DEPARTMENT OF HEALTH AND HUMAN SERVICES
FOOD AND DRUG ADMINISTRATION
CENTER FOR BIOLOGICS EVALUATION AND RESEARCH
BLOOD PRODUCTS ADVISORY COMMITTEE
FRIDAY, MAY 2, 2008
The meeting came to order at 8:30 a.m. in the Plaza Meeting
rooms of the Hilton Washington DC Rockville, 1750 Rockville Pike,
FREDERICK P. SIEGAL, MD, CHAIRMAN
MARK BALLOW, MD, MEMBER
HENRY M. CRYER III, MD, PHD, MEMBER
ADRIAN M. DI BISCEGLIE, MD, MEMBER
MAUREEN A. FINNEGAN, MD, MEMBER
SIMONE A. GLYNN, MD, MSC, MPH, MEMBER
MATTHEW J. KUEHNERT, MD, MEMBER
ROSHNI KULKARNI, MD, MEMBER
CATHERINE S. MANNO, MD, MEMBER
KATHERINE A. MCCOMAS, PHD, MEMBER
FRANCISCO J. RENTAS, PHD, MEMBER
ANDREA B. TROXEL, SCD, MEMBER
ANN B. ZIMRIN, MD, MEMBER
This transcript has not been edited or corrected, but appears as received from the commercial transcribing service. Accordingly, the Food and Drug Administration makes no representation as to its accuracy.
JUDITH R. BAKER, MHSA, CONSUMER
THOMAS P. ATKINSON, MD, TEMPORARY VOTING
ANDREA J. APTER, MD, TEMPORARY VOTING MEMBER
THOMAS R. FLEMING, PHD, TEMPORARY VOTING
B. GAIL MACIK, MD, TEMPORARY VOTING MEMBER
IRMA O. SZYMANSKI, MD, TEMPORARY VOTING
TABLE OF CONTENTS
TOPIC II: Lev Pharmaceuticals Inc.
Clinical Trial for the Use of Plasma-
derived C1 Esterase Inhibitor (Cinryze)
for Prophylaxis of Hereditary Angioedema
A. Introduction...................... 8
B. Lev Pharmaceuticals Presentation
i. Introduction................ 16
ii. Unmet need and patho-
iii. Clinical Program........... 40
iv. Clinical Considerations
For Patient Care........... 59
C. FDA Review of Clinical Data..... 132
D. Statistical Issues
Open Public Hearing....................... 158
Open Committee Discussion................. 204
TOPIC III: Review of the Research Programs in
the Laboratory of Hepatitis and Related
A. Overview of CBER Research....... 239
B. Overview of OBRR Research....... 253
C. Overview of the Division of Emerging
and Transfusion Transmitted
D. Overview of the Laboratory of
Hepatitis and Related Emerging
E. Questions and Answers........... 289
Open Public Hearing....................... 294
Adjourn to Closed Discussion
CHAIRMAN SIEGAL: Okay, here we go. Good morning. I'm Fred Siegal, the Chair of BPAC at this moment. I would like to welcome all of you who were not here yesterday to us today. We have some new temporary voting members today, Dr. Thomas Atkins, Andrea Apter, whom we mentioned yesterday, Tom Fleming who was here, Larry Borish who wasn't here yesterday and the others have been introduced already. Perhaps we should go around and introduce those of us who weren't here yesterday. Introduce yourself.
DR. ATKINSON: I'm Prescott Atkinson. I'm a Pediatric Immunologist at the
DR. BORISH: Larry Borish, I'm a Professor of Medicine at
the University if
DR. APTER: Andrea Apter, Professor of Medicine, Allergy
DR. BALLOW: Mark Ballow, Allergy and Immunology, SUNY
DR. CRYER: Gil Cryer,
DR. DI BISCEGLIE: Adrian DiBisceglie, a Hepatologist at
DR. FINNEGAN: Maureen Finnegan, Orthopedic Surgeon, UT
DR. GLYNN: Simone Glynn, NHLBI.
MS. BAKER: Judith Baker,
DR. ZIMRIN: Ann Zimrin, Hematology,
MS. TROXEL: Andrea Troxel from the Biostatistics at the
DR. RENTAS: Frank Rentas, Blood Services,
DR. McCOMAS: Katherine McComas, a Professor of
DR. MANNO: Catherine Manno, a Pediatric Hematologist at
Children's Hospital in
DR. KULKARNI: Roshni Kulkarni, Professor of Pediatric
DR. FLEMING: Thomas Fleming, Professor of Biostatistics,
DR. SZYMANSKI: Irma Szymanski, Professor of Pathology, U
Mass, now working in
DR. MASCIK: Gail Mascik, Hematologist,
CHAIRMAN SIEGAL: I'd like to mention that unfortunately Lou Katz, our non-voting member from industry had to leave and I know that there are a number of members who have flights to catch and they have to leave a little early but as long as you can stay, we hope that you can because we do have to vote on the last part of this meeting.
So, let's proceed. I'm sorry, Mr. Jehn would like to make a statement.
MR. JEHN: Yes, I just have a conflict of interest statement for me today. This brief announcement is in addition to the conflict of interest statement read at the beginning of the meeting on May 1st and will be part of the public record for the Blood Products Advisory Committee meeting on May 2nd, 2008. This announcement addresses conflicts of interest for Topic II on the committee discussion, review and recommendations on Lev Pharmaceutical Incorporated clinical trial for the use of plasma derived C-1 esterase inhibitor, Cinryze for the prophylactics of Hereditary Angioedema Attacks. Based on the agenda and all financial interests reported by members and consultants related to Topics II, conflict of interest waivers have been issued to Dr. Mark Ballow in accordance with 18 US Code 208, Section 3, and 712 of the Food and Drug and Cosmetic Act. Dr. Ballow's waivers include a consulting arrangement with a firm that could be affected by the today's discussion of Topic II. The waivers allow Dr. Ballow to participate fully and vote on the committee discussions
For Topic III, the committee will hear an overview of the research programs in the laboratory of hepatitis and related emerging agents to vision and emerging in transfusion transmitted diseases. There is no conflict of interest involved with this overview. This conflict of interest statement will be available for review at the registration table. We would like to remind members and participants that if the discussions involve any other products or firms not already on the agenda for which an FDA participant has a personal or imputed financial interest, the participants need to exclude themselves from such involvement and their exclusion will be noted for the record. FDA encourages all other participants to advise the committee of any financial relationships that you may have with any firms, its products and if known, its direct competitors. Thank you.
CHAIRMAN SIEGAL: Thank you, Don. So let's proceed to Topic II, Lev Pharmaceuticals, Incorporated clinical trial for the use of plasma-derived C1 esterase inhibitor (Cinryze) for the prophylaxis of heredity angioedema attacks. The introduction will be given by Dr. Felice D'Agnillo of FDA. Dr. D'Agnillo.
DR. D'AGNILLO: Okay, good morning, everyone. My name is Felice D'Agnillo. I'm a Product Reviewer for the Office of Blood Research and Review at the FDA. The topic of discussion today is the original license application sponsored by Lev Pharmaceuticals for C1 esterase inhibitor derived from human plasma. This is indicated for use in individuals with hereditary angioedema. This is a rare but very serious disease associated with a deficiency in the functional levels of this inhibitor.
My role today is going to be to provide a very brief introduction and to briefly describe the product. Dr. Golding, also from the FDA, who will be speaking immediately following the sponsor, will describe the regulatory chronology of this application and he'll give an overview of the clinical studies that were performed and then discuss issues related to efficacy, safety, and immunogenicity.
So I'd like to start off by just saying a few brief words on the protein. Again, C1 esterase inhibitor is a plasma protein. It is a member of a family of proteins called Serpins and this is short for serine protease inhibitor. The plasma concentration is in the range 180 micrograms per ml. It's molecular weight is 105 kD based on SDS-Page analysis. It's a heavily glycosylated protein and like Serpins in general, it contains in its structure a reactive site loop shown here which plays a very important role in the inhibitory function of this molecule. And the way this works is that serine proteases cleave this loop at this amino acid residue and the protease remains attached to the inhibitor and subsequent to a confirmational change in the inhibitor, the active site of the protease is distorted and it loses its function.
Now, unlike most Serpins that tend to regulate one serine protease, C1 inhibitor is able to regulate a number of important serine proteases in the plasma. These include, among others, C1s, the pointer is going down a little bit, C1s and C1r. That in conjunction with C1q form a C1 complex which play -- which regulates the classical compliment pathway. C1 inhibitor also regulates Kallikrein, Factor 12 and 11, that play roles in the coagulation and Kinin generation pathways and C1 also inhibits Plasmin and tissue Plasminigen activator which play roles in the fibrinolytis. Now before I move onto the next slide, I'd like to make one more point and that's that the inhibition of the disregulations of the Kinin pathway is very important in that it leads to uncontrolled production of bradikinin levels and bradikinin is a vasodilator and it's believed that the levels of bradikinin, the uncontrolled levels of bradikinin play an important role in the etiology of the disease which I'll describe in my next slide.
Hereditary angiodema is an autosomal
dominant disease. It has a low incidence
and it's estimated that there are about 10,000 individuals in the
The attacks can last from a period of hours to days and as I mentioned, this disease is caused by a deficiency in functional levels of C1 inhibitor. Now, there are two types of the disease. The most prevalent form of the disease, Type 1, is associated with a decrease in the production of the inhibitor. Type 2 is associated with normal or elevated levels of production but the protein is mutated and dysfunctional. And this is further illustrated in the next slide where this table shows some laboratory markers used to classify HAE. In Type 1, as I just mentioned, the production of C1 inhibitor is decreased and we're going to need a -- the production of C1 inhibitor is decreased and this leads to decreased levels of functional C1. In Type 2, production can be normal or elevated but the protein is dysfunctional. So this leads to decreased functional levels of the inhibitor in the plasma.
Now in both these cases, this is typically associated with a reduction in compliment four levels in the plasma, but C3 and C1 levels are typically normal. Now, another angioedema listed on this table is estrogen dependent inherited angioedema. This used to be called Type 3 HAE but this is very distinct from HAE in that there is no deficiency of the C1 inhibitor.
As far as some of the approaches to manage HAE, avoidance of known triggers, such as estrogens and ACE inhibitors is important. Some therapeutic interventions include anti-fibrinolytic agents to control the fibrinolytis. Attenuated androgens have been used to increase the production of C1 inhibitor and fresh frozen plasma replacement is also an approach -- it is also an option but the risk/benefit associated with this therapy is sometimes questioned and finally, C1 inhibitor replacement therapy has been used in Europe for many years, but in the US this therapy has only been available under IND.
And this brings me to the C1
inhibitor product that we're going to be discussing here today. It's a produce sponsored by Lev
Pharmaceuticals with the trade name Cinryze, and this is a lyophilized
preparation of the protein derived from human plasma and it's manufactured
under contract to the Sanquin Blood Supply Foundation in the
It's manufactured from US licensed source plasma and the manufacturing process contains two dedicated independent viral reduction steps that include heat treatment at 60 degrees for 10 hours and nanofiltration. And a third polyethylene glycol precipitation step has also been shown to remove viruses. And this is illustrated in the next table.
This table shows log reduction factors in various virus reduction -- virus spiking studies using enveloped and non-enveloped viruses and without getting into -- we've analyzed the data and without getting into all the details, we feel that these results show that the steps provide very effective viral clearance. Now, I'm going to end my very brief talk on that note but before having the -- but before listening to the more detailed presentations that are to follow, I'd like to present the questions that we would like the committee to consider today.
And Dr. Golding will also be repeating these questions at the end of his talk. Question 1, is the safety and efficacy evidence sufficient for approval of Cinryze for prophylactic treatment of HAE? Question 2, if the answer to question 1 is yes, should post-marketing studies be performed to further evaluate the following, the optimal dose for prophylaxis in males and females, immunogenicity, and long-term safety?
CHAIRMAN SIEGAL: Okay, thank you Dr. D'Agnillo. We're now going to hear from Lev Pharmaceuticals. I'd ask the presenters to keep in mind that you have not longer than an hour to present your case. Thank you.
MR. BABLAK: Good morning.
My name is Jason Bablak, and I'm Vice President of Regulatory Affairs
and Product Development at Lev Pharmaceuticals.
We are excited to be here today to Cinryze, human C1 inhibitor for the
treatment of hereditary angioedema. HAE
is a chronic debilitating and potentially life-threatening disease that has a
profound impact on the lives of patients and their families for which there is
no adequate treatment option available in the
After this introduction, Dr. Michael
Dr. Paula Busse, from
Cinryze is a highly purified C1
inhibitor. Cinryze is manufactured by
the Sanquin Blood Supply Foundation, formerly the Central Laboratory of the
Dutch Red Cross. Sanquin has a 36-year
history of producing successive generations of C1 inhibitor products, including
the currently marketed product called Cetor, a highly purified pasturized C1
inhibitor which has been available in the
The manufacturing of Cinryze is an
enhancement to the Cetor manufacturing process.
Cinryze is produced from pooled
Cinryze manufacturing includes
multiple steps to insure the safety and quality of the product. Cinryze is derived from
The virus removing capacity for Cinryze manufacturing has been validated and provides reduction of envelope viruses ranging from greater than 16.7 to greater than 19.1 logs. And for non-envelope viruses ranging from greater than 8.7 to greater than 10.5 logs. A study of the nanofiltration step demonstrated that it achieves the complete removal of spiked prion protein with a reduction factor of greater than 4.25 logs as measured by Western Blot.
Two pivotal Phase 3 studies assess the safety and efficacy of Cinryze. The first study was for the treatment of acute HAE attacks and the second was for prophylactic treatment to prevent HAE attacks. Both studies met their pre-specified primary end points and drew upon the same population of HAE subjects initially enrolled into the program.
The clinical program also included a pharmacokinetic study in these subjects who were not experiencing an attack. We are also providing continued access to Cinryze for HAE patients through ongoing open label studies for both acute and prophylactic treatment in which we are collecting additional safety and efficacy information. One hundred and eighty HAE patients have participated in our studies with over 6,000 doses administered. More than 12 subjects have each received over 100 doses extending well beyond one year on continuous treatment with Cinryze prophylaxis.
The clinical development program
demonstrated that Cinryze if efficacious with no reported safety concerns and
an adverse event profile similar to placebo.
The results for both trials were statistically significant, clinically
meaningful and consistent with the experience in
DR. FRANK: Thank you.
Good morning. It's a pleasure to be here today. I was invited to come by Lev because of an
interest in hereditary angioedema and particularly the treatment of hereditary
angioedema that goes back more than 35 years.
What I've been asked to do is discuss the clinical disease, the
pathophysiology, current treatment as it exists in the
As you heard from Dr. D'Agnillo,
hereditary angioedema is an orphan disease.
We don't know the actual incidents, but we think it's one in 10,000 to
150,000 people. It has been estimated
that 6,000 to 10,000 people in the
Now, a company in Europe just a few
years ago did a survey of the same kind of information and in
I'm going to briefly discuss the clinical manifestations which include extremity attacks, abdominal attacks facial laryngeal and genitourinary attacks. This is the kind of attack that effects the extremities. It's in many studies the most frequent attack. On the left is a swollen hand and on the right is a normal hand of the same patient at the same time. As you can see, this attack can be functionally disabling. If it effects that hands, it may impede the use of a keyboard, a phone. If it effects the feet, it can impede walking or driving. It can effect the joints and there can be immobility and dysfunction and discomfort of the joints. But it rarely results in hospitalization. It can interfere with work and school. It's really not the reason we're here today.
The second very common attack in some series the most common is the abdominal attack and this is the reason that we're in part here today. This GI series shows the spiculation or thumb printing of the bowel due to edema of the wall of the bowel which is extraordinarily painful. This can lead to debilitating symptoms, very severe pain, occasionally intestinal obstruction, nausea, vomiting and dehydration. These patients literally climb the wall with pain.
It usually leads to an emergency room visit. It frequently leads to hospitalization and because these patients' pain is so severe, they frequently get operated on even though they don't need an operation at that time, so they have unneeded surgery.
The facial attacks can be temporarily disfiguring as shown in this patient of mine. The picture on the left was taken when the patient was free of an attack and the picture on the right was a Polaroid taken by her husband. It was one of a series and in fact, it wasn't the most serious of the series. This lady was just sitting at home in an armchair while her husband was watching here face get more and more disfigured. In fact, she should have been in an emergency room.
Here is a series of pictures that were taken not by me but quite extraordinary, showing a patient before an attack, as the facial attack proceeds, even more severe facial attack and ultimately leading to intubation in this patient. In fact, this underscores some of our problem. And that is we do not have good therapy to end an attack in this country. So facial attacks can lead to extreme swelling, temporary disfigurement. Subjects of course, tend not to leave their home and the risk of local extension to the larynx is what we're talking about at the present time.
Here is a pair of radiographs. The radiograph on the right is a nine-year old girl who was not having an attack of hereditary angioedema at this time and you can see the normal cervical curve and the open airway. The picture on the left is the same girl during an attack of hereditary angioedema and you can see both the change in the curvature of the spine and the occlusion of the airway in this young girl.
So the laryngeal attacks can be
life-threatening. When we did this first
clinical study, as I talked about earlier, we asked people, "How many
members of your family who had hereditary angioedema died of the disease by
choking to death"? And the answer
was 30 percent. That was a long time
ago, and 30 percent is not the figure now, but there are still people who die,
Now, the urogenital attacks also occur and should be mentioned. The typical triggers are sexual intercourse or local trauma. You can get swollen genitalia. You can even have painful urination or be unable to urinate because of swelling in the region of the urethra. So the impact on patients' lives of this disease is really quite extraordinary. It's a life-altering disease. It interferes with work, school and their social life.
Attacks typically last two to five days but they can last up to nine days. They can move from place to place, a hand, a foot, et cetera. It's been estimated that patients, some patients lose up to 100 days of school or work a year. There are about 15,000 emergency room visits annually in the United States it's been estimated and it is frequently misdiagnosed. This leads to unnecessary surgery and the treatment, as we have now, as we'll talk about in a minute, is really ineffective. We have ever-present risk and there is a major psychological impact and that's worth a few more words.
These patients have anxiety, depression and feelings of isolation. Many of them have seen members of their family choke to death of a disease that they have that can't be adequately treated. The abdominal pain is so severe that these patients learn to go into the emergency room and get narcotics and a very frequent problem with this patient group is narcotic addiction which is very difficult to deal with.
Now, the diagnosis is straightforward if you have a typical clinical diagnosis. In fact, the first attacks usually occur in childhood and often the disease is missed in childhood. It usually gets much worse at the time of puberty, both in males and females. The clinical findings we've discussed and Dr. D'Agnillo discussed some of the laboratory findings. The C1 inhibitor is functionally low. The C1 itself is normal because the inhibitor is now present, but C1 is present. C4 and C2 are low typically and C3, the most common laboratory compliment protein that's studied is always normal in these patients.
There is no correlation between C1 inhibitor levels in disease burden and I'll show you that in a second. As I've mentioned, the family history is not reliable because of the new mutations and so we usually are helped by a family history but it doesn't make the diagnosis.
The C1 inhibitor level and severity of attacks is interesting. In our original studies, we divided patients into patients that we considered having very serious disease and patients having very mild disease. The normal range is shown in green and the red dots are the patient who have a protein but it does not have normal function.
As you can see, there's no correlation between the seriousness of attacks and the level of C1 inhibitor and this, I think, is a reflection of the fact that we do not understand every aspect of the pathophysiology of this disease at the present time and we can talk about that later if there's any interest.
As Dr. D'Agnillo mentioned, C1 inhibitor is a Serpin, serine protease inhibitor and inhibits many different systems in the blood. It inhibits the compliment system, multiple proteins is shown in yellow. It inhibits the contact activation systems factors 12A and 12F. It inhibits the clotting system, the Kinin system, and the Fibrinolytic system inhibiting both plasma and tissue Plasminigen activator. We believe it's the Kallikrein system that's critical in the development of attacks of swelling in hereditary angioedema as I'll show on the next slide. Now, here is a complicated slide showing some of the aspects of the Kinin generating and Factor 12 system and I'm not going to go through it in detail.
The first thing I'm going to mention though is that all of the yellow x's are places where C1 inhibitor can function. And so you see it functions in many places in this complex system of biochemical steps. Let's turn our attention to the dotted box. As you can see in this box, we have prekallikrein, which gets activated to kallikrein. Kallikrein is an enzyme capable of cleaving high molecular kininogen and releasing Bradikinin. It is that step that we think is critical in the development of hereditary angioedema. The generation of Bradikinin is not inhibited. Now, as you also heard, C1 inhibitor is a suicide inhibitor. It's a single chain molecule that presents a bate sequence shown as a white triangle in this slide. The bate sequence is cleaved by the enzyme which is show as a Pac Man in this slide that I drew. And when this happens, the yellow triangle, a highly reactive group within the molecule, becomes available, binds to the enzymatic site and destroys the enzyme. So the C1 inhibitor is used up during this process and the product of one normal gene and one abnormal gene is not sufficient to keep you from having attacks.
Well, triggers are highly variable in this disease. Usually patients don't know what brings on an attack except about a third of patients know that physical trauma will bring on attack and that may be mechanical pressure or repetitive motion. A seamstress who uses a pair of scissors repeatedly will find that her hand swells up or someone who uses a power lawn mower will find that their hands swell up. Similarly, infection can bring on an attack. Strep throat can bring on an attack in the throat.
Emotional stress is another thing that's very interesting and that we don't understand. But emotional stress can have a major impact in the frequency of attacks. Hormonal influences are also important. We were the first to describe estrogens worsening the severity of the disease and occasionally you can have a woman who you just take off birth control pills and their disease becomes much better. Most of the referred patients are women probably reflecting this importance of estrogens in making the clinical symptoms of the disease worse.
So what are the current therapies? We haven't got time to go into this in great detail given the one hour, but I'd like to say a word about prophylaxis and a word about acute treatment. I was the one that introduced impeded androgens for prophylaxis. We published a double-blind study on the use of danazol and we showed that it's efficacious in prophylaxis. I put down that it has limited utility here because I want to talk about that in detail. It is useless in acute settings.
First of all, it takes at least two days before it starts to have a biological effect. And it's only -- danazol and the other impeded androgens are only available orally. What I mean by that is that if you have a patient with an abdominal attack, and their bowel is swollen, you really can't give them an oral medication and expect it to have an effect. It's contra-indicated in both pregnancy and children, and pregnancy because there can be masculinization of the fetus, in children because it can be premature closure of the epiphysis. And finally, in some people it's ineffective. Some people simply don't respond to androgens. The side effects of androgens, I think, are probably well-known to this group. It causes weight gain. It causes lipid abnormalities regularly and that includes elevated LDL, decreased HDL. It can have psychological effects, feelings of aggression, changes in libido, both in men and in women. In women, it can cause virilization in some women, certainly menstrual irregularities. Since it was developed, danazol was developed as a contraceptive.
It can cause muscle toxicity. Hepatocellular abnormalities including
transaminase elevations are frequent but occasionally patients will develop
adenoma and even carcinoma has been described and these patients are taking
these drugs for decades. All hereditary angioedema patients are at
risk for acute attacks and prophylactic treatment is not completed
preventative. I had a patient who was
not mine, who came into the Duke Emergency Room about a year ago on 600
milligrams of danazol a day and proceeded to be unable to intubated and had to
have an emergency tracheotomy. So
triggers vary over time, breakthrough attacks occur and I believe that there's
no adequate acute treatment approved in the
So what do we do for acute attacks? Well, for abdominal attacks, we give narcotics and we've talked about that. For laryngeal attacks we use supportive therapy. We use epinephrine which has limited efficacy in this disease. We use intubation or tracheotomy if it's necessary.
Fresh frozen plasma has been mentioned and I'd like to say another word about it. It has been reported to be effective in many case reports. I would say that 90 percent of people get better with fresh frozen plasma, but if you think about it, you're giving C1 inhibitor and at the same time you're giving high molecular weight kininogen, the substrate of kallikrein which will lead to more greater kinin production. I and I think everyone who have seen many people treated, have seen people get worse on fresh frozen plasma and I personally believe it's contra-indicated.
Antifibrinolytics have been used. EACA we were the first to do a double blind study with EACA and I don't want to talk about it in detail except to say that, yes, it works and yes, the toxicity profile is even worse in the androgens. We use antihistamines and steroids. They're commonly used. There really isn't any evidence of efficacy but the antihistamines do have sedating properties. What about C1 inhibitor?
Obviously, it's the protein that's
low and so it's disease specific treatment.
It's widely used in
We published our first studies with C1 inhibitor in the treatment of hereditary angioedema in 1980 in the New England Journal of Medicine. That was 28 years ago. And we reported at that time, that it was effective in the treatment of the disease but this was not a double blind study. In 1996, we published a double blind study with the last Fred Rosen, using an immuno-product, a product that's no longer available. We published the prophylactic side of the study and Fred Rose actually did the acute side of the study and I'm going to talk about the prophylaxis.
We brought in a group of six patients into the hospital who had severe hereditary angioedema and had failed all therapy. We treated them every three days as you can see by the red triangles on this slide. The C1 inhibitor concentration rose rapidly as shown in yellow and then fell rapidly reflecting its about two-day half-life. It does not have a very short half-life in the circulation. It does not have a very long half-life in the circulation.
Placebo, as you can see in blue, had no effect. If we follow the level of C4 as we did in these patients, what we found was that the C4 gradually came up into the normal range and stayed there and the effect of placebo, again was negative. It didn't have any effect. These patients who were very severely ill, having about five attacks per month, responded to the C1 inhibitor and got better. They didn't respond completely. They still had about -- occasional attack but at least 60 percent of their attack frequency was decreased.
Frankly, when I published this data, I thought that C1 inhibitor would become available for use in this country but in fact, that was 12 years ago and it's still not available. We did not find antibody in our patient population. So in conclusion, we think that there's an unmet need, at least I do.
European patients have had access to C1 inhibitor for decades. There are many papers, mostly uncontrolled on the -- on saying that C1 inhibitor is effective and no papers that say it's not effective. It works in acute therapy as I've said. It works in prophylaxis. It has demonstrated safety and efficacy and there has been 36 years of experience with this drug. Thank you.
DR. KALFUS: Good morning.
I'm Dr. Ira Kalfus, Vice President of Medical Affairs at Lev. I have worked extensively in the development
of Cinryze and I'm pleased to be here with you today. The pivotal studies demonstrated the safety
and efficacy of Cinryze in the treatment of hereditary angioedema in the
Numerous studies have demonstrated
the activity of 1,000 units of C1 inhibitor for treatment of acute
Based on the documented experience with Cetor, the Cinryze dose was 1,000 units in both pivotal trials. For long-term prophylaxis the dosing frequency is twice weekly reflecting the roughly two-day half-life of C1 inhibitor. A randomized parallel group open label pharmakinetic study of Cinryze in asymptomatic HAE patients confirm the expected half-life. Subjects receive either a single dose of 1,000 units or 1,000 units followed by a second injection 60 minutes later. The mean half-life of Cinryze was 56.5 hours for a single does and 62.2 hours for the double dose. The intravenous administration of Cinryze demonstrated a temporary increase in plasma levels of C1 inhibitor within one hour of administration.
Traditional Pharmakinetic methodologies are difficult through the variable levels of endogenous C1 inhibitor as well as the variable utilization of both endogenous and exogenous C1 inhibitor. The clinical benefit of Cinryze is demonstrated in two pivotal trials. Based on the European Cetor data, and consultations with FDA, we conducted two pivotal multi-center Phase 3 studies, both of which included and open label rescue option. The acute treatment trial was a randomized placebo controlled double-blinded study designed to evaluate the efficacy and safety of Cinryze as a therapeutic agent for treating acute attacks of angioedema. The prophylactic treatment trial was a randomized placebo controlled double-blinded cross-over study designed to evaluate the efficacy and safety of Cinryze as prophylactic treatment to reduce the incidence, severity and duration of HAE attacks.
To enter the Phase 3 program, subjects needed to be at least six years old and have a documented history of HAE based on evidence of a low C4 level plus either a low C1 inhibitor antigenic or C1 inhibitor functional level. Subjects could also be enrolled with a documented HAE causing mutation, HAE causing C1 inhibitor mutation, excuse me. The same pool of enrolled subjects was the source of subjects for both the randomized acute and prophylactic trials.
Exclusion criteria included B-cell malignancy, presence of an anti-C1 inhibitor antibody, history of allergic reaction to C1 inhibitor or other blood product. Narcotic addiction, participation in any other investigational drug study within the past 30 days, participation in a C1 inhibitor trial or having received blood or blood product in the past 90 days, pregnancy, lactation, for any clinically significant medical condition such as renal failure that in the opinion of the investigator would interfere with the subject's ability to participate in the study.
After pre-qualification, to confirm the diagnosis of HAE, subjects presenting to a clinical site within four hours of the onset of an acute HAE attack were evaluated for potential randomization. Subjects who were experiencing a laryngeal attack received immediate open-label Cinryze and remained eligible for randomization for a subsequent attack.
Subjects with an attack limited to their extremities, were treated with standard medical and did not receive Cinryze. These subjects also remained eligible for randomization of a subsequent attack. Subjects presenting with either moderate or severe attacks that involved the GI system, face or genital urinary system were randomized to be treated in a double-blinded fashion with either 1,000 units of Cinryze or an identical volume of normal saline placebo.
A second injection of the same study drug could be given in 60 minutes if the attack had not started to resolve or was getting worse. Subjects were evaluated for four hours following the initial injection of the study drug. Open label Cinryze could be given as rescue therapy if the subject had not reported onset of relief by four hours or if the subject had airway compromise at any time.
Subjects were eligible for a second dose of open label rescue medication if they had not responded to the initial rescue dose within one hour. The primary end point of the acute treatment trial, the median time to unequivocal onset of relief, was positive with a P value of 0.026. After randomization into the acute trial, subjects were eligible to enter the prophylactic trial if they had a prior history of at least two HAE attacks per month. This was to insure that the trial would have a sufficient number of events for analysis.
In addition, subjects were required to have had no change in the androgen or EACA dosing within 30 days of trial entry. Once enrolled in the prophylactic trial, no changes in the dose of androgens or EACA were permitted. All subjects were enrolled and randomized into the prophylactic treatment trial prior to completion and unblinding of the acute treatment trial. The prophylactic trial was a randomized double-blind placebo controlled cross-over, multi-center study. Subjects received two periods of 12 weeks of treatment for a total of 24 weeks. During the first period, half the subjects received placebo, while the other half received Cinryze in a blinded fashion. At the end of the first 12-week period, the subjects crossed over such that those who had been receiving placebo received Cinryze and vice versa. There was a treatment-free interval of two to 11 days between the last dose of blinded study medication in the first period and the first dose in the second period.
Subjects were eligible for open label rescue for any acute attack. The subjects who enrolled in the trial were reflective of the presenting HAE population. The mean age was 38 with a range of nine to 73 years. The majority of subjects were female and white. There were no notable differences between the treatment sequence periods in terms of demographic characteristics. The results from the controlled prophylactic study demonstrated a statistically significant and clinically meaningful reductions in disease burden. The protocol specified enrollment was 24 subjects with a goal of 20 being evaluable in the efficacy set. Twenty-four subjects were enrolled and treated with randomized study medication. Two of the 24 subjects were excluded from the efficacy set because they failed to complete the first period of the study and did not cross over to receive at least one treatment in the second period of the study. The remaining 22 subjects crossed over and were treated with both Cinryze and placebo and are therefore, included in th efficacy set. Two of the 22 subjects included in the efficacy set withdrew prior to completion of the second period.
The remaining 20 subjects completed the entire 24 weeks of the study. The protocol defined primary end point of the prophylactic study was the normalized number of attacks of angioedema per day during each treatment period using subjects as their own controls. The number of attacks consisted of all angioedema that occurred during treatment, irrespective of whether the subject received Cinryze -- or the label Cinryze or not. An angioedema was defined as the period between the development and resolution of symptoms of
angioedema. Attacks involving a progressing to multiple sites were considered to be single attacks. Analysis of the data demonstrated a statistically significant and clinically meaningful difference between the Cinryze and placebo periods.
Subjects treated with placebo experienced a mean of 12.7 attacks over the 12-week treatment period compared to a mean of 6.3 attacks for those subjects treated with Cinryze. This demonstrated a 51 percent reduction in the total number of attacks with a P value of less than 0.0001 without regard to the severity, duration or location of each individual attack.
The interpretation of a cross-over design is clearest when there are no period or sequence effects. The results show no evidence of these effects in this trial. A per patient analysis demonstrated the consistency of the effect. Because each subject was his or her own control it is helpful to look at the attack frequency during the Cinryze blinded treatment period and compare it to the attack frequency during the placebo treatment on a per patient basis. Twenty of the 22 subjects showed improvement, though one of the 20 had only a minimal reduction in attack frequency. The secondary end points consistently support the conclusions of the primary analysis.
All secondary end points were statistically significant. The P values demonstrate that there was a significant difference in the severity of attacks, the mean number of open label injections administered for acute attacks, the duration of attacks and the total number of days of swelling. Each of the end points demonstrated a clinically meaningful benefit. Represented is the median of the percent difference in placebo minus Cinryze. There is a consistent benefit from treatment with Cinryze.
The primary end point was the reduction in the number of attacks and the effect favored Cinryze. Severity of attacks was reduced by 26 percent. The number of open label infusions of Cinryze was reduced by 97 percent. The duration of attacks was reduced by 21 percent and the number of days of swelling was reduced by 75 percent.
The 95 percent confidence interval of these changes demonstrate the robustness of the benefit of Cinryze. In addition to the efficacy demonstrated in the protocol defined analysis, looking at median percent differences by treatment period, the positive effect of Cinryze treatment is also apparent for the majority of subjects when the data is analyzed on a subject by subject basis.
For the primary end point of the number of HAE attacks, 91 percent of the subjects showed positive results on the Cinryze period. For the secondary end point of attack severity, 85 percent of subjects showed improvement. Ninety-five percent of subjects experienced a reduction in the number of Cinryze open label rescue treatments. The percent of subjects experienced a reduction in the duration of attacks with 77 percent and 95 percent of subjects had a decrease in their total days of swelling. And event chart allows us to look at the time course of events and treatment by individual subject.
For example, here is subject number 51001. The clinical course is represented along each line with placebo treatment period on the upper line and the Cinryze treatment on the lower line. The magenta bars represent days and severity of swelling. The yellow bars represent open label treatments with Cinryze and the gray dots indicate scheduled blinded treatments.
Duration of individual attacks are represented by contiguous magenta bars. The height of the magenta bars reflect the severity of swelling and the length of yellow bars represent the number of open label doses administered. Looking at the results of every subject individually reveals the benefit of Cinryze on a per patient basis. On the left are individual subject identification numbers. The preponderance of color on the placebo side of the graph reflects the extent of swelling and the need for open label treatment. By contrast, the Cinryze size of the graph has less color reflecting the benefits seen in the majority of subjects.
Cinryze was successful in the
prophylactic treatment of hereditary angioedema. The study met its primary end point and every
secondary end point with reductions in disease burden that were statistically
significant and clinically meaningful.
Cinryze treatment reduced the frequency of attacks, the severity of
attacks, the number of open label treatments required, the duration of attacks
and perhaps most importantly, the total number of days with swelling. These effects were consistent in the
prospectively defined protocol analysis by treatment group and were confirmed
by graphical analyses of individual subject data. The safety of Cinryze has been demonstrated
in the US Phase 3 pivotal studies which showed the safety profile of Cinryze to
be similar to that of placebo. The
safety is further supported by the ongoing open label studies and years of safe
No drug interactions or
contraindications have been identified with Cinryze or with C1 inhibitor
products in general. Cinryze was
administered to 96 unique subjects in the placebo controlled and PK studies. This includes the acute treatment study, the
prophylactic treatment study and a 27-subject PK study. In total, these subjects received 1413, 1,000
unit doses of Cinryze. Overall, more
than 6,000 injections of Cinryze have been given in the
During the acute study, the most common adverse events were mild. Six subjects had treatment emergent adverse events in the Cinryze arm and seven subjects experienced treatment emergent adverse events in the placebo arm of the acute treatment study. The most common treatment emergent adverse event reported was sinusitis which occurred in two subjects both on the Cinryze arm. There were also two reports each of nausea and decreased blood pressure which were evenly split between arms. Twelve subjects who did not randomize to Cinryze or placebo received open label treatment with Cinryze. None of these open label treatment subjects had treatment emergent adverse events. There were no reports of serious adverse events during the acute treatment study.
In the prophylactic treatment trial, because all subjects received open label Cinryze while in the placebo period, safety data is presented as an overall analysis reflecting contributions throughout both periods of treatment. This approach conservatively regards all subjects as receiving Cinryze throughout the trial.
Twenty-one of 24 subjects in the safety population had one or more adverse event reported in approximately seven months of treatment and observation. The most common adverse events were upper respiratory infection and sinusitis reported by seven subjects. There were five reports of rash and four subjects reported headache. There were four reports of serious adverse events requiring hospitalization while on treatment during the prophylactic phase and one additional SAE requiring hospitalization was reported prior to dosing with study medication. All the SAEs were attributed to HAE itself or some other unrelated medical condition and resolved without discontinuation of treatment.
There were no deaths during the study. There were no withdrawals from either period of the study due to adverse events. There were no significant changes in clinical, laboratory or hematology findings. Viral surveillance studies demonstrated no seroconversion for parvovirus, Hepatitis B, Hepatitis C or HIV.
There were a significant number of unexpected positive C1 inhibitor antibody results at screening and during treatment which raise questions regarding the validity of the assay. Confirmatory tests showed that only two screening tests were positive and these patients were excluded from the trial. No patients had positive confirmatory tests during treatment. To further support these findings, we are currently in the process of testing all subjects in the open label studies at Sanquin Clinical Reference Laboratory and will provide these results to FDA.
The overall safety profile with
Cinryze in double blind and open studies has been consistently favorable. No Cinryze related SAEs have been
recorded. The type and severity of other
adverse events have been similar between Cinryze and placebo. Adverse events throughout the studies have
been mild. The safety of Cinryze is
consistent with the reported safety of Cetor in
The safety profile of Cinryze is
favorable. There are few treatment
emergent adverse events reported from all studies and those reported on placebo
were of the same type and level of severity as on Cinryze. Five SAEs were reported in the prophylactic
study and another 28 SAEs have been reported in the ongoing open label
studies. All have been determined to be
unrelated to Cinryze. The history of
Cetor use in
DR. BUSSE: Good morning.
My name is Paula Busse and I'm an Assistant Professor in the Division of
Clinical Immunology at
HAE can present unpredictably. There is variability in the type of the attack, severity of the attack, timing of the attack and pattern and frequency of attacks. One example of this variability is the occurrence of a first laryngeal attack. It can occur at any point in a person's life who has HAE. A German retrospective study looked at six fatal laryngeal attacks in patients with HAE. Five of these attacks were the first laryngeal attacks that the patients had ever experienced. This also included a nine-year old boy for whom it was his first HAE attack ever of his life.
The sixth patient had experienced over 100 prior laryngeal attacks. This demonstrates the importance of educating patients and their families about the unpredictability of HAE and the ever-present risk of a laryngeal attack even in a person who has never experienced a laryngeal attack or any HAE attack previously.
While HAE is hereditary, genetics alone do not determine the course of the disease. A good example of this is a case report on twins -- monozygous twins, both of whom had HAE. These identical twin sisters were in fact, genetically indistinguishable but their disease was phenotypically different. Each twin had different triggers of attack, duration of edema and sensitivity to fluctuation of sexual hormones. The authors concluded that beyond genetics multiple factors can influence the manifestations of HAE. Those of us who treat HAE further recognize that similar clinical manifestations can have different impacts on the patients' lives. This makes it essential to understand how the disease effects each patient's life and to treat each patient differently.
The goal of HAE therapy is to allow each patient to live a normal life as possible. We need to individualize each patient's medication regiment. The disease is variable and its effects on patients' lives also vary. Similarly, a patient's response to therapy can vary. Therefore, therapy will vary from one patient to the next. It will also vary over time for any given patient. For many patients, prophylactic therapy is an important option at some time point in the course of their disease. In addition to reducing the physical manifestations of this disease, prophylactic therapy can provide peace of mind for patients and help them lead more normal lives. Several studies have demonstrated that neither the severity of the disease nor the response to therapy is correlated with any biochemical marker or laboratory value.
Two patients may have the exact same levels of the C1 inhibitor but may have completely different burdens or responses to treatment. While decreased functional C1 inhibitor and decreased C4 levels are important for making the diagnosis of HAE, we do not follow these levels during treatment. The actual treatment of HAE focuses upon the management of clinical symptoms and their impact on patients' lives. The current treatment approach recognizes the need for individualizing care. It relies upon a discussion between the patient and the physician. The treating physician can generally not decide a priori which patients will need prophylactic therapy. When we discuss this decision with our patients, there are some well-defined considerations that we must keep in mind.
Those patients most likely to
benefit from prophylactic therapy include those with frequent attacks, rapidly
progressive attacks, and those with a history of a laryngeal attack. Patients who also live in remote areas
without access to emergency rooms or hospitals and those patients who also have
had a history of multiple hospitalizations, ICU's days or intubations are strong
candidates for prophylactic therapy. The
dependency upon narcotics is also another important consideration. Perhaps, most importantly, there are patients
whose diminished quality of life makes them strong candidates for
prophylaxis. These patients, many of
whom cannot otherwise maintain gainful employment or complete school have the
greatest need. I have completed
disability paperwork on one of my patients because she could no longer sit in
an office because of her frequent abdominal attacks. This was in spite of androgen therapy, the only
current therapy that we have for prophylaxis in the
Because of their contra-indications and side effects, androgens are not appropriate for all patients. Patients who should not receive androgens include children, patients with heart disease, and patients who cannot tolerate the side effects. Most women have difficulty taking androgens due to the side effects which include weight gain, unwanted hair growth, and menstrual abnormalities. It is also contra-indicated in pregnancy. While androgens can be effective, they may not completely prevent attacks. Patients are usually dosed to the highest dose to gain control of their symptoms. Then patients are adjusted to the lowest effective dose based upon the frequency of attacks and the patient's ability to tolerate the side effects of these medications.
Patients end up on a wide range of doses because there is substantial variation and response to androgens. We have a patient who had regularly had attacks several times a week. We prescribed and she received high doses of two different androgens. However, neither helped control her attacks. The availability of Cinryze will expand the potential for prophylaxis.
Prophylactic treatment with Cinryze is an important and much needed option for any patient who is a candidate for prophylaxis. In addition, Cinryze will also help patients for whom androgens are ineffective, intolerable, or simply inappropriate. Treatment with Cinryze makes sense. Cinryze therapy is a rational approach to treating HAE because it is a disease specific replacement therapy. The Cinryze dose of two times per week has demonstrated activity in 90 percent of the patients. In clinical practice we will need to dose patients based upon response. As with androgens, we will start with the dose that is effective for the majority of patients. With Cinryze, we see that most patients responded to two times per week dosing. Based upon the individual response, there may be some patients who benefit from a dose frequency modification. All 22 patients from the controlled prophylactic study continue to take C1 inhibitor including my prophylaxis patients. Fourteen of the 22 subjects entered the open label prophylaxis extension study. The eight other patients are importing or self-importing Cetor through a program with the HAE Association. Thirteen of the 14 Cinryze patients have remained on the twice weekly dosing, the 14th patient receiving dosing three times per week. My two patients have remained on the twice weekly dosing. Both of these prophylactic patients had considerably fewer attacks and days of swelling. Neither patient needed any open label rescue treatment while on the Cinryze arm. Witnessing the benefits of Cinryze is compelling.
One of my patients, 06018, has a markedly different profile while on the Cinryze treatment arm. Her days of swelling were reduced from 59 to 2 and the number of rescue treatments were reduced from seven to zero. My other patient has done very well and feels much better. Patient 06001 saw her days of swelling reduced from 17 to zero and the number of rescue treatments reduced from five to zero. Furthermore, she is currently off androgens and doing very well.
While my patients recognize that C1
inhibitor represents the standard of care for HAE, they know it is not a
cure. Even a fully compliant patient may
have a new or amplified trigger such as emotional stress or physical illness or
trauma which cannot be predicted but can cause a breakthrough attack. The goal is to enable patients to live as
normal a life as possible by reducing and preventing attacks. Cinryze significantly reduced the number of
these events. Cinryze works. It has a clearly positive risk benefit ratio
and meets an important unmet medical need.
It is safe and effective. We have
strong evidence from our Phase 3 trial as well as supportive evidence from its
Cinryze should be approved and
available for use in the
CHAIRMAN SIEGAL: Thank you for that discussion. Is there anything that you'd like to add? You have a couple of minutes.
MR. BABLAK: No, we'd be happy to answer any questions from the committee at this time.
CHAIRMAN SIEGAL: Okay, then, this is open for discussion.
DR. APTER: I have a quick question. Why was 1,000 units chosen instead of a dose suggested by weight as most of the protein replacement therapies are?
MR. BABLAK: The 1,000 unit dose was selected based on the European experience with Cetor and the half-life of approximately two days of the drug. I'm going to ask Dr. Kalfus to come up and explain in a little more detail.
DR. KALFUS: As Jason mentioned, the half-life also was consistent with the stabilization of C4 levels demonstrating biological activity of C1 inhibitor. Slide up. When we looked at actual weight and response to weight during the study, we saw that in the scattergram, there actually is no correlation to response to therapy to the weight of the subjects.
DR. APTER: How were HAE episodes identified to go -- to have the required number to go on prophylactic treatment and also how was laryngeal edema diagnosed in the acute trial?
DR. KALFUS: The number -- to obtain the number to the attacks on the prospective trial, that was base on historical record of the patients.
DR. APTER: So not physical exam.
DR. KALFUS: It was not, no, that was based on patient history. And the identification of the evidence of laryngeal tap was basically, I'm not sure, for the treatment it was -- all the treatments for laryngeal attacks were provided by physicians who were evaluating subjects who had presented with complaints of laryngeal attacks and were treated by physicians for laryngeal attacks.
DR. APTER: So you don't have records of soft tissue laterals of the neck or --
DR. KALFUS: No, if the clinical circumstance dictated for whatever time that there was additional testing but there was no required radiographic studies. It was a clinical decision. The subjects were treated clinically and were given Cinryze as rescue therapy. It was not part of the acute trial itself.
DR. ZIMRIN: Why were patients with B-cell malignancies excluded? I'm here.
DR. KALFUS: Sorry. Patients with B-cell malignancies were excluded because B-cell malignancy and other lymphoproliferative disorders are common for the cause for required angioedema. The exclusion in the criteria of B-Cell was to exclude those subjects who happened to have acquired angioedema who could present very, very similarly to hereditary angioedema but their treatment is different. They both require C1 inhibitor. Acquired patients require significantly higher levels of C1 inhibitor.
DR. ZIMRIN: Also, was there any pattern in terms of when the attacks occurred? If you look at twice weekly dose, did it occur on day 7? It didn't look like it from the two patients that I could see in detail.
DR. KALFUS: I'm happy to look at it again. There was no pattern that we noticed on the -- across the board as far as when subjects were having their attacks or not.
CHAIRMAN SIEGAL: Dr. Kulkarni?
DR. KULKARNI: Two questions. What was the volume of the -- you know, the medication and did these patients require central venous access devices for the prophylaxis?
DR. KALFUS: The medication is 10 ccs of 100 units per cc and administered intravenously. These subjects did not require central venous access. It was administered either through a butterfly or through an IV.
DR. MANNO: I'm interested in the inhibitory antibody development. Can you tell us a little bit about how you assay for inhibitory antibodies and what the prevalence is in patients who haven't received the plasma derived concentrate?
DR. KALFUS: I'm going to have Dr. Zuraw to come up to discuss the antibodies. Dr. Zuraw was the principal investigator for the study as well as being an antibody specialist.
DR. ZURAW: Hi, my name is Bruce
Zuraw. I'm a Professor of Medicine at
In my experience, acquired C1 inhibitor deficiency is usually associated with anti-C1 inhibitor antibodies. I've looked at about 50 of my own hereditary angioedema patients and a number of other samples sent to me from around the country and I don't believe that patients with hereditary angioedema have any auto antibodies against C1 inhibitor. I don't think that really does occur.
DR. MANNO: Even after treatment with replacement therapy.
DR. ZURAW: Well, we had an opportunity in this study to look at that and so my lab did look at a number of these patients after therapy and I certainly saw no evidence of antibodies developing, nor in general if you talk to European investigators, who have been treating with C1 inhibitor for quite a long time, there's no relationship between the administration of C1 inhibitor replacement therapy and auto antibodies developing. Remember that this is a disease that's autosomal dominant and the patients all have C1 inhibitor in their plasma.
DR. SZYMANSKI: I was very impressed with the results that
you presented. And it's a very long
missing drug finally coming to the
MR. BABLAK: I'll try an introductory answer to that and then I'll ask Dr. Frank to come up and talk a little bit about the variability but certainly within HAE patients there is a wide variability in terms of the manifestation of the disease. We noticed that some patients, obviously, did not have any attacks while on the Cinryze arm, and other patients, while they had minor attacks, didn't have attacks that required open label Cinryze. There were other patients who did require open label treatment even on the two times a week dosing. I'd ask Dr. Frank to come up and explain a little bit about the variability.
DR. FRANK: Yes, I can't speak to the Cinryze situation but I can speak to variability. This is a highly variable disease in which we don't understand all of the parameters that cause attacks. So for example, someone can have this abnormality in their cord blood and never have an attack until their 70. It's actually well-described. When we developed Danazol for the treatment of this disease, we figured that we would find a dose that was useful in most patients and that would be the end of it.
And in fact, that's not exactly what happened. What happened is we found that many patients responded to 600 milligrams a day. That was a high dose. Some patients responded to 800 milligrams a day. We then started to lower the dose to see what would be the sort of the cutoff point and we found that there wasn't any cutoff point. We found patients that would respond to 50 milligrams once a week which is I would have thought a homeopathic dose.
What happens is that the other factors that we talked about including emotional state, including, I'm sure, things that we have no knowledge of, make an enormous difference in the way that patients respond. When we did our prophylactic study, the one that I told you about, we actually used a higher dose of C1 inhibitor.
The patients were very sick and we got about a 60 percent response rate, but even with a higher dose, we didn't completely turn off attacks.
DR. FLEMING: I had a couple questions and the overall efficacy for the measure that you used certainly appears to be established. Dr. Frank, though provided some very important insights that were consistent with issues that I have been thinking about as I have been reviewing this. He showed us a number of graphs and the graphs included episodes or attacks that involve hands and facial attacks and then he focused very much on the abdominal attacks and laryngeal attacks referring to the sequelae there. ER, is it hospitalization, life-threatening and he said this is why we're here today. So could you show us the results by treatment arm for the events, the attacks that in fact specifically involved ER visits, hospitalizations or were viewed as life-threatening?
MR. BABLAK: The primary end point was looking at total attacks.
DR. FLEMING: I understand.
MR. BABLAK: Not broken down.
DR. FLEMING: So what I'm trying to get at is his point that I very much endorse, why we're here today. In particular, are these more serious? Can you show us by arm, the numbers of attacks that were attacks characterized as involving ER visits, hospitalizations or were life-threatening?
MR. BABLAK: We don't have the data broken down in that type of an analysis.
DR. FLEMING: Well, let me go on then. If you could get that for us, that would be very helpful. The second issue is, when you look at the scale in the FDA advisory or briefing document on pages 21 and 22, the scale of mild, moderate and severe appears to be very non-linear. Your primary end point is treating it as linear, it's scaled 1, 2, 3 and it's looking at average which views it as linear but mild is events or attacks that didn't interfere with daily living, moderate somewhat interfered and severe significantly interfered.
My sense is, looking at all the graphs in CC 12, 14, 16, 17 to 20, 22, 23, and 24 shown to us by Dr. Frank my understanding is these were severe scenarios that you were showing us for those specific symptoms. When you look at patients by severity, for example, Patient 53002, that patient had two attacks on treatment, nine attacks on control, but nearly all of the nine attacks on control were mild. The two attacks -- excuse me, nearly all the attacks that occurred on the control arm were mild. The two attacks that occurred on treatment were severe.
So the impression, when you look at the scale as you're presenting it for that patient is you've reduced from nine attacks to two but in the control, those nine were essentially mild. The two on treatment were both severe. So could you show us the results by treatment arm, if you look at severe attacks? So basically take all the severe attacks and show us how treatment is playing out in terms of reducing the rate of what Dr. Frank said are the kinds of events that we're here today about?
MR. BABLAK: I'm going to ask Dr. Kalfus to come up and respond to that question.
DR. KALFUS: You brought up -- I'm going to start with Subject 53002 that you brought up. Can I have the event plot? This subject actually had two attacks, slide up, please, during the Cinryze treatment arm that actually were of more significant severity than the attacks that she had during the placebo period. What was of note is we actually looked into this. There were only -- there were a couple of patients that we actually have been speaking, when we source data like this and what we found out is if you looked at these attacks from around day 18 to 20, they're on their Cinryze arm, this is actually a high school junior or senior who was having exams and preparing for prom at that particular time.
So while we can't really speak to everything that's going on, because we don't understand everything about this disease, we do know that the physiological triggers and the emotional triggers are such that patient symptoms can manifest differently based upon what's going on. And we believe that this is a possibility that's what happened to this particular patient during that particular time during her treatment period.
If we bring up the event plot or the event chart for all the subjects, you will see that while we haven't broken them down by severity, you can look at the severity of attacks by the slide up please, I'm sorry. The severity of attacks is demonstrated by the height of the magenta slides and just looking at the height of the magenta slides, we'll be able to determine what we did to the severity of attacks from the placebo treatment arm to the Cinryze treatment arm.
DR. FLEMING: If you could provide that, if some time today, you could actually provide an analysis that shows the reduction in the rate if there is one, in severe attacks, that would be very informative.
DR. BALLOW: Just kind of a follow-up if you'd actually put that slide back up, the one you just -- there's two patients actually on the treatment arm were worse and I wonder whether there's anything to learn from those two patients. Were they using any medication, you know, during the trial which may have adversely effected their clinical response to the drug or is there any understanding why those two patients did worse on the treatment arm?
DR. DI BISCEGLIE: And if I can add to Dr. Ballow's question, I was going to ask about the graph that you showed of the number of attacks per person, and there are -- I think it's maybe three in whom the number of attacks increase. Maybe the same that he's referring to.
DR. KALFUS: Different questions and I'll answer them sequentially. Slide up, please. This is Subject 16005. This is one of the two subjects who had an increase of attack. She actually had one increase, one more attack during the treatment period than she did during the placebo treatment period.
Slide up; however, if you look at the secondary end points, we see that despite that fact that she had one more attack, she actually had clinically meaningful benefit in some of the other parameters that we were looking at. Slide up, please.
This is subject 17002, the other subject who had a worsening and actually was clearly and outlier in the study. This particular subject, slide up, had almost double the number of acute attacks, had increased days of swelling, and attacks of shorter duration and had increase in severity. And as we mentioned, there's significant variability of the disease and we don't understand everything about the disease.
We do know that this particular subject had significant stressors during her time on the Cinryze period. She actually lost her job. She had a significant loss of income. Her finances, her business was -- she lost her business. She had to close her attorney practice and she also entered menopause. So there were significant triggers that was going on during this particular patient.
This subject actually continues in the open label extension trial, is on 1,000 units twice a week and because she's such an outlier, we actually have spoken to her investigator because there was a question as to whether he thought that the subject was actually benefitting from the treatment and he said, absolutely the subject is doing extremely well. Her life situation has changed.
She's actually requiring less than half the dose of treatment that she required while on the placebo arm and has had half the number of attacks than she's had on placebo arm. So clearly, this subject actually had a change in her triggers and had a change in her response to therapy.
Can I have the slide up, please. This is, I believe, the slide you were referring to. And it's actually quite interesting. We looked at this slide and we knew the data. We know -- imagine you're looking at the subject near number 6. Slide up. We knew the subject actually had a 1.2 percent differential in the normalized number. That's because he had six attacks and it just wasn't quite a 12-week period. So we drew a line, just to make sure that it was a straight line and this -- you know, this was not an increase. And what we discovered, slide up, was that this is actually an optical illusion. This is the Zollner effect and if you take parallel lines and you intersect them with diagonals, you will actually give the impression that the lines are not parallel.
I don't want to get into the mathematics of this. There's a reference at the bottom. I clearly cannot explain it.
DR. APTER: But these attacks are self-report, correct?
DR. KALFUS: Yes, these attacks are self-report.
DR. BALLOW: So and this individual -- because these individuals were also used for acute therapy as well, correct?
DR. KALFUS: All the subjects in the prophylactic treatment trial were -- had gone through the acute treatment.
DR. BALLOW: Yes, so how did she respond during the acute phase of her attack with Cinryze?
DR. KALFUS: The -- when the subjects were entered into and randomized as the prophylactic treatment trial, the results -- the Part A of the acute treatment trial had not yet been completed or unblinded.
DR. BALLOW: No, no, but I thought that was an open part. In other words, on the prophylactic part of the study, if they had an attack I thought that they were administered Cinryze as an open --
DR. KALFUS: We actually are in the midst of compiling the data across the board for how subjects have been responding to acute label. We have not submitted that data to FDA for review. If we look at some of the other charts, you can see just on responses, days of swelling. Dr. Frank would like to say something.
DR. FRANK: Obviously, I don't have the Lev data but we actually in the trial that I talked about, broke out the attacks by type; abdominal, extremity, laryngeal, et cetera, and all were benefitted by C1 inhibitor.
CHAIRMAN SIEGAL: I have a couple of questions. First of all, can you tell us a little bit more about the case of lymphadenopathy. Did that play out as anything that we can understand?
DR. KALFUS: It was actually, it was more of a -- it wasn't really lymphadenopathy. It was more of an infection that -- it was just an infected node. Somebody had a thyro-glossal duct and it was not related to anything hematologic whatsoever and it's listed as an SAE primarily because she required hospitalization to have that drained and in the course of having that drained, she actually wound up having a port placed.
CHAIRMAN SIEGAL: The other question is, has there been any experience with subcutaneous administration of this product?
DR. KALFUS: There has not been any subcutaneous administration of Cinryze.
CHAIRMAN SIEGAL: Is that something that might be feasible?
DR. KALFUS: It's something that might be feasible. It's nothing that we have actually made any plans for right now.
DR. BALLOW: Can I follow up on that because I was going to ask a related question. These patients are going to be using this at home, I assume, correct?
DR. KALFUS: Currently, the application is for use with a healthcare provider and a home healthcare provider clearly would be --
DR. BALLOW: But eventually, they'll self-infuse, I assume. What happens if it infiltrates? Does it damage any of the tissues? Did you have any feedback on that occurrence?
DR. KALFUS: We have anecdotal references from one or two patients that have had some infiltration and I guess by extension, we have some anecdotal reference on subcutaneous administration via infiltrated IV. The product seemed to work and there were no secondary adverse events from that.
DR. GLYNN: I had a couple of questions, one related to
in terms of the experience and I guess he's from
DR. KALFUS: I would like to call up Dr. Marshall Levi,
who is from the
DR. LEVI: Good morning, I'm Marshall Levi. I'm Professor of Medicine University of Amsterdam. We have quite some experience with long-term prophylaxis in patients. A couple of patients are using the product for more than seven or eight years now on a very regular basis and we haven't seen any adverse events. We're checking our patients regularly for viral serology and also for any formation of antibodies. We didn't see any one of them.
DR. GLYNN: How about clotting?
DR. LEVI: How about?
DR. GLYNN: Clotting or phlebitis?
DR. LEVI: Well, we haven't seen any complication in our patients.
DR. GLYNN: So I had another question also on long-term. In terms of how often you change the dose. I mean, we heard about the androgen, but I haven't heard about this particular treatment, how often we need to change the dose, either you know, going lower or higher, more often, less often? And again, that's I would guess would come from the European experience.
MR. BABLAK: We also have the open label studies that are ongoing with prophylaxis. Some patients who have been on for longer than two years. Typically, patients are started on a dose. We've only had one patient go from the two times per week to three times per week in that period.
DR. GLYNN: And has anyone tried to give it less often?
MR. BABLAK: We actually have some patients in the open label study who are on once a week as well.
DR. GLYNN: And the dose?
MR. BABLAK: It's 1,000 units. Always 1,000 units given starting out twice a week and then adjusted and Dr. Busse could come and talk to that more in terms of clinical practice.
DR. BUSSE: Unfortunately, treating HAE is very difficult especially prophylactically and acute because we don't really have anything but that's a different hearing. But anyway, prophylactically we start with a dose in the trial, a dose of 1,000 units two times a week seem to work for most patients.
Unfortunately, with HAE, unlike asthma where we have guidelines, not to say that asthma is not difficult to treat but we don't have guidelines for HAE to, you know, tell us how we should treat these patients. We have some simple -- we have some things actually that can suggest how we should change the dose.
The first and most important is the patient. The patient knows their -- his or her disease better than anyone else and they can tell us how the disease is effecting their life, if they're missing school, missing work. Also we know for prophylactic -- well, for the dosing, you know, if they're having more breakthrough attacks, we know that we should potentially increase the frequency to three times a week as per two, but I would start with two times per week and then really work with the patient to see, you know, see how effective this dosing regiment is.
DR. KULKARNI: Is there a rule for adjunct therapy with antifibrinolytics in the European thing that showed any kind of efficacy or --
MR. BABLAK: In the European experience you're saying?
DR. KULKARNI: Right, I mean or use of antifibrinolytics and Cinryze?
DR. FRANK: I think I'm probably the person with most experience with the antifibrinolytics. The dose that we use in patients with hereditary angioedema that's effective is about eight grams a day. That's not a very strong dose in terms of antifibrinolysis. Exactly how it works, we don't know. For example if you do pharmacokinetics, 97 percent of the drug is out in six hours but the drug doesn't work fro two or three days. The toxicity profile is really quite severe. You don't see any early toxicity but in two or three months, people will start to have muscle aches and pains and they'll start to have tremendous feelings of fatigue. So we don't see anything in terms of clotting problems but we do see that.
We use it in children and the reason is we don't have another -- we don't have another agent to use in children because we don't want to use androgens. Now, I've never used the antifibrinolytics with C1 inhibitor because we've never had C1 inhibitor available. But I have used it with androgens and I've seen no augmentation of the effect of either the androgen or the antifibrinolytic when they're used together.
DR. KULKARNI: I just have one more question was. Is there any pheno-type, geno-type -- you said the levels don't really tell you much but is there a pheno-type, geno-type correlation and from --
DR. FRANK: We have not detected any and so that there obviously is something going on and remember, what we're looking at is the generation of Bradikinin. There's a metabolism of Bradikinin and there may be more than one protein involved in that metabolism. We know that we can't give adults ace inhibitors. Ace does -- is responsible for the -- one of the proteins responsible for the degradation of Bradikinin. Ace inhibitors make the disease much worse, as do estrogens.
We do not even understand why estrogens make the disease so much worse, so there's still things to learn.
DR. ATKINSON: Both Dr. Frank and Dr. Busse have mentioned that this treatment of children is problematic. Is there -- is the company -- is there an age range that you're applying for the use of this product and if it's going to be used in young children, what will your recommendations be or what will your suggestions be as far as dosing?
MR. BABLAK: We -- in our study we included children down to the age of six. The youngest child who was in the study was a nine-year old and the dosing was the same for all patients across the board of 1,000 units twice a week.
DR. ATKINSON: So the application will not have a lower age range or what does that --
MR. BABLAK: For the prophylaxis study, we're still under negotiations in terms of the label with the FDA. In our open label studies we have the age down to one-year old. We are currently not treating any one-year olds on prophylaxis and as Dr. Frank referred