And I would
be comfortable with that, and I would say then, I would prefer this ‑‑
as I said, I'd be comfortable with a recommendation for approvable with a post‑market
surveillance annually of that initial cohort.
You had pre‑ops for a total of five years.
DR.
WEISS: Dr. Mathers.
DR.
MATHERS: When you say
"approval" there, you're talking about three different groups here,
and they are very different. You have
myopes for minus 3, myopes for 15 to 20.
DR.
WEISS: We're going to get to that in a
moment.
DR.
MATHERS: Okay. But that's ‑‑ I mean ‑‑
DR.
WEISS: We're just talking about the
specular microscopy portion, and then in terms of the different categories, we
will be getting to that. Have no fear.
DR.
MATHERS: Okay.
DR.
WEISS: Dr. Macsai. And I'd sort of like to wrap‑up
this. Dr. Macsai, then Bandeen‑Roche,
and then I'd like to wrap‑up this particular issue. Yes.
DR.
MACSAI: I agree with Joel about post‑market
surveillance. I would add two
comments. One, if approvable, it's got
to be labeled that this stability has not been documented, and it's got to be
an education for patients and physicians.
And if data comes out later that shows there's massive problems, the FDA
has an obligation to take an action.
Number
two, if perhaps we're all wrong, and we don't have to wait until 2007, and at
2006 the biostatisticians, or 2005, the biostatisticians say hey, this was much
ado about nothing, then the labeling be changed at that point, and we accept
the statistician's interpretation that it is, in fact, stable.
DR.
WEISS: With that in mind, if you want
to put in labeling that stability of endothelial cell loss has not been
documented, would you want to put a warning in there that there could be risk
of corneal edema or no? Dr. McCulley.
DR.
McCULLEY: I don't remember well
enough. There are different
implications to these words, and I don't ‑‑
DR.
WEISS: Dr. Rosenthal. Would it be fair, if we're going to be
putting in labeling that there is no documentation of a stabilization point as
far as endothelial cell loss by specular microscopy, would it be fair to put in
labeling there could be the risk, or the risk of corneal edema is undefined. Or because it's undefined, we shouldn't say
it?
DR.
ROSENTHAL: That's the panel's decision.
DR.
WEISS: Dr. Macsai.
DR.
MACSAI: I don't ‑‑ we don't
have corneal edema. We don't have one
patient yet with corneal edema. What we
have is ‑‑
DR.
WEISS: Well, that's what we're talking
about, isn't it?
DR.
MACSAI: Right. But no ‑‑
DR.
WEISS: That's what we're afraid of.
DR.
MACSAI: No, what we're talking about is
long‑term endothelial cell loss.
So what we say is that the data and the outcomes and long‑term
effects on the endothelium are unknown.
DR.
WEISS: But for patient labeling, I
think you'd have to put that in terms that it means something to someone,
because endothelial cell loss doesn't have any significance to a patient. And I would maybe defer this one to Glenda
Such.
MS.
SUCH: Yes. I was just going to say, I don't know if this belongs in the
labeling section of our discussion or not, but I was going to say there should
be something at least at the bottom of the precautions that says something
about the fact that no information is known about this beyond four years. Whether or not it's regarding this issue or
any of the issues.
DR.
WEISS: So maybe we'll get back to that
when we get back to labeling. When
we're talking about ‑‑ so we've talked about, and I think hopefully
to your satisfaction, we've talked about a post‑ market study, and
following the cohort. Does anyone want
what's suggested, taking another fresh cohort of patients who are having this
done after, if it gets approved, after approval, and following these patients. Does anyone want that?
DR.
SCHEIN: May I make another comment?
DR.
WEISS: Dr. Schein.
DR.
SCHEIN: What is the logic of having a
post‑market surveillance study for an extended wear contact lens where not
a single ulcer is seen in a pre‑market trial? The logic is that there's a concern about the particular end‑point,
which requires a different kind of study.
And I think the situation is exactly analogous. We have a new kind of device. We don't have any historical data to rely
on. The situation is analogous to the
way the rigid anterior chamber lenses were when ophthalmologists were putting
them in their mothers, which is just after the pre‑market approval. There was a lot of excitement, so I think to
not set up some mechanism that's an early warning is completely irresponsible
on our part. And I do believe it's the
industry's responsibility, if they want to introduce these kinds of products.
The
idea is not to stifle innovation. As
you'll see, I'm going to be voting for approval. But the idea is to set up a mechanism that we can trust to either
restrict labeling in the future, pull back the product, or to provide very
sound information about its safety.
DR.
WEISS: Well, in that case I think what
we'll do is we'll confine that one to labeling. If anyone else wants to comment on specifically a labeling
issue. Dr. Matoba.
DR.
MATOBA: In the case of the contact lens
issue, that we had an indication from your study that there was a certain risk
for microbial keratitis, and here we don't have any information that there is
that type of calamitous outcome that could occur, so here you'd be fishing.
DR.
SCHEIN: The rate of retinal detachment
is higher in this study is higher than ulcerative keratitis was in any of the
other studies. The rate of cataract is
higher, so it's not just corneal edema.
DR.
WEISS: Dr. Bandeen‑Roche, then
Dr. McCulley, then Dr. Mathers, then Dr. Sugar. Not Dr. Sugar.
DR.
BANDEEN‑ROCHE: If you want to
defer this to the safety discussion, that's fine. But I have to at least raise it now, which is that we saw no hint
of stabilization through three years. I
mean, it was just, you know, all of the year‑to‑year changes were
pretty even. So suppose the data come
in, and my overly pessimistic tendencies for once, you know, bear out, and we
see exactly the same continuing rate of decline, once all of the data are
in. Would you then declare the product
safe and go ahead?
DR.
WEISS: Dr. McCulley.
DR.
McCULLEY: Yeah. Could we ask maybe the FDA to respond to
that? And could we also ask the FDA to
respond to Oliver's suggestion for ‑‑ I don't ever recall a
discussion at a panel, at least that I've been at, where that kind of study
post‑market surveillance, or whatever the term would be for that
particular one, would come up. I'd like
to hear what the FDA says about both of those issues in terms of authority and
practicality.
DR.
ROSENTHAL: We have a member of the
staff from the Office of Science and Biometrics who's ready to address this
issue for you. Dr. Roselie Bright.
DR.
BRIGHT: One minute.
DR.
ROSENTHAL: I still ‑‑ while
Dr. Bright is getting ready, you still have to decide whether you want this
fourth and five year data on the existing cohort before it goes to market, so
you have assurance of ‑‑ a reasonable assurance of safety and
efficacy. Or do you have that
reasonable assurance of safety and efficacy now, and the follow‑up can
occur after it is put on the market.
That is different than this type of approach, which is in addition to
the follow‑up of the endothelial cell.
DR.
WEISS: So I think what Dr. Rosenthal is
pointing out is we've put the cart before the horse.
DR.
ROSENTHAL: A little bit.
DR.
WEISS: And that if everyone is in
agreement that we have no evidence there's stabilization of endothelial cell
loss, then is anyone in the panel bothered by the potential of a continued cell
loss rate of 2 percent per year in these patients. And if anyone in the panel is bothered by that fact, how do you
justify that, or explain that, or accept that?
DR.
McCULLEY: Jayne, I've said it before
and I'll say it again. We don't have
the solid data. We need more data. My sense of this, based on everything
including my broad clinical experience and past history with things, is that I
would be comfortable enough with this being recommended for approvable. But to further give us assurance and comfort
that we follow it post‑market.
DR.
WEISS: Then I would ask you, Dr.
McCulley, can you explain to the panel why you're comfortable with
approval? What factors about this PMA
in the face of no documentation of stabilization of the cell loss make you
comfortable with approving this?
DR.
McCULLEY: Okay. I don't think there's no documentation. I think there's suggestion that there is,
but I don't think there's proof. And
the suggestion to me is that we have stabilization in the cell size,
variability in shape, and that it does appear that with a limited number of
patients that the cell loss between years three and four is leveling off. And I've seen ‑‑ and in the
absence of any apparent known reason for continued endothelial cell loss,
absence of any known mechanism to support continued endothelial cell loss,
those give me the degree of comfort that I think this is reasonable. But do I think I have data that would let me
nail that down if I wanted to switch sides and argue it the other way? No.
But I think that it would be reasonable to try to gather more data to
give more comfort to everyone else, and to myself. I could be wrong. I don't
think I am, but I have reasonable comfort, but I don't have as solid a data ‑‑
if I did, we wouldn't be having this discussion.
DR.
WEISS: But the question for the panel
really now is whether there should be pre‑market data or post‑market
data, if there's ‑‑
DR.
McCULLEY: And what I'm saying is, I
think we have sufficient assurance now to recommend approvable with continued
surveillance post‑market.
DR.
WEISS: Dr. Mathers, and then Dr.
Macsai, and then Dr. McMahon.
DR.
MATHERS: well, finish this
discussion. That goes more to Oliver's
question.
DR.
ROSENTHAL: Finish your discussion about
this.
DR.
WEISS: Finish our discussion, and then
go forward.
DR.
ROSENTHAL: And then we'll move on.
DR.
MATHERS: It's a philosophic point. You're saying that we don't know, so let's
go ahead. I would say we don't know, so
let's make sure before we go ahead. And
again I'll say that I don't think that what we say about minus 10 to 15, or 15
to 20 applies to what we say about the 3 to 10. But in the absence of some indication of safety in this regard, I
think going ahead is not the correct answer.
DR.
WEISS: Dr. Macsai.
DR.
MACSAI: If you look at my review, I
didn't make a slide of this ‑ I'm sorry.
I did make a table of the rate of annual endothelial cell loss, assuming
a pre‑operative mean count of 2,657, which was the pre‑operative
mean endothelial cell count here. And
if we take the average loss, I'm not going to argue with Mike or Bill Bourne,
but if you take the average loss at .6 percent by natural attrition, that would
mean you'd lose 15.9 cells per year.
In
that August `02 panel meeting that Dr. Grimmett did his report on, he said 1.5
percent would be okay. And that's 39.8
cells per year. This PMA has 1.8
percent, which is 48 cells per year.
And then the ANSI Standard is set at 2 percent, which would be 53.1
cells per year, so this PMA lies right smack dab in the middle between the
recommendations of the August `02 panel meeting, and the ANSI ‑ which was
1.5 percent, and the ANSI guidance document referred to, which was 2
percent. So at 1.8 percent, it ain't
bad. I just don't know if it's going to
be bad in the future, so I think looking at these patients to five years is
prudent.
I
guess my question to ‑‑ I have another question I just want to ask
Dr. Schein, since I can't ask him private, is ‑ what if you look at this
cohort for five years, this endothelial cell counted cohort for five years to
see about retinal detachments, and cataracts, and I forgot what else you
said. Would that answer your question? No?
DR.
WEISS: Dr. Schein.
DR.
SCHEIN: The reason it wouldn't answer
the question is, one, sample size; and two, representativeness, the latter
being more important. So I would want
some sample of patients that are actually getting the device post‑market,
and some sample of surgeons that are doing it.
DR.
MACSAI: Oh, to see who performs the
same?
DR.
SCHEIN: Absolutely. And also a larger number, but not for cell
counts. That's a different story. That's a longer term issue.
DR.
WEISS: Dr. McMahon.
DR.
McMAHON: This is to Ralph, and this is
sort of a semantics question, because we're dealing with a situation with
regard to endothelial cell loss, where we kind of don't know. And so the obligation of the panel of voting
on safety and efficacy, one can be that we have to have reasonable assurances
that the device is safe, versus reasonable assurance that it's not unsafe.
DR.
WEISS: Well, the way it reads is
"reasonable safety and efficacy".
DR.
McMAHON: Yeah, but I want to know the
spirit of that view, because it makes a difference on how I would vote.
DR.
WEISS: Well, I'll call on our spiritual
counselor, Dr. Rosenthal.
(Laughter.)
MS.
THORNTON: Ralph, could you speak into
the microphone, please. We want to get
this one.
MR.
ROSENTHAL: The reasonable assurance of
safety and efficacy.
DR.
WEISS: Okay. So with this in mind, since it seems ‑‑ from what I
understood from the vote before, most of the panel members didn't feel the
stabilization was ‑‑ the data showed stabilization. Do most of the panel, even with that fact,
would most ‑‑ those panel members who would feel that there is
still ‑‑ this is still reasonably safe to have a post‑market
study, and go ahead with approval under any means, or we're not talking about
what type or whatever, in terms of labeling or other issues. What number ‑‑ if you could
raise your hands.
DR.
ROSENTHAL: Excuse me, Dr. Weiss. It's a post‑market follow‑ up of
the existing IDE subjects.
DR.
WEISS: Fine.
DR.
ROSENTHAL: That's very different than a
post‑market study of another group of patients.
DR.
WEISS: So we're talking post‑market
study in order to get further data, and approval with the information we have
at the present. At the present point,
and we haven't gone through the other issues, the members of the panel who
would ‑‑ yes.
DR.
BRIGHT: Well, I have a presentation
that goes over what's appropriate for pre‑market, what's appropriate
after the device is allowed on the market, what you can get in a pre‑market
setting versus condition of approval, versus post‑market. And that might short‑circuit some of
the questions.
DR.
WEISS: Okay.
DR.
McCULLEY: Jayne, can I say one thing,
and I do want to hear what she has to say.
DR.
WEISS: Yes.
DR.
McCULLEY: In response to Bill's
philosophical question, the issue is do we have reasonable assurance of safety
and efficacy. I think we do. I don't think we have absolute, and I would
like to go ahead and get the absolute.
That's the reason for requesting additional surveillance. I think we have reasonable, but it's not
absolute.
DR.
WEISS: Would I be able to ‑‑
just in the interest of time, would you be able to show whatever that you have
that speaks specifically to the choice of studies the panel might have, as
opposed to the background information that you might have, that we could look
at concrete stuff as far as what our choice in terms of studies that we might
recommend?
DR.
BRIGHT: Well, I have two concrete
choices, but I want to lead up why I got there, if that's okay.
DR.
WEISS: If you can make a quick lead‑up.
DR.
BRIGHT: I'm covering many slopes. Okay.
Well, the disclaimer is that just because I'm presenting about those
market studies, doesn't mean that I think it's approvable right now, but it
would apply even if there was a later discussion about approvability.
The
reasons for doing post‑market assurance would be that the study
population for the pivotal study is small, and not large enough to detect the
potentially serious adverse events. And
the study population for the pivotal study is highly selected. It doesn't include vulnerable sub‑populations.
The
study duration is typically shorter in real‑world exposure, so we've been
talking about the 3 and 4 year effects, versus 30 and 40 years. And it can detect problems due to improper
or unskilled use of the device in the real‑world. And study centers ‑‑ but the
study centers that you already have the data from are typically highly skilled
and motivated.
And
another general reason is to detect adverse events due to drug‑device, or
device‑device interactions that would not be detected in controlled
studies. So questions that might need
to be addressed for this particular device are the longer term decline in
endothelial cell count, long term development of cataract. Dr. Schein mentioned some other outcomes.
Some
issues for phakic IOLs is the prior history in the 1980s with an implantable
lens that was associated with safety concerns after 10 years of use, so we
would want ‑‑ might want an earlier warning system. And PIOLs could be implanted in a large
number of young adults with moderate vision problems. And, therefore, in the worst case scenario, there's a potential
for a large number of middle aged to elderly adults needing corneal
transplants.
So
what are the three authorities we have for requiring studies? We have the pre‑market authority, the
study has to be done in order for the device to get to market. But the disadvantage is a small sample size
and short follow‑up time. The
condition of approval study is one where the approval is conditional until the
results of that study are satisfactory, but you have to order it before the
device even gets the conditional approval.
And the post‑market surveillance study, we can order that study
any time, but patient and physician approval is the most difficult during that
time because the device is freely available.
So
in considering the type of conditional approval study, it has to be least
burdensome. We can consider any
appropriate study design, and it does not need to be simply an extension of the
pre‑ market study. The sponsor
could be asked to report progress and results to the panel each year if the
panel desires, and the sponsor can use the results to change the labeling and
marketing.
So
there are two main types of observational study designs. There's case control and follow‑up. The advantage of the case control study is
you can be more efficient with a smaller sample size, but in this instance, I
think it's impractical because I think the use of this device is likely to be
relatively uncommon. And you also have
to decide in advance what outcomes you're going to look for.
But
in the follow‑up study, you can enroll patients as they get the PIOL, so
if it's vastly popular, you get your cohort up and running very quickly. If it takes longer, then it takes longer to
accrue, but that's fine because it's affecting a smaller portion of the
population anyway. You get flexible
follow‑up time, and you can discover new outcomes that weren't
anticipated. But the disadvantage is
are that you need to minimize the drop‑out rate, and you need a large
number of patients.
We
worked out two options. There's nothing
required about any of these, but they're basically discussion and talking
points. The first option was called
registry, so you could ask patients at less than one year intervals whether
they had an ophthalmic visit for a problem.
And we said less than a year because if we use the mail system, which is
considered least burdensome of different kinds of ways you could contact
patients, they're forwarding interval is one year. And you could ask a very simple question, did you have to go to
the ophthalmologist. And then if they
say yes, ask for the details for getting their records. And you could follow as many patients as
possible for a decade or more, whatever time period the panel is interested in.
The
advantages are, you can readily describe and identify the population of users
in the event that some kind of regulatory intervention is needed. And it's a relatively inexpensive study. The disadvantage is that there's no early
warning of impending problems. You get
the warning when somebody has the problem that's bad enough to go to the
ophthalmologist.
The
other option that could be considered is something called a nested cohort,
where you could build on the existing clinical trial population, and then
sample some new patients, collect cell counts at baseline and regular
intervals. And have all of the specular
microscopy results assessed at a central location for the sake of comparability
of results.
You'd
want the sample to reflect the diversity of patients and implanting physicians
so that you can get at the real‑world aspects, and follow as many sample
patients as possible for 30 years, or whatever time is deemed proper.
And
the advantages of doing this would be that the follow‑up would be
concentrated at expert centers, and there would be central reading of the
counts. There would be early warning of
cell count decline, and it could be used to detect other adverse events, such
as cataract or the other outcomes.
Disadvantages
are you need aggressive persuasion of the sample patients to come in for their visits,
and it would be more expensive. Is
there any questions?
DR.
WEISS: Okay. Thank you. What I'd like
to do is sort of cut to the chase, because I feel we're ‑‑ the
reason we're raising this question, and I couldn't delay it as long as I wanted
to, to get to other issues, was because I feared we were going to go around in
circles, and that's what's begun to happen.
So what I'd like to do is just address ourselves to the issues of safety
to sort of hone down on what our concerns are, as bespeaks the endothelial cell
count.
What
I'd like is, those who are concerned that any of these patients, even if they
didn't have any other surgery, could develop corneal decompensation, corneal
edema from this procedure, I'd like a show of hands for those members of the
panel who are concerned that from the data they've seen, these patients could
develop corneal edema, at any point down the line. Are you concerned that that could happen?
(Vote
taken.)
DR.
McCULLEY: That's an open‑ended
question.
DR.
WEISS: That is an open‑ended
question. So that's true, it is an open‑ended
question, Jim. Then the second question
I have for those of you who have that concern, do you think a large percentage
of patients ‑‑ are you concerned that a large percentage of
patients could develop corneal edema from just the implantation of this device?
(Vote
taken.)
DR.
WEISS: So you have ‑‑ no
one has any ideas on ‑‑ so is that what the safety concern is
here? Because if that's what the safety
concern is, then I think we're talking about specifically the loss of
endothelial cells, and we should address ourselves to doing a study that
addresses that particular concern, which is the loss of endothelial cells. Is that the concern on the panel, is the
loss of corneal endothelial cells?
DR.
MATHERS: That's one concern.
DR.
WEISS: That's one concern. Okay.
So let's address ourselves to that concern. What ‑‑ is there any problem ‑‑ why ‑‑
would not following the cohort of 306 patients for up to a five year period of
time to see if there was stabilization with an additional year, address the
concern of loss of endothelial cell count, or why would that not address that
concern? Dr. Mathers.
DR.
MATHERS: It might or might not,
depending on how the data came out. It
would certainly help.
DR.
WEISS: Dr. Bradley.
DR.
BRADLEY: It seems we've had a
discussion of do the data stabilize or do they not stabilize. And I wonder whether that's the appropriate
question we should be challenging the Sponsor and the FDA with, in terms of
this post ‑‑ possible post‑approval analysis. Mike Grimmett a couple of years ago
suggested 1.5 percent per year loss was okay.
The current data is 1.8 percent, I believe. Is that what Marian said?
A simple statistical question is whether or not the data show a
significantly greater decline than the decline that is considered safe. If the decline is concerned safe as 1.5
percent per year, it becomes a statistical question to analyze the data. And it may take five years to do that, to
show whether or not the data are declining not significantly more than this
supposedly safe decline rate of 1.5 percent.
So the issue of stabilization versus not, doesn't seem to be the issue
here. It seems to be whether or not the
decline is greater than what is considered safe. And that becomes a very straightforward statistical question,
which surely the Sponsor and the FDA could sort out.
DR.
WEISS: Dr. Bandeen‑Roche.
DR.
BANDEEN‑ROCHE: More from a public
health point of view, you could state it the other way. Right?
In other words, you might want to demonstrate that it's at least that
safe, you know, that it's no greater than 1.5, rather than just that it's not
statistically different than 1.5.
DR.
BRADLEY: I think that surely that's all
one is able to do, to say whether it's statistically different or not.
DR.
BANDEEN‑ROCHE: Right, but you
might want to reverse the Type 1 and Type 2 error, and require evidence that
the rate is lower than 1.5, rather than just saying it's not statistically
greater.
DR.
WEISS: Dr. Rosenthal, could we have
some help, because I could see we're getting nowhere here. And we're taking a long time to get nowhere. Do you have any suggestions for the panel?
DR.
ROSENTHAL: The panel has to decide
whether they want follow‑ up of these patients before they give an
approvable. They can give approvable
with conditions, and the conditions can be follow‑up of the patients
before it goes on the market, or after it goes on the market. And give not‑approvable because then that
‑‑ with the same ‑‑ of course, in the not‑approvable
situation, it would be because they don't have the data before they give the
approvable.
DR.
WEISS: At the present time, as concerns
the issue of endothelial cell loss, can the panel members who feel there is not
enough information right now to make a decision on safety before this is
released into the market, could raise their hands. Dr. Matoba.
DR.
MATOBA: What about if we vote on
whether panel members would be satisfied if Sponsors were to follow for an
additional amount of time, the patients for whom they have pre‑op
endothelial or specular microscopy, and then vote on whether it should be four
years or five years.
DR.
WEISS: Well, the first question that we
need to answer, and which the FDA is bringing forth to us, is if we don't have
that data, I'm getting ‑‑ I'm not getting a sense from the panel
whether that data can be given after this is released into market, or it's a
condition for ‑‑
DR.
MATOBA: But I think we can agree on
whether we want ‑‑
DR.
McCULLEY: Vote on it.
DR.
MATOBA: I think we can agree on whether
we want the data or not. And then we
can decide whether we would be willing to approve or not approve.
DR.
WEISS: Fine.
DR.
McCULLEY: We want the data.
DR.
MACSAI: We want the data.
DR.
WEISS: Everyone ‑‑
DR.
MATOBA: Okay. So but then do we agree that if they follow those patients who
had pre‑operative specular microscopy that's adequate, or are we going to
ask for something ‑‑
DR.
WEISS: Well, why don't we just break
this down into simple points. Is
everyone in agreement that we would want to get at least five year data for the
patients who've had pre‑operative specular microscopy? Those who are in agreement with that, could
you raise your hand?
(Vote
taken.)
DR.
WEISS: Does anyone want longer than
five year specular microscopy or would like the FDA to determine the length of
the study depending on what the results of five year microscopy? Depending on the results of the five year
microscopy, that would determine the length of that particular study.
DR.
MACSAI: Jayne, we can request that that
be brought back to panel, that five year data for review, or the FDA can review
it.
DR.
WEISS: Well, I think FDA will look at it.
I don't think that has to be ‑‑ if we're ‑‑
well, whether or not it got brought back to panel depends on whether this gets
approved with conditions or not, so that's ‑‑ am I correct, Ralph,
on that?
DR.
ROSENTHAL: Yes.
DR.
WEISS: Yeah. Okay, so we ‑‑ I think ‑‑
DR.
ROSENTHAL: It's whether you do not
approve it.
DR.
WEISS: Then it would come back for
another go around. So the panel is in
agreement that they would like the cohort that's had pre‑operative
specular microscopy, have another specular microscopy done at five years time,
and then ‑‑
SPEAKER: Annually until five.
DR.
WEISS: Annually until five years, and
then have the FDA determine how long after, in terms of those results. Now on that basis, what I need to find out
from panel is, would that be information that is needed before this gets
approved? And how many of you would
require that information before you would feel comfortable voting for saying
that this is a safe device?
DR.
GRIMMETT: Jayne, there's two issues
there. How many would feel comfortable
just having year four, or needing both, so there's two parts to that.
DR.
WEISS: No, I don't want to break it
down any further. We're splicing ‑‑
I'm stating the question. Actually ‑‑
okay. I don't ‑ ‑ if we
keep on deviating, we're going to be here until tomorrow, which I don't ‑‑
I'd just like to hone in on this particular question. We've talked about up to five years. We want specular microscopy.
We've talked about perhaps extending that, depending on what that data
shows. What I just want is a show of
hands from the panel, is this needed to vote for approval? Would you need this data before you would
feel that this is approvable, with or without conditions?
DR.
GRIMMETT: All the way to five,
inclusive of everything, needing five.
DR.
WEISS: So, Mike, you would need five ‑‑ you would need an additional year data
before you would approve this?
DR.
GRIMMETT: No. I would need four year data as a condition of approval, in order
to approve it.
DR.
WEISS: Okay.
DR.
GRIMMETT: With five year being a post‑market
surveillance.
DR.
WEISS: Fine.
DR.
GRIMMETT: That's my position.
DR.
WEISS: Fine. Does anyone have a position different than what Dr. Grimmett
said? Dr. Sugar.
DR.
SUGAR: I would suggest conditional approval
with continued acquisition of that data up to five years; that is, this would
be a marketable device once the agency approves it, while we're still acquiring
that data.
DR.
GRIMMETT: When they see four year data,
‑‑ just as a clarification, Dr. Sugar, when the FDA sees four year
data, and feels that it shows a reasonable level of stability, then it can be
approved.
DR.
SUGAR: Well, no. It would still ‑‑ it would be
conditionally approved, so it would be marketed now.
DR.
GRIMMETT: Oh, so your's are all post‑market. Year four and year five are post‑market.
DR.
SUGAR: Unless I misinterpreted Dr.
Bright's statement, that we could conditionally approve it, and it could be
marketed with the condition that that data continued to be acquired; that is,
this is a marketed device ‑‑
DR.
GRIMMETT: Isn't that post‑market
surveillance?
DR.
ROSENTHAL: You can do it two ways. You can require the data to be submitted to
us before it can go to market, four years, five years, four years only, four
and five years, or you can say it can go out right now, but once it's out in
the marketplace, we have to get the data at four and five years.
DR.
SUGAR: The latter is ‑‑
SPEAKER: You want post‑market
surveillance. You are in agreement on
that.
DR.
SUGAR: Post‑market acquisition of
data through five years, with it being conditionally approved.
DR.
WEISS: So I'm getting a sense from the
panel right now, there are these two different choices. But from what I'm hearing from the panel,
they would feel comfortable with the post‑market surveillance, post‑market
‑‑
DR.
McCULLEY: Get a vote on the two.
DR.
WEISS: Dr. Bandeen ‑‑
DR.
GRIMMETT: Four years before it gets out
with continued post‑ market to five.
That's choice one. Choice two
is, let it go now and do post‑market surveillance on four and five when
it's already out in the market. That's
choice two. Vote for one or two.
DR.
WEISS: Dr. Bandeen‑Roche.
DR.
BANDEEN‑ROCHE: Am I correct in
presuming that by the time the four year follow‑up is complete, there
will be some five year data?
DR.
WEISS: Yes.
DR.
BANDEEN‑ROCHE: So that's another ‑‑
DR.
WEISS: So why don't you state the first
choice, and we can have panel ‑‑
DR.
GRIMMETT: Let's state the second. How many would vote for approval now with
the current existing data, with post‑market surveillance of endothelial
data at four years and five years?
(Vote
taken.)
DR.
GRIMMETT: That was your choice, if I
stated correctly. That's enough.
DR.
ROSENTHAL: How many were there?
DR.
WEISS: And how many would vote for ‑‑
restate the first one.
DR.
GRIMMETT: For gathering the four year
data now as a condition of approval, and if satisfactory by review of the FDA,
then approve it, and then continue post‑market surveillance out to year
five.
(Vote
taken.)
MS.
THORNTON: It was six to five.
DR.
GRIMMETT: You want to take it again?
DR.
ROSENTHAL: Yeah, could we.
DR.
GRIMMETT: Take it again.
MS.
THORNTON: It was six to five.
DR.
GRIMMETT: Which way?
DR.
ROSENTHAL: Could we have the other
first?
DR.
WEISS: Now I just want to clarify the
four year data that we're trying to get, you have a continual number of
patients who are getting four year data, so when will you get this four year
data? At what time point would you ‑‑
DR.
ROSENTHAL: We need you to tell us.
DR.
WEISS: I know it's ongoing, so if the ‑‑
so you would ‑‑ so the panel ‑‑
DR.
ROSENTHAL: Ten more eyes, 20 more eyes?
DR.
WEISS: How many ‑‑
DR.
ROSENTHAL: All the eyes. It's up to you.
DR.
WEISS: Okay. So then I would ‑‑ I'd like the panel to understand
that if they went with, I believe it's the first option, it's undefined when
that condition would be met. Am I
correct?
DR.
ROSENTHAL: Do you want to explain?
DR.
WEISS: When would that condition that
all the four year data for all these patients would be met? Because we also have to realize that they
only have four year data on 57 patients at the present time, so how many more
patients would they be able to get four year data on?
MS.
LOCHNER: At the present time, they
obviously have more than that number.
That cut‑off on the database happened a couple of months ago, so
as we speak, more and more people are reaching four years. I think the Sponsor can address, you know,
the issue is when was the last patient enrolled. When will the last patient be out to four years in that cohort,
and so they'll know exactly when they'll have the complete group.
DR.
MACSAI: It's December of 2006.
DR.
WEISS: What I would like to know from ‑‑
MS.
LOCHNER: No.
DR.
WEISS: Yeah. I'd like to know from Dr. Gray statistically what number would
you need, or what number of patients would you need to have four year data
before you feel that you could make a ‑ ‑ Dr. Gray, do you have any
comment on finding four year data for all the remaining patients helpful?
DR.
GRAY: Helpful?
DR.
ROSENTHAL: Oh, no. He's not to give you any ‑‑
DR.
GRAY: I can't answer that kind of a
question without a lot more information.
I mean, that's a difficult ‑‑
DR.
WEISS: How many ‑‑
DR.
GRAY: I can't do it off the top of my
head. I'm sorry.
DR.
WEISS: From the FDA, how many ‑‑
the last four year data would be coming back when? When would be the ‑‑ Sponsor, please.
DR.
LAMIELLE: Helene Lamielle. December, 2006.
SPEAKER: What did she say?
DR.
WEISS: December, 2006. Dr. Macsai.
DR.
MACSAI: Dr. Lamielle, is that ‑‑
because I ‑‑ that's what I thought too, but now I'm rethinking
it. Is that the last person enrolled,
or is that the last person with specular microscopy? I don't get that clear.
DR.
LAMIELLE: That's the last person on the
whole.
DR.
MACSAI: But when was the enrollment of
the 306 specular microscopy patients completed?
DR.
LAMIELLE: We have to look at the data,
when the last microscopic specular patient was enrolled.
DR.
MACSAI: Okay.
DR.
LAMIELLE: But the specular microscopy
data have been done all along the study, so there is no reason ‑‑
it's earlier than the rest of the cohort.
DR.
WEISS: So I would just like
clarification from the panel members who would require this data that perhaps
may go out to approximately two years from now in order to release this into
the market. I would presume that you
would want to delay approval of this for two years, or more than two years,
because you have concerns about safety because of the specular microscopy
data. Am I correct ‑‑ for
those of you who voted for Option 1, am I correct on assuming that's the cause
of the vote in that direction? Dr.
Mathers?
DR.
MATHERS: Concerns about the endothelial
issues ‑ I'm sorry.
DR.
WEISS: Yes, because you would be
delaying the vote, or it would have to come back to ‑‑ you'd be
delaying this for more than two years, because you have concerns about safety
as regards to the issue of the findings on the specular microscopy.
DR.
MATHERS: That is precisely the problem,
and I think that it is a very significant issue, and we should know more before
we get approval. That's why I voted for
conditional approval, that we need to know this before we approve it.
DR.
WEISS: Yeah, Donna.
MS.
LOCHNER: I was just going to say, it is
possible that as the Sponsor theorized that the rate is essentially going, you
know, dramatically down at four years, that the data will have sufficient power
before the last of the patients are enrolled.
So if what they're theorizing is true, they may not have to wait as long
as you're saying to have sufficient power to show that the loss is decreased
from the three year point.
However,
in a worst case situation, maybe they'll need all their data, and have to wait
that long. But if their theory is true,
one would expect that they would be able to have sufficient power much earlier
than that.
DR.
WEISS: So the panel could say that they
would want acquisition of four year data until ‑‑ for the number,
until which point the FDA deems that they can determine with certainty that the
data shows stability, at which point then that would be the condition that
would be met for it to be released into market.
MS.
LOCHNER: Certainly. And no matter what the panel or FDA says,
the sponsor will push that point in any case, so you don't have to worry ‑‑
DR.
WEISS: Dr. Mathers, and then Dr.
Bradley.
DR.
MATHERS: I would like the condition to
be achieved, such that at the end of the lifetime of the device, that the
patient would still have 1500 cell count.
MS.
LOCHNER: Right. And if you just use the data the sponsor
has, you can do that calculation and see where they are.
DR.
MATHERS: That's correct. It is a lower rate than 1.5 percent per
year.
MS.
LOCHNER: We understand.
DR.
WEISS: Dr. Bradley.
DR.
BRADLEY: Again, just to clarify, the
stabilization, absolute stabilization is not the gold standard here. It is the rate which is ‑‑ rate
of decline which deemed safe. And we've
got a 1.5 is okay, and a 1.5 is not okay. so there is some debate about what
the rate actually is.
DR.
WEISS: Dr. Grimmett.
DR.
GRIMMETT: Let me clarify. That 1.5, the figure came about at last
year's meeting due to the fact that in looking at what would be a sample size
needed to show a specific rate of cell loss.
And if we set the bar too low, the sample sizes would have to be
enormous. It wasn't that 1.5 was deemed
a safe level. It was that 1.5, if you
wanted to screen that they were under that, your sample sizes could be
reasonably sized so it wouldn't be onerous.
That's where it came up.
DR.
WEISS: Dr. Bandeen‑Roche.
DR.
BANDEEN‑ROCHE: I just wanted to
say that I agree with this discussion that's been happening in the last couple
of minutes and, you know, just so long as we also keep in mind representation,
as well as just power. You know, that
we're not ‑‑ we don't have an overly selective group, both
sufficient numbers, and decently representative of the whole cohort.
DR.
WEISS: Dr. Macsai.
DR.
MACSAI: I'd like to speak in favor of
my disagreement with the majority of the panel. We had a presentation by Dr. Edelhauser who's deemed
internationally as an expert in the field of endothelial cell data of all
sorts, and we've seen that the pleomorphism and polymegathism are pretty darned
good here, and they're stabilizing. And
then we looked at that they counted 90 cells, but probably 100 to 150 cells
would have been better. And there's a
lot of room for error in the 90 cell count, and now we're arguing about 1.8
versus 1.5, versus 2 percent. Where, if
you looked at the confidence interval of those numbers, and then took a
confidence interval of those counts, and then, you know, multiplied it by all
those factors out, I think you'd wash this whole thing away.
You
know, I'm concerned as everyone, and I started out my whole review as saying
that this ‑‑ we don't want to create ORC ‑ I can't ‑ a
situation with a lens ‑ excuse me ‑ take that from the thing ‑
a lens that might cause endothelial cell decompensation, but we have a device
that's really effective, probably more effective than what's out there. And I know safety is really important, and
you're talking to Mikey who doesn't like anything here, but I mean, do we
really want to wait until 2006?
We
approved these contact lenses when we already had your study saying, you know,
they're dangerous. Okay?
DR.
WEISS: I think at this point we have
the data, and everyone, I think, has their opinions or has quite a few
opinions. And at some point, this may
come to a very close vote. But I think
the information is out there, and we all have our perspective on, and we still
have a couple of questions. And I don't
want to tell you how many hours behind we are, so we're going to ‑‑
I think we have the information on endothelial cells. We're going to end up putting it to a vote, and when it gets put
to a vote, and what I'd like to do is go on to a non‑controversial topic,
like cataracts. I bet the Sponsor
didn't think that was going to be the non‑ controversial portion.
DR.
EYDELMAN: Question 2(a) ‑
"Do you believe that the three year follow‑up is sufficient to
establish a lens pacification profile associated with this device? If not, what is your recommendation?"
DR.
WEISS: Dr. Macsai.
DR.
MACSAI: It's sufficient.
DR.
WEISS: I think the panel has gotten
beaten into submission.
DR.
SUGAR: I think we should ask for post‑marketing
acquisition of data on cataracts that accrue in this five year period while
we're looking at their endothelium.
DR.
WEISS: Sounds good. Dr. Schein.
DR.
SCHEIN: As I said before, I'm more
concerned about cataract and retinal detachment, than I am about the
cornea. Because although it is
uncertain on endothelium, there has not been progression to any clinical
disease, while there has been, in a relatively short time period. I frankly don't believe most of the cataract
rating. I don't disbelieve it because I
think investigators are dishonest, but I know, and it's well‑published,
that using clinical grades, whether it's the LOC system or the Wisconsin
system, is incredibly unreliable. You
need a photographic standard to really believe it, and that may be why there's
such variation between Canada, these investigators, site‑ to‑site,
and Dominican Republic, and maybe more than just position skill. So I think this is a real issue. People who get cataract surgery, their
myopes. They're going to have the eye
entered twice, retinal detachment rate will behave accordingly, so I don't
think this is adequate information to establish a lens opacification profile. You need a larger sample and representative
surgeons.
DR.
WEISS: Well, certainly I would think it
would be not difficult if we're going to be getting data at four years, five
years, to include cataracts in that.
DR.
SCHEIN: It's not a large sample, and
it's not a representative group of surgeons.
DR.
WEISS: Dr. Sugar had mentioned
considering IOL removal if there's progression of cataract formation. Did anyone want to put that in the labeling,
as well? And that goes later on, but I
have it.
DR.
SUGAR: I don't think it's ‑‑
DR.
WEISS: Is that what you said, Joel, or
is ‑‑
DR.
SUGAR: No. I expressed lack of information ‑‑
DR.
WEISS: Lack of data.
DR.
SUGAR: ‑‑ on what the
toxicity of the removal event is, in terms of, do cataracts get worse after you
take the lens out? I don't know.
DR.
WEISS: So you ‑‑
DR.
SUGAR: And I don't think the Sponsor
has sufficient numbers within this cohort to give us an answer that would
satisfy me.
DR.
WEISS: So you're not going to ask the
Sponsor for an answer ‑‑ it's a question that remains and will stay
unanswered. Or would you like to ask
the Sponsor ‑‑
DR.
SUGAR: Again, if the Sponsor has data
on ‑‑ you know, certainly if they find that removing the IOL is
cataractogenic, obviously, they need to let us know that. And I assume that they're mandated to let us
‑‑ to let the FDA know that as an adverse event.
DR.
WEISS: As part of the ‑‑
Dr. Rosenthal.
DR.
ROSENTHAL: Unfortunately, the adverse
event issue, if they're informed of it, they are mandated to let us know. But if they are not informed of it, unless
the physician reports it through the MDR system, we will never know about it.
DR.
WEISS: Well, we can ask them at this
point if they have the information to let the FDA know. Is that correct?
DR.
ROSENTHAL: Well, at this point you have
the information because it was submitted in the PMA.
DR.
SUGAR: No. We don't have information on whether removing the lens halts
progression or induces progression of whatever opacities were there.
DR.
ROSENTHAL: No, you don't have that.
DR.
WEISS: So we can ask them for that
information, and that's ‑ ‑ if they have it.
DR.
ROSENTHAL: When? When do you want them to give it to us?
DR.
WEISS: If it was ‑‑ if the
panel wanted, that could be a conditional, could it not?
DR.
EYDELMAN: I just want to make it clear.
DR.
WEISS: Yes.
DR.
EYDELMAN: Are you trying ‑‑
there's no data from the PMA cohort that you're discussing obtaining the data
from post‑market, or what exactly ‑‑
DR.
WEISS: I think Dr. Sugar is talking
about the patients who've already had this done. Am I correct?
DR.
SUGAR: Well, then the number is too
low.
DR.
EYDELMAN: Yes.
DR.
WEISS: Okay. So then do you have ‑‑ is there a statement you want
to make, or is that just sort of a wish list that's not going to get answered?
DR.
SUGAR: I guess I don't know how to make
the statement about the statement, but yes.
DR.
WEISS: Dr. Eydelman, do you have a
suggestion on how to make a statement about a statement?
DR.
EYDELMAN: If you want to find out the
specific rate, you need to collect data.
If you want to have a general warning, a precaution about lack of data,
you can do that in labeling. Those are
the two options.
DR.
SUGAR: I guess both is what I would
like, which is to find out if ‑‑ and I don't know how you find this
out. Assuming, as I think we are, that
this is a low frequency event, it's going to be hard to acquire that data in
any very short period of time. It would
be nice to know what appropriate recommendations are for dealing with lens
opacification in these patients that is not visually significant. Does removing the implant cause progression
or halt progression?
DR.
ROSENTHAL: Ralph Rosenthal. I think at this point in time, all we can do
is put a warning in saying that you do not know what the effect would be on the
cataract that develops following implantation when you explant it.
DR.
SUGAR: Then I think the labeling should
reflect there is a lack of data on the impact of removing and/or replacing the
lens on the endothelium and on the lens.
DR.
WEISS: Fine. Dr. Matoba.
DR.
MATOBA: Well, okay. I hate to ask this question because of
labeling conditions, but is someone keeping track of all the labeling
questions?
DR.
WEISS: I am, as well as Dr. Mathers, I
hope. Any other issues about cataract?
DR.
SUGAR: I guess I raise the other one,
the axial length measurement. Is axial
length measurement accurate with the lens in place? And I don't know how to deal with that in this.
DR.
EYDELMAN: That is actually something we
can ask the Sponsor, and work out the proper ‑‑ that is the easiest
of the issues. We have not heard the
answer to Question 2(a).
DR.
WEISS: So the question ‑‑
Question 2(a) is ‑ "Do you believe a three year follow‑up is
sufficient to establish a lens opacification profile associated with this
device"? All of those who feel
that it is, and would like to answer yes, please raise your hand.
(Vote
taken.)
MS.
THORNTON: We have eight.
DR.
WEISS: So it's a majority, not
unanimous, but a majority. And we'll go
with the majority. B. Question B is ‑‑
DR.
EYDELMAN: "In light of the findings,
they believe surgeon experience to have be an important factor in ASC
development secondary to surgical trauma.
If yes, they believe that future users of this lens should be required
to undergo special training."
DR.
WEISS: So I think that there was a
consensus that there should be special training. Would the FDA need to know from us what type of special training,
or you can determine that with the Sponsor?
Dr. Macsai had mentioned ‑‑ Dr. Sugar and Dr. Macsai, I
think both had mentioned mandate ‑ perhaps proctor for early cases, but
that's something that you all can determine with the Sponsor, so we do not have
to get involved in that.
DR.
ROSENTHAL: I think I should
clarify. We can mandate training. We generally do not mandate what type of
training.
DR.
WEISS: So would it be acceptable to the
panel that training or some sort be mandated?
(Vote
taken.)
DR.
WEISS: Fine. Dr. Macsai had brought up tracking and recalling. If there were multiple surgical problems
with a physician, I would assume that would be too burdensome and beyond the
usual scope that we advise. Am I
correct on that?
DR.
EYDELMAN: Yes.
DR.
ROSENTHAL: I've never heard it
recommended before. If the sense of the
panel is that that's what they feel is reasonable, we can ask the agency ‑‑
well, we are the agency. We can ask
higher up in the agency what their feeling is about the recommendation. We may not take it, and we may take it.
DR.
MACSAI: Jayne, can I clarify?
DR.
WEISS: Dr. Macsai, yeah.
DR.
MACSAI: The recommendation really
wasn't to the agency, it was to the Sponsor.
The recommendation was simply to the Sponsor, that if there's a
disproportionate number, I assume these are not ‑ ‑ these are going
to be consignment lenses, and if somebody, you know, keeps ordering new ones,
and keeps sending back ones they implanted wrong, or they tore upon implanting
because they can't manage to get them through the shooter, red flag. Go retrain that person. Rescind their certification. As simple as that.
DR. WEISS: So the agency can take that under advisement. Okay.
The Sponsor. C.
DR.
EYDELMAN: Has to do with recommendation
for replacement of ICL.
SPEAKER: I think we dealt with that at one point.
DR.
EYDELMAN: Yes, we did.
DR.
WEISS: WE did this one. Okay.
What was the answer?
SPEAKER: We don't know.
DR.
WEISS: We don't know. Always nice to have definitive answers for
the agency. Question 5, "Do the
safety and efficacy outcomes support approval of the STAAR ICL for the eyes
with the following pre‑operative manifest. (A) is minus 3 to minus 7."
Now one thing I will point out, obviously, the results in these patients
were much better. But then again, you
might ‑‑ the panel might determine the risk benefit ratio is also a
little bit different because there are effective treatments in these
patients. A minus 3 has a whole choice
of treatments, where a minus 15 does not.
But having added that introduction, I'd like a vote. For those who agree that the safety and
efficacy outcomes, safety and efficacy support approval for eyes with minus 3
to minus 7 ‑ if you agree, vote with your hand in the affirmative.
(Vote
taken.)
MS.
THORNTON: I've got one, two, three,
four.
DR.
ROSENTHAL: No, there are five.
MS.
THORNTON: Five. Where's the other one? Tim, keep your hand up.
DR.
ROSENTHAL: There's one, two, three,
four, five.
DR.
WEISS: Okay. Five out of 11.
DR.
ROSENTHAL: No. You have to vote.
DR.
WEISS: Why don't we have ‑‑
DR.
ROSENTHAL: There has to be another vote.
DR.
WEISS: Five people are voting in the
affirmative. For those who disagree
that safety and/or efficacy do not support approval for minus 3 to minus 7, can
you vote? They disagree.
DR.
ROSENTHAL: Please vote. You can abstain. Please vote either yes, no, or abstain.
DR.
MACSAI: Minus 3 to minus 7.
DR.
ROSENTHAL: There's four against.
DR.
WEISS: This is a no vote. Dr. Bandeen‑Roche.
DR.
BANDEEN‑ROCHE: We're taking
everything into account, including the discussion on ‑‑
DR.
WEISS: Every single thing.
DR.
BANDEEN‑ROCHE: ‑‑
endothelial cell count. Right?
DR.
WEISS: Everything. Safety and efficacy.
DR.
EYDELMAN: Well, you're voting both
ways.
DR.
WEISS: Okay. What are we voting now?
Okay. Let's have a vote again. Those who agree that safety and efficacy
outcome support approval for minus 3 to minus 7 ‑ those who ‑‑
DR.
GRIMMETT: With or without the prior
endothelial concerns. Are you
separating that out? Are you concluding
it, the endothelial safety issue?
DR.
WEISS: Yes.
DR.
GRIMMETT: We already went over, or are
you separating it out?
DR.
SUGAR: With the condition, I assume.
DR.
GRIMMETT: Point of clarification.
DR.
WEISS: Well, with the conditions of ‑‑
let's ‑‑ if you want to break it out, let's break it out into
needing the four year data as a condition of approval. And then we'll have a vote for not needing
the four year data, but as a condition of approval having it ‑‑
DR.
SUGAR: We just did that. We voted that way.
DR.
WEISS: So let me ‑‑ I'm
going to defer to FDA. Since we've
done, how do you want this phrased at this point to give you any information?
DR.
EYDELMAN: Okay. I will assume that you're not expecting to
stratify the four year data by preoperative refractive bins, because then we'll
never have enough. So, therefore, you
have to take into consideration then endothelial cell data as you know
currently. And assuming that overall
four year data will be looked upon until this device is marketed, do you
consider that safety and efficacy ‑‑ do they support approval for
minus 3 to minus 7?
DR.
WEISS: So for those of you who require
that four year data before as a condition of approval, four year data on the
rest of the cohort as a condition of approval, do you believe it's efficacious
for minus 3 to minus 7?
DR.
COLEMAN: Excuse me, Jayne. Can I have safe and efficacious.
DR.
WEISS: Safe and ‑‑ is that ‑‑
DR.
GRIMMETT: For everything else but the
endothelium.
DR.
WEISS: No. Once you have your four year data, you're going to have your four
year data as a condition of approval.
MS.
LOCHNER: Can I say something?
DR.
ROSENTHAL: Can I clarify?
DR.
WEISS: Yes, please clarify.
DR.
ROSENTHAL: Are you ‑‑ do
you want ‑‑ what ‑‑ do you want to limit the power ‑‑
the refractive error for which this device should be used or do you not?
MS.
LOCHNER: And to say that another way, I
think the panel already voted on the endothelial cell issue. And the motion seemed to carry that the four
year data would be obtained pre‑marketly.
DR.
ROSENTHAL: That was a straw vote, and ‑‑
MS.
THORNTON: Would you please use the
microphone.
DR.
WEISS: It would be a straw vote. I'm sorry.
Maybe it wasn't in the ‑‑
DR.
ROSENTHAL: It was a straw vote, and you
still don't know what the ultimate vote will be, and what the conditions will
be.
MS.
LOCHNER: But I think we want you to set
aside the endothelial cell issue at this time, and speak to the refractive
ranges.
DR.
WEISS: So we're speaking now basically
of efficacy. If we're speaking about ‑‑
MS.
LOCHNER: No, safety and any other ‑‑
DR.
WEISS: Safety and endothelial cell
data, and efficacy. We're trying to get
at whether, setting aside the endothelial cell issue, which we already had a
straw vote on, and we assume that that issue wouldn't change based on the
refractive ranges. Setting that aside,
are there additional concerns that might make you vote differently by the
different refractive ranges? Dr.
Coleman.
DR.
COLEMAN: Yeah, but one of my issues that
hasn't been addressed, because we've been voting on safety based on corneal
endothelium, is the safety related to glaucoma, and also the lack of
gonioscopic data. And one of the things
that I need in terms of for my feeling,
the safety of this procedure is having post‑ operative gonioscopic
evaluations on the cohort in this PMA.
And that information is not available.
DR.
WEISS: Okay. I would like to ‑‑ I'm getting disturbed how the
proceedings are going. I would like to
emphasize, this is reasonable safety and efficacy. I mean, there ‑‑ I think it would be nice to have
gonioscopy, and I think there were other parts that could have been included in
the study. But with all fairness to the
sponsor, at the point that this study was approved, it was approved with the
input of the agency, so we can't hold them up to a higher requirement, which
would be nice, but it's not fair for information that we've subsequently
gathered.
With
the data that we have, and that the agency required from them, and that they
performed, do we have reasonable safety and efficacy? I would be disturbed if at this point this was ‑‑ it
was not approved on the basis they didn't have post‑operative gonioscopy
because that was not a requirement that the agency made, and there is nothing
in particular ‑‑
SPEAKER: That was a requirement that the panel ‑‑
DR.
WEISS: Well, the panel made that, but
that was not a binding requirement. I
mean, can the agency comment if I'm out of line here?
DR.
COLEMAN: It's not in the study, but the
thing is that they could ‑‑ this is Dr. Coleman again ‑
excuse me. I thought that you could
when you're doing the four year reviews or the five year reviews of these
individuals, same with conditional approval, but they could also have
gonioscopy by the surgeons to see how the angles were doing, whether there's
pigment deposition ‑‑
DR.
WEISS: No, I think that ‑‑
DR.
COLEMAN: So it's definitely doable,
even now in this current cohort. It's
just that information hasn't been obtained.
And you have an increased rate of interocular pressures of about ‑‑
in three years in this cohort about 6.8 percent of the cohort has a pressure
elevation of more than 5 millimeters of mercury from baseline. If you believe the ocular hypertensive
treatment study, that's associated with a 50 percent increased risk of glaucoma
in these young individuals. And so
specular microscopy
DR.
WEISS: What percent of higher myopes
would be expected to get glaucoma?
DR.
COLEMAN: That issue is debatable. The investigators went ‑‑ the
Sponsors went over it, but one of the issues is, is it's still considered
debatable whether or not high myopia is associated with an increased risk of
glaucoma.
DR.
WEISS: Okay. So you would like to put as ‑‑ if data is gone that
four years of specular microscopy, you would like gonioscopy to be done at four
years, as well.
DR.
COLEMAN: To looking at pigment
deposition and increased peripheral anterior synechiae, because those
references that Dr. Grimmett found did show that in those eyes that had
elevated pressures that were having problems, they did have increased pigment
deposition, and also peripheral anterior synechiae. Glaucoma is a long‑term risk for these individuals. I mean, I think that it's something they're
going to be living with for a lifetime if they do have an increased risk of
glaucoma, because a 40 year old's prevalence of glaucoma is about .18 percent
when you look at the Baltimore Eye Survey in Caucasians. And if you do some extrapolations, this
could be actually increasing and doubling that prevalence in this age group.
DR.
WEISS: Dr. Grimmett.
DR.
GRIMMETT: Michael Grimmett. I'm certainly in favor of warning clinicians
in the labeling about our concerns about pigment deposition and need for
gonioscopy, so that clinicians go ahead and do the correct thing, but the study
was approved without gonioscopy. And
while I think it's regrettable, I am not in favor of mandating the Sponsor to
gather further gonioscopy data. I don't
think that would be fair.
DR.
WEISS: Dr. Matoba, and then Dr. Schein.
DR.
MATOBA: Okay. I want to ask Dr. Eydelman, when the FDA put this question
together, did you want us to just address safety efficacy for each of these
refractory subsets, or do you want us to also take into consideration
philosophical ideas, such as whether we think that an interocular procedure is
justified in a patient who is minus 3?
DR.
EYDELMAN: As I tried to explain in my
presentation, what I was hoping that the panel will do is look at each of the
refractive ranges, and look at the risk benefit analysis for this device, and
for other alternative devices for each of these refractive ranges, and make a
decision upon that.
DR.
WEISS: So with that in mind, let's talk
about minus 7 to minus 10.
DR.
SCHEIN: So to clarify that, because
that is my question.
DR.
WEISS: Yeah.
DR.
SCHEIN: So the answer is, compared to
what? And so the comparison here is not
spectacles or contact lenses, it's compared to other refractive ‑‑
DR.
WEISS: Dr. Rosenthal.
DR.
ROSENTHAL: You're not meant to compare
it to anything.
DR.
SCHEIN: Well, that's not what you said.
MR.
ROSENTHAL: You're meant to take the
risk benefit ratio of this device.
DR.
WEISS: We have the safety and efficacy
minus the endothelial cell data for each of these refractive ranges,
irregardless of what else is out there.
That's what we have to look at.
So I'm going to ask ‑‑
DR.
SCHEIN: That makes no sense whatsoever,
does it?
DR.
WEISS: But is that what the agency is
asking?
DR.
SCHEIN: I mean, what ‑‑
obviously, it's inappropriate to ‑‑
DR.
ROSENTHAL: We're asking do you feel a
patient with a minus 3 diopter myopia have a interocular lens put in their eye
to treat their minus 3 diopter myopia.
DR.
MATOBA: That's not the way the question
is worded. I thought that's what you
were getting at, but that's not the way the question is worded.
DR.
ROSENTHAL: And minus 4, and minus 5,
and minus 6. So I think maybe we should
look at it ‑ is there a range at which you would feel comfortable
subjecting a patient with myopia to an interocular procedure in which this
device is implanted?
DR.
SCHEIN: Okay. So in other words, it is in comparison to other data that ‑‑
SPEAKER: No.
MR.
ROSENTHAL: Not comparison.
DR.
SCHEIN: Not in a quantitative way, but
it's ‑‑
DR.
WEISS: Okay. Dr. Bradley has suggested the following wording, which I think is
good wording. If the Sponsor can
establish that the endothelial cell count is not declining at dangerous levels,
depending on how you want to classify that word, does the panel consider this
device safe and efficacious for the following ranges. So let's first talk about minus 7 to minus 10. If there was no issues with the endothelial
cell count data, I'd like a raise ‑‑ a show of hands ‑‑
Dr. Matoba.
DR.
MATOBA: I think risk benefit is
different from what you're saying, because safety is never absolute. It's all relative. And so the benefit for a minus 3 is different from a benefit for
minus 12 ‑‑
DR.
WEISS: That's why I'm talking about
minus 7 to minus 10 first.
DR.
MATOBA: You can't take that phrase out
of the question, I don't think.
DR.
WEISS: But that's why I'm speaking
about minus 7 to minus 10 first. I'd
like to clear up those, and then obviously, when we get into the minus 3s, it
sounds like it's going to get more contentious. Minus 7 to minus 10, are there any issues that the panel has with
safety and efficacy, regardless of ‑‑
DR.
ROSENTHAL: Excuse me.
DR.
WEISS: Yes, Dr. Rosenthal.
DR.
ROSENTHAL: I just want to clarify what
I was ‑‑ a risk benefit analysis, Mrs. Lochner has told me, does
take into account other options. But
you are not to compare the option. You
are to use a clinical judgment to say whether or not you feel that a certain
range would be appropriate for this device.
DR.
WEISS: Minus 7 to minus 10, can we have
a vote for those who would feel that this is safe and efficacious if the
endothelial cell data shows such for minus 7 to minus 10.
(Vote
taken.)
DR.
WEISS: So we have a majority of the
panel who feels it would safe and efficacious for minus 7 to minus 10. Minus 10 to minus 15, can we have a similar
vote, with some prompting by Dr. Macsai.
That's all right. We'll use you
for other votes here, Marian. I'm
enlisting you.
(Vote
taken.)
DR.
WEISS: This is in favor of. So minus 7 to minus 10, and minus 10 to
minus 15, it is safe and efficacious.
How about minus 6?
SPEAKER: What?
DR.
WEISS: I know who I'm dealing with
here.
SPEAKER: Excuse me.
DR.
WEISS: Minus 6, how many of you ‑‑
I'm not going to go the minus 3 to minus 7 range, because there's going to be
possibly a breakdown, so I avoid breakdowns.
SPEAKER: Call a vote.
DR.
MACSAI: Can I ‑‑
DR.
WEISS: Yes, Dr. Macsai.
DR.
MACSAI: If we're looking at efficacy
and safety, and we have a guidance document that exists for minus 3 to minus 7
for safety and efficacy, and we look at this group, which is how we've broken
out minus 3 to minus 7 or 6.9 ‑ I don't remember ‑ compared to the
guidance document, okay. You can
eliminate the endothelial issue. It
meets the criteria, safe and effective.
DR.
WEISS: So you would ‑‑ you
feel for minus 3 to minus 15, it's safe and efficacious. So we can go to minus 3‑minus 7. Let's go to minus 3‑ minus 7. Minus 3‑minus 7, can we have a vote by
hands for those who feel that this is safe and efficacious.
MS.
THORNTON: One, two, three, four, five,
six.
DR.
WEISS: Hey, it's a good day.
DR.
MACSAI: You may not put it in your eye,
but it meets the guidance.
DR.
BANDEEN‑ROCHE: May I just say
something for the record?
DR.
WEISS: Dr. Bandeen‑Roche.
DR.
BANDEEN‑ROCHE: I just want to
make clear that I was abstaining because I don't feel like I have the clinical
expertise to make the complicated risk benefit decision that you seem to be
asking for.
MS.
THORNTON: Yeah. Then I'd like to have a negative vote, are
there any other abstenders?
DR.
WEISS: We're going to have a vote for
minus 3 to minus 7, those who did not feel it had evidence of safety and
efficacy. Dr. Schein, Dr. Matoba, Dr.
Mathers and Dr. Coleman. And then we
had one abstention by Dr. Bandeen‑Roche.
MS.
THORNTON: Okay. I've got it. That's minus 3 to minus 15.
DR.
WEISS: Minus 3 to minus 15 at this
point. Are we finished with that
question, Question 5. So we're going to
go to Question 7 ‑ additional labeling recommendations. What I will do is, interest of time, is
mention some of those that have been brought up already, and see if there's
consensus or disagreement. There was
one comment about adding in the labeling that the stability of the endothelial
cell count has not been documented.
That might be a moot point if a condition for approval is getting the
four year data.
DR.
SCHEIN: It's not moot.
DR.
MACSAI: It's not moot at all.
DR.
SCHEIN: There's still going to be
labeling of whatever goes out there. If
we approve it with condition of acquiring that data post‑approval, then
that would have to be in there.
DR.
WEISS: Fine. So we'll include that.
Dr. Grimmett had indicated white‑to‑white is not sufficient
to determine the lens size. I don't
know that that would go into labeling.
Dr. Macsai wanted non‑Caucasian eyes from the Dominican Republic
included. Dr. Coleman.
DR.
COLEMAN: Yeah. I wanted to include that
long‑term risk for glaucoma are unknown, and then to also in the table
that they have on page 20 of 25, they have glaucoma there too. And I would change that to elevated
interocular pressure, ocular hypertension, whatever definition they use. And also, for the interocular pressure
greater than 25 or greater than 10 ‑‑
DR.
WEISS: Can you ‑‑
DR.
COLEMAN: Slow down.
DR.
WEISS: Slow down a little.
DR.
COLEMAN: I have one, and I think that
that's misleading because they had five patients that had pressures of greater
than 25, or greater than 10 millimeter increase during baseline to 36 months. And so I think it's misleading just to use
that last visit, because pressure does vary, and we don't just use one ‑‑
DR.
WEISS: So tell me what you want.
DR.
COLEMAN: So I want IOP greater than 25,
or greater than 10 increased from pre‑op. And I want the exact number, which is 5, instead of 1. And so that would be a percentage of 1.4
percent instead of 0.2 percent. This is
in table ‑‑
DR.
WEISS: I'm going to actually need you
to write this down, because it's going too quick for me.
DR.
COLEMAN: Okay.
DR.
WEISS: Dr. Macsai had included data
about halos and wanted to include data about patients having complaints of
halos and glare.
DR.
MACSAI: Can I elaborate?
DR.
WEISS: Okay. Yes, Dr. Macsai.
DR.
MACSAI: I also wanted to include limbal
pathology as an exclusion criterion. I
mean, the same as a pterygium, you can't measure white‑to‑white.
DR.
WEISS: I'm just wondering if the
Sponsor had any patients with pterygias or things along ‑‑
DR.
EDYLMAN: I think in general, most of
those ociopathology was excluded.
DR.
WEISS: Okay. So that's fine. Dr.
Grimmett had suggested having something in labeling about a learning curve, that
there's a learning curve of the surgeon with a higher rate of upside down
lenses and cataracts, and surgeons with less experience.
Dr.
Macsai had also requested, and I don't know ‑‑ this may not go on
labeling, but had requested that the 65 excluded eyes was ‑‑ if you
could elaborate on that.
DR.
MACSAI: Sixty‑five eyes with pre‑existing
conditions were included in the study.
It would be nice to know what were the pre‑ existing conditions,
what happened to those patients. It
would give the implanting surgeon and patient tremendous information, so let us
know what happened. What were the pre‑existing
conditions, and what happened to those patients?
DR.
EYDELMAN: There was actually a section
in the PMA that talked about that.
DR.
MACSAI: Oh, I missed it. Sorry.
We'll include it then.
DR.
WEISS: So we don't have to get involved
in that then.
MS.
THORNTON: You want that included in the
labeling?
DR.
MACSAI: Yeah, in the surgeon's
information.
MS.
THORNTON: Okay.
DR.
WEISS: Dr. Schein, Dr. Matoba, and then
Dr. Bradley.
DR.
SCHEIN: I would like to see the more
severe complication rates reported on a per‑patient basis, rather than on
a per‑eye basis.
DR.
MATOBA: Under patient precautions,
pigment dispersion should be listed.
DR.
MACSAI: Can you talk a little louder?
DR.
MATOBA: Yes. Under patient precautions or relative ‑‑ yeah, under
patient precautions, I would like pigment dispersion to be listed. I don't think it is right now. And on page ‑ let's see ‑ L‑36,
which is the beginning of the patient information draft, the third paragraph
where they mentioned the term "phakic interocular lens surgery", I
don't think that the average patient knows what phakic means. That term should be explained. It never comes up again as you go on reading
it. It should be explained, and I think
there should be a clearer discussion of the alternative treatments for myopia.
And
then lastly, on page L‑43, "List of Adverse Events and
Complications", I think they should ‑‑ even though it was not
observed in the study, I think they should mention the possibility of
endophthalmitis and loss of the eye, even though it's very rare, but that's
risk with interocular surgery.
DR.
WEISS: Dr. Ho, and then Dr. McMahon.
DR.
HO: Allen Ho. I would propose that the
labeling include the increased risk of vision loss from retinal
detachment remains unknown.
DR.
WEISS: Well, the risk, not the
increased risk.
DR.
HO: Yes, I'm sorry. The risk.
DR.
WEISS: Dr. Bradley, then Dr. Sugar,
then Dr. Bandeen‑Roche.
DR.
MACSAI: You missed McMahon.
DR.
WEISS: Dr. McMahon. Excuse me.
DR.
McMAHON: I'd like to bring up a
completely new issue, and that is, I have a problem with the name of this
device. This device has nothing to do
with a contact lens, and I think it is a disservice to the public by using this
term. I think it's a Euthanism probably
from the marketing department gone hog wild.
And I would like to see all mention to this in the device and labeling
removed.
DR.
MACSAI: What?
DR. McMAHON: The word "contact lens" I want removed from the name
and all labeling.
DR.
WEISS: Doctor ‑‑
Sally. Sorry.
MS.
THORNTON: I'm Dr. Sally.
(Laughter.)
DR.
WEISS: AT this point, I'll give out
free M.D.s just ‑‑
MS.
THORNTON: It sounded like part with Dr.
Phil and Dr. Ruth.
DR.
WEISS: Your book comes out soon.
MS.
THORNTON: I also think we need to get
some comments on the labeling from the consumer representative.
MS.
SUCH: Now?
DR.
WEISS: Now is as good a time as any.
MS.
SUCH: Okay.
MS.
THORNTON: Before we leave this subject.
MS.
SUCH: Good. Glenda Such. A couple of
things. One is, I could ask a question
first and that is, precautions ‑‑ excuse me. On the precautions versus the
contraindications, there's a mention about ‑‑ we have just brought
up also about retinal detachment. And I
wonder if there shouldn't be something in the contraindications about retinal
detachment. How long after retinal
detachment should you not have this process?
That actually should be in there.
Also
‑ I just went blank.
DR.
WEISS: I believe it was an absolute
contraindication for inclusion into the study, so we don't ‑‑ we
won't change that. And that would be up
to an individual physician if they intended to use this in ‑‑
DR.
MACSAI: It's not a contraindication.
DR.
WEISS: A retinal detachment is not a
contraindication?
DR.
MACSAI: No.
DR.
HO: Correct. The definition was stable retinal exam, so that ‑‑
you can have a very stable retinal exam post retinal detachment, and in fact,
after a retinal detachment surgery, you may be at less risk for a problem,
i.e., retinal detachment if you have it, so I'm comfortable with that. To answer your question, Glenda, I would say
‑‑ I would leave that to surgeon discretion really.
MS.
SUCH: And not have it in the patient ‑‑
DR.
HO: Not have a specific time frame.
MS.
SUCH: Okay. I was just concerned about that.
The other is something that's very small housecleaning part. It's on the same issue as the phakic, and that
is talking about in the very beginning of the patient brochure, they talk about
that it's 3‑D to 20‑D before they get into what a diopter is. And let me tell you, most people wouldn't
know a diopter from a hole in the wall, so that should be spot up right
away. And even though there's a mention
about that there's a glossary, most patients won't look at the glossary unless
they really, really a very, very academic minded, so anywhere you can, to write
out the actual words, even though I know it's going to add to printing cost to
actually write out the words. That's
the majority I have right now, this very moment.
DR.
WEISS: Just in terms of the patient
information, I had ‑‑ looking at the labeling, I think it should be
listed in patient information that the higher myopes should not expect the same
results as low myopes, because this reduces, does not correct myopia. I'd like long term effect on the endothelium
is not known. And in mentioning ‑
sort of following up on Dr. McMahon's comment ‑ in the glossary, there's a definition, Collamer ICL is a collagen‑
based contact lens. I have to say,
that's the name of this device, but if I ‑‑ I think the average
person, if they see Collagen‑based contact lens, that certainly invokes
something different than an interocular lens, which we're discussing. I'm not sure how to address that issue, but
Dr. Bradley will tell me.
DR.
BRADLEY: Yeah, two points. One, on the issue of naming, I agree with
Dr. McMahon. I think calling this a
contact lens will be grossly misleading to the public. They already have a sense of what a contact
lens is. It's well‑defined. This is not a contact lens. It never will be a contact lens, and to tell
the public that it is, I think is misleading.
So perhaps we could take a vote on that, if there's some contention over
that.
Second
issue, in spite of what Dr. Schallhorn assured us this morning, the issue of
pupil size still concerns me with this product. I mean, it has a small optical zone. An optical zone size that would not be considered safe for
standard refractive surgery. And even
with the larger optical zones used in current LASIK, we're still concerned that
the procedure might not be appropriate for people with very large pupils. And I wonder if some labeling for this
particular device should also warn the physician and the patient that if they
happen to have large pupils, this device may cause them problems at night.
DR.
WEISS: Well, I think what would be more
accurate to say is the effect of pupil size is not known, because we have no
evidence that it does or doesn't. Sally
has pointed out to me, I could see the National Enquirer headline saying I got
endophthalmitis from my contact lens.
Those weren't her exact words, but distancing herself from my comments
already, didn't take long. Dr. Coleman,
Dr. Grimmett.
DR.
COLEMAN: So for patient labeling
issues, I also wanted to recommend, concerning putting in that they may need to
use medications chronically to control eye pressure, because a lot of the
patients had ‑‑ they had like ‑‑ they have so far two
patients that have needed to use topical beta blockers chronically for their
ocular hypertension.
DR.
WEISS: Well, wouldn't it be more fair
to say glaucoma is a risk, than to tell you what the treatment is going to be?
DR.
COLEMAN: They haven't shown that you've
gotten glaucoma. They're just
describing that you've gotten high eye pressures. And according to them, they didn't have glaucoma. They just ‑‑ that's why I wanted
to change that labeling, because the risk of glaucoma is unknown. They weren't really ‑‑ they
aren't doing visual fields, and you don't see anything about the optic
nerve. And so you really can't say
anything about glaucoma. They aren't
doing angle evaluations. I mean, they
aren't doing a glaucoma evaluation, so they really ‑‑
DR.
WEISS: Okay. The agency will describe it.
DR.
COLEMAN: Yeah.
DR.
WEISS: Okay. Any other ‑‑ yes.
Go ahead.
MR.
CROMPTON: Just a little fair balance
from the industry rep on labeling, is FDA really does work closely with the
Sponsors on labeling. And a lot of the
comments that I'm hearing, these kind of generic comments that aren't specific
to the study here, really can be addressed in precautions, black box warnings,
things like that. And I know that all
companies want to represent the product correctly.
When
we get into trade names of products, that is a matter of some concern to
companies and the agency. And I think
the agency guides that, rather than the panels. So trade names get into patent issues, copyright, all that sort
of stuff. As long as claims are not
being misrepresented, I think that is a key thing.
DR.
WEISS: The only problem is that contact
lens is ‑‑
MR.
CROMPTON: I understand the issue.
DR.
WEISS: I would say that's somewhat
deceptive.
MR.
CROMPTON: I understand the issue, and I
think FDA has a lot of practice dealing with companies in terms of how they
name their products.
DR.
WEISS: Ralph, do we need ‑‑
does the panel need to get involved in this issue, or does not?
DR.
ROSENTHAL: (Nodding head no.)
DR.
WEISS: Fine. I had two things on the physician labeling. Is on page 6, there's a discussion of
calculation of lens power. I'd ask the
panel and the agency, should they be specifying the two formulas that they
specifically used in this study, or just say calculation of lens power? Do you think it would be helpful to specify
the formulas that they used, or not really?
Anyone. Dr. Sugar. No, just leave it as is.
Page
14, they indicate the post‑op regime should be Ocuflox and Tobradex. I don't think that it has to be specifically
‑‑ there's no reason why they have to use those particular
drugs. And I think that could read that
the post‑op regime used in the PMA were those drugs. Does anyone disagree with that? No? Any other labeling?
DR.
GRIMMETT: I have a question.
DR.
WEISS: Yes, Dr. Grimmett.
DR.
GRIMMETT: Is the agency going to obtain
stratified data by lens optic size on the symptom data, the halos and
stuff? Yes. Okay. Moot point.
DR.
MACSAI: That's what I asked for.
DR.
GRIMMETT: I just want to make sure it's
stratified.
DR.
WEISS: Does anyone want to have any
warning in there that 20 percent of patients fell out of the usual endothelial
cell loss, and had a higher rate of endothelial cell loss? Dr. Schein.
DR.
SCHEIN: I think the most direct thing
to do is simply to show some data at a level that the people reading this would
understand. Maybe a histogram of cell
counts at baseline and at 3 or 4 years.
DR.
WEISS: Dr. McMahon has pointed out to
me that there's a ‑‑ I have one list of questions, and he has
another. And on his other, a very
important question that has been not handled by panel at this point, so I'm
going to jump around. It is, do the
safety and efficacy data for eyes with pre‑operative myopia of greater
than 15 to 20 support approval in this refractive range? We've gone up to 15.
MS.
THORNTON: We voted on that.
DR.
ROSENTHAL: You just did efficacy. I would like to hear your discussion on
safety issues, other than endothelial cell counts, which you're addressing
globally.
DR.
WEISS: Above 15. We've gone up to 15, but we omitted above 15
to 20. Those had a higher rate of loss
of best corrected vision. I think we ‑‑
we did talk ‑‑ what do you specifically want us to address, because
I have highlighted that the panel did say it was efficacious for reduction of
myopia over minus 15.
DR.
ROSENTHAL: The other safety issues.
DR.
WEISS: The other safety ‑‑
is the panel satisfied with the safety profile, aside from endothelial cell
counts, in this group of higher myopes?
Dr. McMahon.
DR.
McMAHON: I have some concerns in that
in almost all categories, there's a higher incidence of troubles, if you're
looking at the troublesome categories, and the numbers are relatively small. I think it was 57 eyes, and so I have my
concerns about that. And actually would
like to see either more data to expand the range to 15 to 20 that demonstrates
an acceptable safety profile, or to exclude it.
DR.
WEISS: Does anyone else have any
concerns? Dr. Mathers, then Dr.
Coleman.
DR.
MATHERS: But I think in this particular
group, this device has a very, very strong appeal, because there is nothing
else that can help these people besides a contact lens, so in the risk benefit
ratio, I think that this is ‑‑ it's my own opinion that this
actually has the best risk benefit ratio of any of the other degrees of myopia,
because nothing else is available.
DR.
WEISS: I apologize. As I recall, I think 100 percent of people
in that group would have it done again, so even though the satisfaction wasn't
the highest, they had the highest rate of deciding they made the proper
decision, probably particularly for the reason that you mentioned, that if you
have a majority of those people ending up 20/40, that's probably a miraculous
result for them.
DR.
MATHERS: The alternative treatment is
clear lens extraction, and this is preferable.
DR.
WEISS: Dr. Coleman, then Dr. Ho, then
Dr. Bradley.
DR.
COLEMAN: Yeah. I just wanted to point out that in this
group, the incidence of pressures greater than 10 millimeters of mercury over
from baseline was greater. It's about 4
percent versus the 1.4 percent.
DR.
WEISS: So, I mean, that could be ‑‑
and this is separate, and I apologize for digressing, but it probably ‑‑
I mentioned putting in the patient information that the high myopes didn't have
the same level of efficacy, and we should also probably indicate they had a
higher level of risk at the same time.
Dr. Ho.
DR.
HO: Yeah. Dr. Mathers makes a very good point. The issue here for those 28 eyes that were over 15 diopters is ‑‑
I'm, you know, very concerned about the possibility of retinal detachment with
any kind of procedure in those large myopic eyes. But if you look at those that are willing to do it again, it's
very telling. I think it was, as you
mentioned, zero out of 28 were not willing to do it again. And the point of the other procedure being
clear lens extraction, I think potentially could be fraught with more
risk. And that's why I'm supportive for
this group.
DR.
SCHEIN: Jayne.
DR.
WEISS: Dr. Schein.
DR.
SCHEIN: This could be dealt with in
labeling by simply saying this is the highest risk group. Notice, one of the people that wanted to
have it again had a macular detachment, isn't seeing very well. Now how do you interpret that?
DR.
WEISS: Hope springs eternal. Dr. Bradley.
DR.
BRADLEY: Just to clarify a point Dr.
Mathers made. I think you perhaps meant
to say these people have no other surgical options. They clearly have other options.
DR.
MATHERS: Contact lens, and spectacles.
DR.
WEISS: You get terrible vision
though. DR. BRADLEY: They don't work very well.
DR.
MATHERS: But yes, it's something.
DR.
WEISS: Dr. Bandeen‑Roche.
DR.
BANDEEN‑ROCHE: Would someone
briefly speak to the clinical significance of the trace anterior subcapsular,
so in other words, between those and the nuclear cataracts, there were 13.5
percent in this group who had a cataract of some type. And is that an acceptable trade‑off?
DR.
WEISS: Dr. Eydelman, can you speak to
that?
DR.
EYDELMAN: The slide is up.
DR.
WEISS: Okay. Great. Well, you know, we
are speaking though a very small number of eyes.
DR.
EYDELMAN: Thirty‑one.
SPEAKER: They're at risk for cataract in any case.
DR.
WEISS: I'm not sure what conclusions
can be reached on that small number.
DR.
MACSAI: They're at a greater risk for
nuclear sclerotic cataract.
DR.
WEISS: Dr. Macsai.
DR.
MACSAI: Oh, sorry. Dr. Macsai.
These patients are at greater risk for nuclear sclerotic cataracts at an
earlier age, whether or not they have this implant ‑‑ this device
implanted.
DR.
WEISS: So I would suggest that this
could be handled in ‑‑ the sentiment I'm getting is that there
aren't a lot of good options, that even though the safety and efficacy were not
as good as other ranges, this could be addressed in labeling to let the
patients know that their expectations should be less. I see some nodding by the panel, so that will be good enough for
me.
And
we already indicated that we wanted this to be listed as reduction of myopia,
as opposed to correction. Dr. Sugar had
mentioned a couple of other things.
There is something in patient and physician labeling, indicating that
this device improves the quality of vision.
I think you mentioned reduction as opposed to correction, if we're
talking about contrast sensitivity or rather than just saying the quality of
vision. Am I correct on that, Joel?
DR.
SUGAR: Well, I can't speak to why the
Sponsor put it in there, but they did, I think, ask the patients about their
quality of vision. I don't think that's
sufficient. I think you could say it
may improve the quality of vision, but then they should put the data in.
DR.
WEISS: And then you wanted a brochure
with a picture of the device and the positioning. Anything else in the labeling?
I think we answered above 15 to 20.
Dr. Grimmett.
DR.
GRIMMETT: Let's take a vote on it.
DR.
WEISS: I don't ‑‑ I mean,
unless you want to vote, Ralph?
Fine. Above minus 15 to minus
20, excluding endothelial cell data, who would agree that this shows safety and
efficacy?
(Vote
taken.)
MS.
THORNTON: Six for.
DR.
WEISS: Six for, and who would ‑‑
DR.
ROSENTHAL: Four there, three there ‑
that is seven.
MS.
THORNTON: Well, why don't you
count. I can ‑‑ one, two,
three, four, five, six, seven. You're
right. Seven for.
DR.
WEISS: And those would disagree with
safety and efficacy, please raise your hand.
MS.
THORNTON: Two against.
DR.
SCHEIN: There's this problem that I
would vote for approval, but I don't think it's particularly safe.
DR.
WEISS: Well, it's both. It's a marriage, safe and efficacious.
DR.
SCHEIN: Yeah, that's the problem.
DR.
WEISS: So life is full of ‑‑
so would you vote for ‑‑ with those two, safe and efficacious,
would you vote for approval or not?
DR.
SCHEIN: Presuming all the information
is in the labeling, I would vote for approval.
DR.
WEISS: Okay. Fine. Eight‑one. Any other labeling issues? Okay.
Seeing no other labeling issues, does the FDA have any other questions
that they want the panel to address?
MS.
THORNTON: Last chance.
DR.
WEISS: Last chance. Okay.
Seeing no other questions, then we are going to go to our open public
hearing. And seeing no one for the open
public hearing, we will now move on from that.
I hear applause, so that might have been the correct decision. FDA closing comments. No closing comments. I think everyone has been beaten into
submission. Sponsor closing
comments. Ah, FDA closing comments.
DR.
CALOGERO: Yes. Hi there, Don Calogero. I'd like to clarify something. I think there's a little sort of confusion
here in terms of these rates. And we
were throwing out rates, Dr. Macsai threw out rates, 1.8 percent, ANSI is 2
percent, the panel gave a rate of 1.5 percent, all in the same ball park. But the rate that you threw out, 1.8 percent
and Gerry calculated 2 percent, those are mean rates. The rates from ANSI and the rates from that panel discussion are
the upper 90 percent confidence intervals.
So in terms of ANSI and that discussion, the upper 90 percent confidence
interval needs to be below that point.
If
you look at the upper 90 percent confidence interval of the data out to three
years, it's actually about 3‑1/2 percent. So you're saying 3‑1/2 percent, then is acceptable. If you look at the Sponsor's data, from year
3 to year 4, at the upper 90 percent confidence interval, they have met that
criteria of 1.5. It's 1.42 or
something.
The
only problem that I hear from the discussion about that data is, it may ‑‑
that group may not be representative of the entire population. You may sort of a sampling bias or
something, so I just want to point out that there's sort of a little
miscommunication here, or confusion.
The actual rates that the Sponsor has from year ‑‑ three
months to three years are very different than the levels that ANSI has, and ISO
has, and was recommended previously by the panel, so I just wanted to clear
that up.
DR.
GRIMMETT: Thank you.
DR.
WEISS: Sponsor closing comments.
DR.
SLADE: The battery on our laptop is not
up to the length of your discussion.
DR.
WEISS: That comforts me, Dr. Slade.
MS.
THORNTON: Do you want the projector on?
DR.
SLADE: Yes. We would like the projector on.
I really appreciate you all staying to listen to my talk. Okay.
There. Okay. And what I would like to do is give you our
closing comments from the Sponsor.
Excuse me just a minute. This is
not actually my computer. Is the toggle
F10? F8. Okay. Super.
Let's
just go right to the chase to our comments.
What do we know, and what do we not know about this PMA and this
device? What are the current standards
of requirements for safety of the corneal endothelium for any device? And what do we know about endothelial safety
for this particular device? What
information do we have to support a determination of reasonable assurance with
post‑market labeling and follow‑up, a reasonable assurance of
safety today, and how do we best add to the evolving knowledge‑base in
this area over time, a needed area, a needed area for our patients.
We've
looked at the standards for endothelial cell safety. The ANSI standards of 1‑1/2 percent. You add the .6 percent, somewhere around 2
percent, and we don't have any targets for hexagonality, or coefficient of
variation, although we've seen that those can be the most sensitive indicators
of endothelial stress. That's what we
know is the standard.
Endothelial
safety with the ICL, we have a cumulative total mean loss of 8.4 to 9.7
percent. We do have suggestion of
endothelial cell stabilization, or a leveling of cell loss between 3 to 4
years. We have it with two different
cohorts, the 57 eye cohort, and the 37.
While those aren't our largest numbers, those are our best models. The 37, for example, are the people who made
every single visit, so it's the best models, and we can certainly post‑
marketly follow that particular cohort up.
And
then in addition to that, in addition to that, we have the percent hexagonality
and the coefficient of variation data, which easily supports the absence of
chronic endothelial stress. This is
that 37 eye cohort I just mentioned.
And if anything, it's trending to a leveling‑out, or certainly no
farther down.
It's
important to look at these again. This
is the percent of hexagonal cells.
Anything over 45 percent is a winner, and this is clearly, throughout
the entire follow‑up, over that, and it's stable. It's not dancing around.
The
coefficient of variation is the same thing.
Anything that is not above 45 is, again, a winner. And this does fit into that to the adequate
confidence intervals, and it's stable.
It's stable over time, just like the visual acuity results, just like
the refractive stability that I showed you.
Further,
if you're trying to figure out the safety of this lens, I would challenge you
to postulate a clear mechanism for chronic endothelial cell loss due to the
clinical procedure, which is cataract surgery with a lot of the steps left out,
or the ICL, the material itself, which is a proven approved material behind the
iris. We have no evidence of
inflammation over time when assessed with the most sensitive methods we have
today. Don Sanders, I think, made that
point clear. And we have no evidence of
corneal stress or instability based upon the most sensitive measures of morphology
by I think who we ‑‑ the person, Henry Edelhauser, who we all
respect, over time. Again, you've seen
the morphology of endothelial cells. If
we look at the cell flare study, at no point in time did we ever get the cohort
outside the normal range. That's
significant.
Further,
I think we should stress again what Hank Edelhauser presented to us. There's a change. We're learning about our understanding of the corneal
endothelium. There does appear to be a
reservoir of endothelial cells in the corneal periphery, based upon his lab,
and earlier confirmatory studies.
There's even the good evidence for peripheral corneal endothelial stem
cells, even in adult corneal tissue.
And again, Dr. Edelhauser, I think, has well‑documented this, just
the simple references, the fact of increasing cells. And then when we make our incision into the cornea, we're not
even approaching where we have most of these safety cells, which is superior.
Further,
our understanding of the corneal endothelium, I think we've all struggled
today. And if anything, it's proven
that a linear modeling of endothelial cell loss over time is difficult based
upon our current knowledge‑base.
The non‑homogenate
endothelial cell density, the presence of an endothelial cell reserve in
the periphery, including the stem cells, and the potential for these cells to
migrate from the higher density periphery to the lower density central
endothelium further supports reasonable safety for this device.
From
Dr. Edelhauser, the higher endothelial cell density found in the paracentral
and peripheral cornea affords an additional reassurance of safety beyond the
morphology for the endothelium in patients implanted with the ICL. The surgical incision for the ICL is
corneal, and temporal, and it's at a distance, and it's only a couple of clock
hours away from the largest endothelial reserves which reside in the superior
corneal.
So
to finish this out, what do we know today?
And we actually know, I think, a fairly good deal. Well, we realized, and we continue to
realize the need for additional options, additional good clinical options in
refractive surgery. And one note about
this ‑ the beauty of this is it's a non‑dose dependent
procedure. LASIK, the more LASIK you
do, the more trouble you run into. This
is the same procedure, the same lens, whether it's a minus 3 or minus 15, or a
minus 20.
Endothelial
morphology represents a highly sensitive measure or indicator of corneal
endothelial stability, and I think we've seen the results, seen the studies
that back that up. And in the ICL
population, I don't know how the results could be any better. It clearly indicates a stable endothelium
without stress by morphology.
We
believe the stabilization of endothelial cell loss occurs between three to four
years. We have the absence of any cases
of corneal decompensation in ten years of history greater than 30,000 implants
internationally. Again, as I mentioned,
I don't know if we got all of the data from those patients, but I do believe
that the first person that had a corneal decompensation would be quite ‑ ‑
we'd know about that.
There
is a iron‑clad Sponsor commitment to continued specular microscopy
data. I don't have a financial interest
in STAAR. I wasn't an investigator in
this study. I am a paid consultant, but
I can assure you of their commitment to continue the collection of specular
microscopy data post‑market approval, in all study patients through five
years or beyond with the same rigor of analysis, the same lab, the same Dr.
Edelhauser looking at the specular microscopy images.
So
a long‑term commitment to surveillance of study patients for all safety
findings. A well‑developed
training program. Now we've had the ‑‑
you know, is this something that only the creme de la creme surgeons can
do? Well, remember when LASIK came
along and everybody would say well gee, that's pretty crazy. You know, only corneal surgeons should be
doing that. And it just didn't pan out
that way.
I
would submit to you that that was a procedure where surgeons had to learn new
steps. This, they don't. It's all cataract steps. I do believe strongly, having been involved
in directing the LASIK courses, that the training program will be excellent and
superlative beyond what we've had before.
And finally, the Sponsor is totally committed to labeling to encompass
your recommendations, no matter how many volumes, or how the package insert
becomes. And that to the panel and the
FDA, to provide further assurance of safe use of the ICL.
I
submit to you that the clinical data presented in the PMA does establish the
effectiveness of the myopic ICL for the correction or reduction, as labeling ‑‑
as we are dictated to by you for labeling, between minus 3 and minus 20. And I submit to you that the clinical
outcomes presented in this PMA provide a reasonable assurance of safety of the
myopic ICL in this patient population, this study designed for moderate to high
myopia. Thank you very much.
DR.
WEISS: Thank you very much, Dr.
Slade. I would like to thank the
Sponsor for an excellent presentation, the primary reviewers, and the member of
the panel, as well as the agency for the usual detailed evaluation of the data,
and now we will move to the voting options, which will be read by Sally
Thornton.
MS.
THORNTON: "The Medical Device
Amendments to the Federal Food, Drug and Cosmetic Act as amended by the Safe
Medical Devices Act of 1990 allows the Food and Drug Administration to obtain a
recommendation from an expert advisory panel on designated medical device pre‑market
approval applications that are filed with the agency. The PMA must stand on its own merits, and your recommendation
must be supported by safety and effectiveness data in the application, or by
applicable publicly available information.
Safety
is defined in the Act as reasonable assurance based on valid scientific
evidence that the probable benefits to health under conditions on intended use
outweigh any probable risk.
Effectiveness is defined as reasonable assurance that in a significant
portion of the population, the use of the device for its intended use is in
conditions of approval when labeled will provide clinically significant
results.
Your
recommendation options for the vote are as follows. Number one, approval, if there are no conditions attached. Number two, approvable with conditions. The panel may recommend that the PMA be
found approvable, subject to specified conditions, such as position or patient
education, labeling changes or a further analysis of existing data. Prior to voting, all of the conditions
should be discussed by the panel. Not‑approvable. The panel may recommend that the PMA is not
approvable if the data do not provide a reasonable assurance that the device is
safe, or if a reasonable assurance has not been given, that the device is
effective under the conditions of use prescribed, recommended, or suggested in
the proposed labeling.
Following
the voting, the Chair will ask each panel member to present a brief statement
outlining the reasons for their vote."
Thank you. Jayne.
DR.
WEISS: Thank you. I'd like to have someone make a motion. Dr. Sugar.
DR.
SUGAR: I'd like to move approval with
conditions with the volumes of conditions that Steve Slade mentioned.
DR.
WEISS: Well, one of the ‑‑
MS.
THORNTON: Well, you can't do that.
DR.
SUGAR: I know, but Jayne has them all
listed on her computer, and she can give us the words.
DR.
WEISS: Okay. Do we have a second for approval with conditions? Dr. Mathers and Dr. Macsai second it. There were two conditions, there was a
choice of one condition that I think we do need to have the panel list. We will, of course, vote on the secondary
motions, the conditions, before we vote on the primary motion. But the secondary motion, as far as data to
be included for specular microscopy and when that would be needed ‑ I
need someone to phrase that for me, because there was a disagreement among the
panel, and I need that to be included here.
MS.
THORNTON: Are you calling for a
condition now?
DR.
SUGAR: Yes.
DR.
WEISS: What is your ‑‑
DR.
SUGAR: With the condition that after
approval, data continue to be acquired on endothelial cell density on an annual
basis, up to a minimum of five years.
MS.
THORNTON: Is there a second?
(Seconded.)
DR.
WEISS: So there's a second for the ‑‑
and can you repeat that condition, Dr. Sugar, because what ‑‑ if
it's all right with agency, before we go on with additional ‑‑
MS.
THORNTON: We can discuss it after the
second.
DR.
WEISS: Okay. Can you repeat what that motion is and then we're going to have
discussion of that. And the a vote of
that condition.
DR.
SUGAR: Approvable with conditions. One of the conditions being that data
continue to be acquired on an annual basis on endothelial cell density to at
least five years.
DR.
WEISS: Can you ‑‑
DR.
GRIMMETT: For clarification, he's
recommending approval now, post‑market later.
DR.
ROSENTHAL: Approval now, and the
endothelial cell data will be collected after the approval ‑‑
DR.
SUGAR: Correct.
DR.
ROSENTHAL: ‑‑ for four and
five years. And longer, if need be.
DR.
WEISS: Okay. So approval now, and I would like the panel to be extremely clear
when they vote on this. This is
approval now, and then the endothelial cell count data will be collected
afterwards, after approval. We will
have a discussion, and Dr. Bradley will have the first point. After we have discussion of this secondary
motion, we will vote on the secondary motion before we go on to other labeling. Dr. Bradley.
DR.
BRADLEY: I thought in our earlier
discussions that approval was going to be conditional upon the four year data
convincing us that, in fact, endothelial count decline was not at a dangerous
level.
DR.
GRIMMETT: Then vote against this
motion.
DR.
WEISS: This is why I wanted a
particular motion put forward for a vote.
If you disagree with this, as Dr. Grimmett so kindly pointed out, then
you vote that you disagree. And if you
agree with it, then you vote that you agree.
Is there any discussion, aside from when you disagree you vote no, and
when you agree you vote yes. I assume
not, so Dr. Ho.
DR.
HO: Allen Ho. I would like to add to that, as part of discussion, that the
annualized rates of retinal detachment be included.
DR.
WEISS: This is separate. That's a separate condition. This is not, as Dr. Slade indicated, we will
have a volume coming up. But hopefully,
it will be done shortly enough. This is
just this particular point. Dr.
Bradley.
DR.
BRADLEY: A question ‑‑ the
motion is that the data be collected post approval.
DR.
SUGAR: That's correct.
DR.
BRADLEY: Do you have any desire that
something specific be done with the data once collected, or is that irrelevant
to your motion?
DR.
SUGAR: It's certainly not irrelevant. I
don't know how specific we need to be with that, but the data be reviewed by
the agency and apropos of our discussion, if the endothelial cell density
continues to decline at the same rate, that the issue be represented either to
the panel, or that there be some further discussion about whether approval
should be continued.
DR.
WEISS: Just for clarification, Ralph,
what would the ‑‑ aside from the statement that Dr. Sugar just made
as far as collecting the data, do you need any further clarification at this
point from the panel what we mean by collecting the data, what we want you to
do with the data, or that would be sufficient for you at this point?
DR.
ROSENTHAL: I think we understand the
mood of the motion.
DR.
WEISS: Okay. The mood ‑‑
DR.
ROSENTHAL: The question is, and I'm not
sure I can give you an answer, is if the endothelial cell count continued to
drop at 4 and 5 years, I'm not sure what our options would be. And that is something we would have to take
up with higher order people in the agency.**
DR.
SUGAR: Well, could not rescind
approval?