1

DEPARTMENT OF HEALTH AND HUMAN SERVICES

FOOD AND DRUG ADMINISTRATION

CENTER FOR BIOLOGICS EVALUATION AND RESEARCH

BLOOD PRODUCTS ADVISORY COMMITTEE

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.

Friday, July 23, 2004

8:00 a.m.

Gaithersburg Holiday Inn

2 Montgomery Village Avenue

Gaithersburg, Maryland 20877

2

PARTICIPANTS

Kenrad E. Nelson, M.D., Chair

Linda A. Smallwood, Ph.D., Executive Secretary

Pearline K. Muckelvene, Scientific Advisors

& Consultants Staff

MEMBERS:

James R. Allen, M.D., M.P.H.

Kenneth Davis, Jr., M.D.

Donna M. DiMichele, M.D.

Samuel H. Doppelt, M.D.

Jonathan C. Goldsmith, M.D.

Harvey G. Klein, M.D.

Suman Laal, Ph.D.

Katherine E. Knowles,

Acting Consumer Representative

D. Michael Strong,

Non-Voting Industry Representative

TEMPORARY VOTING MEMBERS:

Liana Harvath, Ph.D.

F. Blaine Hollinger, M.D.

Katharine E. Knowles

Matthew J. Kuehnert, M.D.

Susan F. Leitman, M.D.

Keith C. Quirolo, M.D.

George B. Schreiber, Sc.D.

Donna S. Whittaker, Ph.D.

3

C O N T E N T S

PAGE

Update on West Nile Virus, Hira Nakhasi, Ph.D. 6

IV\. Hepatitis B Virus Nucleic Acid Testing (NAT)

for Donors of Whole Blood:

A. Introduction and Background,

Gerardo Kaplan, Ph.D., Laboratory

of Hepatitis and Related Emerging

Viruses, DETTD, OBRR, FDA 28

B. Serological Course of Hepatitis B,

F. Blaine Hollinger, M.D.,

Baylor College of Medicine 32

C. Preclinical and Clinical Data for

HBV MP NAT, Steven Herman, Ph.D.,

Roche Molecular Systems 51

Allan Frank M.D., M.S.,

Roche Molecular Systems 65

Open Public Hearing:

Michael Busch, Blood Centers

of the Pacific 103

William Andrew Heaton, Chiron 121

Sherrol McDonough, Gen-Probe 129

Richard Smith, NGI 136

Harvey Alter, AABB 144

IV\. Hepatitis B Virus Nucleic Acid Testing (NAT)

for Donors of Whole Blood:

E. Committee Discussion and

Recommendations 154

V. Current Trends in Plasma Product Manufacturing

A. Introduction and Background,

Mark Weinstein, Ph.D., Associate

Deputy Director, OBRR, FDA 223

B. Presentation, Jan M. Bult, CEO,

Plasma Protein Therapeutics

Association 225

Open Public Hearing:

Patrick Schmidt, CEO, FFF Enterprises 258

4

1 P R O C E E D I N G S

2 DR. SMALLWOOD: May I ask all advisory

3 committee members to, please, take your seats?

4 Welcome to the second day of the Blood Products

5 Advisory Committee meeting. Yesterday I read the

6 conflict of interest statement that applies to this

7 meeting, however, we have a new process now and we

8 will read a conflict of interest statement for each

9 day.

10 So, if you will indulge me, I will read

11 that at this point. This brief announcement is in

12 addition to the conflict of interest statement read

13 at the beginning of the meeting yesterday, and is

14 part of the public record for the Blood Products

15 Advisory Committee meeting on July 23, 2004. This

16 announcement addresses conflicts of interest for

17 topic V.

18 Drs. Liana Harvath, Blaine Hollinger,

19 Matthew Kuehnert, Susan Leitman, Keith Quirolo,

20 George Schreiber, Donna Whittaker and Ms. Katherine

21 Knowles have been appointed as temporary voting

22 members for this meeting

5

1 Dr. Michael Strong is participating in this meeting

2 as the non-voting industry representative, acting

3 on behalf of regulated industry. The Food and Drug

4 Administration has prepared general matters waivers

5 for the special government employees participating

6 in this meeting who required a waiver under Title

7 XVIII, United States Code 208.

8 In addition, there are regulated industry

9 and other outside organization speakers making

10 presentations. These speakers have financial

11 interests associated with their employers and with

12 other regulated firms. They were not screened for

13 these conflicts of interest. I would just like to

14 remind everyone participating to, please, make

15 known, if you have not already done so, any

16 affiliation you may have and your status with that

17 affiliation prior to speaking.

18 Our committee chairman, Dr. Kenrad Nelson

19 has joined us this morning, and we also have Dr.

20 Blaine Hollinger who will also be part of the

21 committee this morning.

22 I just wanted to announce to those who

6

1 were not here yesterday that the next date, which

2 is tentative however pretty much firm, for the next

3 Blood Products Advisory Committee meeting will be

4 October 21st and 22nd, 2004.

5 At this time I will turn over the

6 proceedings of the meeting to the chairman, Dr.

7 Kenrad Nelson.

8 Update on West Nile Virus

9 DR. NELSON: Thank you, Dr. Smallwood. I

10 will try to keep awake after the 24-hour airplane

11 ride. I came in last night but I feel really

12 pretty good and I am very interested in the topic

13 today so I think that will help.

14 The first topic is an update on West Nile

15 virus by Hira Nakhasi.

16 DR. NAKHASI: Good morning. I just want

17 to give you an update, as Dr. Kenrad Nelson

18 mentioned, on the West Nile epidemic and donor

19 testing which is happening now, in 2004. First I

20 will try to wrap up last year\'s things and then

21 come up to 2004.

22 Next slide, please. The topics which I

7

1 will update you on are, as I said, last year\'s

2 epidemiology and the investigational West Nile

3 testing outcome of that, and some of the

4 transfusion-transmitted cases, and then the trigger

5 for the ID-NAT testing. Then I will update you on

6 the West Nile donor and product management

7 recommendations with the recent revelations we have

8 got. Then I will update you on the 2004 epidemic

9 and investigational West Nile testing, and also our

10 efforts in-house on the panel development and other

11 scientific issues\--you know, the variation among

12 the strains of viruses infectivity of these

13 studies.

14 Next slide, please. If you summarize in

15 one slide the last year\'s epidemic, it really

16 basically sums up that we had approximately 1000

17 \[sic\] cases or, to be precise, 9862 cases, human

18 cases, and 264 deaths. And, the proportion of the

19 West Nile meningitis/encephalitis was 29 percent,

20 whereas, the fever was 69 percent in the human

21 cases.

22 Forty-six states, including Washington,

8

1 D.C., were endemic, and donor testing started, as

2 all of you know, in July of 2003, using two

3 investigational NAT testing. In some cases, a

4 small proportion started in the middle of June.

5 Despite this testing, I think these two

6 investigational NAT testing\--these are minipool and

7 the two tests were the Gen-Probe test and the Roche

8 test, and Roche tested, as you know, in pools of 6

9 and the Gen-Probe test involves a pool of 16.

10 Despite testing, there were some

11 transfusion-transmitted cases and CDC had

12 investigated a total of 23 cases. They were

13 confirmed by NAT and IgM reactivity and also by

14 follow-up of both the donor and the recipient. Out

15 of the 23, 6 were confirmed cases. Only 4/6, you

16 may recall, had very low viremia, around 0.1

17 pfu/ml. Eleven cases did not confirm; 3 were

18 inconclusive because of the follow-up situation;

19 and 3 were open investigations.

20 Next slide, please. As I said, since it

21 started on July 1 of last year, screening using

22 minipool NAT and IND, all geographic regions of the

9

1 U.S. were screening at that time. With that, what

2 happened 1000 units of West Nile infected blood

3 donors were interdicted after screening

4 approximately 8 million donations. So, I think it

5 was a very, very vast improvement over the year

6 before when there was no testing. The last

7 positive donation was reported in the middle of

8 December in 2003.

9 Despite this testing, as you see, the

10 majority of cases were interdicted, more than 75

11 percent, but there was a small percentage which

12 went through because, as you know, this was done in

13 minipool NAT.

14 Next slide, please. This slide is Mike

15 Busch\'s slide where he showed why we were missing

16 some of these cases, and we knew that minipool NAT

17 sensitivity was such. The areas, you know, where

18 the wrap-up takes place when\--you know, he calls it

19 stage I, II, III, IV and V, and in stage I and II

20 they are ID-NAT positive but minipool NAT negative,

21 IgM negative. So, it could be plus/minus. So,

22 during that stage they become IgM positive but they

10

1 become minipool negative and they are still ID-NAT

2 positive. So, this region and this region were the

3 ones where they went through. But, you know, these

4 were IgM negative and these were IgM positive so

5 the question is what is the infection of these

6 types of samples.

7 Next slide, please. So there was a

8 potential for transmission of West Nile through

9 minipool NAT negative blood of low viremia in some

10 patients. Therefore, what happened at that time is

11 that limited prospective ID-NAT testing started in

12 high incidence areas. If you remember last year,

13 Colorado, Kansas and certain other areas, and

14 Nebraska were hot spots and ID-NAT was triggered at

15 that time, and the trigger was based on if the

16 preceding the rate of 1/200 minipool NAT positive

17 rate of 1/250, then they would start testing with

18 ID-NAT testing. Also, what happened at that time

19 is that there was voluntary withdrawal of the

20 frozen transfusables in the high incidence areas

21 before the ID-NAT was initiated by some blood

22 establishments.

11

1 Next slide, please. There was also

2 another initiative started at that time. The

3 initiative was to go back to do the retrospective

4 study on the minipool NAT negative samples and test

5 them by ID-NAT to find out how many we missed. It

6 would also let us know what was the low level of

7 viremic high incidence samples in high incidence

8 areas where minipool NAT did not pick them up.

9 The other purpose of the study was also to

10 identify samples which are like minipool NAT low

11 titer, minipool NAT negative but ID-NAT positive

12 for infectivity studies. I told you that we do not

13 know whether those samples are still infectious at

14 low levels, and what is the level of infectivity.

15 So, these samples would be tested in various animal

16 models including non-human primates. Also, the

17 purpose of these samples is to really find out the

18 relative clinical sensitivity of various West Nile

19 investigational testing. I will report in a minute

20 what is happening with the infectivity state.

21 Next slide, please. Based on the

22 observation that we had minipool testing and we

12

1 missed some of the samples because the viremia was

2 low, and also in the ID-NAT testing in the high

3 incidence areas\--based on those studies and based

4 on the logistics issues, the question was what

5 should be the trigger for ID-NAT, and also logistic

6 issues such the availability of adequate resources,

7 recruitment, reagents and trained technologists.

8 So, the discussion about the trigger for

9 ID-NAT was held in collaboration with the AABB task

10 force. By the way, we are very indebted to the

11 AABB task force for the biweekly meetings almost

12 throughout the year, and weekly meetings with the

13 task force during the epidemic to update us and

14 jointly discuss the strategies for how to go

15 forward with the testing performance, as well as

16 the epidemic.

17 So, based on that discussion, which was

18 held in February, the recommendations were the

19 following for the ID-NAT trigger: It was discussed

20 that we should monitor reactive rates by zones

21 daily, enrolled 7 days when the epidemic was

22 starting, which was usually, you know, around the

13

1 beginning of July and early June even and this year

2 even May some cases were found. The trigger was

3 that if you have 2-4 cases in any geographic

4 area\--that is the blood collection, and the

5 frequency of 1/1000. This was based on the fact

6 that every 1/4 would be missed by minipool NAT and

7 require ID-NAT. This was the study done by ARC and

8 BSL and they found out that that would be the

9 trigger. And, you go back to minipool NAT only

10 when you see ID-NAT reactivity and you don\'t find

11 zero cases in a consecutive 3-4 day period or the

12 rate is less than 1/1000. So, that was the trigger

13 because, you know, we wanted to be prepared this

14 year because last year it was on an ad hoc basis to

15 start ID-NAT testing in those hot areas. So, we

16 wanted to be prepared this year if these areas

17 become hot so that we get the logistics present

18 there so we can start without interruption of the

19 ID-NAT testing.

20 Next slide, please. Now we come to 2004,

21 where are we now? As of July 20, which is a couple

22 of days back\--as you see, every week the numbers

14

1 keep changing. Last week there were 108. This

2 week it is 182 human cases out of which there were

3 4 deaths. There are 2 from Arizona, 1 from Texas

4 and 1 from Iowa. Out of total infections, 74

5 percent of cases are neuroinvasive West Nile

6 illness and 26 percent cases are West Nile fever.

7 At the moment there are 35 states endemic for West

8 Nile. This slide has been kindly provided by Jen

9 Brown, from CDC, and other slides which I will

10 mention later.

11 The total number of presumptive West Nile

12 viremic donors reported to the CDC ArboNet\--that is

13 why I highlighted this, is 23. There are more

14 cases than that but, as you know, there is a delay

15 in reporting to the ArboNet from the health

16 departments. So, using minipool NAT as well as

17 ID-NAT in select areas, starting on May 4. Out of

18 these 23 presumptive West Nile viremic donors, 21

19 are from Arizona. The majority are from the

20 Maricopa county near Phoenix, in Arizona; 1 from

21 New Mexico and 1 from Iowa. But this is the tip of

22 the iceberg.

15

1 Next slide, please. This slide, again, is

2 provided by Jen. You can see the distribution of

3 the West Nile, both the animal, avian and mosquito

4 infection, which is in this color, and the blue

5 color shows you the human cases. You can see it is

6 very high in Arizona and California. I am telling

7 Mike Strong that it is creeping up in Washington

8 soon. So, he has been telling me we don\'t see

9 anything and I said, well, wait and watch! As you

10 remember, in 1999, how this started and how it is

11 spreading and, you know, it just keeps on going. I

12 hope it will end up in the ocean sometime.

13 Next slide, please. This is just to give

14 you how early the human cases can be detected. As

15 you see from the slide, the earliest one was in

16 April. So, you know, there is an expansion of this

17 epidemic, it looks like. We were told in the

18 textbooks it is mostly in August and September or

19 late July but you can see it as early as April now,

20 and last year we saw it as late as December, in the

21 middle of December. So, you know, it is almost a

22 year-round activity now.

16

1 Next slide, please. Thanks to all the

2 blood establishments and testing establishments, I

3 got these data from several folks and I will

4 acknowledge them as I speak. The total number,

5 according to my calculations but this may not be

6 right, is 61 presumptive viremic donors reported,

7 starting in May, 2004. As I said, some of them are

8 reported to ArboNet and some of them are not. So,

9 it is not in addition to that; it is inclusive of

10 the ArboNet reports. ARC has told me\--Sue Stramer

11 gave the data from June 16 to July 20, 7 hard

12 cases. Again, this is also in the Arizona area.

13 But she says no region has their ID-NAT trigger.

14 Mike Strong gave me this data from Roche.

15 There are 2 positive confirmed by ID-NAT\--around

16 300,000 donations screened.

17 BSL, Sally Caglioti and Mike Busch told me

18 that there are 23 confirmed, out of which 16 came

19 from minipool NAT and 7 came from ID-NAT, confirmed

20 positives. There are 14 pending and he was saying

21 that some of them are ID-NAT and would have been

22 missed by minipool NAT. Also, some of them are low

17

1 viremic and also there are some which are IgM

2 positive. The denominator is around 400,000.

3 Gen-Probe, Leanne Kiviharju, gave the

4 data. These are non-ARC data but I am not sure\--I

5 sent an email to Leanne\--whether this is also

6 non-BSL but I am not sure; maybe we can find out

7 from here, but 21 confirmed positive and 7 are

8 pending. I am glad that you guys sent me several

9 slides. I was basically trying to summarize what

10 the presumptive donors are and, you know, I really

11 appreciate your sending extra slides.

12 The Department of Defense, Ron Hagey sent

13 me the data which has 8 confirmed out of 62,774

14 since January of 2004.

15 So, you know, this is the majority of the

16 screening going on at this time and there may be a

17 few cases which have not been reported yet, but

18 this is where we stand as of today.

19 Next slide, please. I just wanted to sort

20 of briefly remind you that FDA is still continuing

21 to work closely with the test kit manufacturers and

22 we would like to facilitate implementation of these

18

1 tests and expediter test licensure. I just want to

2 remind you that we issued two guidances in October,

3 2002 and May, 2003. There are 3 INDs for West Nile

4 minipool-NAT. One is from Roche, one from

5 Gen-Probe and one from ARC. This is public

6 information. FDA is continuing to work with the

7 AABB task force. I think that has been a

8 wonderful, wonderful collaboration with the AABB

9 task force and the people on the task force are

10 really helpful in doing this project together, and

11 with the CDC, NIH help, and to monitor the epidemic

12 and monitor the testing.

13 Next slide, please. Both ARC and BSL did

14 a study, which is unpublished observation. We had

15 a small discussion at the task force on what they

16 found out in some of the viremic donors when they

17 followed up. They wanted to find out what is the

18 rate of the disappearance of RNA when they convert

19 IgM and IgG. As you remember, in the last years

20 before the testing started the literature was that

21 it can go as long as 28 days of viremia. But from

22 their studies, and I don\'t want to go into detail

19

1 here because these are unpublished and, you know, I

2 don\'t want to divulge information\--the gist of that

3 was that what they found out in both cases is that

4 the viremia may last up to 49 days in one case and

5 39 days in the ARC study, and in the BSL 49 days,

6 and West Nile RNA may go coexist with IgM.

7 Therefore, this sort of started us thinking. In

8 the guidance document we put 28-day donor deferral

9 and so we may have to rethink the deferral for

10 that.

11 Next slide, please. We have not discussed

12 it with the AABB task force but we will be

13 discussing with the task force that, you know, the

14 integration of West Nile testing information. We

15 are thinking about maybe 56-day deferral for West

16 Nile diagnosis of symptoms, including headache and

17 fever, or 14 days after symptom resolution if it is

18 more than 56 days. Potential reinstatement of

19 donor deferral for West Nile symptoms only

20 following 30 days without symptoms, and negative by

21 West Nile IgM or ID-NAT. Again, this is current

22 thinking. We have nothing in the works yet but we

20

1 have internal discussions, and we will discuss it

2 at our next regular AABB task force before we come

3 up with a recommendation. Dr. Alan Williams is

4 spearheading this initiative.

5 Next slide, please. With regard to our

6 activities in-house, as I mentioned last year also,

7 we are still working on the panel development. The

8 purpose is to monitor sensitivity of assays to

9 detect viral nucleic acid antibodies, and also

10 trying to isolate and characterize West Nile

11 strains from human samples during 2003 and 2002

12 epidemics. The purpose of this study, which is done

13 by Dr. Maria Rios in our group\--and all these

14 studies actually really are done by Dr. Maria Rios\'

15 group\--is the genetic variation of viral strains;

16 detection by currently available West Nile assays.

17 The purpose is to really see if there is any

18 genetic variation and also infectivity studies

19 using animal models. Currently, the samples have

20 been identified which could be used for infectivity

21 studies. However, there are logistic issues about

22 the animals, baboons, which are being worked out

21

1 with the Southeast Medical Center. I guess the

2 task force is working on that. Hopefully, we will

3 get some information by fall and we will be set to

4 do those studies.

5 Next slide, please. Briefly, they have

6 two isolates, NY99 in 2002, which have been

7 characterized by genetic sequencing which I can

8 show you in a minute. The viral infectivity is

9 determined by in vitro studies using cell lines and

10 primary human blood cell cultures. Final panel

11 specifications are being established through the

12 collaborative studies, and the range of

13 concentration ranges between 1000-5 copies/ml.

14 Next slide, please. Just a piece of

15 information here that Maria was kind enough to

16 provide to me. You know, she did the comparison of

17 the human 2002 strain and the NY99 flamingo isolate

18 and then passed through the Vero cells. She found

19 there were 20 nucleotide mutations and one

20 insertion. The mutations are distributed all

21 across the region which result in 5 amino acid

22 substitutions. She is characterizing more isolates

22

1 and she already has 6 from 2002, 11 from 2003 and 6

2 from 2004. So, the purpose is to really compare

3 and to see what the differences are and how those

4 differences impact on our tests.

5 Next slide please. The outcome of the

6 panel testing\--six laboratories participated in

7 that. She tells me there were no false-positive

8 results reported. More variability in detection

9 was found towards the lower end of the viral

10 concentration, i.e., 80 percent of the time

11 detected 100 copies/ml member but all laboratories

12 detected 100 percent of the time the panel members

13 of 500-1000 copies/ml. Further testing is going to

14 define the consensus copy number.

15 Next slide, please. This is the important

16 slide. I would like to thank all the people who

17 really helped to make this talk possible. Jennifer

18 Brown, whom I have always been bugging to provide

19 the slides. Thank you, Jennifer. Dr. Sue Stramer,

20 Dr. Mike Busch and Sally Caglioti, Dr. Mike Strong,

21 Leanne Kiviharju, Roland, Maria and all these

22 people\--whoever I send an email they are kind

23

1 enough to respond quickly. Also my colleagues at

2 the FDA, Maria Rios, Alan Williams, Dr. Epstein,

3 Martin Ruta, Indira Hewlett\--always helping in this

4 whole project and, last but not the least, the AABB

5 task force. I am really, really grateful to them

6 for providing all the information and helpful

7 discussion. Thank you very much.

8 DR. NELSON: Thank you. Any questions or

9 comments? Yes?

10 DR. GOLDSMITH: Do you have additional

11 data on the level of viremia in these samples that

12 you have been studying? What is the maximum level

13 of viremia?

14 DR. NAKHASI: Which samples are you

15 talking about?

16 DR. GOLDSMITH: The ones that you

17 recovered from the viremic donors.

18 DR. NAKHASI: From the viremic donors, I

19 don\'t know. Maria, do you know what the levels

20 are?

21 DR. RIOS: Between 10

5 and 106 is the high

22 level of viremia that we have found. Are you

24

1 asking for the range of viremia or the high level

2 of viremia?

3 DR. GOLDSMITH: I was just curious about

4 the high but it is fine to give the range.

5 DR. RIOS: It varies. It varies. The

6 assays, in general, that use lower volumes do not

7 detect them. Assays that have higher volume and

8 high throughput detect, but do not give accurate

9 quantitation, to 10

6 copies/ml.

10 DR. NELSON: One of your slides had 23

11 positives with 16 by minipool and 7 by ID. Were

12 those 7 not detectable by minipool or was it just

13 that ID screening was triggered and they weren\'t

14 tested by minipool?

15 DR. NAKHASI: I think they came for the

16 ID-NAT testing. Is that true? Yes. You know, in

17 BSL they had already started ID-NAT testing in

18 Maricopa County. The trigger had started earlier.

19 DR. NELSON: So, they were negative by

20 minipool?

21 DR. STRONG: No, the trigger was activated

22 and they started doing ID screening so they haven\'t

25

1 gone back yet, I think, to see if those would have

2 been picked up by minipool.

3 DR. BUSCH: Actually, 7/12 that were

4 picked up in the region that had been converted to

5 ID-NAT, 7 of them had been fully worked up and 5 of

6 those 7 are negative at 1:16 dilutions so they

7 would have been missed by minipool. Of those 5, 1

8 of them is antibody negative and 4 have IgM and

9 IgG.

10 DR. NELSON: Has anybody looked at the

11 characteristics of the donors that have low levels?

12 Are there host factors that might influence whether

13 somebody has high level or low level? I know one

14 feature may be antibody but in those that are

15 antibody negative, I wonder if there are any donor

16 characteristics that influence the level of

17 viremia.

18 DR. BUSCH: Sue has looked at that I think

19 more formally and there wasn\'t any correlation.

20 These are representative donors of the donor pool

21 in terms of the viremics, non-viremics and low

22 viremics. I think it is just by chance. This

26

1 phase of early viremia is completely asymptomatic.

2 DR. RIOS: It may have some inherited

3 characteristics that limit the viral replication.

4 The reason why we think that is because we have

5 performed some in vitro studies with human primary

6 macrophages and there is a great variability not

7 only in the day of the viral peak, but some

8 individuals can have a very steady and low titer

9 that doesn\'t progress to peak. So, that indicates

10 that some inheritance variability may interfere

11 with replication.

12 DR. NELSON: That is interesting. Other

13 questions?

14 DR. LAAL: Unless I misunderstood, I

15 noticed that in 2003 we had a majority of your

16 isolates from people who had fever, and about

17 one-quarter were from neuroinvasive cases. In 2004

18 it is reversed.

19 DR. NAKHASI: Yes, that is an important

20 point. I discussed it with the CDC folks and they

21 said, you know, don\'t pay attention to that because

22 the fever cases were\--you know, this year they are

27

1 paying more attention so some of the fever cases

2 were not real fever cases. You are right, you saw

3 the switch.

4 DR. LAAL: But then in the isolates that

5 you are picking up now for the genetic studies, are

6 you carefully making sure that you look at both

7 types?

8 DR. NAKHASI: Maybe Maria can say; I don\'t

9 know.

10 DR. RIOS: The isolates that have been

11 studied so far don\'t come from patients. Actually,

12 that is the effort we are going to move towards

13 now. They are identified through the blood

14 screening. So, in order to evaluate if there is

15 any isolate that may not be picked up by the blood

16 screening we need to acquire samples from cases

17 that are non-blood donors to investigate this

18 possibility.

19 DR. NELSON: Yes, Mike?

20 DR. STRONG: Just a quick comment on the

21 donors. In the studies that were done last year,

22 many of the donors that were interviewed, in fact,

28

1 were symptomatic either shortly before or shortly

2 after their donations but the screening questions

3 just didn\'t pick them up.

4 IV. Hepatitis B Virus Nucleic Acid Testing (NAT)

5 for Donors of Whole Blood

6 DR. NELSON: Thanks. The next topic is

7 hepatitis B virus nucleic acid testing for donors

8 of whole blood. Dr. Gerardo Kaplan will introduce

9 this and give us background.

10 A. Introduction and Background

11 DR. KAPLAN: Good morning.

12 \[Slide\]

13 I am Gerardo Kaplan, Chief of the Lab of

14 Hepatitis and Related Virus Emerging Agents. I am

15 with the Office of Blood, and I will introduce for

16 you the hepatitis B virus n nucleic acid testing

17 for donors of whole blood.

18 \[Slide\]

19 The general agenda for this meeting is

20 that after the introduction and background, Dr.

21 Blaine Hollinger will give us an update on the

22 serology of hepatitis G. This will be followed by

29

1 two presentations from the Roche Molecular Systems

2 and their preclinical and clinical data in support

3 of their application. Finally, I will come back to

4 give you the FDA perspective on hepatitis B MP-NAT

5 and present the questions for the committee. I

6 understand that there will be a break and then a

7 public hearing.

8 \[Slide\]

9 So, the issue is that the FDA is seeking

10 the opinion of the committee on the performance of

11 the Roche COBAS AmpliScreen HBV test in minipools

12 of 24 samples to screen blood for transfusion by

13 nucleic acid testing, and its proposed intended use

14 as an alternative to hepatitis B surface antigen

15 testing in conjunction with testing for antibodies

16 to hepatitis B core antigen.

17 \[Slide\]

18 In support of their claims, Roche

19 Molecular Systems performed a clinical trial. The

20 study objectives of the clinical trial were to

21 determine whether the COBAS AmpliScreen test, which

22 is a minipool of 24 samples of plasma from

30

1 volunteer blood donors, can detect hepatitis by DNA

2 in hepatitis B surface antigen-anti-core negative

3 window period cases. This is the primary objective

4 of the study. In hepatitis B surface

5 antigen-positive donors, who are acutely infected

6 or chronic carries, and in persons previously

7 exposed to hepatitis B as the secondary objective.

8 \[Slide\]

9 During the clinical trial, Roche Molecular

10 Systems identified two window period cases in about

11 600,000 volunteer whole because donations screened

12 by hepatitis B NAT using their minipools of 24

13 samples.

14 RMS, Roche Molecular Systems, claims that

15 the use of the COBAS AmpliScreen HBV test in

16 conjunction with the anti-core test would reduced

17 the residual risk of transfusion-transmitted

18 hepatitis B, and also that this test, the COBAS

19 AmpliScreen, could be used as an alternative to the

20 commonly used hepatitis B surface antigen donor

21 screening test. I would like to point out that

22 blood in the U.S. is currently being tested by

31

1 surface antigen and core antibodies.

2 \[Slide\]

3 So, we would like to request comment of

4 the committee on three questions. Basically, the

5 firs would be do the sensitivity and specificity of

6 the Roche COBAS AmpliScreen hepatitis B test in

7 minipools of 24 samples support licensing of the

8 assay as a donor screen?

9 \[Slide\]

10 If so, assuming continued use of screening

11 tests for anti-hepatitis B-core, do the data

12 support use of the Roche COBAS AmpliScreen

13 hepatitis B test in minipools of 24 samples to

14 screen blood for transfusion as an equivalent

15 alternative to the surface test? If not, which

16 studies would be required to validated such a new

17 test?

18 The third question is do the data support

19 use of the Roche COBAS AmpliScreen hepatitis B test

20 on minipools of 24 samples to screen blood for

21 transfusion as an added test in conjunction with

22 licensed donor screening tests for hepatitis B

32

1 surface and anti-core?

2 Now I would like to introduce Dr. Blaine

3 Hollinger. He will give us an update on hepatitis

4 B serology.

5 B. Serological Course of Hepatitis B

6 DR. HOLLINGER: Thank you, Gerardo. It is

7 always a pleasure to come to these meetings and I

8 always tend to learn more than I think anyone here

9 because there is always so much information.

10 \[Slide\]

11 The talk today is about serology, and

12 serology can be confusing. It is confusing to our

13 GI residents and fellows in trying to determine

14 what happens after hepatitis B infection. The

15 clinical and serologic changes that occur following

16 infection represent a complex interaction between

17 the host, the virus and specific antigens. If you

18 have an understanding of these items, I think it

19 becomes very easy to understand what happens.

20 There are certain changes that occur after

21 infection with all viruses that seem to be very

22 similar. Viruses are either enveloped or

33

1 non-enveloped. Hepatitis B virus happens outcome

2 have a lipoprotein envelope that contains hepatitis

3 B surface antigen as the envelope protein. There

4 are also some other particles in this serum which

5 are seen in excess of the infectious virion, and

6 these are the small particles here, and these

7 tubular forms which actually come off, in many

8 cases, from the hepatitis B virion.

9 The inside, or the nucleocapsid of the

10 virion is comprised of the hepatitis B core

11 antigen, and this encloses a relaxed, circular,

12 partially double-stranded DNA molecule. Another

13 antigen which is seen also is the hepatitis B

14 antigen, but this is not part of the virion in any

15 way. It is a secretory protein, about 16-17 kd in

16 size, that is secreted during active infection, and

17 is representative usually of high concentrations of

18 virus in the bloodstream. We don\'t really know

19 what is the reason for this particular antigen.

20 \[Slide\]

21 This is the HBe genome. It has four open

22 reading frames. One of them is responsible for the

34

1 hepatitis B-surface antigen and is comprised of a

2 small, a medium and a large protein. A second one

3 is the core gene which expresses the core-antigen,

4 the hepatitis B core-antigen and also the e-antigen

5 as well. There is a DNA polymerase that is

6 important for the replication of this virus, and

7 there is an x-gene here which is very important for

8 initiation and probably maintenance of the

9 infection. It is probably also weakly oncogenic as

10 well. Now, once one understands these things, you

11 can then start to see what happens after an

12 infection.

13 Next slide, please. This slide shows what

14 happens in the typical course\--now, I am going to

15 talk about typical things here. Certainly all of

16 us know about the exceptions and we have all seen

17 them at one time or another, but I think it is

18 important to deal right now with the typical

19 changes that can occur. Again what happens, you

20 have a hepatocyte that is infected. There is a

21 very short eclipse phase in which we would not see

22 virus in the hepatocyte. Then viruses start to be

35

1 produced and are transported out of the cell.

2 Then, one sees initially HBV DNA in the

3 bloodstream. It precedes the expression of

4 hepatitis B-surface antigen which then starts to

5 occur here very early in the course of the disease

6 and peaks usually during the acute phase of a

7 clinical illness.

8 What happens then in this non-cytolytic

9 infection is that there are usually some holes that

10 are punched in the plasma membrane of a hepatocyte.

11 ALT, which is in the cytosol, aminotransferase

12 enzyme which is in the cytosol of hepatocytes, are

13 released into the bloodstream. So, the ALT is

14 elevated in these patients and then follows the

15 clinical symptoms of anorexia, fatigue, jaundice,

16 etc.

17 Usually about the time the ALT begins to

18 appear, HBeAg and IgM anti-HBc are found. IgM anti

19 HBc appears in high titer or high concentration in

20 individuals as a response to the synthesis of

21 nucleocapsids and, therefore, represents active

22 viral replication. The IgM rises during the early

36

1 courses of infection and then starts to disappear.

2 Usually by 4-6 months or so, or 6-9 months, the IgM

3 anti-HBc disappears, although it may be present for

4 up to 2 years in individuals, if you use very

5 sophisticated research tools.

6 Usually the HBV DNA disappears in the

7 acute infection at the time that a hepatitis

8 B-surface antigen disappears. So, you have a

9 pattern here. HBV DNA first; HB surface antigen,

10 and the HBsAg disappears and usually about that

11 time HBV DNA is gone, or at least is

12 non-detectable.

13 Again, another pattern appears. When

14 HBsAg disappears it is replaced by its antibody,

15 anti-HBs. Now, we know that probably anti-HBs is

16 produced very early in the course of the infection,

17 even probably back in this area here, which results

18 in serum sickness, vasculitis or other things, but

19 you don\'t detect it because there is so much

20 hepatitis B surface antigen available so it is

21 non-detectable. But eventually the surface antigen

22 goes; anti-HBs then is detected. When HBeAg

37

1 disappears in the active infection, then anti-HBe

2 replaces it. Anti-HBe lasts in most patients for a

3 long period of time but in about a third of the

4 patients disappears after about 6 months of

5 follow-up.

6 Of course, the IgM anti-HBc\--there is a

7 switch-over between the IgM anti-HBc and IgG

8 anti-HBc. What is important to recognize is that

9 the assay, the total anti-HBc assay, detects not

10 only IgM but IgG antibodies. It is not an IgG

11 test; it detects both IgG and IgM. So, whenever

12 IgM is present you ought to see the total anti-HBc

13 test positive.

14 Next slide, please. This is an older

15 slide I have but I think it helps us a little bit

16 understand the relationship of all these assays

17 that we are looking at. The EIA assay and those

18 that are being developed can detect down to about a

19 tenth of a nanogram of HBsAg. HBsAg circulates up

20 to 200 mcg or more per ml of blood. These tests

21 really have an upper level of sensitivity of about

22 1 mcg/ml. So, usually they are at their upper

38

1 limits of detection for most infections.

2 The second test that came along them were

3 the hybridization assays, the liquid phase and the

4 filter hybridization assays. These could detect

5 down to a tenth to 1 pg of genomic equivalence in

6 the blood. At least, at 24 hours if you have the

7 autoradiographs stay for maybe up to 5 days, you

8 can detect anywhere from 2- to 10-fold more virus

9 in the blood. So, they are detecting about this

10 level here, somewhere between here and here, and 1

11 pg is equivalent to about 300,000 copies/ml. You

12 will see 280,000, 330,000 but let\'s just talk about

13 300,000 copies/ml. So, 1 pg is here, 300,000,

14 30,000, 3,000 and 300 down at the femptogram

15 levels.

16 The PCR assays, which are somewhere

17 between 700-7,000 times more sensitive than

18 hybridization assays, can detect down to 50 copies

19 or less per ml. So, they are down in this range,

20 here. As I said, this is 300,000, 3,000 and 300

21 copies/ml. This would be 30 copies/ml. These are

22 usually with nested PCRs or other assays, nucleic

39

1 acid\--the tests that are available today.

2 So, you see the differences between these

3 assays. One might ask why is it then that the EIA

4 tests are detecting HBsAg very closely to the HBV

5 DNA. Part of the reason for that is that there are

6 anywhere from 1,000 to 10,000 times more\--at least

7 10,000 times more hepatitis B surface antigen

8 particles per infectious virion, and there may be

9 even more naked HBV particles. So, you have a lot

10 more HBsAg produced initially than you do

11 infectious virions. That is the reason I think

12 that there is not a great deal of difference, at

13 least initially, in the detection of these

14 particles.

15 Next slide, please. So, during the course

16 of infection HBV DNA is detected from 2-5 weeks

17 after infection and up to 40 days before the HBsAg

18 is detected. However, there is a wide coefficient

19 here of variation but the mean of that is around

20 6-15 days, and there are some exceptions to this.

21 It rises slowly during the course of infection at a

22 relatively low level, say 10

2 to 104 copies/ml

40

1 during the seronegative period, that is, before the

2 HBsAg appears.

3 Next slide, please. HBsAg, on the other

4 hand, appears 1-3 weeks before the ALT becomes

5 abnormal or 3-5 weeks before the onset of symptoms

6 or jaundice. It reaches a peak during the acute

7 stage of the disease and then it declines to

8 undetectable levels within 4-6 months.

9 Next slide. IgM anti-HBc is indicative,

10 as I said, of ongoing viral replication and appears

11 at the onset of ALT abnormality at high

12 concentration. It is present but undetectable in

13 some chronic infections and may reappear,

14 therefore, during reactivation of HBV during

15 chronic infection.

16 Now, one of the questions that often

17 arises is when you have acute hepatitis how do you

18 determine that this is not a reactivation of

19 chronic disease compared to an acute disease? That

20 has always been an issue. For all practical

21 purposes, the IgM anti-HBc test can be utilized to

22 determine that. It is at high concentrations.

41

1 Whereas, patients who have reactivation of their

2 hepatitis B virus infection from chronic disease

3 often have a relatively low concentration of IgM

4 anti-HBc in their test. We use a sample to cut-off

5 ratio and it is usually somewhere between 1-3 in

6 those cases, whereas in acute disease it is at its

7 maximum.

8 In addition, the other way, if you have

9 the means to do this, is that the IgM has a 19S

10 sedimentation coefficient during acute infection.

11 It has a 7S sedimentation coefficient during

12 chronic infection. That is another way that one

13 could use to determine acute from chronic.

14 Next slide, please. The anti-HBs is a

15 neutralizing antibody occurring during recovery and

16 after infection, and in most cases indicates

17 protection against reinfection. However, it may

18 become undetectable in up to 20 percent of patients

19 after several years.

20 Next slide. This slide sort of shows what

21 happens in a patient who gets acute disease and

22 gets over it. The anti-core is a very strong

42

1 antibody, high concentration of antibody compared

2 to anti-HBs. Over time, as I said, in about 20

3 percent of patients this antibody will disappear.

4 Then you are left with a person who has only an

5 anti-HBc response.

6 Next slide. One of the ways that one can

7 tell that that is present is you can do an HBsAg

8 vaccine challenge. You can give them a vaccine.

9 About 2-4 weeks later you have them come back in

10 for a quantitative anti-HBs test and if the

11 response is greater than 10 milli-international

12 units/ml, that is indicative that this person

13 probably had a prior infection and was immune. It

14 is unusual for a susceptible person or a person

15 with a low-level infection to respond to the

16 hepatitis B surface antigen by 2-4 weeks. Probably

17 less than 3 percent in 2 weeks will respond to the

18 vaccine at this particular level.

19 Next slide. I have talked a little bit

20 about chronic infection. The difference is that

21 arbitrarily, say, if the HBsAg is still positive

22 after 6 months or the person has ALT abnormalities

43

1 for a period of time, then they probably have

2 chronic infection. In addition, the HBsAg is at

3 very high concentrations through that period of

4 time. It doesn\'t start to decline. So, if you

5 could dilute these samples as a patient is being

6 followed along, you will find that the HBsAg

7 concentration is declining. Just remember that the

8 upper level of their reference is about 1 mcg/ml so

9 you do have to do some dilutions in order to see

10 this happening. The IgM does disappear but remains

11 usually positive at very low levels. With research

12 tools you can detect it in most patients. It just

13 isn\'t positive in the way the test is done, which

14 is to dilute the sample about 1:1000 or 1:2000.

15 That is why you don\'t see it in these individuals.

16 That is how the test is configured. Part of that

17 is because of prozone effects and other things

18 which could make a positive test negative if you

19 did not dilute.

20 E antigen is usually present initially,

21 but over time about 5-10 percent of patients will

22 seroconvert from HBeAg positivity to anti-HBe

44

1 positive. During that period of time they usually

2 show reactivation of their disease. Often it is

3 just an elevation of the liver enzymes but they may

4 become jaundiced and they may develop symptoms that

5 look just like acute disease. Until we understood

6 this, this was one of the reasons we used to think

7 that 10 percent of patients who had acute disease

8 would become chronically infected. Now that we

9 know that many of these patients were chronically

10 infected to start with, we now feel that probably

11 less than 3 percent of the immunocompetent patients

12 who develop acute disease will actually become

13 chronically infected. Of course, the anti-core and

14 HBsAg remain positive in most patients.

15 Next slide, please. Let me just go

16 through, finally, some of the findings that we just

17 talked about. This is HBVd and a surface antigen,

18 anti-HBc and anti-HBs. You can see in the

19 pre-seroconversion window period\--we have a couple

20 of windows here because we used to talk about a

21 window period between the end of the HBsAg phase

22 and the development of anti-HBs in which the IgM

45

1 anti-core is present during acute disease. But

2 here I am talking about the pre-seroconversion of

3 antibodies or the seronegative, if you will, window

4 period.

5 Then, in the early acute infection both

6 the HBVd and a and HBsAg are positive. The

7 anti-core and the anti-HBs are negative. The

8 presence of HBsAg is indicative of a hepatitis B

9 infection, either acute or chronic. Just the HBsAg

10 alone\--you can\'t tell. But the presence of all

11 three of these together in the absence of anti-HBs

12 indicates an HBV infection, either acute or

13 chronic. Eventually you will lose these markers

14 and you are left with anti-HBc and anti-HBs, which

15 means a previous infection with immunity.

16 Next slide. The other findings are in

17 individuals who have a solitary anti-HBc test

18 present. They have no anti-HBs and no HBsAg. Some

19 of them may contain HBV DNA and these represent

20 low-level carriers which do not have enough surface

21 antigen present in the blood to be detectable by

22 the current assays.

46

1 The other thing is that if this is

2 negative, this could also indicate an early

3 convalescent period in which this anti-HBc will be

4 IgM. It could represent an HBV infection in the

5 remote past, as we talked about, in which the

6 anti-HBs has disappeared and you could do a vaccine

7 challenge, or it could be in many cases a

8 false-positive reaction. Most of these reactions

9 show anti-core at a very low level, again, a sample

10 to cut-off ratio somewhere between 1-3. The

11 anti-HBe is usually absent in these individuals as

12 well, and they don\'t respond to the vaccine

13 challenge.

14 Then you have a group that have no

15 markers. This usually excludes an HBV infection in

16 this case. Then you have individuals with anti-HBs

17 only. This represents a vaccine type response. It

18 is really unusual to see something else happening,

19 or you shouldn\'t see anything other than anti-HBs

20 in a patient who gets the vaccine because it only

21 contains HBsAg.

22 Next slide. This is my final slide. It

47

1 looks at discordant or unusual hepatitis B

2 serologic profiles requiring further evaluation. I

3 have probably seen all of these at some time or

4 another in my career. For example, I have a

5 patient right now who has HBsAg positive only, who

6 is anti-core negative, with 900 million copies or

7 IU of virus per ml of blood. He has been like that

8 most of his life. It happens in some young

9 children who get hepatitis B and become chronically

10 infected. It is seen in other adults, particularly

11 in Asians. But it is a really unusual phenomenon.

12 So, that is a possibility but really rare.

13 Finding of all these three markers in one

14 patient does occur in about 5-10 percent of

15 patients. It is mostly in drug users or people who

16 have been exposed to different genotypes of the

17 virus. It could be found in people who have been

18 vaccinated and have made antibodies to a different

19 genotype, and it usually is in patients who have

20 more serious liver disease.

21 Anti-HBs or anti-HBc positive only\--we

22 have talked about those phenomena. The are not so

48

1 uncommon. HBsAg negative individuals who are HBeAg

2 positive\--you shouldn\'t really see that but I have

3 seen at least two cases that have been HBeAg

4 positive, HBV DNA negative but do not have the

5 presence of surface antigen present.

6 You could have patients who are positive

7 for both e antigen and anti-e at the same time.

8 That has to do with the nuances of the test and

9 probably nothing else. And, you can find patients

10 who are anti-core negative\--I mean, you should not

11 find a patient who is anti-HBc negative but IgM

12 anti-HBc positive.

13 Well, I hope now you are a little bit more

14 familiar with the serology of this disease.

15 Antigens are followed by antibodies. HBV DNA

16 precedes the development of antigens very early in

17 the course and usually remains throughout the

18 disease entity itself. Thank you very much.

19 DR. NELSON: Thanks, Blaine. Are there

20 any questions? Harvey?

21 DR. KLEIN: Blaine, there have been a

22 number of reports of people who have low levels of

49

1 HBV DNA and have anti-HBs. Do you know if any of

2 those are infectious? Have you ever seen one?

3 DR. HOLLINGER: Well, it is not whether we

4 have ever seen one. The issue I guess is that we

5 have this question all the time about occult

6 infection in HBV DNA even though there are no

7 markers, usually in people who are very sick and

8 would not be donors, for example, liver cancer

9 patients and immunocompromised individuals. So,

10 you wouldn\'t find these as donors anyway. It is my

11 belief that most of these issues of finding nucleic

12 acid in the presence of antibodies probably means

13 it is neutralized and it is not infectious. You

14 see that with RNA found very late in the course of

15 the disease. In the presence of antibody it

16 doesn\'t appear to be infectious biologically,

17 clinically or in trials.

18 So, I think that finding anti-HBs at a

19 reasonable concentration and HBV DNA would probably

20 not indicate somebody is infectious. But you just

21 have to do these studies, and no one has really,

22 say, taken a chimpanzee and looked at these. I

50

1 think Prince did so a few years ago and the data

2 was that they were not infectious.

3 DR. NELSON: You didn\'t mention the

4 genetic variations in the surface antigen. Could

5 those lead to a false-negative surface antigen test

6 in people who were actually infectious?

7 DR. HOLLINGER: Yes, Kenrad, it is a good

8 question. There are about six or seven genotypes

9 of this disease, from a to h, but because they all

10 have a group a antigen present, they all seem to be

11 detectable by the usual tests which are available

12 today. Now, could it happen? Sure, I think it is

13 possible but I think it would be unusual.

14 DR. NELSON: One other comment too, we

15 have studied hepatitis B in injection drug users

16 and it is extremely common for them to have

17 hepatitis B core antibody only, without surface, at

18 very high levels. They are actually truly infected

19 and it is up to 20 percent of injection drug users.

20 It is possible that co-infection with hepatitis C

21 may play a part in that because they are all

22 infected with hepatitis C as well. It is a very

51

1 complex interaction. But seeing hepatitis B core

2 antibody only in somebody who actually is a drug

3 user and comparing drug users with others without a

4 history, it is like 20 percent of the drug users,

5 maybe 1 or 2 percent in gay men who have had

6 hepatitis B infection.

7 DR. HOLLINGER: Yes, you see it not only

8 in drug users but you see it in volunteer donors

9 who are found to be anti-HCV positive and then you

10 go do some other tests and they are found to be

11 anti-HBc positive only. They don\'t respond well to

12 the vaccine. And, we know that HCV interferes with

13 the replication of hepatitis B virus so that is a

14 possibility.

15 DR. NELSON: Other comments?

16 \[No response\]

17 Thanks. Dr. Herman, from Roche?

18 C. Preclinical and Clinical Data for HBV MP NAT

19 DR. HERMAN: Thank you very much. It is a

20 pleasure to be here to describe to you the results

21 of our non-clinical and clinical performance

22 studies on our COBAS AmpliScreen HBV test.

52

1 \[Slide\]

2 I am going to begin the talk with a

3 description of our non-clinical performance

4 studies, and Dr. Frank will conclude with a

5 description of our clinical study results.

6 \[Slide\]

7 Here is an outline of the talk. I am

8 going to give an overview of the COBAS AmpliScreen

9 system and then I am going to describe the

10 different portions of the non-clinical performance

11 studies and give you their results.

12 \[Slide\]

13 The COBAS AmpliScreen system is designed

14 for screening of minipool samples or individual

15 donor samples. The samples are put onto the

16 Hamilton microlab pipetting robot which prepares

17 the pools. Then the pooled or individual samples

18 are processed to extract nucleic acid with the

19 generic sample processing method. There are two

20 variations of the method, the multiprep method for

21 the pooled samples and the standard method for

22 individual donor samples, and I will describe them

53

1 in the next slide.

2 Aliquots of the extracted material can be

3 processed in parallel with our three different

4 COBAS AmpliScreen tests, the test for HBV and the

5 licensed tests for HCV and HIV. The analysis is

6 done on the COBAS Amplicor analyzer which automates

7 the nucleic acid amplification and detection

8 processes. Then, the software for the analyzer and

9 the software for the pipetting machine interact

10 with the data output management system.

11 \[Slide\]

12 This slide describes the two sample

13 preparation methods, the multiprep method which is

14 used for the minipools, and the standard method

15 that is used for individual donor samples. For the

16 minipool method, 1 ml of the pool is centrifuged at

17 23,500 g to enrich for the viral targets, HCV, HIV

18 and HBV. After the centrifugation, 900 mcL of the

19 supernatant is discarded, leaving behind the pellet

20 and 100 mcL of the supernatant. The nucleic acids

21 are extracted by adding a k-atropic lysis reagent

22 which contains the internal control. After a brief

54

1 incubation, isopropanol is added to precipitate the

2 nucleic acids. The nucleic acids are collected by

3 centrifugation. The pellet is washed with ethanol

4 and resuspended in a specimen diluent, and then an

5 aliquot of the specimen diluent can be used in each

6 of the AmpliScreen tests.

7 The standard specimen processing method

8 for individual samples is almost identical. All

9 the green steps are identical and the differences

10 are highlighted in red. So, the starting specimen

11 volume is 200 mcL instead of 1 ml, and there is no

12 concentration step. The k-atropic lysis reagent

13 with the internal control is added directly to the

14 200 mcL specimen and then the remaining steps are

15 the same.

16 \[Slide\]

17 Now I am going to describe the analytical

18 sensitivity studies that were performed. These are

19 the results using the multiprep procedure. We used

20 the World Health Organization HBV DNA international

21 standard and we prepared dilutions of it between

22 100 and 3 IU/ml and analyzed 120 replicates of each

55

1 dilution, at Roche, using 2 different kit lots.

2 This shows the results. So, we had 100 percent hit

3 rate at 100, 30 and 10 IU/ml and a 95.8 percent hit

4 rate at 5 IU/ml. The predicted 95 percent limit of

5 detection, using the PROBIT statistical method, is

6 4.4 IU/ml.

7 \[Slide\]

8 This slide shows the results using the

9 standard specimen processing procedure. In this

10 study we analyzed dilutions of the World Health

11 Organization standard from 300 to 10 IU/ml. There

12 was 100 percent hit rate on 100 replicates at 300

13 and 100 IU/ml, and 99 percent on 30 IU/ml, and 97

14 percent at 20, and 95.8 percent at 15 IU/ml. The

15 predicted 95 percent limit of detection, using the

16 PROBIT method, is 16 IU/ml for the standard

17 specimen processing method.

18 \[Slide\]

19 This slide describes the results on a

20 panel prepared by CBER. The original panel

21 contained 3 members at 100, 10 and 0 copies/ml, and

22 at Roche we prepared 4 additional dilutions from

56

1 the 100 copy/ml member at 50, 25 5 and 2.5

2 copies/ml.

3 This slide shows the results using the

4 multiprep specimen processing method and on 6

5 replicates, 100 percent hit rate at 100 copies and

6 at 10 copies/ml, then 67 percent and 42 percent

7 hits at 5 and 2.5 copies/ml.

8 Using the standard specimen preparation

9 method, 100 percent hits at 100 copies/ml with 6

10 replicates and 92 percent and 75 percent at 50 and

11 25 copies/ml.

12 \[Slide\]

13 This slide shows the results of our

14 analysis of the performance of the test on HBV

15 genotypes A through H. These samples were obtained

16 from commercial sources, and we analyzed up to 25

17 individual isolates for each genotype. The samples

18 were quantified using the COBAS Amplicor HBV

19 monitor test or, in the case of genotypes G and H,

20 monitor tests that we have in development. Then

21 the samples were diluted to approximately 2-3 times

22 the limit of detection for the multiprep method and

57

1 the standard prep method, and then they were

2 analyzed using the COBAS AmpliScreen test. So,

3 with the multiprep method and the standard method

4 all the isolates yielded positive results. So, the

5 test detected HBV genotypes A through H.

6 \[Slide\]

7 This slide summarizes the results on 40

8 commercially obtained seroconversion panels using

9 the multiprep method and the standard prep method.

10 The slide shows the number of days that DNA was

11 detected prior to detection of surface antigen

12 using a licensed surface antigen test, the Ortho

13 surface antigen test system 3. The orange bars

14 show the results with the multiprep test, and for

15 that analysis the samples were diluted 24-fold to

16 simulate minipool testing. The blue bars show the

17 results with the standard prep on undiluted

18 samples. The panels are sorted by the number of

19 days prior to antigen that DNA is detected with the

20 multiprep method. So, using the multiprep method,

21 in 38/40 panels HBV DNA was detected prior to

22 surface antigen, and in 2/40 panels HBV DNA was

58

1 detected in the same bleed as surface antigen.

2 Using the standard prep method on neat

3 samples in 39/40 panels HBV DNA was detected prior

4 to surface antigen, and in 1 panel HBV DNA was

5 detected on the same day as surface antigen. I am

6 going to show you the results on one of the panels,

7 this panel, 39.

8 Before that, with the multiprep method, on

9 the 38 panels on which DNA was detected prior to

10 surface antigen, DNA was detected an average of 17

11 days earlier, and with the standard method DNA was

12 detected an average of 22 days earlier.

13 \[Slide\]

14 Here are the results on panel 39. This

15 panel had 14 bleeds. This column shows the results

16 with the Ortho Surface Antigen Test System 3, and

17 you can see that this turned positive on bleed 12

18 at day 143. This column shows the results with the

19 minipool test, and you can see that it was positive

20 on the first and third bleed and then positive

21 again at the 11th bleed on day 113.

22 On the previous slide, on this panel it

59

1 was described as having DNA detected prior to

2 antigen 30 days in advance this one bleed. Even

3 though DNA was detected intermittently earlier than

4 that, we made a conservative interpretation and

5 only counted the number of bleeds that DNA was

6 continuously detected prior to surface antigen.

7 In this column, the results with the

8 standard preparation method on undiluted samples is

9 shown. There were 11 bleeds prior to detection by

10 surface antigen and the HBV DNA was positive in 7

11 of them but did not yield a positive result on

12 bleed 11. So, in the previous graph the standard

13 prep method was described for this panel as being

14 detected on the same day as surface antigen.

15 \[Slide\]

16 This just illustrates that even though DNA

17 was detected intermittently earlier, on multiprep

18 method we only counted 1 bleed, which was 30 days

19 in this case.

20 \[Slide\]

21 This slide summarizes the results on the

22 40 seroconversion panels. Using the multiprep

60

1 method on samples diluted 24-fold to stimulate

2 pooling, DNA was detected prior to surface antigen

3 in 38/40 panels and on the same bleed in 2/40

4 panels an average of 17 days prior to surface

5 antigen. Using the standard procedure on undiluted

6 samples, DNA was detected prior to antigen in 39/40

7 panels an average of 22 days earlier, and on the

8 same bleed on the 40th panel.

9 \[Slide\]

10 This slide summarizes the results of the

11 analytical specificity testing and the testing of

12 potentially interfering substances. For the

13 analytical specificity we looked at 38

14 microorganisms and cell lines, and all these

15 samples yielded negative results with the

16 AmpliScreen and valid internal control results.

17 There was no cross-reactivity observed.

18 For the potentially interfering

19 substances, we looked first at 95 clinical

20 specimens with different diseases in patients

21 infected with these viruses or with autoimmune

22 disease or with yeast infections, and multiple

61

1 specimens of each. These specimens were tested

2 both with the addition of HBV target and without.

3 So, the testing with the addition of HBV target was

4 looking for interference. No interference was

5 observed. Testing without HBV target was looking

6 for cross-reactivity and no cross-reactivity was

7 observed.

8 Then we looked at these various

9 potentially interfering substances. Again, they

10 were tested with and without the addition of HBV

11 target. On the tests with HBV target there was no

12 inhibition and on the tests without HBV target

13 there was no cross-reactivity.

14 \[Slide\]

15 This slide and the next look at our

16 reproducibility study. This slide shows the

17 results of the multiprep procedure. The study was

18 conducted at 3 clinical sites using 3 lots of

19 reagent. The study was conducted over 5 days with

20 2 operators at each site. Each day the operators

21 analyzed the 6-member panel, blinded 6-member panel

22 consisting of 2 negative samples and 4 samples at

62

1 low and moderate target concentrations.

2 Essentially the same results were obtained with the

3 3 kit lots and at the 3 sites. So, there was 1

4 false-positive result with lot 3 and that happened

5 at site 3. At the low copy samples the percent

6 hits were nearly identical among the 3 lots and

7 among the 3 sites.

8 \[Slide\]

9 This slide shows the reproducibility study

10 with the standard procedure and the same outcome.

11 Essentially the same results between the 3 lots and

12 between the 3 lights on the negative and the

13 positive samples.

14 \[Slide\]

15 Finally, this slide describes the

16 performance of the AmpliScreen test alone or in

17 combination with the licensed anti-core test on 918

18 antigen-positive clinical specimens. I am showing

19 the results with the multiprep test on samples

20 diluted 1:14 to simulate pool testing and with the

21 standard method on undiluted samples. So, looking

22 at the results of the AmpliScreen test alone with

63

1 the minipool method, 871 of the 918 samples were

2 DNA positive for sensitivity of 94.9 percent.

3 Using the standard method on undiluted samples, 898

4 samples were positive for sensitivity of 97.8

5 percent. These 20 samples that were not detected

6 by the standard test were among the 47 that were

7 not detected by the minipool test. All the NAT

8 negative samples were sent out for anti-core

9 testing and all of them were positive by the

10 anti-core test. So, using the multiprep method, 1

11 sample had insufficient volume for the testing, a

12 sample that was positive with the standard sample

13 prep and negative with multiprep so we couldn\'t get

14 a result on that so it was excluded from the

15 sensitivity analysis. So, for the 917 samples with

16 NAT positive results and anti-core results on the

17 NAT negative samples the sensitivity was 100

18 percent for NAT and core combined relative to

19 antigen. On the 1900 samples with evaluable

20 results using the standard method, again, the

21 sensitivity was 100 percent.

22 \[Slide\]

64

1 To summarize the non-clinical performance

2 studies, the analytical sensitivity was determined

3 on the World Health Organization standard. With

4 the multiprep method the limit of detection at 95

5 percent probability is 5 IU/ml and with the

6 standard method the limit of detection at 95

7 percent probability is 15 IU/ml. The performance

8 on the CBER panel with the multiprep method, 100

9 percent hits at 10 copies/ml and with the standard

10 method 92 percent hits at 50 copies/ml. Genotypes

11 A through H were detected by the test.

12 \[Slide\]

13 On the 40 seroconversion panels using the

14 multiprep method on samples diluted 24-fold, HBV

15 DNA was detected prior to antigen in 38/40 panels

16 an average of 17 days or earlier, and with the

17 standard method on undiluted samples DNA was

18 detected in 39/40 panels prior to antigen an

19 average of 22 days earlier, and there were no

20 panels in which antigen was detected prior to DNA.

21 There was no cross-reactivity or interference

22 observed in the analytical specificity and

65

1 potential interfering substances studies. And, the

2 sensitivity on antigen-positive specimens, in

3 combination with the anti-core assay, was 100

4 percent.

5 \[Slide\]

6 I would like to acknowledge all the people

7 who did this work, Yuanfeng Yang and his group at

8 Roche Molecular Systems did an excellent job

9 developing the assay and performing these studies.

10 Larry Pietrelli coordinated the clinical studies

11 and, in this part of the talk, he coordinated the

12 reproducibility studies. They were conducted at

13 the Community Blood Center of Greater Kansas City,

14 Royal Blood Centers, Minnesota and the Gulf Coast

15 Regional Blood Center.

16 Now I think I will turn the microphone

17 over to Dr. Frank who will describe the results of

18 the clinical performance study.

19 DR. FRANK: Thank you, Dr. Herman.

20 \[Slide\]

21 It is my pleasure to be here today to

22 describe to you a prospective study to evaluate the

66

1 screening of plasma pools from volunteer blood

2 donations for the presence of HBV DNA.

3 \[Slide\]

4 A clinical trial summary will focus today

5 on two areas of primary focus of improved safety of

6 blood donations by HBV minipool-NAT. The key focus

7 in that particular area will be looking at the

8 potential window period or pre-seroconversion areas

9 of HBV. A secondary focus will be replacement of

10 surface antigen by HBV minipool-NAT. To focus on

11 that, we will look primarily at the areas of

12 samples that were surface antigen positive that

13 were picked up by minipool-NAT and surface antigen

14 positive picked up by anti-core.

15 This clinical study was initiated in

16 August of 2002 at 5 U.S. sites, and was completed

17 in April of 2003. A total of 704,902 specimens

18 were tested with HBV minipool-NAT, of which 581,790

19 were included in the sensitivity and specificity

20 analysis. The differential between the two numbers

21 occurred because specimens were excluded if no

22 electronic results for surface antigen and/or

67

1 anti-core were available from the site.

2 \[Slide\]

3 If you look at this chart, which is a

4 schematic of the results listing the analytes

5 anti-core, surface antigen and DNA\--if you can\'t

6 see in the back of the room, the red means they

7 were HBV negative for that particular analyte; the

8 green means they were positive for that particular

9 analyte. The totals are on the far right-hand

10 column, the numbers that had that criteria. As you

11 can see, the majority of the donors were, as

12 expected, negative for all three.

13 \[Slide\]

14 We were primarily interested in looking at

15 this group down here, and those were enrolled in

16 our follow-up study, the protocol for which I will

17 be describing briefly.

18 \[Slide\]

19 Of these 4 eligible for the follow-up

20 study, the 2 areas we wanted to look at are

21 primarily the last row, which is the potential

22 window cases, that is, those cases which were HBV

68

1 minipool DNA positive but negative for core and

2 surface antigen. This represents the type of

3 pattern one would expect in pre-seroconversion

4 window cases, and then the potential surface

5 antigen false-positive results, that is, surface

6 antigen positive but core negative and HBV minipool

7 negative as well.

8 \[Slide\]

9 I mentioned the follow-up protocol that

10 was utilized and this is the follow-up protocol for

11 those columns that we followed up, the test index

12 donation was tested by alternate NAT, provided by

13 the National Genetics Institute. If alternative

14 NAT was positive, the result was quantitated and

15 then the subject was offered enrollment in a

16 6-month follow-up study for weekly draws times 4

17 then monthly draws to complete 6 months of

18 follow-up. The analytes tested during follow-up

19 are as listed on your screen.

20 \[Slide\]

21 The primary objective was to improve the

22 safety by use of HBV minipool-NAT for detection of

69

1 window period cases.

2 \[Slide\]

3 As stated previously there were 23 donors

4 that were HBV DNA positive, surface antigen

5 negative and core negative. Of these 23, 14 were

6 enrolled in the follow-up study. It should be

7 noted that 9 donors declined follow-up and for the

8 purposes of our calculations for sensitivity and

9 specificity these were presumed to be false

10 positive and were negative on additional index

11 testing as well.

12 Of the 14 enrolled donors, 2 were

13 confirmed window period cases, the details of which

14 I will be showing next, and 12 were shown to be

15 valse positive on HBV due to persistently negative

16 anti-core, persistently negative surface antigen

17 and persistently negative HBV DNA, and negative by

18 alternate NAT index specimens.

19 \[Slide\]

20 This window period case is a 26 year-old

21 male repeat blood donor with no known risk factors.

22 His HBV DNA was positive for a quantitative level

70

1 of 2000 on index donation. On day 17 post index

2 donation the surface antigen was positive, and on

3 day 48 anti-core was positive.

4 \[Slide\]

5 The next window case is a subject who is a

6 49 year-old female repeat blood donor, healthcare

7 worker, with a history of HBV vaccination. This is

8 an interesting case because she had a negative

9 anti-surface antibody result 2 months prior to her

10 index donation when she donated blood previously.

11 What is interesting is between that time, where

12 this result 2 months prior was negative, and here

13 index donation was 2,340\--now, this normally

14 wouldn\'t be done during her blood screening but she

15 was HBV DNA positive and she quantitated out at 200

16 copies/ml, which would be an infectious dose. So,

17 this is a window period case of an individual who,

18 on follow-up, never did convert for surface antigen

19 and did, on day 22, convert for anti-core. What

20 this likely represents is that somewhere between

21 the 2 weeks prior to her index donation when this

22 was negative and the result of her index donation,

71

1 she became infected with HBV and had a nice immune

2 system response to her previous HBV vaccination.

3 \[Slide\]

4 There are additional window cases I would

5 like to show to you today, and these were detected

6 by sites continuing to use HBV NAT following

7 conclusion of our clinical study. The dates for

8 those 3 sites were April, 2003 to the present, and

9 there are 3 additional window period cases that

10 were detected in the one million donations

11 screened.

12 \[Slide\]

13 The first case is a 27 year-old male

14 repeat blood donor who reported high risk male

15 sexual partners. He had HBV DNA positive on

16 donation with a quantitative level of 61,000. On

17 day 7 his surface antigen turned positive and on

18 day 36 his core was repeat reactive.

19 \[Slide\]

20 This case is a window period case of a 29

21 year-old male repeat donor who has no appreciable

22 risk factors for hepatitis B, other than a possible

72

1 acupuncture treatment for 8 weeks prior to his

2 donations, weekly treatments. His HBV index was

3 positive at a quantitative level of 2,300. His

4 surface antigen turned positive 7 days later and

5 his core turned positive 28 days later.

6 \[Slide\]

7 This last case is still on follow-up but

8 this is a 50 year-old male repeat blood donor,

9 positive on index donation with 37,000 copies/ml.

10 On follow-up he remains positive on HBV DNA and the

11 traditional blood banking serologies are still

12 pending.

13 \[Slide\]

14 In summary, I thought it was interesting

15 to look at the 5 cases that HBV minipool-NAT picked

16 up. If you look at the left-hand column, and as I

17 have noted in the footnotes of your slides, all of

18 these are repeat blood donors who could normally be

19 expected to be donating blood regularly to the

20 blood pool, and all donated blood units that would

21 have been missed by the current blood banking

22 algorithms. All of them had infectious dose

73

1 concentrations on their index donations. In fact,

2 even the lowest dose at 200 copies/ml, if the unit

3 were divided appropriately, would be sufficient to

4 infect everyone in this room.

5 \[Slide\]

6 Well, what is the yield for HBV

7 minipool-NAT? If you look at the clinical study

8 yield alone we had 2 cases that I showed you out of

9 approximately 0.7 million donations for a yield of

10 1/350,000. If we look at the continuing site data,

11 which I also showed you for the 3 cases in

12 approximately 1 million donations, the yield is

13 similar, 1/330,000.

14 Well, what does this mean in perspective

15 of what we are already doing in blood banking to

16 protect the nation\'s safety of the blood supply?

17 The yield for HBV minipool-NAT is approximately

18 equal to the yield for hepatitis C minipool-NAT and

19 the yield for HBV minipool-NAT is far greater than

20 the yield for HIV minipool-NAT.

21 \[Slide\]

22 If we look at this data that was presented

74

1 by Mike Busch in Paris of this year, this

2 emphasizes what I have just stated, that for HBV

3 the yield is approximately 1/340,000, based upon

4 his presentation. For hepatitis C, 1/230,000, but

5 for HIV, 1/3.1 million. Although these aren\'t

6 quite comparable, West Nile Virus was included for

7 because there aren\'t a plethora of antibody and

8 antigen tests available yet implemented for West

9 Nile Virus but that yield is 1/5,000.

10 \[Slide\]

11 This brings us to a sensitivity and

12 specificity calculation. You can see how we

13 assigned HBV status, on the screen here, for

14 positives, negatives, the HBV status unknown for

15 those that were surface antigen negative but core

16 positive.

17 \[Slide\]

18 So, again, in summary, here are the totals

19 and the results of the initial testing. These are

20 the potential surface antigen false-positive

21 results. These are the potential window cases.

22 This last row I have gone into detail on, the row

75

1 above, the 4 and the 3 will be going into the

2 secondary objective.

3 \[Slide\]

4 The final status determination is here, on

5 the fir right-hand column. The ones that could not

6 be determined are yellow, for those of you in the

7 back of the room. The green is HBV positive. The

8 red is HBV negative. The window cases that were

9 proven in the clinical study are shown here as 2.

10 The remaining 21, which will be accounted for in

11 sensitivity and specificity calculations, were

12 counted as HBV positive but final status HBV

13 disease negative.

14 \[Slide\]

15 To that point, our specificity

16 calculations, if you look at the total number of

17 subjects for which we have data\--the difference

18 between the numerator and the denominator is the 21

19 cases that I just spoke about a second ago to yield

20 a specificity calculation of 99.9964 percent, with

21 the ranges noted on your screen. For sensitivity

22 we looked at the positive AmpliScreen minipool HBV

76

1 results in specimens with positive HBV status and

2 divided by the total number of specimens with

3 positive HBV status. Again, these calculations are

4 for HBV minipool-NAT alone and the sensitivity here

5 is 89 out of 105 or 84.7 percent, with a range of

6 74.4 to 91 percent.

7 \[Slide\]

8 So, the primary objective conclusion is

9 that COBAS AmpliScreen HBV test has identified

10 individuals in pre-seroconversion window period

11 that would otherwise have been undetected by the

12 blood banking system. The COBAS AmpliScreen HBV

13 test is suitable for blood screening with minipool

14 strategies presented today, and these data indicate

15 that HBV minipool-NAT will increase the blood

16 safety.

17 \[Slide\]

18 Let\'s turn now to the secondary objective,

19 and that is consideration for the HBV minipool-NAT

20 and anti-core for replacing surface antigen and

21 anti-core.

22 \[Slide\]

77

1 The index donations of interest for this

2 discussion then would be those that were anti-core

3 negative/ surface antigen positive and we will

4 discuss those first. Those donors fitting this

5 category were 7 out of the total number for which

6 we have data, or 0.0012 percent. Those that had

7 core-negative/surface antigen positive HBV DNA

8 negative were 3. Of those 3, 1/3 enrolled and

9 converted to anti-core. The other 2 remaining

10 donors declined the follow-up study. These were

11 determined to be HBV final status positives. For

12 DNA negatives, that is DNA negative, core negative,

13 surface antigen positive donors, 2 out of these 4

14 enrolled in follow-up. Two of the remaining

15 declined to enroll in follow-up but we do have

16 additional data that has been available and I will

17 make available and show to you today. All 4 of

18 these were assessed to be HBV negative. Let\'s look

19 at some of those details.

20 \[Slide\]

21 This first subject was HBV DNA negative,

22 surface antigen positive, core non-reactive. On

78

1 follow-up this subject remained core non-reactive

2 throughout the follow-up study. On surface antigen

3 the subject has non-reactivity on follow-up, and

4 HBV DNA remained negative, as did the other

5 follow-up indicators.

6 \[Slide\]

7 This would indicate a case of an initial

8 surface antigen test which did not repeat on

9 follow-up, and all other negative serology results

10 indicate this patient had an initial surface

11 antigen positive that is consistent with

12 contamination or carryover.

13 \[Slide\]

14 The next case is a little bit more

15 interesting. This case is surface antigen positive

16 again on index donation, HBV negative, core

17 non-reactive. It should be noted that the surface

18 antigen was positive and repeat reactive throughout

19 follow-up but that the surface antigen was negative

20 on neutralization for all of these testing time

21 points. The donor also states a history of HBV

22 vaccination. Of note, the core never did react

79

1 throughout the course of follow-up and HBV DNA was

2 negative throughout the course of follow-up. The

3 anti-surface antibody was positive and that we

4 attribute to his vaccination status, and the repeat

5 reactive, again, was negative on neutralization

6 throughout.

7 In summary for this case, the anti-surface

8 antibody is explained by the donor\'s vaccination

9 history. And, the persistent surface antigen EIA

10 repeat reactivity, which is negative on

11 neutralization, combined with all the other

12 negative results such as anti-core, is consistent

13 with a false-positive surface antigen result due to

14 cross-reactivity.

15 \[Slide\]

16 We have additional data for the 2 donors

17 who declined the follow-up protocol. Of the

18 remaining 2 donors, 1 donor retested 1 month

19 following his index donation and was negative for

20 surface antigen, anti-core and anti-surface

21 antibody. The other donor was retested a year and

22 a half post index and was negative for surface

80

1 antigen and for core antibody.

2 \[Slide\]

3 This slide may look somewhat familiar.

4 This is a look at the total HBV infected, HBV

5 surface antigen positive specimens. In our study

6 there were 103 specimens fitting that

7 categorization. If we look at sensitivity from

8 that perspective alone, HBV detected 87 of the 103

9 specimens and was negative on 16, for a sensitivity

10 as a stand-alone of 84.5 percent in this clinical

11 study. However, the proposal of HBV minipool-NAT

12 plus anti-core antibody yielded positive in all 103

13 of 103 HBV positive cases and missed none of the

14 cases, for a sensitivity of 100 percent. This

15 parallels the non-clinical data shown to you

16 earlier today by Dr. Herman.

17 \[Slide\]

18 What are the secondary objective

19 conclusions? All 105 HBV positive donors were

20 identified by anti-core and HBV minipool-NAT

21 combined. These 105 include 2 window case donors

22 that would have been missed by anti-core and

81

1 surface antigen combined, and 103 surface antigen

2 positive cases that were identified by the HBV

3 minipool-NAT and anti-core as an alternative.

4 These data then suggest that HBV minipool-NAT

5 combined with anti-core provide an alternative to

6 combined surface antigen and anti-core screening.

7 \[Slide\]

8 In summary conclusion today, I offer that

9 the COBAS AmpliScreen HBV test improves the safety

10 of blood transfusion. I offer that COBAS

11 AmpliScreen HBV test combined with anti-core may be

12 considered as replacement for surface antigen

13 combined with anti-core. This is supported by the

14 clinical trial data, and also supported by the

15 non-clinical trial data, specifically

16 seroconversion panel data shown here today and the

17 other HBV positive clinical specimens shown here

18 today by Dr. Herman.

19 \[Slide\]

20 With that, I would like to acknowledge the

21 blood centers that participated in this large

22 study, as well as the Roche Molecular personnel.

82

1 Thank you.

2 DR. NELSON: Thank you very much.

3 Questions or comments? Yes. Harvey?

4 DR. KLEIN: On the two window period cases

5 that you detected with HBV alone, what was the

6 antigen assay that was used for those?

7 DR. FRANK: In the two in the clinical

8 study, the first window period case was Ortho Test

9 System 2, and all remaining four window cases that

10 were presented were Abbott Auzyme.

11 DR. KLEIN: And, do you by any change have

12 any data with head-to-head comparisons with PRISM?

13 DR. FRANK: I don\'t believe we ran this

14 test against any test that was not approved by the

15 FDA.

16 DR. KLEIN: Even in Europe?

17 DR. HERMAN: We analyzed the

18 seroconversion panels against the PRISM and the

19 Ortho and I can show that data if you would like to

20 see it. That was the European version of the PRISM

21 test that has the Paul Ehrlich Institute approval.

22 Do you want to see that data?

83

1 DR. NELSON: Yes, I think so.

2 \[Slide\]

3 DR. HERMAN: These are the same 40

4 seroconversion panels that I showed you previously

5 and the same NAT results but compared to the Paul

6 Ehrlich Institute licensed Abbott PRISM test, and I

7 guess this is the lot number. Again, these are

8 sorted by the results with the multiprep test on

9 samples that were diluted 1:24-fold. Those are the

10 orange bars. The blue bars represent the results

11 with the standard test.

12 \[Slide\]

13 With the multiprep method DNA was detected

14 an average of 14 days prior to antigen, and with

15 the standard method DNA was detected 19 days prior

16 to antigen.

17 \[Slide\]

18 This slide has the summary. Compared to

19 the European PRISM test, with the multiprep method

20 DNA was detected prior to antigen in 34 of the 40

21 panels, and with the Ortho DNA was detected prior

22 to antigen in 38 of the 40 panels. On the other 6

84

1 panels DNA and antigen were detected in the same

2 bleed. Using the standard method compared to the

3 PRISM test, DNA was detected prior to antigen in 38

4 of the 40 panels, and on the same bleed in the

5 other 2 panels.

6 DR. NELSON: Thank you.

7 DR. HOLLINGER: I just have a question.

8 We talk about the mean and the median between the

9 appearance of one antigen for nucleic acid before

10 the other one. But these are not tests that are

11 done every day so the panels do not include\--and to

12 say 14 days or 19 days is a little misleading I

13 think in some cases because theoretically if you

14 draw blood today and you drew one 200 days from

15 now, and that is all you had, you would say, well,

16 it would detect things 200 days before one was

17 positive and one was negative. So, you know,

18 unless samples are collected every single day for a

19 period of time, this is somewhat misleading. So,

20 give me some feeling about the days between each

21 one of these sample collections.

22 DR. HERMAN: It varies between the panels.

85

1 So, the only data that I have available on the

2 slides here is the one panel I showed you where the

3 interval between bleeds I think was as few as a few

4 days and as large as 30 or 40 days.

5 DR. HOLLINGER: It is not your fault in

6 doing this; it is just that, unfortunately, that is

7 how panels are set up. But I think all of us have

8 to understand that it may be much less than that.

9 It won\'t be more than that but it certainly could

10 me much less than that.

11 DR. HERMAN: That is absolutely correct,

12 and that is a limitation of these studies so one

13 shouldn\'t interpret this to conclude that if

14 testing was done every day these would be the

15 numbers. This is an approximation, subject to the

16 limitations of the interval between the bleed dates

17 and the different panels.

18 DR. NELSON: Actually, often

19 epidemiologists would assume a median\--a mid-point

20 seroconversion between the two days. So, if you

21 had a sample that was taken on day zero and day 14,

22 you would assume that the one that the one that was

86

1 positive on day 14 seroconverted on day 7. That

2 would be one way, a different analysis of the data

3 than probably what you have done.

4 DR. EPSTEIN: Could I get you to clarify

5 whether the apparent window period samples

6 themselves were tested with HBsAg assays with known

7 sensitivities of 0.1 ng/ml?

8 DR. HERMAN: Let me defer to my

9 colleagues. The window period cases from the

10 clinical study?

11 DR. EPSTEIN: Correct, and you say you had

12 five of them. Right? Two from the trials that

13 analyzed sensitivity and specificity and the

14 additional three\--you have five available samples

15 that could have been retested with the most

16 sensitive available HBsAg assays.

17 DR. STRONG: I have to declare my conflict

18 here because I am one of the clinical test sites,

19 but we have been able to test four of the five.

20 The most recent one hasn\'t been tested, but the

21 four have been tested on the Ortho system 3, the

22 new licensed test. It picked up one of the four

87

1 but missed three.

2 DR. KUEHNERT: Could you clarify what

3 those are? You said five.

4 DR. STRONG: The five window cases that

5 are described here. The first four were tested and

6 it picked up the one that you would expect it to

7 pick up, which is the high copy number sample. The

8 fifth sample, which hasn\'t been tested, also has a

9 relatively high copy number and you might expect it

10 to be picked up as well, with 37,000 copies.

11 DR. NELSON: Are there blood donor

12 policies or recommendations for the interval

13 between receiving hepatitis B vaccine and donation?

14 Because that is a source of a false-positive

15 infection for the surface antigen. Are there any

16 policies on that?

17 DR. EPSTEIN: FDA has no policy for donor

18 deferral after HBV vaccination. I am not certain

19 whether AABB has a voluntary policy, but I think

20 for non-live vaccines they would also not recommend

21 deferring. Someone else would need to clarify

22 that.

88

1 DR. KLEINMAN: I think that is right, Jay,

2 except that there have been some instances where

3 people have had false-positive surface antigen so

4 it is sort of unspoken that you might want to defer

5 people for a week or so, but there is no absolute

6 AABB requirement to do that.

7 DR. LEITMAN: Can I ask a different

8 question. I am not sure I am following what is

9 going on in the 16 donors who were HBsAg positive,

10 anti-core positive but multipool-NAT, COBAS

11 negative. Were those individuals individual donor

12 NAT-negative? In other words, are they infectious

13 or are they not infectious? If they are not

14 infectious, do they just happen to have a lot of

15 HBsAg particles circulating but not infectious

16 virion?

17 DR. FRANK: I have to apologize, I can

18 only hear parts of the question because of where I

19 am standing.

20 DR. LEITMAN: I don\'t think I can do that

21 again. The 16 donors who were HBsAg positive,

22 anti-core positive but NAT-multipool negative, were

89

1 they retested in individual donor NAT to see if

2 they have low level viremia or DNA nucleic acid, or

3 are they, in fact, true HBsAg positive but not

4 infectious because they don\'t have intact virion

5 but just have particles circulating?

6 \[Slide\]

7 DR. FRANK: You are talking about these

8 16?

9 DR. LEITMAN: Those 16, yes.

10 DR. FRANK: The final status here is that

11 they were HBV positive. The question you are

12 posing is are these 16 patients infectious. They

13 have surface antigen positivity and core

14 positivity. I have to defer to my colleague as to

15 whether or not we tried to quantitate with NGI the

16 HBV minipool NATs.

17 DR. PIETRELLI: I am Larry Pietrelli, from

18 Roche Molecular Systems. Yes, on those 16 donors a

19 sample was supposed to be tested by alternate NAT

20 and also by individual donation. One donor was not

21 tested by either assay. Of the 15 remaining, 10

22 were positive by ID-NAT, of which 7 sere also

90

1 positive by alternate NAT. Two were negative. One

2 was not done. Of the 5 that were negative by

3 ID-NAT, 2 were positive by alternate NAT; 2 were

4 negative; and 1 was not tested. The viral

5 concentration was low, as expected.

6 DR. LEITMAN: Thank you.

7 DR. KUEHNERT: I have a follow-up question

8 about those 16. They were core antibody positive.

9 Is there any way to quantitate that level of core

10 antibody positivity? Were any of these at an

11 equivocal level? I am just sort of getting at, you

12 know, whether you had greater numbers whether some

13 of these might have been close to a threshold for

14 missing them by core antibody positivity.

15 DR. FRANK: I don\'t have that data. I

16 don\'t know whether my colleagues have access to

17 that data today.

18 DR. PIETRELLI: No, we did not collect

19 that information but we could go back to the sites

20 to see what the S to CO was.

21 DR. HOLLINGER: I have a technical

22 question. Is there are a reason you used 24,000

91

1 times g for pelleting? I know others have used

2 40,000 times g for pelleting for an hour at the

3 enhancement stage, so to speak. Also, why did you

4 use 24 samples in your minipool or multipool?

5 DR. HERMAN: I can answer the first

6 question about the centrifugation. It is a

7 limitation of the instrument that is widely

8 available, which is a table-top centrifuge. It is

9 not quite an ultracentrifuge so it is more

10 convenient and easier to use. That was a choice of

11 what equipment would be the most suitable for the

12 multiprep procedure for all three virus targets.

13 DR. HOLLINGER: And the other question?

14 DR. HERMAN: The choice of pool size, I

15 will defer to Mike.

16 DR. STRONG: The pool size is one that was

17 selected for the HIV, HCV trials which were

18 concluded a couple of years ago and were licensed.

19 So, it was just to continue with the logistical way

20 in which laboratories operate to be consistent with

21 the other testing, and it is what the software does

22 for us.

92

1 DR. NELSON: It is interesting that there

2 are many places, in the Orient particularly, where

3 core antibody testing is not done because of very

4 high rates of positivity. So, that would cast some

5 limitation. Even though the NAT assay would be

6 useful under those circumstances, it wouldn\'t

7 perhaps be as useful as continuing using the core

8 antibodies as is done in the U.S. and Europe. You

9 had a question, Donna?

10 DR. DIMICHELE: Thank you. I was just

11 wondering if anybody can estimate, based on these

12 data or based on your data, what the residual

13 risk\--in using your assay, if your assay was to be

14 implemented with core antibody testing, what do you

15 estimate the residual risk of transmission of HBV

16 would be through transfusion?

17 DR. FRANK: That is a good question, and I

18 can say that we have shown the yield today but in

19 terms of discussion of residual risk, Dr. Kleinman,

20 would you like to comment?

21 DR. KLEINMAN: Yes, Steve Kleinman. I am

22 a consultant to Roche Molecular Systems on this

93

1 project. The residual risk estimate is dependent

2 upon what you think the risk is now prior to

3 initiating HBV NAT. We have estimated that risk

4 through the REDS study on two occasions, one that

5 was published in 1996 and then we kind of confirmed

6 the same numbers about six years later as about

7 1/60,000. The risk estimate is based on the

8 incidence window period model and the data for that

9 model with HBV are not as strong as they are for

10 HIV and HCV. So, other people have estimated the

11 residual risk now prior to NAT as being lower than

12 1/60,000, being about 1/200,000.

13 At any rate, if you accept the 1/60,000

14 risk estimate, and then you take a look\--the

15 question is how much does this new assay decrease

16 the window period. If you draw on data that was

17 published by Robin Biswas and colleagues on their

18 panel testing of decrease of the window period, you

19 get about a 10-day decrease of the window period in

20 that study, and in this study it looks like the

21 window period decreases by 17 to 20 days based on

22 the panel. But, as Dr. Hollinger mentioned, that

94

1 is a maximum case because you don\'t have closely

2 spaced samples.

3 At any rate, if you take a 10-day

4 lessening of the window period and you apply it to

5 what we think the current window period is, about

6 59 days, and you work this through with the window

7 period and the incidence of HBV, you would probably

8 get that the residual risk is still 1/200,000 to

9 300,000 even with this test being implemented.

10 Actually, it may even be 1/100,000. So, you are

11 removing some of the risk but because you are only

12 cutting the window period back 10 days out of a

13 potential 59 days, the likelihood is that most of

14 the risk still remains even with minipool-NAT and

15 that in order to decrease that risk further you

16 have to go to either smaller minipools or

17 individual donation NAT, which would buy you more

18 in terms of lowering the window period. So, you

19 are making an incremental step in decreasing the

20 risk; you are not decreasing the majority of what

21 we think is the residual risk.

22 DR. NELSON: These data are heavily

95

1 dependent on what the window period is, which may

2 vary in different populations.

3 DR. STRONG: Yes, they are dependent on

4 the incidence and what you think the current window

5 period is, and that is something that there hasn\'t

6 really been good data on. We have estimated the

7 current window period as 59 days based on some

8 older work from the TTVS study and then, through

9 REDS, we made a revised estimate of the window

10 period through mathematical modeling to be about 45

11 days now, the infectious window period. So, these

12 are estimates. We don\'t really know what the

13 current window period is so it is a little bit

14 difficult. We don\'t know exactly how much we

15 shortened it so that is why I think you have to say

16 that we can\'t make the kinds of precise estimates

17 that we have made about HCV and HIV.

18 DR. DIMICHELE: Can I just ask you a

19 follow-up question then? What is the

20 estimate\--let\'s say given that residual risk, what

21 is the estimate of the impact of vaccination,

22 widespread vaccinations now going on in the younger

96

1 population with respect to when they become blood

2 donors? Does anybody know how the risk of

3 transmission will be decreased just by vaccination,

4 widespread vaccination alone?

5 DR. KLEINMAN: I don\'t know the answer to

6 that. I will answer kind of a related question,

7 which is what is the risk to recipients? As more

8 recipients get vaccinated, then they should be

9 immune to a challenge, you would think

10 theoretically even if they were exposed. However,

11 most of our recipients are in the older age group,

12 60 and above, and some have compromised immune

13 systems. So, I don\'t think that vaccination is

14 going to protect much of the recipient population.

15 Your question is different, whether it makes donors

16 less likely to acquire new HBV infection and I

17 don\'t know that anybody has worked that through

18 mathematically.

19 DR. ALTER: Harvey Alter, NIH. The

20 mathematical models have been extremely useful but

21 there has always been a little discomfort with HBV

22 in that you just don\'t see the cases as frequently

97

1 as you would have predicted from the model.

2 It seems to me now that if you make the

3 assumption that the real risk would be coming from

4 HBV DNA positive donors, you could actually

5 determine what the actual risk is now by taking the

6 best or maybe all the different HBV DNA assays and

7 testing these samples as single donations. If you

8 are picking up 1/350,000 now in a minipool format

9 you will pick up even more in an individual donor

10 format. That theoretically would be the risk. If

11 we can exclude those donors, that risk would be

12 removed. It seems too simplistic to be true but I

13 would like to hear a counter argument.

14 DR. BUSCH: Mike Busch. I wanted to

15 comment on the vaccine issue. In this study, I

16 think of the yield cases one of the yields that is

17 in the original clinical trial, clearly by history

18 vaccinated person, had an anamnestic anti-surface

19 response, low viremia in the setting of the index

20 sample. I think one of the additional yield cases

21 also had anti-surface on index. It is interesting

22 that the data from Taiwan is showing that when they

98

1 have applied NAT to donor screening\--this is a

2 massively vaccinated population\--they are seeing as

3 these young people, you know, enter adolescence and

4 in their 20s, they are seeing a fairly high rate of

5 the same kind of phenomenon. These are essentially

6 vaccine breakthrough infections. So the vaccine,

7 rather than being sterilizing\--still people are

8 getting exposed and infected and, in a sense,

9 boosted from a wild exposure. In their setting the

10 vast majority of their NAT yield are people who

11 have been vaccinated and have anti-surface and

12 never develop surface antigen, never develop

13 chronic infection. So, the critical question of

14 whether these could transmit I think is still on

15 the table.

16 DR. STRONG: Another point to follow-up on

17 what you were commenting on, on the value of

18 anti-core, I think this clinical trial also

19 demonstrated, as has been published, a small yield

20 of DNA positives from the anti-core positive group,

21 roughly in the same area of 5.5 percent or

22 thereabouts. Also, I think it demonstrated a

99

1 difference in specificity with the anti-core assays

2 between the two licensed tests. So, there is

3 clearly a large number of false-positive anti-core

4 donors that we have excluded on the basis of

5 false-positive reaction. I think those of us who

6 have been involved in this trial, we have been

7 anxious to try to push the sensitivity of the assay

8 to allow us to reenter a lot of those donors

9 because it is a very large number.

10 DR. HOLLINGER: I just want to follow-up

11 briefly on what Mike said. I mean, this shouldn\'t

12 really surprise us very much, if you look at most

13 of the vaccine trials and follow patients for ten

14 years or so you will see anti-core appearing in

15 these patients. I just mentioned that anti-core is

16 a marker of viral replication. So, somewhere along

17 the line these patients will probably have DNA in

18 the bloodstream. The issue is whether it is

19 infectious or not and that is, of course, I think a

20 very critical issue with it.

21 Then I just wanted to ask a question

22 either of Harvey or Steve about how many cases are

100

1 recorded now of transfusion-transmitted hepatitis

2 B? I don\'t see very many. I don\'t want to get

3 back to this argument we had about 20 or 30 years

4 ago when we said there was no hepatitis C or

5 non-A/non-B hepatitis when really there was a lot.

6 DR. KLEINMAN: No, I think that is exactly

7 right, Blaine. There are very few post-transfusion

8 hepatitis B cases reported. As you know, it is a

9 question about whether those people become

10 symptomatic. So, there may be asymptomatic cases.

11 Some may go on to be chronic carriers. That is

12 certainly possible. Secondarily, even if a case

13 occurs, is it recognized by the clinician?

14 It is certainly a correct statement that

15 we don\'t see the number of HBV clinical cases

16 reported as post-transfusion cases as the

17 mathematical models would predict. So, then you

18 have two potential explanations. One, the

19 mathematical models are wrong and these cases don\'t

20 occur or, two, the cases occur and they are not

21 recognized and reported. I don\'t think we have a

22 way to sort out which one of those hypotheses is

101

1 correct. Harvey\'s point is that we would have to

2 take a different approach to estimate risk, that

3 is, we would have to use the most sensitive DNA

4 assay available, hoping we could pick up one

5 copy/ml or even less. By that, we could basically

6 make the equivalence that if we have a DNA-emic

7 specimen that equates to an infectious specimen,

8 and we could do that kind of study that was done 15

9 years ago or I guess 17 or 18 years ago for HIV,

10 but that would be an extremely laborious and

11 expensive study to do.

12 DR. NELSON: I think we will take a break

13 at the moment and then come back for the open

14 public hearing. Maybe 20 minutes.

15 \[Brief recess\]

16 DR. NELSON: The meeting is now in session

17 again and we will start with an open public hearing

18 on the topic presented of HBV DNA testing. Before

19 we start I will read this statement.

20 Both the FDA and the public believe in a

21 transparent process for information gathering and

22 decision making. To ensure such transparency at

102

1 the open public hearing session of the advisory

2 committee meeting, FDA believes that it is

3 important to understand the context of an

4 individual\'s presentation.

5 For this reason, FDA encourages you, the

6 open public hearing speaker, at the beginning of

7 your written or oral statement to advise the

8 committee of any financial relationship that you

9 may have with the sponsor, its product and, if

10 known, its direct competitors. For example, this

11 financial information may include the sponsor\'s

12 payment of your travel, lodging or other expenses

13 in connection with your attendance at the meeting.

14 Likewise, the FDA encourages you at the beginning

15 of your statement to advise the committee if you do

16 not have any such financial relationships. If you

17 choose not to address this issue of financial

18 relationships at the beginning of your statement,

19 it will not preclude you from speaking.

20 With that, Mike Busch?

21 Open Public Hearing

22 DR. BUSCH: Thank you.

103

1 I wanted to just briefly touch on three

2 items. One is just one slide sort of summarizing

3 the different context of some of the issues that

4 were raised in the questions as to the value of HBV

5 minipool-NAT both relative to the other NAT systems

6 and ID-NAT. Then in most of my comments I want to

7 focus on the issue of can we drop either anti-core

8 surface antigen and, if not or if the data doesn\'t

9 support it at this point, what further studies

10 would be useful to address that. I have Roche\'s

11 computer here\--

12 DR. NELSON: That sounds like a conflict

13 of interest!

14 \[Slide\]

15 DR. BUSCH: The committee does have this.

16 This is a published analysis of cost-effectiveness

17 and I am not going to talk at all about sort of

18 cost-effectiveness but I just wanted to show one

19 slide that sort of emphasizes the relevant clinical

20 impact of these three viruses. We tend to talk

21 numbers as if each of these viruses is equivalent

22 and the NAT yield is equivalent, but what this is

104

1 showing is the number of quality life years lost

2 per transmission.

3 What you can see is that for HIV it is

4 about 7 quality life years to the average 60 years

5 old transfusion recipient. Transmission of HIV

6 would cost that person 7 quality life years; HCV,

7 0.6 and HBV, only 1.6. This is because most

8 recipients are older people who naturally resolve

9 the acute infection of HBV, and even if chronic it

10 rarely evolves to significant morbidity/mortality

11 over the persistent life span of the average

12 recipient. So, you can see that essentially HBV is

13 one-quarter as clinically important as HCV and 44

14 times less important than HIV.

15 The other point I wanted to make has to do

16 with this issue of going from current serologic

17 testing to minipool versus serologic testing to

18 ID-NAT, and how much of the yield that would be

19 accomplished by going to ID-NAT is detected by

20 minipool-NAT. For HIV we had very sensitive

21 antibody tests in place so NAT by minipool closes

22 the window by about 5 days and ID closes it by

105

1 another 5. So, we picked up about 50 percent of

2 what could be picked up but the risk is very low.

3 With HCV, because of the long plateau

4 phase, 95 percent of the window period is detected

5 by minipool-NAT. With HBV, because of the slow

6 ramp-up, at least the model estimates and some of

7 the empiric data like in the Biswas paper would

8 suggest that minipool is only picking up about 23

9 percent or a quarter of what could be detected by

10 ID.

11 Next slide. The issue of anti core and

12 could we get rid of anti core\--there are three

13 studies that have been either fully published or in

14 abstract form, actually the Roche data, that have

15 looked at high numbers of donations that were

16 anti-core only reactive\--so surface antigen

17 negative, anti-core positive\--and subjected then

18 HBV NAT. Each of these studies, as you can see,

19 has given almost identical rates both on a per

20 anti-core and, if you extrapolate, on a

21 per-transfused unit basis of detecting DNA in

22 donations that were surface antigen negative. So,

106

1 about a quarter to a half percent in all these

2 studies.

3 What is interesting is that in each of

4 these studies there was quantitation done in one

5 context or another, and all of these viremic

6 anti-core reactive units, surface antigen negative

7 have very low viral loads. In Roche\'s data, for

8 example, 92 percent based on previously presented

9 work of their viremic anti-core only were negative

10 by minipool but only detected by ID-NAT. So, these

11 are very low viral loads that really would require

12 ID-NAT to detect.

13 \[Slide\]

14 This is just a summary and I am not going

15 to walk through this but with respect to low

16 viremic anti-core reactive donations or anti-core

17 only\'s there are a number of studies that have

18 documented transmissions, rare but there are

19 transmissions from these low viremic units. Again,

20 I don\'t have time to go into these but we also know

21 that in liver transplantation from anti-core

22 reactive, surface antigen negative donors very

107

1 frequently transmits the virus. So, these people

2 who have low viremia do harbor infectious virus

3 and, obviously, the anti-surface status is a

4 factor. But I personally don\'t think there is any

5 prospect for dropping anti core.

6 \[Slide\]

7 Next slide. This was alluded to earlier.

8 There was one study where purposeful transfusion of

9 these anti-core reactive, DNA positive, surface

10 antigen negative units into chimps was done. This

11 was by Fred Prince and was published. These did

12 not transmit. Three patients who had remote

13 hepatitis B, persistent anti-core, negative

14 antigen, low-level DNA. However, the caveat is

15 that all three of these donors had anti-surface and

16 the volume inoculated into chimps was quite small,

17 1 ml. So, I think larger studies with larger

18 volumes may be indicated to potentially explore the

19 infectivity of these units.

20 \[Slide\]

21 Next slide. In terms of dropping antigen,

22 which I think is the more likely and I believe

108

1 optimistically we will get there, I think clearly

2 for these viruses like HIV, HCV, HBV where there is

3 not only the acute phase but there are chronic

4 carriers and some of these chronic carriers have

5 low-level infectious viremia the optimal paradigm

6 really is the combination of a front-end sensitive

7 direct assay and a serologic test for antibody.

8 For HBV we have both antigen and NAT which could be

9 viewed as redundant, analogous to P24 antigen in

10 HIV NAT. Clearly, on the front end we know, and

11 saw from Roche and other studies, that HBV NAT is

12 clearly more sensitive than antigen during the

13 acute phase.

14 Next slide. But the problem is, as Blaine

15 summarized, HBV is really an unusual virus in that

16 it produces in chronic infections amazingly high

17 levels of circulating antigen in the absence of

18 infectious particles. Therefore, this excess

19 antigen can occasionally be detected in the absence

20 of detectable DNA by minipool or even ID-NAT. I

21 want to present a recent study on that. Therefore,

22 to really be sure that we are not taking a step

109

1 back and dropping antigen when we have NAT, we need

2 to do large studies and I think Roche\'s data is

3 very impressive but whether it is enough is for the

4 committee to decide. But these studies need to

5 look at these issues in a different context,

6 obviously, the front-end window period anti-core

7 negative as well as chronic carriers. But also I

8 think they need to reflect populations with

9 different endemnicity and different routes of

10 transmission; populations that have been vaccinated

11 because we are, as I mentioned earlier, seeing

12 vaccine breakthrough infections, and how would they

13 play out in terms of antigen versus DNA; and also

14 genotypes and mutants.

15 Next slide. Just to contrast, one of the

16 big differences in acute phase versus chronic is

17 the relationship between the DNA load and the

18 antigen reactivity. This is one of a number of

19 studies. This is a Japanese study. During this

20 acute phase these were all anti-core negative

21 front-end infections. They were actually all

22 detected, 181 units detected as negative by the

110

1 Japanese particle agglutination antigen test.

2 Actually, 105 of these were reactive by the PRISM

3 assay. So, only a subset, about 40 percent of

4 these remained negative. But what you are seeing

5 here is a very nice linear regression relationship

6 between the reactivity in the antigen test and DNA

7 load. That is typical of the front-end acute

8 viremic phase.

9 Next slide. I want to summarize now a

10 paper that is in press in collaboration with Mary

11 Kuhns and Steve Kleinman from the REDS group, where

12 we took 200 antigen positive, anti-core positive

13 donations in REDS. We first subjected them to

14 quantitative HBV DNA using the Amplicor Roche

15 assay. This assay has a sensitivity of 400 copies,

16 and 64 percent of the antigenic units had DNA above

17 400 copies. Those samples that were negative, the

18 72, were taken through a more sensitive assay that

19 had a sensitivity of about 65 copies, which is

20 probably comparable to minipool type NAT, and 12

21 remained negative even at that level. Those 12

22 samples were taken to a very high sensitivity,

111

1 essentially 1 copy/ml assay, high volume, and still

2 there were 6 that were negative. So, we ended up

3 with still 3 percent negative even after taking it

4 through sequential increasing sensitivity assays.

5 So, these are the chronic carriers in whom DNA is

6 undetectable with at least one time point and one

7 high sensitivity assay.

8 Next slide. This is showing the

9 relationship between antigen reactivity and viral

10 load. Unlike that nice linear relationship, here

11 there it is essentially a scatter plot. These are

12 the 3 that were negative by all NAT. These are the

13 ones that were detected only by the high

14 sensitivity. These are the Amplicor negative but

15 single input, not as sensitive, positive. And,

16 these are the quantifiable. You can see that

17 relationship is not observed in chronic carriers.

18 Next slide. That is people who have

19 anti-core. I think Roche did a nice job of sort of

20 saying that if we keep anti-core the issue is not

21 that problem with anti-core positives, antigen

22 positives having absence of DNA. It is really are

112

1 there donations that are antigen positive that lack

2 anti-core that are truly infectious and not

3 detectable by NAT?

4 In the REDS program and in other studies

5 varying 1-5 percent of antigen positive donations

6 lack anti-core. Now, when these are worked up most

7 of these are window phase seroconverters so they

8 have high-level DNA very consistent with acute

9 infection. But in a proportion of DNA negative,

10 and we saw those cases in Roche, the issue is

11 studying enough of those cases to sort out are they

12 true HBV infections, that either there is a

13 mutation not detected by NAT or individuals who

14 have failed to form anti-core, chronic carriers who

15 have low-level DNA and have failed to form

16 anti-core. Do they lack contamination, which I

17 think most of them are? Are they persistent,

18 non-specific antigen reactivity, and Roche showed

19 us an example of that? Or, are they possibly

20 recent vaccinees?

21 Next slide. This is three studies, two

22 published papers and some unpublished data from

113

1 REDS that have looked for these people who are

2 antigen positive, anti-core negative and either

3 lack or have very low-level DNA. I am not going to

4 go through these in detail but in Japan one study

5 identified three such donors who had no history of

6 vaccination and who remained low-level PCR-reactive

7 with only a very high sensitivity enhanced assay;

8 remained anti-core non-reactive, so never

9 converted; and, again, remained antigen positive

10 and very low-level PCR-reactivity for over a year.

11 The French group, Couroce\'s group reported

12 two donors from endemic countries as well, with 0.1

13 percent of their antigen-positive donors who had

14 this pattern of persistent antigen without

15 anti-core and very low-level HBV DNA, and no

16 history of vaccination or immunosuppression and no

17 evidence of mutations to explain the failure of

18 this person to form anti-core.

19 In REDS\--this is a cross-sectional study

20 so we weren\'t able to do follow-up, but we had 20

21 antigen-positive donors who lacked anti-core.

22 Sixteen of these were positive for DNA and were

114

1 probably typical acute phase, but 4 were negative.

2 Three of these were probably contaminations. They

3 had no other serologic markers, probably represent

4 surface antigen carryover. But one had anti-e and

5 could represent an atypical carrier.

6 So, just a caution that there are some

7 studies, particularly from endemic settings where

8 there may be people who have antigen in the absence

9 of anti-core and low-level or absent DNA, and I

10 think we just need to study these further.

11 Next slide. Just in conclusion, I do

12 think that we would see a small incremental yield

13 by minipool-NAT but the clinical impact of that I

14 think needs to be considered as well as the yield,

15 and we also need to view the context of what would

16 we get were we to get all the way to ID-NAT.

17 I am optimistic that we will eventually be

18 able, with ID-NAT or very small pools or high

19 sensitivity HBV DNA, to get rid of antigen,

20 however, I think this is going to require further

21 studies. Particularly, we are capturing units

22 daily that could be worked up to accrue large

115

1 numbers with high volume of the plasma components

2 from these various sort of atypical patterns.

3 Particularly relevant is that I do think the

4 combination of NAT anti-core is the ultimate goal.

5 Particularly relevant are these samples that are

6 antigen positive, anti-core negative, and really

7 both studying these samples and particularly

8 enrolling and following the donors, as Roche did,

9 to determine whether these are false positives or

10 contamination. Thank you.

11 DR. NELSON: Thank you. Comments? Yes,

12 Harvey?

13 DR. KLEIN: Mike, we heard from Dr. Alter

14 earlier that, with the problems in trying to

15 calculate what the residual risk is, it might be

16 reasonable as a start to do a study simply by

17 taking 400,000, 600,000 specimens and using a

18 single unit detection system along with the

19 serology. I would just like to know what your

20 opinion on doing that kind of a study might be.

21 DR. BUSCH: Yes, I think that is a good

22 idea. I mean, we have the Biswas paper included

116

1 comparing assays on window period panels neat

2 versus minipool. That is kind of these model

3 estimates that minipool picks up only a quarter of

4 what might be detected neat. But, yes, I think

5 such a large-scale study either with neat\--you

6 know, one of the issues with Roche\'s system is

7 their multiprep high extraction volume assay\--we

8 saw the data that was comparing the multiprep pool

9 of 24 versus the standard prep neat, but had they

10 applied their high sensitivity multiprep neat,

11 which is what was done in the Biswas paper, they

12 would have seen a greater incremental closure than

13 was documented by ID-NAT. So, doing a head-to-head

14 comparison study of a very small pool with proposed

15 minipool, I expect, would double or greater than

16 double the yield.

17 DR. KLEIN: That might give us at least an

18 idea of what the risk is now. It seems as if no

19 one is very confident about that.

20 DR. NELSON: One other issue too I

21 think\--I know you didn\'t talk about the

22 cost-effectiveness in any detail but your initial

117

1 slide assumes that it is a 60 year-old person that

2 is transfused but there are kids with thalassemia

3 and pediatric, depending on the life expectancy,

4 etc. of the patient, I think those are different

5 issues. Yes?

6 DR. KUEHNERT: On that slide you were

7 reviewing surface antigen positive, core antibody

8 negative donors in the last bullet of the REDS.

9 What is the denominator of those tested?

10 DR. BUSCH: Unfortunately, I don\'t have

11 that number.

12 DR. KUEHNERT: The other question I had is

13 you had 20 antigen positive and 16 DNA positive by

14 the standard PCR assay. So, the PRISM assay was a

15 false negative.

16 DR. BUSCH: These were people who were

17 antigen positive, anti-core negative and 16/20 had

18 ample levels of DNA and were probably acute phase.

19 They were picked up but at that point it was

20 Auzyme\'s. So, they were picked up by Auzyme and

21 those 16 would have been sort of, if you will,

22 run-of-the-mill acute hepatitis B.

118

1 DR. KUEHNERT: So, 16/20 were DNA positive

2 originally.

3 DR. BUSCH: Yes. They were all antigen

4 positive and 16 were DNA positive.

5 DR. KUEHNERT: And then 4 that were

6 negative. Okay, thanks.

7 DR. ALLEN: Mike, thanks for that very

8 nice overview. Obviously, the committee and the

9 FDA, when they are considering how to place these

10 things, is looking at just one test at a time.

11 What is the implication of adding this into the

12 whole system that is already there in a blood bank

13 laboratory with or without discontinuing the

14 surface antigen test?

15 DR. BUSCH: Well, it is certainly

16 possible. Certainly, at sites that are doing Roche

17 today the system is optimal and they have actually

18 already done the extraction and they are just

19 taking a residual aliquot of the resuspended pellet

20 lysate and directing it to an automated system, you

21 know, to get the results. So, it is a moderate

22 workload impact. The other platform, the Gen-Probe

119

1 Chiron platform, you know, that test is I believe

2 in clinical to try that version assay. Especially

3 if you are deriving it off the current pool, I mean

4 that sort of becomes the challenge. You know, to

5 do it on individual donation samples while we are

6 still doing the licensed pooled assay for HIV/HCV,

7 that becomes, you know, a substantially greater

8 task. To go to smaller pools\--I mean, the licensed

9 assays for HIV/HCV are approved for up to a

10 particular pool size so it is possible to go to

11 smaller pool sizes. You are still retaining the

12 licensed status of those other assays, which I

13 personally think is the more appropriate way to go

14 to get to pools of 4 or 6.

15 DR. ALLEN: And in terms of integrating a

16 test into the laboratory software system for\--

17 DR. BUSCH: I think that is not a huge

18 problem.

19 DR. ALLEN: And do you foresee that

20 availability of this test will enable algorithms

21 that will enable entry of donors that are currently

22 deferred who clearly are not infected in any way

120

1 with hepatitis but have some false-positive tests?

2 DR. BUSCH: Right, there has been a lot of

3 discussion about anti-core reentry and, certainly,

4 the current expectation is that that would require

5 that the donors be negative on anti-core on a

6 follow-up period so they can\'t be the real

7 HBV-exposed population or the old false positives.

8 They not only need to be negative on current test

9 of record or improved anti-cores, but they also

10 need to be DNA negative with a single input assay,

11 potentially with a single input assay run on

12 multiple reps in order to make sure everybody is

13 confident that these people do not have occult

14 viremia.

15 DR. ALLEN: Thank you.

16 DR. NELSON: Thanks, Mike. Donna?

17 DR. DIMICHELE: I just want to actually

18 comment on your comment, and that was sort of the

19 basis of my previous comment. You know, in the

20 pediatric populations that are getting chronically

21 transfused, I just want to say that all of them

22 have been vaccinated ever since this vaccine has

121

1 been licensed, and we pay a lot of attention to

2 documenting primary serological response so that,

3 you know, their risk is primarily of getting

4 reinfected bit certainly not chronically infected

5 unless they happen to be immunosuppresed because

6 they have already been HIV infected or HCV

7 co-infected. But, for the most part, you know, in

8 the chronically transfused sickle cell thalassemic

9 and hemophilia populations, they have been

10 vaccinated and monitored for a very long time.

11 DR. NELSON: Thank you. Dr. Andrew

12 Heaton, from Chiron?

13 DR. HEATON: Thank you for the opportunity

14 to present early Ultrio or Triplex test results as

15 part of our worldwide introduction.

16 As you may be aware, Chiron Gen-Probe

17 received CE approval in January of this year. We

18 are beginning to see significant implementation on

19 a worldwide basis. We anticipate, by the end of

20 the year, the availability to those countries

21 covered by that application to be able to perform

22 individual donor testing. We also have reduced

122

1 pool size software under review at the moment in

2 order to allow our customers a wide range of

3 testing options in terms of sensitivity.

4 Next slide, please. As I mentioned, CE

5 approval of our Ultrio test occurred in January,

6 and it allows the availability of HBV NAT testing

7 to European countries. As I will show you in a

8 minute, the high prevalence countries are those who

9 have adopted this first. There has been

10 significant early adoption and I will show you some

11 of the early yield cases that we have experienced.

12 Next slide, please. As you might expect,

13 the countries which have adopted the Ultrio test,

14 dots marked in green, represent the southern

15 European countries who have a higher prevalence of

16 HBV. The second group of countries where we have

17 conducted or are conducting in-country evaluations

18 include the more eastern countries in Europe who

19 are joining the European Union and, therefore, will

20 become the subject to blood safety directive; and

21 then a number of very high prevalence countries in

22 the East. So, there is significant worldwide

123

1 introduction of HBV NAT testing and it is clearly

2 related to the prevalence in the countries

3 involved.

4 Next slide, please. We have had 2 yield

5 cases. The first yield case occurred in Spain, in

6 the Madrid Community Blood Center, where the sample

7 was tested in pools of 8 and they got their

8 positive after 11,000 units had been tested. They

9 have now tested 13,000 so, if you are running the

10 clock, about 1/13,000 is the incidence rate. The

11 donor was hepatitis B core antibody positive and

12 the HBV quantitation, using an in-house

13 quantitative method, was 88 IU/ml and 650 copies/ml

14 when the test was performed by NGI.

15 In Italy, individual donor testing

16 identified 1 positive yield case in 9,732. The

17 donor was also hepatitis B core antibody positive.

18 In-house testing revealed 11 IU and it was tested

19 out at 215 copies by another reference method.

20 Next slide, please. In terms of yield

21 then, or predictive yield, really the world falls

22 into three major categories. The first of those is

124

1 the low incidence countries which use hepatitis B

2 core antibody testing, where the predicted yield

3 may be expected to be very low. The second is

4 really the rest of the world excluding the United

5 States and France, which are the only two countries

6 that now do core antibody testing as routine, where

7 you would expect the yield to be associated with

8 the incidence of hepatitis B core antibody

9 positivity and the yield, which is about 0.5

10 percent DNA positive in that population or around

11 1/40,000. Then, in the very high prevalence

12 countries in the East we have somewhere around 20

13 and 70 percent hepatitis B core antibody positive

14 where you would expect a much higher yield.

15 So, if you average out the first two yield

16 studies, we are running about 1/10,000, which is

17 slightly higher than we would have predicted. It

18 is interesting in that respect that Canada, which

19 has just started HB core antibody testing on a

20 North American type donor population, noted 1.5

21 percent hepatitis B core antibody positive in a

22 donor population that would be expected to be very

125

1 similar to the U.S.

2 Next slide, please. The current questions

3 then as we go through the implementation process,

4 there is a rapidly growing tissue bank sector in

5 the United States which is looking for nucleic acid

6 testing to assure the quality and safety of their

7 components. An issue that badly needs attention

8 there is a definition of sample standards because

9 sometimes what the tissue banks call a blood sample

10 is really neither blood nor a sample, and it

11 certainly isn\'t subject to consistent standards.

12 In another area, the blood banks have

13 asked us to look carefully at hepatitis B core

14 antibody false-positive reentry and correct

15 classification of hepatitis B core antibody and

16 they would like to see HBV NAT testing used to

17 assist in preventing the false classification of

18 donors who are not truly positive for the hepatitis

19 B core antibody.

20 There is certainly a need for infectivity

21 studies of NAT negative, HBsAg positive donations.

22 We have received requests from a couple of centers

126

1 to work with them on reviewing these issues,

2 particularly those centers in the East.

3 Finally, we have made dHBV available under

4 IND and, indeed, 4-5 blood centers have completed

5 our clinical trial and are now using dHBV on a

6 routine basis.

7 The worldwide implementation key issues

8 then are higher than expected yield that will

9 nearly always be core antibody positive. We now

10 need to look at the rate of DNA positivity in a

11 B-core positive population. In the U.S. that is

12 only about 0.5 percent but in Taiwan it is reported

13 to be as high as 10 percent.

14 We need to look at the implications of

15 vaccination. We have already seen one donor who

16 silently seroconverted from anti-HBs to anti-HBc

17 without having a period of HBsAg positivity. So,

18 the implications of bringing this test to make it

19 available on a highly vaccinated population will

20 clearly be significant.

21 Lastly, in the East we are facing the

22 issue of wide-scale vaccination in a highly endemic

127

1 population, a population which is now loaded then

2 with vaccine-escape mutants. In Taiwan they report

3 about 1/1,000 vaccinees seroconverts to HB-core

4 antibody per year. So, there is a significant

5 ongoing breakthrough in a community situation.

6 Finally, as we complete our clinical trial

7 we will be looking to carefully evaluate the

8 relationship between test pool size and the desired

9 sensitivity. Thank you.

10 DR. NELSON: Thank you, Dr. Heaton.

11 Questions? Comments? Yes, Susan?

12 DR. LEITMAN: I have a question on slide

13 5. We have seen that you can\'t measure residual

14 risk because it is so low that you don\'t see it

15 clinically and there is not a large enough

16 prospective study to detect that. So, it is all

17 based on mathematical models. We heard of

18 1/60,000, by Dr. Kleinman on behalf of REDS. What

19 is published I think on behalf of American Red

20 Cross is 1/100,000 or 1/120,000, by Dr. Dodd. And,

21 you have 1/300,000.

22 DR. HEATON: Yes, the 1/300,000 was based

128

1 on the result reports the HBV DNA testing in the

2 U.S. The bulk of numbers are really based on the

3 level of hepatitis B core antibody and the

4 frequency with which hepatitis B core antibody

5 only\'s are HBV DNA positive. The point I was

6 making here is that we are experiencing a much

7 higher rate in our highly endemic European

8 countries in any of these models that are

9 predictive.

10 DR. SCHREIBER: On that same slide those

11 numbers that you showed for the endemic countries,

12 I think those are prevalence rates with the new

13 cases incidence rates and not residual risks. The

14 residual risks would actually be at least a factor

15 of 10 times lower. So, you are talking about

16 something on the order of 1/110,000 and then with

17 the adjustments that were made in the other you are

18 roughly talking about multiplying those by another

19 2.5. So, you are talking about 1/300,000 or so for

20 Spain, if my rough math is right, so that Spain did

21 not come out a hell of a lot different, I don\'t

22 believe, than the United States.

129

1 DR. HEATON: I accept that, and in

2 discussions with experts in Taiwan, one of the

3 points they made there is that so many of their

4 recipients have, in fact, been previously infected

5 with HBV that it is extremely difficult to model

6 out the risk because you have such a high basic

7 resistance level.

8 DR. NELSON: Next is Dr. Sherrol

9 McDonough, from Gen-Probe.

10 DR. MCDONOUGH: Good morning. I will

11 continue the discussion of detection of hepatitis B

12 DNA using NAT, and I will be talking more about the

13 Procleix assay.

14 \[Slide\]

15 As you can see, it was developed for core

16 detection of HIV-I, HCV and hepatitis B in pools of

17 up to 16 down to individual donor testing. In

18 addition, there are 3 discriminatory assays to

19 allow Ultrio reactors to be discriminated.

20 This assay is based on the same

21 technology, same equipment as assay procedures that

22 are used in the licensed Procleix HIV/HCV assay.

130

1 There are a large number of common reagents so we

2 made as few changes as we could. And, the assay

3 reagents and the formulations that are used in the

4 licensed semi-automated Procleix format are the

5 same as those on the fully automated Procleix

6 Tigris system.

7 Next slide. So, I am talking about the

8 assay type shown on the left, the multiplex Ultrio,

9 as well as discriminatory HBV, HIV and HCV, and I

10 am talking about the semi-automated Procleix system

11 as the licensed system and the fully automated

12 Procleix Tigris system. The two rows at the top

13 are what I will be talking about today, focusing on

14 HBV detection.

15 Next slide. To mention some of the

16 features of the Procleix Tigris system, after setup

17 this system is designed to process up to 500

18 samples in a 10-hour period or 1,000 samples in a

19 14-hour period. For the multiplex Ultrio assay

20 that represents 1,500 results in 10 hours. That is

21 500 for each of the analytes, or in 10 hours that

22 would be 3,000 results. Then, of course, the

131

1 specimens are tested in pools of up to 16. That

2 would be 24,000 results in 10 hours or 48,000 in 14

3 hours.

4 Next slide, please. The validation that

5 is ongoing for this assay includes the following:

6 the clinical evaluation is taking place at 5

7 clinical sites, with 3 reagent lots with both the

8 Ultrio and all 3 discriminatory assays and on the 2

9 different instrument platforms. We have included

10 specificity studies in pools of both 16 as well as

11 IDT, and several different populations are being

12 studied for clinical sensitivity. Of course, there

13 is a reproducibility study. The items that are

14 highlighted here, specificity, seroconversion

15 panels or reproducibility are what I will describe

16 today.

17 Next slide, please. In-house analytical

18 testing includes the following. You can see

19 multiple operators, reagent lots and instrument

20 platforms. They include analytical sensitivity,

21 genetic variants, the donor, donation factors,

22 interfering substances, etc., specimen collection

132

1 handling and the validation of use of the assay on

2 cadaveric specimens. Today I will only be

3 describing the analytical sensitivity of the assay.

4 Next slide, please. Analytical

5 sensitivity is demonstrated in this slide. This

6 was performed by taking known concentrations of HBV

7 and preparing panels at various international unit

8 per/ml concentrations. Each group of bars

9 represents a different concentration. The first is

10 45 IU/ml and then we are going down 3-fold, 15 IU,

11 5 IU, etc. The different bars represent either the

12 Ultrio assay on the semi-automated system or the

13 Procleix Tigris system, as well as the

14 discriminatory HBV assay on both semi and fully

15 automated systems.

16 Before you spend too much time scrunching

17 your eyes, I will just say there is no statistical

18 difference between either assay or either

19 instrument platform for any of the copy levels.

20 Next slide, please. Of course, another

21 way of looking at clinical sensitivity is to look

22 at seroconversion panels. We have had a lot of

133

1 discussion about seroconversion panels already

2 today. This is a set of panels that we have

3 analyzed. What I am showing here are the days

4 earlier that you can detect hepatitis B DNA

5 compared to surface antigen. The surface antigen

6 test was the PRISM using the European cut-off. The

7 results are shown for the Ultrio multiplex assay at

8 dilutions of 1:16 as well as neat, and on both

9 instrument platforms. The final set are

10 discriminatory HBV results on both platforms.

11 So, if you focus on the highlighted

12 numbers at the bottom, the median days earlier that

13 we can detect HBV at 1:16 dilution is 6 or 7 days;

14 neat, 17 days on either instrument platform; and

15 the discriminatory assay shows 15 or 14 days

16 earlier.

17 Next slide. I will focus on the word

18 preliminary. This is not final but this is a

19 snapshot in time of where we are with specificity

20 testing. The first row shows the results with the

21 Ultrio multiplex assay on the semi-automated system

22 testing pools. Specificity is 99.5 percent and

134

1 that overlaps with the specificity observed with

2 the licensed HIV/HCV assay.

3 The next slide shows the results from the

4 Ultrio multiplex test again on the semi-automated

5 system, now testing IDT, and we see the same

6 specificity of 99.5 percent. Finally, the results

7 with the Ultrio multiplex assay on the Tigris

8 system, testing individual donor samples, is 99.8

9 percent.

10 Let me address the hatchmarks on the first

11 two rows. The first hatchmark reminds me to tell

12 you that there was a potential HBV yield case in

13 that population. The second row with the 2

14 hatchmarks\--there were another 2 potential HBV

15 yield samples from that population. All 3 of these

16 samples were Ultrio reactive, discriminatory HBV

17 reactive, as well as alternative NAT reactive from

18 a different specimen.

19 Next slide, please. These are the

20 preliminary discriminatory HBV specificity results.

21 Testing IDT, the specificity is 99.9 percent.

22 This, again, includes one of the yield cases

135

1 identified in the previous slide. We are calling

2 that potentially yield case number 3.

3 Next slide. The reproducibility study has

4 been done on both instrument platforms. It

5 includes Ultrio, discriminatory assays, 3 clinical

6 sites, 3 reagent lots, 2 operators per site, and

7 both negative and low panel positive samples.

8 Next slide. The constituents of each

9 panel member are shown at the left. We have both

10 HIV, HCV and HBV positive panel members, as well as

11 negatives and co-infected samples. The agreement

12 in this study was 100 percent for every panel

13 member, and the total variability is shown on the

14 right column at 15.2 percent or lower.

15 Next slide, please. In conclusion, the

16 Ultrio and discriminatory HBV assays show similar

17 performance on the semi-automated Procleix and

18 fully automated Procleix Tigris systems. We

19 believe that the automated system will allow IDT

20 testing to be performed much more easily in the

21 laboratory.

22 HBV was detected in seroconversion panels

136

1 on an average 14-17 days and 6-7 days earlier than

2 PRISM HBsAg in neat and 1:16 diluted samples

3 respectively. There are 3 potential HBV yield

4 samples to date that were identified in the

5 specificity study. Also, we have an additional 6

6 potential yield cases from our high risk study.

7 Again, each of these samples was Ultrio reactive,

8 discriminatory HBV reactive and alt-NAT reactive on

9 a different sample. Thank you.

10 DR. NELSON: Thank you, Dr. McDonough.

11 Questions or comments?

12 \[No response\]

13 Thank you. Next is Dr. Richard Smith,

14 from National Genetics Institute.

15 DR. SMITH: Good morning. Richard Smith,

16 from National Genetics Institute. I believe that

17 NGI has a financial relationship with probably

18 every company in this room so I will just do a

19 blanket statement.

20 \[Slide\]

21 This morning I will tell you about HBV NAT

22 IND for whole blood donations, just started at NGI

137

1 for the American Red Cross, in June of this year.

2 In this study, only those donations that have been

3 found to be repeat reactive for the anti-HBV core

4 antigen antibodies are tested for HBV DNA.

5 Next slide. There are 3 reasons listed in

6 our IND for performing this testing. First, the

7 results are being used as a donor counseling tool

8 for anti-core repeat reactive donors.

9 Next. Second, we plan to analyze the

10 results of this study to help design another IND

11 for establishing a donor reentry algorithm and for

12 potentially false-positive anti-core reactive

13 donors. The new study would also involve a second

14 licensed anti-core assay, hopefully, with improved

15 sensitivity.

16 Next. Finally, to limit the viral load in

17 plasma pools destined for further manufacture.

18 Currently, anti-core repeat reactive donations are

19 included in these pools and we would expect some

20 number of these to be positive for HBV DNA.

21 Next slide. The NAT assay used for this

22 study is the same assay being used for the IND

138

1 established to screen source plasma donors for HBV

2 DNA, and is performed on the same platform as the

3 FDA-approved HCV and HIV PCR assays that have been

4 used for source plasma donor screening for the past

5 several years. DNA extraction for HBV is performed

6 with an initial sample volume of 0.1-2 ml,

7 depending on the desired level of sensitivity and

8 the volume of the sample that is available.

9 For HBV, we use 4 distinct HBV specific

10 primer pairs in separate amplification reactions,

11 and we perform duplicate reactions when increased

12 sensitivity is required for a total of up to 8

13 separate amplification reactions per assay. If

14 just one of those reactions is positive the assay

15 is considered positive. Each reaction also

16 includes an internal control specific primer so

17 that the success of each reaction can be

18 independently determined. Detection of specific

19 amplification products are performed by southern

20 blot analytical on every reaction.

21 Next slide. This slide shows what the raw

22 data of one of NGI\'s HBV NAT assays looks like.

139

1 The underlying image is a scan of an HBV specific

2 southern blot and this membrane represents analysis

3 of just 1 of the 4 HBV specific primer pairs used

4 for each HBV assay.

5 After scanning, the same membranes are

6 rehybridized with an internal control specific

7 probe and bands appear in all positions,

8 representing successfully extracted and amplified

9 material. A reaction such as the one depicted

10 here, in position 14, would be considered invalid

11 and negative for the target but invalid so it would

12 have to be repeated. Membranes also include

13 diluted amplified material, shown here in the last

14 position, to ensure adequate southern blot

15 detection sensitivity.

16 Next slide, please. The testing and

17 algorithm being used for this particular study

18 first involves combining up to 16 individual

19 samples into one pool, and then performing an assay

20 with a 95 percent detection cut-off of 0.9 IU/ml,

21 which translates to a 85 percent detection cut-off

22 of 14.4 IU/ml on an individual sample basis.

140

1 Next slide, please. When a pool of 16 is

2 found to be positive for HBV each individual sample

3 is tested with an assay with a 95 percent detection

4 cut-off of 1.6 IU/ml or

5 if the sample volume is limited we can perform an

6 assay with only 100 mcL but involving twice the

7 number of amplification reactions and, therefore,

8 producing the 95 percent detection cut-off of 9

9 IU/ml. With an anti-core reaction rate of

10 approximately 0.6 percent, we are expecting to test

11 approximately 42,000 donations per year for the Red

12 Cross for HBV DNA. The next slide shows the

13 results we have obtained since starting this

14 project, just in June of this year.

15 Next slide, please. To date, we have only

16 reported results for 1,255 anti-core reactive

17 donations; 900 have been found to be not

18 implicated, which means that the pool they were in

19 was negative; 302 were tested individually and

20 found to be negative for HBV DNA, 50 of them found

21 positive for HBV DNA and 3 had insufficient volume

22 for testing.

141

1 Of the HBV DNA positive donations, we have

2 HBV surface antigen data for 37. Data for the

3 other 13 is forthcoming but was unavailable to me

4 at the time I was preparing this presentation.

5 And, 22/37 are antigen positive and neutralizing,

6 and 15 are antigen negative. So, so far, about 40

7 percent of the HBV DNA positive donations are

8 antigen negative, or about 1.6 of all the anti-core

9 reactive donations screened.

10 Next slide, please. We have gathered some

11 additional data on the DNA positive donations. The

12 average antigen reactive HBV DNA positive donation

13 has an antigen neutralization value of 98.8

14 percent, with a range of 89.3 to 100 percent. The

15 average viral load in these samples is 70 million

16 international units/ml, with some having very low

17 viral loads, in the range of 10

2 and some as high

18 as 10 8.

19 Next slide. In contrast, the average

20 viral load in the antigen-negative DNA positive

21 donations is just 70 IU/ml, one million times lower

22 than the antigen positives, with a range of below

142

1 the sensitivity of the quantitative assay up to

2 just 150 IU/ml.

3 Next slide, please. Prior to initiating

4 the current study we performed a pilot study on

5 anti-core reactive donations. This study was

6 blinded, with no knowledge of whether the donors

7 tested anti-core reactive on a previous donation.

8 So, the population most likely included a mixture

9 of donors that would be ineligible for inclusion in

10 a donor reentry study.

11 In this study only antigen-negative

12 donations were tested for HBV DNA. Of the 3,000

13 anti-core reaction, surface antigen negative

14 donations, 19 were found positive for HBV DNA using

15 an individual PCR test, with a 95 percent detection

16 cut-off of 9 IU/ml. Viral loads for the 19

17 positive donations were determined and the range

18 observed for these was also from below cut-off up

19 to 150 IU/ml, which corresponds to about 500

20 copies/ml. The \"greater than\" sign on the bottom

21 actually should be a \"less than\" sign. Those are

22 all less than the cut-off of the quantitative

143

1 assay. The next slide compares these data with

2 findings from the REDS study, published in 2003 by

3 Steve Kleinman and others in The Journal of

4 Transfusion.

5 Next slide, please. I was going to thank

6 Sue Stramer for this slide but maybe I should thank

7 Mike Busch, or maybe Mike should thank Sue\--I am

8 not sure. Data from the REDS study, conducted over

9 a much longer period, also shows a very low rate of

10 the HBV DNA positivity in anti-core reactive

11 donations. DNA positive donations from the REDS

12 study also had very low viral loads. These are the

13 same results that you have seen presented in

14 multiple talks earlier today.

15 As part of the study currently being

16 carried out, we will enroll antigen negative, HBV

17 DNA positive donors for follow-up to determine the

18 predictive value of the test. We will also follow

19 2 time anti-core reactive donors that test HBV DNA

20 negative upon initial screening. That is it, just

21 a short but sweet presentation.

22 DR. NELSON: Thank you. Comments?

144

1 DR. SCHREIBER: One question, one of your

2 objectives seemed to indicate that you are

3 interested in trying to reduce the viral load in

4 plasma pool. I think you need to be clear that you

5 are talking about recovered plasma since I believe

6 that all source plasma collected is already

7 subjected to HBV testing, NAT testing, in the

8 United States, probably worldwide.

9 DR. SMITH: Yes, you are right. That is

10 absolutely correct. Really this was to help the

11 plasma fractionaters justify the use of recovered

12 plasma that wasn\'t being HBV NAT tested. Likewise,

13 the source plasma units that they use are not being

14 anti-core tested. So.

15 DR. NELSON: Thank you. Harvey Alter?

16 DR. ALTER: Thank you. Could I have my

17 first slide, please\--oh, I don\'t have any slides!

18 \[Laughter\]

19 DR. NELSON: How can you talk without

20 slides?

21 DR. ALTER: I am substituting for Steve

22 Kleinman because he has a relationship with Roche

145

1 and I realized today that I am on the scientific

2 advisory board for Roche, that I have to admit to

3 although, after reading this statement I suspect

4 that will be very short-lived!

5 \[Laughter\]

6 Lastly, I have this horrible bronchitis

7 and I may not make it through this so I am going to

8 give my quick overview and then read the statement.

9 Also, I am representing both the AABB and the

10 American Blood Centers.

11 The three issues that we saw were, one,

12 the company provides sufficient evidence for

13 licensure. Secondly, if the test is licensed,

14 should it be mandated or optional? Thirdly, can

15 the test replace surface antigen in its current

16 minipool format? So, in case I break down or you

17 fall asleep, our position is yes, no and no.

18 I am going to skip the first paragraph,

19 which tells you how great AABB is, and then go on.

20 HBV remains the most common clinically important

21 viral infection recognized from transfusion since

22 the control of HIV and HCV infections through

146

1 improved donor selection and serologic and NAT

2 screening. The data presented by Roche Molecular

3 Systems from its IND study of HBV NAT in minipools

4 of 24 samples are an important contribution to the

5 ongoing improvement of donor testing.

6 AABB sees three issues of primary

7 importance to the blood community to be addressed

8 by BPAC and the FDA. First, is the Roche HBV assay

9 approvable as a donor screening test? Second, if

10 approvable, shall its implementation be required in

11 blood collection facilities? A third question is

12 whether a claim for HBV NAT in minipools to replace

13 HBsAg testing should be granted.

14 Regarding the first question, the data

15 that were available for review by the AABB\'s

16 Transfusion-Transmitted Diseases Committee indicate

17 that the Roche minipool HBV NAT assay appears to

18 perform adequately in terms of analytical

19 sensitivity and specificity, and generates

20 incremental yield of NAT positive specimens over

21 current serologic tests. This suggests that the

22 assay may be approvable in the currently proposed

147

1 minipool NAT context, but its efficacy should be

2 greater if it were applied to individual donations

3 or significantly smaller minipools.

4 The second question is more difficult to

5 answer. The minipool-based assay under

6 consideration appears to yield between

7 1/250,000-300,000 positive donations that are

8 negative on currently licensed tests for HBsAg and

9 anti-HBc. This rate is similar to the yield rate

10 for HCV minipool NAT, and substantially higher than

11 that for HIV NAT. It is comparable to or slightly

12 higher than predicted by the Biswas et al. study in

13 a comparative study of NAT and serologic assays.

14 As suggested from the data on the

15 evolution of markers of HBV infection, these

16 donations tend to contain low copy numbers of HBV

17 genome, and incomplete data suggests that some

18 HBsAg assays, either available or under development

19 for evaluation by FDA, maybe able to interdict some

20 of these yield donations. These include HBsAg

21 tests from Abbott, Ortho Clinical Diagnostics and

22 Genetic Systems. It is critical for the accurate

148

1 analysis of the true impact of HBV minipool NAT

2 that samples from these current yield cases, and

3 those identified in the future by HBV NAT assays,

4 be tested not only by the currently licensed

5 serologic tests, but also by the developmental

6 tests that are likely to be licensed in the future.

7 Studies of the infectivity of yield cases are also

8 desirable, and particularly or units that

9 concurrent HBV DNA and anti-HBs in the absence of

10 detectable HBsAg and anti-HBc, as seen on two of

11 the yield cases in the Roche trial.

12 Thus, despite measurable yield,

13 introduction of HBV minipool NAT will offer only a

14 minuscule increment in transfusion safety compared

15 to currently required tests for HBsAg and anti-HB

16 core. The result of this low incremental yield,

17 coupled with low rates of chronic infection and

18 clinical disease after HBV transmission, renders

19 the marginal cost-effectiveness of HBV NAT in

20 minipools very poor. There is a reference to

21 Jackson\'s paper in Transfusion. This

22 cost-effectiveness will decline further into the

149

1 future as a larger and larger proportion of the

2 population has vaccine-induced immunity to HBV

3 infection.

4 Regarding the third question, current data

5 are not robust enough to support elimination of

6 either serologic marker. It is possible that HBV

7 NAT will eventually allow discontinuation of HBsAg

8 screening, but this will require a larger data set

9 including parallel testing by HBV DNA, likely on

10 individual donations rather than minipools, anti-HB

11 core, and HBsAg, using maximally sensitive antigen

12 assays.

13 In summary, minipool HBV NAT is an

14 expensive new screening assay that offers little

15 clinical benefit and that will not be offset by

16 discontinuation of any current testing. More

17 sensitive HBsAg tests are available now and more

18 will become available in the foreseeable future.

19 More specific anti-HB core tests will also become

20 available. Based on these considerations, AABB

21 does not support\--and that would be American Blood

22 Centers as well\--a requirement for the use of NAT

150

1 in minipools for blood donor screening at this

2 time. Rather, if HBV DNA NAT is licensed, its use

3 should be optional. The requirement for HBV NAT

4 testing should be reconsidered when technology

5 allows for individual unit testing. Thank you.

6 DR. NELSON: Questions for Harvey? Yes?

7 DR. STRONG: I am curious about your

8 clinical opinion since there are yield cases that

9 will be missed if we don\'t do that testing, and you

10 are recommending that we don\'t have to do NAT

11 testing. Do you see that as a significant clinical

12 risk?

13 DR. ALTER: Well, we really struggled with

14 this. You have so many variables that you have to

15 measure. First of all, we think the test is

16 licensable. Secondly, if licensable, it will be

17 easy for places that have Roche testing in place

18 but it is going to be a major, major implementation

19 for people who are using other systems. Is the

20 yield sufficient to warrant that, knowing that

21 within a reasonable short time there will be

22 alternate NAT assay and there will be improved

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1 surface antigen assays? I guess an interim measure

2 would be that the FDA could set a time interval in

3 which to implement this test that was sufficiently

4 long that non-Roche establishments could possibly

5 catch up.

6 But when you get to the issue of if you

7 pick up one or two cases a year, does that make it

8 mandatory to do this test, that is a very difficult

9 thing. I think this decision is similar to that

10 for third generation anti-HCV assays versus second

11 generation assays where the yield was considered to

12 be sufficiently small that blood banks were allowed

13 to use either second or third generation testing,

14 even though it was known that third generation

15 testing was slightly more sensitive. It is a

16 complex issue. Would I want to go on a stand? I

17 don\'t know.

18 DR. STRONG: Just a follow-up, it sounds

19 like part of that is logistical, which I certainly

20 understand as a blood tester. But I am still

21 interested in whether or not you think there is a

22 significant clinical risk for those that are

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1 missed.

2 DR. ALTER: There is some clinical risk.

3 You know, if this was HIV I would be talking

4 differently but HBV generally is a recoverable

5 disease in 95 percent of the people and the other 5

6 percent has this long duration of usually

7 non-progressive disease. So, in the current

8 setting it is a very, very small margin of

9 significant clinical disease. Nonetheless, we

10 don\'t want to transmit disease so that is a tough

11 issue. You know, my feeling is we need to get to

12 individual testing as soon as possible and then we

13 should we should be doing HBV DNA testing on NAT

14 when the yield will be higher.

15 DR. EPSTEIN: Harvey, AABB has suggested

16 that it feels, based on its own review of data made

17 available, approval would be reasonable but the

18 test should remain optional. What would be the

19 practical consequence if FDA acted to approve such

20 a test and was silent on a recommendation? Would

21 it not be a chaotic situation in the marketplace

22 where some entities might implement it?

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1 DR. ALTER: Well, yes. I mean, FDA has

2 always tried to license two tests at once sort of

3 to get around this issue. It will create some

4 chaos if it is licensed and it is mandated

5 immediately. We feel that Roche has proven its

6 case that it is a good assay and it has yields. I

7 can\'t say it shouldn\'t be licensed. They got there

8 first and they shouldn\'t be punished for that. But

9 for those people who are not using the Roche assay

10 it will create chaos if it is mandated immediately.

11 Then the other issue is the PRISM issue

12 and when will that be licensed, and will that be

13 implemented, and will that decrease the yield even

14 further and make the need for HBV DNA less in a

15 minipool format? So, there are a lot of things

16 riding here, and when do you go from minipool to

17 individual testing or to mini-minipool? So, there

18 are really three things going on simultaneously and

19 I am glad I am not you.

20 \[Laughter\]

21 But I think one possible scenario would be

22 to license, to leave it optional for the time

154

1 being, to re-address this at some time interval.

2 The second option is to license it and make it

3 mandatory but give sufficient lag time that it will

4 be reasonable that the alternate assay will be

5 available also.

6 DR. NELSON: Thank you. the open public

7 hearing is closed, I am told. Could you restate

8 the questions for the committee?

9 DR. HOLLINGER: Just a question, is there

10 not a statement from Red Cross?

11 DR. NELSON: Not on the list here.

12 DR. PAGE: Red Cross has chosen not to

13 make a statement on this issue.

14 DR. HOLLINGER: Do you have a reason why

15 not?

16 \[Laughter\]

17 Committee Discussion and Recommendations

18 DR. KAPLAN: I will try to wrap up this

19 session and then given the FDA perspective and then

20 go through the questions. What I will try to do is

21 to just put together some of the elements that Dr.

22 Blaine Hollinger gave us in his great talk, with

155

1 some of the points from the clinical trial that Dr.

2 Herman and Dr. Frank, from Roche, explained to us,

3 and also bring up some of the points that Dr. Busch

4 and Dr. Alter brought to this equation. Basically,

5 most of the things I am going to say you have

6 already heard so I will try to wrap it up.

7 \[Slide\]

8 The Roche clinical trial for HBV NAT, 059,

9 was done in about 600,000 volunteer whole blood

10 donations. The index donations were tested for

11 surface anti-core with their minipool NAT test.

12 These are the concordant results. Basically, all

13 three markers are positive. However, as you might

14 expect, there are many discordant results here

15 which are important for analysis of this trial and

16 licensing. Basically, you can have the possibility

17 that the surface antigen is positive and the other

18 two markers are negative. So, what this trial did

19 is they performed alternative NAT, quantitative NAT

20 and then they followed up the donors.

21 Another possible discordant result is that

22 the surface is positive and DNA is positive. What

156

1 they did is an alternative NAT and quantitative NAT

2 and then they followed up the donors.

3 The third possibility is that the surface

4 and anti-core are positive, and what they did was

5 an alternative NAT and quantitative NAT.

6 Another possible discordant is that only

7 the core is positive and all the others are

8 negative. So, what they did is the alternative

9 NAT, individual donation NAT, quantitative NAT

10 anti-surface, IgM anti-core and then they followed

11 up.

12 The other possibility is that the core was

13 positive and DNA was positive and then they

14 performed alternative NAT, quantitative NAT and

15 they followed up.

16 The last discordant possibility is that

17 the DNA was positive. So, what they did was

18 alternative NAT, quantitative NAT and then they

19 followed up the donors.

20 \[Slide\]

21 So, I will give you an idea of the

22 numbers. About 600,000. As expected, most of them

157

1 were negative for the 3 markers. What they found

2 in trial 059 is that 84 donations were positive for

3 the 3 markers. They found 4 positive for the

4 surface; 3 positive for surface and DNA; 16

5 positive for surface and anti-core; 2,988 positive

6 for core; 1 for core and anti-core DNA; and 23 for

7 DNA. I will focus o the last one. This is pretty

8 important because it gives you the yield of the

9 whole trial that was discussed several times here.

10 From these 23, what they found is that 21

11 samples were false-positive samples and only 2 were

12 window period samples. So, the whole yield would

13 be 2 in about 500,000 to 600,000 donations. That

14 will imply about 3-4 per million. If you have 15

15 million donations a year you have around 60 units

16 that can be interdicted with this test.

17 Several considerations were raised here

18 regarding which of these donations could progress

19 to severe clinical outcome after transfusion, and

20 that is a consideration that we want the committee

21 to address.

22 The other group that I would like to point

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1 out to you is related to the safety of the

2 implementation of the company claim regarding

3 alternative use to surface. I would mainly like

4 you to focus on these 4 cases that were only

5 surface positive. Upon follow-up, 2 out of the 4,

6 as the company mentioned, were negative in

7 follow-up in the trial. Basically, 1 was a

8 false-positive surface antigen and it was

9 vaccinated.

10 Two were not followed up in the initial

11 clinical trial, however, the company just showed

12 you some of the data and basically both cases did

13 not seroconvert. So, for these 2 cases that were

14 not followed up, the alternative and ID-NAT or the

15 index samples were negative and after follow-up,

16 after the trial was finished, they did not

17 seroconvert. So, I think we have a good take here

18 that these 4 were false positive for infection.

19 From this, 3 that had both markers, only 1 was

20 followed up and was positive, and the others were

21 not followed up.

22 So, regarding the sensitivity in general

159

1 of this test, there were 107 donations that were

2 positive for surface; 100 donations were surface

3 anti-core positive; and 7 of them were anti-core

4 negative. As a note, Roche, indeed, accounted for

5 the 4 surface only donations in support of the

6 replacement claim. However, these numbers are

7 small and several points were raised by Dr. Busch

8 and Dr. Alter, and we are asking the committee to

9 consider whether with this small number of

10 discordants this data is enough to support the

11 Roche claim to use it as an alternative of the

12 surface.

13 \[Slide\]

14 I would like to talk a little about the

15 surface and anti-core positives, and in this case

16 they found 16. This pertains to the sensitivity of

17 the assay. So, when they did ID-NAT they found 10

18 positives and 5 negatives using their own ID test.

19 Using the alternative NAT, a test by NGI that was

20 described by Dr. Smith, none were positive and 4

21 were negative. These are not exactly the same.

22 There is no exact agreement here.

160

1 When they quantitated the 16, 3 of them

2 were 100 copies/ml; 1 was 200 copies/ml; 1 was 700

3 copies/ml; 1 was 1,200 copies/ml; 1 was 2,600

4 copies/ml; and 1 was 5,900 copies/ml. The rest

5 were below the detection level. The sensitivity of

6 this then is that 12/16 were detected by ID-NAT and

7 alternative NAT; 3/16 were negative by NAT and

8 alternative NAT and 1 was not tested. A note which

9 I would like to make is that although 16 donations

10 were minipool NAT negative, all were anti-core

11 reaction. This indicates a sensitivity issue but

12 not a safety issue.

13 \[Slide\]

14 So, I would like to present the questions

15 to the committee. The first question is do the

16 sensitivity and specificity of the Roche COBAS

17 AmpliScreen hepatitis B test in minipools of 24

18 samples support licensing of the assay as a donor

19 screen?

20 DR. NELSON: Thank you, Dr. Kaplan.

21 Comments?

22 DR. KAPLAN: I will go through the three

161

1 questions and then come back to the first one.

2 \[Slide\]

3 Second question, if so, (2(a), assuming

4 continued use of screening tests for anti-core, do

5 the data support the use of the Roche COBAS

6 AmpliScreen hepatitis B test in minipools of 24

7 samples to screen blood for transfusion as an

8 equivalent alternative to the surface antigen test?

9 2(b), if the data do not support use of

10 the Roche COBAS AmpliScreen hepatitis B testing

11 minipools of 24 samples as an equivalent

12 alternative to HBsAg to screen blood for

13 transfusion, what additional data would be required

14 to validation such use?

15 \[Slide\]

16 The third question, do the data support

17 the use of the Roche COBAS AmpliScreen HBV test on

18 minipools of 24 samples to screen blood for

19 transfusion as an added test in conjunction with

20 licensed donor screening tests for HBsAg and

21 anti-core?

22 And now we will go to the first one.

162

1 DR. NELSON: Comments? Questions?

2 Anybody? Yes, Susan?

3 DR. LEITMAN: I have a question for the

4 FDA. Is there precedent in the past for this

5 committee recommending licensure of a screening

6 assay without mandating its use? Dr. Alter

7 mentioned third generation HCV EIA. Is that the

8 only example?

9 DR. EPSTEIN: Of course, we did recommend

10 HCV EIA screening; it is just that we were neutral

11 whether the EIA-3 should replace EIA-2. We let

12 them coexist on the market. CMV EIA is approved as

13 a screen and its use is voluntary. When we first

14 reviewed the Abbott P24 test we ended up approving

15 it as a diagnostic but not a donor screen even

16 though studies had been done on its use for donor

17 screening. Of course, we had a different set of

18 results. So, I think that really the CMV is the

19 best example.

20 DR. ALLEN: Let me just follow-up on that.

21 Again, as I understand the question, the committee

22 is being asked for a recommendation only on

163

1 supporting licensing and not on its use?

2 DR. EPSTEIN: That is correct. In other

3 words, question one is should it be approved with a

4 claim as a donor screening test. Questions two and

5 three have to do with what recommendations for use

6 FDA might make or not make. So, question two is

7 could you replace HBsAg testing, treating them as

8 equivalent alternatives? That is the EIA-3 versus

9 EIA-2 model for HCV. Then question three is if we

10 do not regard it as an equivalent alternative,

11 should we consider recommending it as an additive

12 test? That is where we ended up in 1996 with P24

13 where we recommended it as a screen that was

14 additive. Of course, there was no issue of

15 replacing a test at that point.

16 DR. KLEIN: Well, not being a lawyer, I

17 don\'t really care much about precedent. It seems

18 to me what we saw this morning, in my opinion, is

19 that it is a sensitive assay that has been

20 developed, that has been applied in the screening

21 format that picks up additional cases of hepatitis

22 B. I think I find no reason why it shouldn\'t be a

164

1 licensed screening assay.

2 DR. GOLDSMITH: Are we just considering

3 this for screening blood donations? In other

4 words, donors of source plasma would not be

5 subjected to this test?

6 DR. KAPLAN: Yes, at this point we are

7 only considering the blood donations.

8 DR. EPSTEIN: Let me just clarify that

9 source plasma donations are not screened for anti

10 core, and we have seen data that DNA NAT will miss

11 anti-core positives, some of which would have DNA

12 on an ID-NAT test or alternative test. So, no one

13 contemplates, and the company has not requested a

14 label to screen source plasma. So, this is blood

15 for transfusion.

16 DR. NELSON: I agree with Harvey. I can\'t

17 see any reason that it shouldn\'t be licensed, and

18 this may not be as severe clinical outcome as HIV

19 but it is associated with chronic disease\--cancer,

20 cirrhosis, etc. in some people and I think we

21 should try to prevent it.

22 There are some sub- populations in the

165

1 U.S. that have much higher rates of both prevalence

2 and incidence from HBV. Although there were

3 600,000 donors screened, there was no attempt, I

4 don\'t think, to find the highest risk donors to

5 screen, or anything like that. So, my guess is

6 that applied to the entire donor system the yield

7 will be somewhat irregular; maybe not entirely

8 predictable by the data that are available. I

9 mean, in some populations may be more useful than

10 others in terms of picking up higher numbers of NAT

11 positive surface antigen negative donors. Anybody

12 feel that this shouldn\'t be licensed?

13 DR. HOLLINGER: I guess the question is

14 really, at least in my mind, not that the assay is

15 going to pick up some samples I think prior to HBs

16 antigen positivity. There is a lot of information

17 we don\'t have to make that decision, as I look at

18 it, anyway. One, we don\'t know what the carrier

19 state potential is in the people who receive this

20 kind of blood. We don\'t know what the disease

21 potential is in patients receiving this type of

22 blood. We don\'t know the outcomes\--I think is a

166

1 whole problem here.

2 We are trying to make a decision about

3 doing a licensing assay on something we have very

4 little, if any data on in the seronegative window

5 periods regarding a disease outcome. Even if you

6 forget the disease outcome and look at it

7 straightforward with what we know in ordinary

8 circumstances, the fulminant hepatitis and you will

9 see numbers like three-tenths percent or

10 four-tenths percent of people will get the disease,

11 I think that is very high and I think in reality it

12 is much less than that. So, if you get one person

13 out of 200,000 donors who gets one of these units

14 of blood and four-tenths percent of 1/200

15 individuals eventually who will get this will

16 develop fulminant hepatitis, that is looking at

17 something\--if my evaluation is simple, it would be

18 like one out of 40 million units of blood that

19 might result in fulminant hepatitis. I may be

20 erroneous in that assumption, but the risk is

21 really very small.

22 On top of that, even people who get

167

1 chronic disease, which is probably less than 3

2 percent\--now, some of these are immunosuppressed

3 patients and recipients so we can\'t probably use

4 that number appropriately but, certainly, half the

5 recipients will die over a certain period of time,

6 many of them around 60 years of age or so, getting

7 blood. If they do get this disease, chronic liver

8 disease, to progress to cirrhosis takes decades, on

9 an average about 10 years a stage and if there are

10 4 stages, about 40\--30 to 50 years probably before

11 you reach cirrhosis. Even people who get

12 cirrhosis, 80 percent are still alive and doing

13 well 10 years after the diagnosis of cirrhosis is

14 made, and probably longer than that but that is

15 where the data leads us.

16 So, even with hepatitis B, those numbers

17 are probably very similar. So, I think this is a

18 little different than the HIV situation that we are

19 dealing with here. So, while the assay certainly

20 is a good assay and I have no problem with that,

21 the issue is whether it should be a donor screening

22 assay at this juncture. I mean, I could see that I

168

1 would approve the assay because it can be useful to

2 any blood banking situation. The issue is whether

3 we have enough information to make the

4 recommendations as a donor screening tool at this

5 stage.

6 DR. NELSON: You have certainly raised

7 some of the unknowns about natural history. The

8 other side of the coin is that there are, if you

9 will, worse case scenarios for hepatitis B. It is

10 not an innocuous virus. It is certainly more

11 significant than HAV and others that can be

12 transmitted by transfusion. Chronicity varies,

13 certainly by immunosuppression, age and infection.

14 If these are kids that are transfused you are going

15 to see some liver cancer and some cirrhosis. So,

16 given this, I just can\'t see that this is totally

17 innocuous. It is unknown how severe the outcome

18 is, but it is potentially significant.

19 DR. KLEIN: you know, I agree with you,

20 Blaine, entirely but I guess the question in my

21 mind is that if it is not licensed, then if I have

22 patients in my cancer hospital and they are

169

1 primarily bone marrow transplant patients or

2 patients who are immunosuppressed, then I can\'t use

3 this as a screen unless it is licensed unless I get

4 an IND. If it is licensed I have the choice of

5 using it in my high risk population as others do.

6 So, I guess what I am saying is I would

7 like to see it licensed although not necessarily

8 mandated, and I think there is a difference there.

9 DR. HOLLINGER: I was under the impression

10 that makes it very difficult. I could agree with

11 that but I thought Jay was saying this is a real

12 difficulty to license something without mandating

13 it.

14 DR. KLEIN: Well, I guess that would be

15 his problem.

16 \[Laughter\]

17 DR. EPSTEIN: We can license the test and

18 be silent whether its use is recommended. But I

19 think that that will create a chaotic situation.

20 Just as in the other direction, if we license it

21 and we recommend use within some period, even if it

22 is a fairly long period, since it would then become

170

1 available very quickly to users who have the right

2 platform, it would also be a chaotic situation.

3 In other words, you know, I think we have

4 disruption to our system whichever direction we go,

5 assuming that it is a licensed product, whether we

6 are silent on recommended use or whether we

7 recommend the use, either way.

8 DR. STRONG: This is a bit of deja vu for

9 me. We had this very debate on our medical staff

10 because we are one of the clinical trial sites.

11 When the trial came to an end, do we continue or

12 not continue since we have the platform in-house?

13 So, we spent half a day in discussions, many of the

14 same points being made. Now, in Seattle, of

15 course, we do have a patient population with a lot

16 of bone marrow transplants, a lot of cancer

17 patients, a large clinical children\'s hospital,

18 etc. Our medical staff, which is made up of 8

19 hematologists and a couple of lab medicine people

20 were unanimous to continue to test. In fact, the

21 three new cases are all our yield cases. So, they

22 feel justified in having continued testing.

171

1 DR. ALLEN: If, as Dr. Epstein says, there

2 is no recommendation to mandate its use if it is

3 licensed, I understand the forces of the

4 marketplace and it is likely to drive it very

5 quickly and fairly uniformly. There is the cost

6 factor. There are rising healthcare costs and the

7 pressure to try to maintain those as well as

8 possible, not add any unnecessary increase. There

9 are certainly liability concerns and

10 considerations. I think the marketplace will speak

11 to this and that is the way that our system works.

12 I think the question before us is very

13 simple, do the sensitivity and specificity in the

14 minipools, as the data presented, support licensing

15 the assay as a donor screen? I think Dr. Klein\'s

16 first comment spoke very clearly to that.

17 DR. STRONG: I think there is a mixed

18 feeling in the marketplace, much as has been voiced

19 here. Of the five clinical sites that were

20 involved, two have stopped testing and three have

21 continued. So, it is a debatable issue.

22 DR. NELSON: Are we ready to vote on

172

1 question one? Linda?

2 DR. SMALLWOOD: Question one, do the

3 sensitivity and specificity of the Roche COBAS

4 AmpliScreen HBV test in minipools of 24 samples

5 support licensing of the assay as a donor screen?

6 Dr. Allen?

7 DR. ALLEN: Yes.

8 DR. SMALLWOOD: Dr. Davis?

9 DR. DAVIS: Yes.

10 DR. SMALLWOOD: Dr. DiMichele?

11 DR. DIMICHELE: Yes.

12 DR. SMALLWOOD: Dr. Doppelt?

13 DR. DOPPELT: Yes.

14 DR. SMALLWOOD: Dr. Goldsmith?

15 DR. GOLDSMITH: Yes.

16 DR. SMALLWOOD: Dr. Klein?

17 DR. KLEIN: Yes.

18 DR. SMALLWOOD: Dr. Laal?

19 DR. LAAL: Yes.

20 DR. SMALLWOOD: Dr. Harvath?

21 DR. HARVATH: Yes.

22 DR. SMALLWOOD: Dr. Hollinger?

173

1 DR. HOLLINGER: No.

2 DR. SMALLWOOD: Dr. Kuehnert?

3 DR. KUEHNERT: Yes.

4 DR. SMALLWOOD: Dr. Leitman?

5 DR. LEITMAN: Yes.

6 DR. SMALLWOOD: Dr. Quirolo?

7 DR. QUIROLO: Yes.

8 DR. SMALLWOOD: Dr. Schreiber?

9 DR. SCHREIBER: Yes.

10 DR. SMALLWOOD: Dr. Whittaker?

11 DR. WHITTAKER: Yes.

12 DR. SMALLWOOD: Ms. Knowles?

13 MS. KNOWLES: Yes.

14 DR. SMALLWOOD: Dr. Nelson?

15 DR. NELSON: Yes.

16 DR. SMALLWOOD: Dr. Strong, your opinion?

17 DR. STRONG: Yes.

18 DR. SMALLWOOD: The resulting votes are 15

19 yes votes and 1 no. The non-voting industry

20 representative agrees with the yes vote.

21 DR. NELSON: Can we move on to the second

22 question?

174

1 DR. KAPLAN: Question 2(a), assuming

2 continued use of the screening tests for anti-core,

3 do the data support use of the Roche COBAS

4 AmpliScreen HBV test in minipools of 24 samples to

5 screen blood for transfusion as an equivalent

6 alternative to the HBsAg test?

7 DR. NELSON: Comments? Questions?

8 DR. KLEIN: Since I want to get to lunch,

9 I guess I will start off\--

10 \[Laughter\]

11 I would address this in a similar way to

12 what Blaine said earlier. I don\'t think that these

13 are equivalent. I think we have seen data to

14 suggest that there may be more sensitivity in acute

15 cases and we don\'t know too much about chronic

16 cases, and we have a very small amount of data at

17 this point in time. So, I certainly don\'t think

18 that I would accept that as an equivalent

19 alternative.

20 DR. ALLEN: I concur with that assessment

21 and I think certainly we have had speakers this

22 morning during our discussion periods who have

175

1 spoken to the need for additional data, the type of

2 data that could be collected. I think this is very

3 exciting and promising and look forward to the

4 collection of additional data so that we can make

5 further decisions down the road.

6 DR. LEITMAN: I just want to say that it

7 is a relatively simple answer. We saw data

8 presented to tell us that it is no an equivalent

9 alternative, not yet. We saw the data that says it

10 is not.

11 DR. HOLLINGER: I think the test is

12 probably a better test in general, I should say it

13 is a more sensitive test for detection at the

14 seronegative window period time. But, again, I

15 agree. I think we need more data. There are some

16 benefits to redundancy. If you look at some of the

17 reproducibility assays you will see some false

18 negatives by log; you will see some false negatives

19 by site, and so on. So, there has always been

20 benefit to redundancy with it is the HBs antigen

21 test or the anti-HBc test, and so on. Until we

22 have enough information with testing down the line

176

1 in several assays and a variety of other things, I

2 think it is too early to make that determination at

3 this time.

4 DR. KLEIN: We also have several

5 generations experience with HBsAg testing and I

6 would be very reluctant to step away from that

7 right now on the basis of a few hundred or even a

8 few thousand assays that we have seen here.

9 DR. NELSON: One question for the blood

10 bankers in the audience and the panel is when a

11 surface antigen screening test is positive is a

12 neutralization assay performed routinely? Because

13 I saw in some of the data that were presented that

14 they talked about surface antigen screening and

15 then they went back and said it was neutralization

16 positive or negative. I thought that maybe that

17 was part of the routine. It is, I guess.

18 DR. ALLEN: But am I correct that that is

19 not to exclude a unit of blood, obviously; it is

20 only to give information back to the donor?

21 DR. KLEIN: Well, the unit of blood is

22 going to be excluded anyway.

177

1 DR. NELSON: Harvey?

2 DR. ALTER: Just to reiterate what Harvey

3 Klein said, you know, this test is the apple pie of

4 blood banking. It was the first test we introduced

5 for specific hepatitis screening. It has really

6 served us incredibly well for 35 years, and one

7 would have to have overwhelming evidence to drop it

8 at this point. I think certainly the evidence is

9 not overwhelming. And, I just want to remind you

10 that we are still doing syphilis testing.

11 \[Laughter\]

12 DR. ALLEN: We still have syphilis too!

13 DR. KLEINMAN: I just wanted to comment

14 that surface antigen tests\--obviously, there are

15 multiple licensed ones on the market and we have

16 seen that one recently introduced test has had

17 tremendous specificity problems. My remarks really

18 aren\'t predicated on whether the test should be

19 dropped but in those cases having an HBV NAT will

20 help resolve some of the interpretation of a newly

21 introduced hepatitis surface antigen test that is

22 not performing in the way we expected it to. So,

178

1 there are different caveats.

2 DR. SCHREIBER: We also know from the

3 Biswas paper that the improved antigen tests are

4 going to have incremental yield so that should

5 decrease the incremental yields of the NAT test

6 introduction. So, I think that is not a

7 replacement.

8 DR. KLEINMAN: I do have a sort of a

9 conceptual question to the FDA though. I mean, we

10 know that there is a test out there in the pipeline

11 that is supposed to be more sensitive, but it seems

12 kind of odd to compare a test that is pending

13 licensure to one that isn\'t licensed yet. I mean,

14 it seems like a kind of odd bar to set that we

15 think that newer tests for another analyte are

16 going to be better, therefore, we should use that

17 information in deciding about whether a current

18 test should or should not be used or should replace

19 one. I mean, I can argue it both ways. If we know

20 that something better is coming along, we can\'t

21 disregard that data and, yet, it is not an

22 FDA-licensed test that we are comparing to. So, it

179

1 is a sort of dichotomous way to think about things

2 and I just wonder how FDA thinks about this because

3 they know more about whether the tests coming

4 through the pipeline, in fact, are more sensitive

5 and, in fact, are going to be licensed.

6 DR. NELSON: As I recall the Biswas paper,

7 certainly the individual NAT tests were still more

8 sensitive than any of the pipeline tests for

9 surface antigen, and it wasn\'t that the surface

10 antigen tests in the pipeline were more sensitive

11 than the NAT so these are two different assays.

12 Here is Robin. He can tell us about it.

13 DR. BISWAS: All I wanted to say is that

14 you have to deal with really the here and now. You

15 have a test which we are asking you questions

16 about, how we should manage it, whether we should

17 license it or not and whether it should replace the

18 HBsAg. Keep in mind that technology improves and

19 changes. For example, the study which has been

20 referred to several times today, remember that that

21 was published a year ago, over a year ago, and it

22 was actually done two or three years before that.

180

1 So, these tests do change. In a nutshell, we

2 compared the then investigational tests to the at

3 that time currently licensed tests. We compared

4 pooled NAT as it was then to the currently licensed

5 tests at that time. And, we compared single unit

6 NAT as it was at that time to the currently

7 licensed tests at that time. I should also say

8 that some of the investigational NATs a year ago,

9 two years ago, three years ago have, in fact been

10 licensed.

11 DR. NELSON: In the interest of lunch, are

12 we ready to vote on this question?

13 DR. HOLLINGER: I am just a little

14 confused about this question. I mean, the question

15 is asking should this assay replace HBsAg. Is that

16 correct? If that is what it is then, of course, I

17 would say no.

18 DR. NELSON: That is not the way, it says

19 is it an equivalent alternative, and in some ways

20 it is better and in others we don\'t have enough

21 data.

22 DR. HOLLINGER: If the question is asking

181

1 should it replace the HBs antigen obviously, for

2 me, I would say no. But that is not sort of the

3 way it is worded.

4 DR. NELSON: It is worded is it an

5 equivalent alternative.

6 DR. KAPLAN: Yes, because the company

7 claims it could be used instead of,

8 basically\--instead of the surface, you could use

9 the surface or you could use the NAT. That is the

10 claim.

11 DR. HOLLINGER: So, basically it says

12 should it replace the HBs\--I like the word

13 \"replace\" myself.

14 DR. NELSON: Jay?

15 DR. EPSTEIN: First of all, we are asking

16 the committee to comment on the strength of the

17 science and leave the policy decision to the FDA.

18 That said, the implication of this question is the

19 science base for considering replacement of HBsAg

20 by minipool NAT. So, I think you have the question

21 right, it is just to clarify that we are asking how

22 strong is the science.

182

1 DR. BUSCH: It is in the context of

2 anti-core screening. So, as Roche presented, the

3 only concern is if anti-core failed to detect

4 something.

5 DR. NELSON: Right, that is true. If

6 there were no core testing it would be a different

7 scenario, right, which, in much of the world, is

8 the case.

9 DR. BISWAS: I just wanted to say for the

10 record that I think I said HBV NAT investigational

11 when I meant HBsAg investigational.

12 DR. NELSON: Okay. Linda, we are ready.

13 DR. SMALLWOOD: Question number 2(a),

14 assuming continued use of screening tests for

15 anti-HBc, do the data support use of the Roche

16 COBAS AmpliScreen HBV test in minipools of 24

17 samples to screen blood for transfusion as an

18 equivalent alternative to the HBsAg test? Dr.

19 Allen? DR. ALLEN: Not at the present time, no.

20 DR. SMALLWOOD: Dr. Davis?

21 DR. DAVIS: No.

22 DR. SMALLWOOD: Dr. DiMichele?

183

1 DR. DIMICHELE: No.

2 DR. SMALLWOOD: Dr. Doppelt?

3 DR. DOPPELT: No.

4 DR. SMALLWOOD: Dr. Goldsmith?

5 DR. GOLDSMITH: No.

6 DR. SMALLWOOD: Dr. Klein?

7 DR. KLEIN: No.

8 DR. SMALLWOOD: Dr. Laal?

9 DR. LAAL: No.

10 DR. SMALLWOOD: Dr. Harvath?

11 DR. HARVATH: No.

12 DR. SMALLWOOD: Dr. Hollinger?

13 DR. HOLLINGER: Gosh, I feel more

14 comfortable with this one now; I am not left out

15 hanging. No.

16 DR. SMALLWOOD: Dr. Kuehnert?

17 DR. KUEHNERT: No.

18 DR. SMALLWOOD: Dr. Leitman?

19 DR. LEITMAN: No.

20 DR. SMALLWOOD: Dr. Quirolo?

21 DR. QUIROLO: No.

22 DR. SMALLWOOD: Dr. Schreiber?

184

1 DR. SCHREIBER: No.

2 DR. SMALLWOOD: Dr. Whittaker?

3 DR. WHITTAKER: No.

4 DR. SMALLWOOD: Ms. Knowles?

5 MS. KNOWLES: No.

6 DR. SMALLWOOD: Dr. Nelson?

7 DR. NELSON: I guess you can\'t vote maybe

8 so I will vote no.

9 DR. SMALLWOOD: Dr. Strong, your opinion?

10 DR. STRONG: Despite my conflict, I guess

11 I have to vote no.

12 DR. SMALLWOOD: The results of voting for

13 question number 2(a), unanimous no. The non-voting

14 industry representative agrees with the no vote.

15 DR. NELSON: Do you want to read the next

16 question?

17 DR. KAPLAN: Yes, 2(b), if the data do not

18 support use of the Roche COBAS AmpliScreen HBV

19 testing minipools of 24 samples as an equivalent

20 alternative to the surface to screen blood for

21 transfusion, what additional data would be required

22 to validate such use?

185

1 DR. NELSON: This one isn\'t yes or no.

2 DR. ALLEN: In the interest of time, I

3 would suggest that I think there have already been

4 a lot of suggestions made earlier during the

5 discussion. In particular, I think the

6 presentations by Dr. Alter and Dr. Busch addressed

7 this. Unless the FDA wants additional, more

8 specific discussion, perhaps we can move on.

9 DR. NELSON: I guess just more data.

10 Since blood donors are routinely screened for

11 surface antigen, you know, larger numbers could be

12 screened for DNA. That would seem to be one way to

13 approach it. Harvey?

14 DR. KLEIN: I would just like to see a

15 larger field experience, such as we would get if

16 this were a licensed assay and some people, such as

17 in Seattle, who are using it.

18 DR. KLEINMAN: Yes, I wanted to pose one

19 question though because Mike, in his slides,

20 suggested that studies should not only be done in

21 blood donor populations but should be done in

22 subpopulations who acquire infection through

186

1 different means, and done in vaccinated recipients,

2 and I am not sure that I agree with that. I don\'t

3 know whether I agree with that or not at this point

4 because we are really looking at the assay in the

5 donor context, and if you find that there are

6 discrepancies in other contexts, if those people

7 don\'t become donors I don\'t know whether it is

8 important or not. Clearly, you need to give some

9 direction to the manufacturers, or FDA eventually

10 needs to give some direction to the manufacturers

11 about whether studies in donors are sufficient or

12 whether they have to go and do their studies in

13 other population groups. So, I think a little bit

14 of discussion on that might be helpful.

15 DR. NELSON: Except that the donor

16 population is somewhat heterogeneous. It is made

17 up of many subpopulations and I would see some

18 justification\--when we looked at hepatitis

19 B-infected IV drug users we found a different

20 serologic pattern than was common among other

21 subpopulations. Whether or not that would

22 translate to different HBsAg dynamics I don\'t know

187

1 because we were looking at core. But there are

2 population variations and, you know, most donors,

3 thankfully, aren\'t drug users but some are.

4 Because of that, I think understanding this better

5 in subpopulations\--I can see some justification for

6 that.

7 DR. KLEINMAN: Kenrad, I don\'t doubt that

8 the dynamics might be different and the findings

9 might be different. I am really posing the

10 question whether if you find different results in a

11 population of IV drug users, if they contradict the

12 results you get in screening of millions of blood

13 donors, would that be enough to persuade you that

14 you still don\'t want to drop the test if the

15 dynamics are different. Because if it is not

16 enough to persuade you, then why require it? I

17 mean, the studies are interesting from a scientific

18 point of view and really need to be done, but they

19 wouldn\'t be a requirement for data to drop the

20 test. So, that is the question I am posing.

21 Scientifically, it should be studied but whether it

22 needs to be studied for getting a claim is really

188

1 the issue I would like to hear discussed.

2 DR. NELSON: Well, I would agree when you

3 talk about millions but there are small, hopefully

4 small subpopulations in a donor population that

5 comes from a different universe.

6 DR. BUSCH: The reason I kind of argued

7 that that data are needed is I do think that the

8 donor pool here does have a sampling of these

9 atypical cases in endemic infections. For example,

10 the vaccine breakthrough infection that Roche

11 detected are seen routinely in Taiwan now. By

12 participating in studies there we would better

13 understand what is going on, get volumes from these

14 people and be able to look at infectivity. There

15 are two cases in France of surface antigen positive

16 donors persistent who lacked anti-core were both

17 people from Africa who were probably infected based

18 on the work perinatally. So, it may be they never

19 formed anti-surface because they were essentially

20 colonized in utero to the antibody.

21 So, I agree that the data that is relevant

22 for the U.S. decisions is large-scale donor data

189

1 but I think the numbers of these unusual cases that

2 trickle up in our setting are small and we can

3 better study them and understand them by these

4 collaborative studies.

5 DR. ALTER: I just want to go on record

6 that, as much as I love this test, the concept here

7 is correct. It is just premature. I think

8 ultimately HBV DNA will replace HBsAg testing when

9 we go to smaller pools or individual testing and

10 when the data are larger, when we have a greater

11 database. But I think the database will support

12 going from this test to the DNA.

13 DR. GOLDSMITH: Just to add, I think that

14 this test will apply to blood donors and non-blood

15 donors, disease state subjects, that we might get

16 additional clinical information that might add to

17 the validity of the test. So, it would be useful

18 for the manufacturer to apply the test outside the

19 primary donor group.

20 DR. DIMICHELE: That is exactly what I was

21 going to say so I would like to second that.

22 DR. STRONG: Just one comment, I mean, we

190

1 have continued to screen, as have two other

2 centers, so we are collecting more data. I think

3 these kind of cases that are surface antigen

4 positive only are going to be very hard to find. I

5 mean, they just don\'t happen, at least with the

6 numbers that we have which are approaching a couple

7 of million now. They are either false positives

8 when they are surface antigen alone or they are

9 positive along with anti-core. So, those surface

10 antigen only are going to be hard to come by.

11 DR. BUSCH: But they could be found

12 routinely from the Red Cross Blood Systems. What

13 we are talking about is taking surface antigen

14 positives that are anti-core negative in programs

15 that aren\'t doing NAT studies, and those units are

16 being found all the time and if they are just

17 worked up in some sort of national collaborative

18 study by the different NAT assays, in follow-up I

19 think we could generate a larger data set fairly

20 quickly.

21 DR. STRONG: I agree we can generate a

22 larger data set. I am just saying with our limited

191

1 experience we have thus far, all of those have

2 turned out to be either false positives or core

3 positives.

4 DR. KAPLAN: So, would you say Phase IV in

5 a high risk population to get the correct numbers?

6 DR. BUSCH: Yes, I mean, we routinely

7 screen for antigen and anti-core, and the units

8 that are antigen reactive and anti-core negative

9 are the problematic cases. I don\'t know how many,

10 but we pick up a moderate rate of those and if we

11 were to simply put into place a protocol that

12 captured those units, and made them available to

13 Roche and any other company and enrolled those

14 donors, in a blood donor context we could capture

15 these cases.

16 DR. KAPLAN: Yes, but it would require a

17 large number of these cases so you are talking

18 about a prolonged Phase IV, or what is your idea

19 about the number of total cases?

20 DR. KLEINMAN: Well, we can address that

21 because when we looked at data from 1996, I think

22 it was, in REDS we documented surface antigen

192

1 positive in the absence of anti-core in about

2 1/100,000 tested donors, and then we did some DNA

3 studies, which have remained unpublished. If you

4 look here, in the Roche study, it was 7/600,000, so

5 about the same. So, I think this finding with

6 stable HBsAg assays occur about 1/100,000 donors.

7 Now, the Ortho version 3 test that has some

8 specificity problems, this would not be a good test

9 by which to find such donors unless they fix those

10 problems because we know that that is the exact

11 profile of false-positive surface antigens so we

12 would be overwhelmed by samples that don\'t actually

13 fit the bill. But I think with stable assays,

14 either with the Abbott Auzyme or presumably once

15 Ortho\'s assay gets fixed, we are looking at a rate

16 of 1/100,000.

17 So, if you had a program to say we are

18 going to try to do this in the large blood

19 collection systems across the U.S., so let\'s say

20 American Red Cross, BSL and a few others, so now

21 you have 8 million units or so a year, 9 million

22 units, 1/100,000 so what does that come out to be?

193

1 Ninety. So, 80 or 90. We might be able to accrue

2 80 or 90 units a year. Even if the estimates are

3 half of that we might be able to accrue 40 units a

4 year. If we could get those donors in for

5 follow-up and capture those plasmas and capture the

6 samples, test by various surface antigen assays,

7 various DNA assays, we might be able to accrue a

8 larger sample set, not in a short amount of time

9 but not in too long a period of time.

10 DR. NELSON: This was an essay question,

11 which I think we have already answered. So, let\'s

12 move on to the third one.

13 DR. KAPLAN: The third question is do the

14 data support the use of the Roche COBAS AmpliScreen

15 HBV test on minipools of 24 samples to screen blood

16 for transfusion as an added test in conjunction

17 with the licensed donor screening tests for HBsAg

18 and anti-hepatitis B core?

19 DR. NELSON: Yes?

20 DR. SCHREIBER: Based on all the

21 discussions, can we add the word \"voluntary\" after

22 \"added?\" Added voluntary tests?

194

1 DR. KUEHNERT: I thought the spirit of

2 this question was a required test. That is what I

3 thought was being asked. Which is it?

4 DR. EPSTEIN: We are not asking you to

5 comment on the policy question, which is should we

6 recommend additive testing. We are asking you to

7 comment on the strength of scientific data. In

8 other words, are these valid results? What is

9 their magnitude? Are there caveats?

10 DR. KUEHNERT: I am sorry, how is question

11 one and three different?

12 DR. EPSTEIN: Question one is whether the

13 sensitivity, specificity, reproducibility or

14 comparable to other tests for hepatitis B virus

15 that we have approved as screens. So, does it meet

16 the standard of screening tests? Question two was

17 if it does, is it sufficiently better as an advance

18 that it should replace HBsAg? We heard your

19 answer. Question three is really is there an

20 additive yield that we feel is meaningful? You

21 don\'t directly have to answer the policy question

22 of should we go on to recommend it.

195

1 DR. NELSON: Yes, this doesn\'t include a

2 \"win.\" It just includes do the data suggest that

3 added to the surface antigen and core antibody,

4 would it be an improvement or would it be

5 scientifically valid.

6 DR. EPSTEIN: I mean, committee members

7 can express caveats if they wish.

8 DR. ALTER: But, Jay, if there wasn\'t an

9 additive yield we wouldn\'t have voted yes to the

10 licensure. So, the two are really\--

11 DR. EPSTEIN: I actually disagree with

12 that, Harvey. I mean, it could have had no

13 additive yield and still be an adequate screen.

14 DR. ALTER: So, we can\'t ask the question

15 we really want to ask.

16 \[Laughter\]

17 DR. EPSTEIN: Well, I think committee

18 members can comment. I mean, they are here to

19 advise the FDA and they can certainly express their

20 thinking about what we ought to do, but the

21 scientific advisory committees are intended to be

22 advisory on the science and we are trying to ask

196

1 you the science question.

2 DR. NELSON: Well, it seems to me that the

3 data are pretty clear on this, that adding the NAT

4 test to the surface antigen and core true positives

5 were detected.

6 DR. KLEIN: Well, I would like to add a

7 caveat because I certainly agree more with what I

8 heard Blaine say at the very beginning, and that is

9 that while there is no question in my mind that you

10 picked up additional donors who might transmit, we

11 really don\'t have any evidence that the public

12 health impact is going to be significant, for all

13 of the reasons that were stated earlier. So, I

14 think we are too early in the game to say there is

15 going to be a public health impact of requiring

16 such a test, and I think I would leave it at that,

17 not recommending to the FDA whether they should

18 require it or not but saying that, in my mind, I

19 don\'t think the public health benefit would push me

20 to require it.

21 DR. NELSON: I am not convinced that the

22 public health benefit or lack of benefit has been

197

1 adequately studied. I think that what has been

2 adequately studied\--not adequately but what we have

3 some data on is that NAT testing will pick up some

4 infectious units in the context of surface antigen

5 and core-antibody, all the testing that is being

6 done. Coupled with what we know about hepatitis B,

7 I think it is likely that there is some public

8 health benefit. The magnitude of it is unclear I

9 think.

10 DR. KLEIN: Just looking at the wording

11 here, it says did the data support use? I mean,

12 everyone can express their opinion on whether they

13 think there would be additional yield with this

14 test but it asks specifically about the data

15 presented. But it is very difficult to answer this

16 question because there is what is on the paper and

17 what people think it means if there is a yes vote.

18 So, that is what I think is very difficult for me

19 in voting on this.

20 DR. ALLEN: I think Dr. Epstein is very

21 clear that we are basing our decision as a

22 scientific decision or recommendation on the data

198

1 presented, and not making a policy decision for the

2 FDA or even really a policy recommendation. I am

3 comfortable with that as long as that is the

4 interpretation. I have no doubt that this will

5 prevent some hepatitis B infections because it does

6 move into the window period; that there will be a

7 relatively small number of infections eliminated.

8 The clinical impact of that I think is a little

9 more difficult. Certainly, in children, in people

10 who are immunocompromised I think the clinical

11 impact for those individual people could be

12 significant although the numbers are going to be

13 relatively small and probably decreasing over time

14 as our donor population more and more becomes those

15 who have been immunized earlier.

16 I am a little conflicted in terms of

17 exactly what the cost-benefit value is going to be,

18 but I don\'t think we are being asked to make that.

19 Very clearly, if you want to close the window

20 period as much as possible, given this test, you

21 would do individual testing rather than minipools

22 of 24. And, I think these are some of the

199

1 questions that need to be investigated by blood

2 collection centers, by public health officials and

3 others as we move forward with a licensed test in

4 place and see how it best fits into the total

5 testing scheme. And, I would certainly encourage,

6 as additional data become available, to reopen the

7 question of whether we then need three tests or can

8 move to a combination of two tests based on hard

9 data in actual situations and careful evaluation

10 over a period of time.

11 DR. NELSON: Steve?

12 DR. KLEINMAN: Judging by the comments of

13 the panel, I feel like the wording of the question

14 is not being interpreted the same by everybody on

15 the panel. By that, I mean the specific words

16 support the use. I think you could interpret the

17 words \"support the use\" as do the data indicate

18 that there is increased yield from this test. If

19 you interpret it that way you might answer the

20 question one way. The other way you could answer

21 the question of \"support the use\" is not only do

22 the data show there is increased yield but do I

200

1 personally think the test should be done if I were

2 making the decision. That means not only do they

3 support increased yield but I would then take into

4 account all the other factors and vote according to

5 that.

6 I don\'t think everybody on the panel is

7 even trying to answer the same question right now

8 so I think you need to know whether you are asking

9 the question do the data support that an increased

10 yield would be achieved by implementing this test

11 in conjunction with surface antigen and anti-core,

12 or is the question do the data support the fact

13 that we recommend that this test be used? They are

14 different questions and I don\'t think they are

15 being interpreted the same by everybody on the

16 panel.

17 DR. NELSON: There was no data presented

18 on the natural history of infection. There were a

19 few opinions but there was no data. We have to

20 deal with the data that was presented so I think

21 the first of your questions is the way we should

22 vote. That is my own opinion. I am not sure that

201

1 all the potential hepatitis B infections are

2 benign. You know, there is no data on that and

3 certainly we have people with a lot of clinical

4 experience but we need better data on this I think

5 if we are going to interpret it more broadly. Yes?

6 DR. HEATON: There is one key issue that I

7 would like to add to the discussion, putting on my

8 advisory committee for blood safety and

9 availability hat. I made the point that there is

10 an enormous reimbursement implication of this

11 recommendation. If it is recommended that this

12 test does improve public safety and the BPAC would

13 support that, then it becomes a much better case

14 for the blood centers to get reimbursement. In the

15 absence of such a recommendation, for the average

16 blood center which might wish to implement this

17 test the hospitals will view this as entirely

18 discretionary and may, in fact, push back on

19 covering the cost.

20 From one of the manufacturer\'s

21 perspective, I can tell you that in pretty well

22 every case nucleic acid testing detects this virus

202

1 before the protein is present. So, in terms of

2 safety, whilst you may argue about the level of

3 improved safety, on the front end of the case you

4 get good detection. So, there is a reimbursement

5 issue here as well as a medical issue.

6 DR. NELSON: Harvey?

7 DR. ALTER: Yes, I think Steve framed the

8 issues very well. If you break it down into two

9 separate questions. For the first question, do the

10 data support that the test does something positive,

11 you can\'t vote no on that if you voted yes on

12 number one. Number one is sort of a minimalistic

13 thing saying it can be licensed even if it is

14 equal, but everybody feels it is better so you have

15 to vote yes on number three.

16 But I think the way it is worded now, if

17 people outside this room are going to see that

18 question and then see the vote, it is going to give

19 the other, the part two impression, that is, that

20 the committee is recommending that the test be

21 used. So, I think either the wording needs to be

22 more specific or question three should be dropped.

203

1 You got the sense of the group and you don\'t want

2 our opinion on policy.

3 DR. HOLLINGER: This is just sort of an

4 aside, but if you want public safety in this

5 country you vaccinate everybody. The other two

6 diseases we talked about have no vaccines

7 available; we have an excellent vaccine for

8 hepatitis B. We are spending a lot of money for

9 donor testing and screening on this issue which

10 could be spent for vaccine policies of the

11 population in this country. Then there is no risk

12 if you immunize everyone.

13 DR. NELSON: Providing everybody responds

14 and gets the vaccine, and all those kind of things.

15 Jay?

16 DR. SIEGEL: I think, given the difficulty

17 of a consensus interpretation of the question, it

18 might be better not to have votes but to hear the

19 committee members\' individual discussions of how

20 they see the issue of additive testing framed.

21 Clearly, we are saying something about additive

22 testing and people can just comment on what they

204

1 think about a scenario in which minipool HBV NAT

2 would be an additive test to HBsAg, and just avoid

3 up and down votes.

4 DR. LEITMAN: Everybody said the data

5 suggests that at the front-end of an infection in

6 the seronegative window period this clearly adds

7 something, adds something small, and I heard

8 somewhere between one-fourth to one-sixth of all

9 cases undetected by current methods would be

10 detected by this assay. So, it is not the

11 majority; it is the minority. And, we heard

12 suggestions and data that one would head towards

13 the majority with individual donor NAT and that

14 that might be substantially equivalent to and

15 better than in all cases HBsAg but we are not there

16 yet.

17 So, Jay phrased it as is there an additive

18 yield? Yes, there is clearly additive yield but I

19 have seen nothing to suggest that that additive

20 yield translates to something real in terms of

21 better outcomes in the patients that we transfuse.

22 I have no idea what the risk of those very low

205

1 viremia window period donations is in the absence

2 of that. Given all the substantial changes and

3 upheavals required to implement a new test, I would

4 wait until there is individual donor NAT data or

5 something that moves me further to do that.

6 I was also very moved by Dr. Hollinger\'s

7 comments. My oldest child is 16 and all three of

8 them have been vaccinated. So, if you get

9 pediatric care, you are vaccinated. I don\'t know

10 that there is a public health recommendation to

11 vaccinate the American adult population though.

12 DR. NELSON: Well, there is for pregnant

13 women, screening and vaccination, and for the

14 military and for healthcare workers. But this

15 country is very diverse. We get people from all

16 over the world who, you know, sleep in subways and

17 what-have-you. Some of them become blood donors,

18 unfortunately. I am all in favor of vaccination

19 but I am not sure\--it is going to take a while to

20 solve this problem by vaccination, and it is

21 primarily viewed I think as pediatric, pregnant

22 women and certain subpopulations with higher

206

1 exposure. So, you know, I think it is a great

2 vaccine and it is very important but we are not

3 quite there yet.

4 DR. HOLLINGER: The other thing that I

5 thought was interesting in the discussion today is

6 the fact that the assays, even very sensitive

7 assays, pick up something differently. I think

8 there was some testing where one alternative test

9 picked up things that another test did not pick up.

10 That, of course, is an issue that has me somewhat

11 concerned in looking at false-negative tests, not

12 so much false-positive but false-negative assays.

13 That is what we are really worried about, not the

14 false positives. A lot of false positives also

15 were in there\--the number is small considering the

16 number of people that are tested so, I guess, in

17 that way it is not a real big issue. But I think

18 that is another interesting part of what we have

19 been discussing.

20 DR. NELSON: I guess we are not going to

21 vote on this. Yes?

22 DR. DIMICHELE: I would just like to make

207

1 one comment, and that is that one of the statements

2 that was made earlier on the licensing question was

3 that the licensing would give people and blood

4 banks specifically options with respect to testing

5 in high risk populations. I think we can\'t forget

6 those high risk populations. In my opinion, the

7 data does support its use in picking up some

8 additional potentials for infections and I think we

9 have to recognize that we have both congenital and

10 acquired immunosuppressed populations. We have the

11 cancer populations and even in pediatrics,

12 unfortunately, there is a population that isn\'t

13 covered by vaccine and that is our neonatal

14 population. Much like we do tests, neonatal blood

15 for CMV and making sure neonatal blood is CMV

16 negative because of the risk in that particular

17 population, given the risk of hepatitis B in the

18 neonatal population, for instance, I could see this

19 as being a very important screening tool for

20 neonatal blood. So, I think it is very important

21 to consider it as an additional tool because, if

22 not widespread use, certainly for selective

208

1 populations I think it would be extremely

2 important.

3 DR. ALLEN: I would certainly hope, based

4 on what has been said today, that there will be

5 blood centers, once the test becomes licensed, that

6 will implement appropriate laboratory and

7 epidemiological studies that will enhance our

8 knowledge in a variety of ways. I would hope that

9 other blood centers that are collecting blood from

10 populations that tend to have a higher incidence

11 and prevalence of hepatitis B infection might

12 choose to implement this as a routine. And, I

13 think we certainly need to encourage the situation

14 where independent blood centers in areas of the

15 country where there is very little hepatitis B

16 incident infection, that they not feel compelled to

17 implement the test unless local data suggest that

18 it would be helpful.

19 DR. STRONG: That is an interesting

20 comment because of the three test sites that have

21 continued to test, one of them is Minnesota which

22 probably has the lowest B activity in the country.

209

1 They have decided to test. But I think it is

2 affected by, one, ease of implementation because we

3 already have it; two, the patient population we are

4 serving, and in our situation, in Seattle, it is

5 the cancer patients, the bone marrow transplant

6 patients, a large hemophilia population, and our

7 medical staff didn\'t have trouble with that

8 particular decision but I am sure it would be

9 complicated if we had to implement a whole new test

10 system.

11 DR. GOLDSMITH: I guess we could also then

12 encourage the use of smaller minipools as they

13 proceed with their research, maybe with 12 or 6,

14 and there would still be some benefit of numbers,

15 or single donors to see if there is an additional

16 benefit that would actually improve the public

17 health.

18 DR. HOLLINGER: And at the same time, in

19 terms of looking at these things in follow-up, it

20 would be important, as I think Jim mentioned, to

21 get a lot of other information, epidemiological

22 information. We saw they picked up two people that

210

1 were within that window period. I would like to

2 know more about those two people, their background,

3 their epidemiology, something of that nature, what

4 happened to them clinically, and so on. We need

5 that kind of information to know if our

6 questionnaires are working and other things too.

7 DR. NELSON: Yes, the sentinel county

8 study that the CAC has done has shown in the last

9 few years that the heterosexual transmission of

10 hepatitis B is one of the major routes. The

11 incidence has actually declined overall in these

12 sentinel counties but heterosexual transmission\--of

13 the incident cases that occur are probably the most

14 important in the general population. These are

15 potential donors, some of them. Let\'s break until

16 about 1:45.

17 \[Whereupon, at 1:00 p.m., the proceedings

18 were recessed for lunch, to resume at 1:45 p.m.\]

211

1 A F T E R N O O N P R O C E E D I N G S

2 DR. NELSON: In discussions with Dr.

3 Epstein after the conclusion, he would like to

4 either have a vote or a further statement\--and I

5 hope we can make it brief\--on the previous

6 question, question three, on hepatitis B NAT

7 testing. Jay?

8 DR. EPSTEIN: Yes, I appreciate that there

9 was difficulty with getting a common understanding

10 of the question. This is question three to the

11 committee on HBV minipool NAT. What I would like

12 to do is try to clarify what exactly is FDA asking

13 and let you determine, Kenrad, with you feel the

14 committee can vote on the question with that

15 understanding. If not, it might be helpful to the

16 FDA if we could have individual committee members

17 simply state their views.

18 So, on the question of what do we mean,

19 first of all, I need to explain that we are asking

20 the committee for scientific advice. We understand

21 that in any ultimate decision there are factors

22 such as feasibility of implementation, the

212

1 logistics, time scales and cost-effectiveness of

2 intervention. But we are not asking this committee

3 those questions. There will be a process through

4 the DHHS, which has an advisory committee on blood

5 safety and availability, to ask more global

6 questions about public health significance and

7 cost-relatedness of any FDA decision.

8 So, it is with the understanding that the

9 question is narrowed to a scientific point of view,

10 putting aside issues of cost-effectiveness, and the

11 implication of that is that the committee members

12 should not feel that if they vote that there is

13 significant benefit that that will in any way

14 obligate the FDA to make a policy decision in favor

15 of additive testing.

16 Then, what we are asking is whether

17 additive testing with HBV minipool NAT as described

18 would provide a benefit, a benefit to blood safety,

19 a benefit to patient health. We understand that

20 there may be different points of view on the degree

21 of such benefit, but it is hard to avoid the

22 question because, after all, the committee has

213

1 basically has advised that the data support

2 approval as a screen; that the data do not appear

3 to be sufficient at this point in time for use of

4 the minipool test to replace HBsAg. But, if FDA

5 were to approve it, what exactly do we say about

6 it? And, the question will hang in the air whether

7 it ought to be recommended as an additive test.

8 So, the question won\'t go away. FDA will

9 ultimately have to make a policy stand. So, what

10 we are then saying is, well, we would like to be

11 advised by this committee whether, on scientific

12 grounds, we are or are not looking at health

13 benefit. I think part of what has concerned the

14 committee is that there are really two dimensions.

15 One is an additional pickup rate of positive units.

16 The other is the significance of transfusing any

17 such units in terms of medical outcome. You know,

18 we assume that you will be considering both factors

19 if you decide to vote on the question.

20 Again, we are asking you in this question

21 whether additive testing is a benefit, and we would

22 like you to answer that question with the

214

1 understanding that that is putting aside the

2 questions of economics and logistics.

3 DR. SMALLWOOD: The proceedings of an

4 advisory committee require that after we have

5 closed discussion on an issue that we do not reopen

6 it because we have not made it public that we are

7 doing something differently. We had previously

8 stated that we would not vote on question number

9 three and to open it up again, after individuals

10 have left, even the principals that are involved

11 here, would not be fair. So, we would be going

12 against the advisory committee procedures.

13 DR. NELSON: Principles don\'t have a vote.

14 There may be one committee member that has gone. I

15 don\'t see why we couldn\'t\--

16 DR. SMALLWOOD: Excuse me, it is the

17 discussion, Dr. Nelson\--

18 DR. NELSON: It is not a discussion now.

19 We are only going to vote. The discussion is over.

20 DR. SMALLWOOD: Excuse me, this is an open

21 public meeting. Under the rules for an open public

22 meeting we have to announce what we are going to do

215

1 in advance. We have closed out the discussion. We

2 closed out the discussion on this issue before we

3 went to lunch, and I am just quoting what the rules

4 are.

5 DR. EPSTEIN: Is it permissible to have

6 individual expressions of opinion?

7 DR. SMALLWOOD: Dr. Freas?

8 DR. NELSON: Is the Supreme Court in

9 session? Do we need to see what Justice Thomas

10 thinks about it?

11 DR. FREAS: I really believe that it is

12 okay. This meeting was announced in the Federal

13 Register. There is nothing other than a statement

14 of clarification and I believe that if we went

15 around the table quickly and the committee members

16 made their comments, that would be permissible. I

17 would prefer no votes at this time.

18 DR. SMALLWOOD: To be clear, there will be

19 no votes but there will be committee comments

20 coming from individual members.

21 DR. NELSON: It will take longer but do

22 you want to announce the names so they can make

216

1 comments then? Dr. Doppelt?

2 DR. DOPPELT: I think that there is some

3 benefit clearly that you can pick up some cases in

4 the window period. It isn\'t a lot of cases that

5 you pick up though you do pick up some. So, you

6 know, I think most people would probably say if it

7 didn\'t cost anything, what the heck, just do it.

8 But it does. So, not commenting on the issues of

9 cost benefit, but just from the simple fact of what

10 does the data show, yes, you pick up cases and

11 there is benefit.

12 DR. GOLDSMITH: I think the information we

13 saw does support the idea that there were a couple

14 of cases found but the testing algorithm that was

15 used hasn\'t been studied long enough to see if this

16 is the most powerful way to find additional cases;

17 that the 24 samples used for screening is probably

18 not the best way to use this new technology.

19 Therefore, if I had to vote, I would probably say

20 no at this time about this question, that the

21 sponsor should do additional work to find out the

22 real utility of this test, and also do additional

217

1 clinical work to find out what the outcome is of

2 potential transmissions.

3 DR. KLEIN: For the record, I was not

4 considering either logistics or cost in my comments

5 this morning. I think the data that was presented

6 clearly demonstrate that this assay will detect

7 some otherwise undetected donors infected with

8 hepatitis B virus. From what we know about

9 hepatitis B virus, that would very likely infect

10 recipients. The amount of public health benefit I

11 believe, based on those two statements, is finite.

12 It is real but it is very small.

13 DR. HARVATH: I concur with the comments

14 that have just been made. It is what I would have

15 said.

16 DR. KUEHNERT: I think there is, you know,

17 the data presented and it is all we have to go on.

18 It seems to indicate that you pick up a small

19 number of additional cases. I think you also have

20 to consider whether in implementing the test you

21 clarify or further muddy the picture as far as, you

22 know, possible false positives, and how those then

218

1 get reconciled. So, to me, that all needs to be

2 added into the decision processes. You might be

3 able to detect some additional cases but also what

4 is the full picture as far as the impact on false

5 positives? You have to resolve those false

6 positives as well. So, this question, to me, I

7 sort of have to consider those things as well. So,

8 to me, I am not sure that it is a benefit when you

9 add all that in.

10 DR. NELSON: I thought that the results

11 were fairly impressive, that it could actually pick

12 up additional cases and narrow the window period

13 particularly in the incident cases, and also pick

14 up some that were core positive who would have been

15 deferred with current screening. So, when I look

16 at the international situation I see this as even a

17 more important application where core antibody

18 testing is not\--I realize that is not part of the

19 U.S. algorithm, but I think that preventing

20 hepatitis B, which may be benign and self-limited

21 in many adults who have a normal immune system,

22 nonetheless, this is an oncogenic virus and it is

219

1 not all normal adults that are transfused, but

2 sometimes immunocompromised children. So, I would

3 support it and I think it should be implemented

4 when it can be.

5 DR. ALLEN: I would agree with the prior

6 comments. It seems to me that the evidence is

7 fairly clear that this test, even in a minipool of

8 24, does narrow the window during the

9 seronconversion of early infection state and,

10 therefore, would result in a very slightly safer

11 blood supply, looking at the nation\'s blood supply.

12 I think the impact for individual people who might

13 otherwise receive those units is variable. It

14 could be significant in some people.

15 In terms of the implementation, I think

16 there are many issues that need to be examined,

17 including cost benefit, the impact on the ability

18 of blood bank laboratories to implement the test

19 easily and successfully. I think we need quite a

20 bit of additional research, as was discussed,

21 including examining the relationship between the

22 NAT test and the surface antigen test and, once we

220

1 have additional data, what the optimal combination

2 should be for routine screening in blood centers.

3 I think we need to examine the issue of whether

4 smaller minipools or even individual donor testing

5 provides any additional benefit versus the cost.

6 DR. DIMICHELE: Given the data that was

7 presented earlier today and the discussion that

8 followed, I believe that there is strong enough

9 evidence for the FDA to give strong consideration

10 to adding this test to the complement of tests

11 already used for hepatitis B detection. I believe

12 that the preliminary data mandates further

13 research, the nature of which has already been

14 stated.

15 DR. DAVIS: I think the test will pick up

16 cases that would not have been discovered

17 otherwise. I don\'t know that those cases are

18 enough to justify adding the test. I would have

19 voted no.

20 DR. HOLLINGER: I agree with much of what

21 has been said here. One thing that has not been

22 added, I personally think the clinical impact will

221

1 be insignificant overall. We have not talked even

2 about treatment, and there are some good nucleotide

3 and nucleoside analogs which are available which

4 work very well in acute viral hepatitis B in

5 stemming fulminant hepatitis, and so on. So, even

6 if someone were to get clinically sick, the

7 probabilities are that they would have good

8 response to therapy and that would make this even

9 less significant.

10 DR. QUIROLO: Well, I am a pediatrician

11 and all the people that I transfuse are children.

12 So, all those people would have hepatitis B for

13 decades if they were to contract it from a

14 transfusion. Not only that, I take care of

15 minority children and immigrants and most of those

16 people are not immunized, the families aren\'t, so

17 the child would transmit that to his parents and

18 his siblings.

19 So, I think that the test is worth

20 considering. I also don\'t see it as a stand-alone

21 test. It says in conjunction with those tests. I

22 don\'t think you can use it without using those two

222

1 tests; it is not a stand-alone test the way it is.

2 DR. WHITTAKER: I think the data support

3 the use of this test, however, I think additional

4 testing is needed in smaller pools before we add it

5 as a mandated test for blood donor testing.

6 MS. KNOWLES: I think also the data

7 support using this test as an added test. I think

8 this is a part of the evolving armamentarium of

9 screening tools that we really need to keep pushing

10 on forward.

11 DR. STRONG: If I were allowed to

12 comment\--

13 \[Laughter\]

14 \--we made the decision locally, as I have

15 already stated, with our medical staff that we will

16 continue to use it. I think it has provided us

17 some additional benefits. One, for example, is

18 that with the anti-core positive donors, and we

19 have a large number of false positives, but

20 remember that we are allowed to have two positive

21 anti-core results and we have had some pickups with

22 the first time anti-core that would be DNA

223

1 positives. So, that would obviously be a

2 circumstance in which we would want to defer that

3 donor on a first time anti-core result. So, it

4 adds that additional benefit.

5 It clearly has helped us pick up some

6 window cases, I think to some degree to our

7 surprise. Our yield is more like 1/150,000, but

8 because we have had the three cases recently that

9 number will be diluted with time. But the staff

10 certainly feels that it has had an added benefit.

11 I think there still needs to be data collected in

12 terms of the hepatitis B surface antigen issue and

13 core, clearly, will need to be continued.

14 DR. NELSON: Now maybe we can move on.

15 Jay, is that satisfactory?

16 DR. EPSTEIN: That is fine.

17 DR. NELSON: The next item is current

18 trends in plasma product manufacturing,

19 introduction and background with Dr. Weinstein.

20 V. Current Trends in Plasma Product Manufacturing

21 A. Introduction and Background

22 DR. WEINSTEIN: Thank you, Kenrad. I am

224

1 going to curtail my talk severely and just bring

2 out the important points. I know that people have

3 to go at three o\'clock and we do want to hear the

4 industry presentation as well as further comments

5 from the audience here. So, let me just comment

6 here that the plasma fractionation industry has

7 undergone a number of notable changes, significant

8 changes within the last year.

9 \[Slide\]

10 We have heard about closures of plasma

11 collection facilities. We have heard about layoffs

12 of personnel. Some of the major plasma

13 fractionaters have reduced their plasma collection

14 significantly by a couple of million liters. We

15 have also heard about the consolidations and

16 restructuring of the industry. Alpha Therapeutics

17 has been absorbed by Grifols and Baxter. Beyer has

18 put its fractionation plant up for sale. Aventis

19 has been purchased by CLS to form ZLB-Behring, and

20 Octapharma is the new player on the U.S. market.

21 The question is do we have to fear chronic

22 shortages because of these changes? What is

225

1 industry doing? What is the state of the industry?

2 I called Jan Bult, representing the Plasma Protein

3 Therapeutics Association, to give us an overview of

4 where the industry is.

5 Presentation

6 MR. BULT: Thank you, Dr. Weinstein, for

7 this introduction. I am going to, hopefully, tell

8 you in my presentation that we don\'t see a

9 near-term threat for supply, just to immediately

10 respond to one of your opening comments, and in

11 this presentation I would like to explain why.

12 \[Slide\]

13 What I am going to cover today is changes

14 since \'98, the last time when we were facing

15 serious shortages in the United States; a little

16 bit about our data collection and how we

17 fractionate and therapies; what has happened

18 recently; what is going on with supply; tell you a

19 little bit about economics of plasma fractionation;

20 and then conclude with our statements.

21 \[Slide\]

22 Well, I think the most important thing

226

1 that has changed since 1998 is that we have

2 immediately implemented monitoring systems to

3 assess changes in supply dynamics. That

4 information is available on a monthly basis. It is

5 available on a website. We do believe that

6 industry as a whole is much better positioned to

7 meet consumer demand. You have seen from the list

8 from Dr. Weinstein that we have new companies

9 entering the market. In addition to Octapharma

10 that you mentioned, also Grifols or Provitas has

11 entered the U.S. market with their immune

12 globulins. So, we have companies now with broader

13 product portfolios.

14 But it must also be said that a lot of

15 things have changed, especially when it comes to

16 economics. In order to guarantee long-term

17 viability of industry, we have responsibility and a

18 need to address the current industry economics.

19 \[Slide\]

20 Coming back to April, \'98 when we were

21 dealing with shortage of immune globulins, which

22 was also the subject for a congressional hearing

227

1 and a lot of media attention, we have made a

2 commitment, and the commitment was that we will

3 start a data collection effort, originally on a

4 quarterly basis so that all parties will understand

5 the dynamics of supply.

6 What has happened in the meanwhile is that

7 we quickly moved to monthly reporting. That

8 information is available since six and a half

9 years. It is provided on an Association website

10 and is publicly available. But also the situation

11 that we have right now is that we use a traffic

12 light system, green, yellow and red. Green means

13 there is sufficient supply of inventory. Yellow

14 means let\'s be careful, and red means we have a

15 problem. We haven\'t had a red situation. We had

16 two months of a yellow indication and what we have

17 done, we immediately informed the patients about

18 the situation so we have been very transparent and

19 open about the developments.

20 \[Slide\]

21 A couple of things that need to be said

22 are that we can, as an association, talk about

228

1 publicly available information. Some of that has

2 already been shown by Dr. Weinstein. But we need

3 to be careful because this is a very concentrated

4 industry and, because of that, we cannot sit

5 together with individual companies and agree on

6 what is going to happen with production trends. We

7 have to respect anti-trust laws.

8 Also, we have to accept that certain

9 things are unpredictable. We would like to know

10 everything in the world but that is simply not

11 possible so unpredictability is a factor that we

12 have to take into account. We can only comment

13 about things that are within our control. We are

14 only part of the entire chain.

15 But, as I said before, we do not see a

16 near-term threat to supply. What we will see is

17 that individual companies will take actions to make

18 sure that the economic situation that we are facing

19 is going to be addressed, and I will explain to you

20 in the presentation later on why.

21 \[Slide\]

22 Don\'t be frightened by this slide, but I

229

1 have to do this. I just want you to understand

2 what we can and what we cannot do. The points that

3 are pointed out in red are things that are simply,

4 by law, illegal. We cannot as an industry agree to

5 limit production or to reduce or increase

6 inventories. We cannot coordinate output. We

7 cannot allocate capacity. We cannot determine

8 quotas. We canon talk about continuation or

9 discontinuation of products, and we cannot limit

10 supply of particular products.

11 This is important because you can have

12 those conversations with individual companies but

13 once you are together you can simply not talk about

14 that. And, if you have a lawyer in the room, they

15 will immediately stop that discussion.

16 \[Slide\]

17 Now, having said that, we want to be

18 cooperative. We want to share as much information

19 as we can. Therefore, I am going to tell you what

20 we believe the situation is. Let\'s focus on some

21 of the products that are made from plasma. As you

22 can see, I focus here only the major products,

230

1 alpha-1, Factor VIII, immune globulins, albumin.

2 As you can see, these are proteins that are

3 available in plasma in different amounts. What you

4 see here are the quantities estimated industry

5 aggregate, but that may differ from company to

6 company and differ in the technology that is being

7 used.

8 \[Slide\]

9 In the fractionation process a combination

10 of temperature, pH, time and alcohol is going to

11 separate the different fractions that are used to

12 manufacture the different therapies. I am not

13 going to go in detail here.

14 \[Slide\]

15 What you have seen, and Dr. Weinstein

16 already pointed that out, is that in the last

17 couple of years we have seen consolidations. We

18 have seen companies making a decision to divest

19 their interests in the plasma industry. We have

20 seen closures of plasma collection centers. We

21 have also seen some closures of fractionation

22 plants. As a result of that, there is a reduction

231

1 of the plasma that is used for manufacture, and

2 also we have seen massive layoffs, people that are

3 losing their jobs. Of course, everybody would like

4 to avoid that but this is the reality of today.

5 \[Slide\]

6 The good news is that we have seen new

7 companies entering the market. We have seen new

8 product approvals. We have seen upgrades and

9 build-outs in the facilities. We have seen better

10 technology. We have seen technology nowadays that

11 allows us to obtain products with a higher yield

12 which means that you need less plasma, and we see

13 utilization of both source and recovered plasma as

14 starting material.

15 \[Slide\]

16 Going back to 1998, the problem that we

17 were facing is that the supply did not meet demand.

18 if you look at this graph, which basically points

19 out the true distribution of immune globulins in

20 the United States since January, 1998, the bottom

21 line is that on an annual basis, in 1998, we were

22 supplying about 14,000 kg into the U.S. marketplace

232

1 and today it is between 26,000 and 27,000. I think

2 it is a very impressive improvement and it is a

3 clear demonstration that the commitment that the

4 industry made to act upon the shortage was turned

5 into practice.

6 \[Slide\]

7 What we need to understand is the

8 economics associated with the manufacture of these

9 therapies. The collection of plasma, which is used

10 as a starting material, is not a static process.

11 It is a very dynamic process and it is dependent on

12 the type of products which you need what the driver

13 is for the total volume of collection plasma. As

14 you can see on the left side of this slide, in the

15 past the quantity of albumin was the one that

16 really determined how much plasma was needed. What

17 we see today is that it is the volume of immune

18 globulins that determines basically how much plasma

19 needs to be collected.

20 \[Slide\]

21 So, what I am going to do now, I am going

22 to try to explain to you with a model how this

233

1 really works. In this model, I am going to explain

2 to you five possible therapies, immune globulins,

3 albumin, Factor VIII, alpha-1 and other proteins.

4 \[Slide\]

5 Here is how it basically works. If you

6 look at this slide, you can see that a company or a

7 country or global there is a certain capacity that

8 you can use to manufacture your products. If you

9 look at the bottom column, it shows you in this

10 particular case the sales of immune globulins. As

11 I mentioned before, the driver for collection is

12 plasma, so you need more plasma to manufacture

13 immune globulins but you are also manufacturing

14 albumin. What you can see in the yellow column is

15 the volume of albumin that is being sold in this

16 particular model. Then, companies sell Factor

17 VIII, other proteins and alpha-1. On the left side

18 you can see there is a revenue per liter if you

19 calculate what the revenue for the industry is. As

20 you can see in the grey line, there is a cost to

21 manufacture and basically what you can see here is

22 that in order to recover the cost of manufacture,

234

1 you need to sell multiple products. It is

2 impossible to make up your cost with the sale of

3 one product. This may differ from company to

4 company based on their technology and so on. But

5 the reality is that some companies do not

6 manufacture Factor VIII. You can imagine that the

7 cost of manufacture then needs to be recovered by

8 less products.

9 \[Slide\]

10 The other thing that we need to understand

11 is that if we manufacture immune globulins, here,

12 as a result of the fractionation process,

13 automatically you also end up with more albumin,

14 more albumin than can be sold on the marketplace.

15 What that means is that this volume goes in

16 inventories. There is no need for it; there is no

17 demand for it but there is a cost to manufacture.

18 So, the simple question that one could ask

19 is, well, why not resolve any discussion about the

20 potential shortage in the future just by making

21 more?

22 \[Slide\]

235

1 Well, this is what is going to happen

2 then. What you can do is you can make more, but

3 you can see this is what is being sold. So, now

4 you are going to manufacture more products which

5 are not needed on the market. They end up in

6 inventories. You also end up with more albumin and

7 you are losing money. And, this industry is not in

8 a position to continue to lose money.

9 \[Slide\]

10 Look at what happened if we go back to the

11 year \'98-99, and you see what the revenue per liter

12 was for the entire industry. You see a significant

13 reduction of about 50 percent in income of the

14 industry as a result of multiple factors. That is

15 the reason why industry needs to make adjustments

16 and ensure that it is healthy or becomes healthy

17 again.

18 \[Slide\]

19 One of the reasons is that this industry

20 is totally different than the pharmaceutical

21 industry. In many cases we are compared to the

22 pharmaceutical industry but if you just look at the

236

1 cost of manufacturing, two-thirds of the production

2 costs are the result of the cost of source

3 material, the testing and manufacturing compared to

4 about 20 percent for the pharmaceutical industry.

5 As a result of that, if you take into

6 account total cost, I have seen other slides that

7 basically said that the profit margin of this

8 sector is somewhere between 5-10 percent if

9 everything works well. But if you go to the

10 pharmaceutical industry, it is about 20 percent.

11 It is this profit margin we need in order to make

12 further investments in researcher and development

13 and that margin is simply not there. So, we need

14 to be very, very cost conscious for the future.

15 \[Slide\]

16 But there are implications of differences.

17 One is that what people tend to forget is that we

18 are not making products for diabetes patients or

19 high blood pressure. We are talking about a

20 relatively small number of patients that are using

21 these therapies which means that the cost needs to

22 be shared by a limited number, which is totally

237

1 different than what we are seeing in the

2 pharmaceutical industry. Nevertheless, when we

3 talk about public policy, public health policy, we

4 are many times caught in measures for

5 pharmaceuticals because we are considered to be the

6 same.

7 We are providing biologicals. The

8 technology that is being used is very specific,

9 very complicated. We are certainly no generic

10 manufacturers that has a different product life

11 cycle development because those therapies are used

12 for decades, in contrast to the pharmaceutical

13 industry where 10, 15, 20 years maximum is a life

14 cycle. And, we are working in a regulatory

15 environment which is the most stringent within this

16 sector. We are not complaining about it. What we

17 are saying is that this is the case and should also

18 be recognized when it comes to compensation. The

19 working capital, the up-front investment is

20 enormous. It takes about 7-8 months to get your

21 product out of your manufacturing site after

22 collecting your plasma\--enormous investments.

238

1 The clinical trial requirements are very

2 complicated because we have a small number of

3 patients. It is not that easy to get large number

4 of trials, especially when you do it in a

5 randomized, placebo-controlled fashion. It is

6 complicated.

7 Then, what we see is an enormous pressure

8 on reimbursement and, if this is going to continue

9 like we have seen in the last couple of years, this

10 may lead to further industry consolidation, further

11 company exits\--we have already seen that

12 sufficiently. Then, it will reduce the choice of

13 therapy, which is not a good thing.

14 \[Slide\]

15 If we look at the revenue factors, and I

16 am not going to talk about the details but just to

17 point out, because I know this is not on the

18 charter of the BPAC but I think it is important for

19 you to understand what is going on, what we see,

20 especially when we talk about the reimbursement

21 areas, is if you look at the lower expenditures you

22 might think about issues like prospective payment

239

1 and the sales price as a basis for reimbursement,

2 or competitive bidding. While they may sound nice,

3 there are really important differences between the

4 products you cannot use\--change immune globulins

5 from one patient to the other, what happens then

6 is, once this is done on the federal level, we see

7 also state average sales prices used as a basis for

8 reimbursement. We see other issues like prior

9 authorization. We see single source contracts, and

10 we see cluster pricing.

11 With these examples, what we see is that

12 the private payers are going to use that to develop

13 their own measures and talk about what is the

14 coverage, what is the reimbursement, and you have

15 all kinds of managed care plans. I am not going to

16 go into further detail here because I believe this

17 is an issue that most likely needs to be addressed

18 with the committee on blood safety and

19 availability, but it is important to realize that

20 what we can do is look at another factor which is

21 to take away, in my view, wrong perceptions.

22 \[Slide\]

240

1 If we talk about reimbursement of

2 therapies, a lot of people think that reimbursement

3 is what the manufacturers get. That is absolutely

4 not the case. It is not the case. The

5 manufacturer is the one who has to put in the

6 testing, the plasma collection and fractionation

7 and there is an enormous amount of added value in

8 this chain but if you go back to the reimbursement,

9 it goes to the providers, it goes to the

10 distribution chain and then, at the end, it is what

11 the manufacturers get. If you make an analysis

12 about what the margins are, I think there is some

13 room for some further investigation.

14 \[Slide\]

15 Now, what can we do? If you look at the

16 costs, that is an area where we can have a

17 meaningful discussion. I think it is important to

18 look at a couple of areas, the regulation

19 requirements; we can look at team biologics; we can

20 look at clinical trials. Let me give you one

21 example of a regulation requirement that, in our

22 view, needs some reconsideration.

241

1 About 20 years ago, 25 years ago, there

2 was a requirement that every donor needs to be

3 weighed before plasma collection to determine the

4 amount of volume that could be drawn from the

5 donor. In that period, when AIDS developed, there

6 was also a significant weight loss seen as an

7 indicator to point out that you needed to do

8 further investigation. But everybody knows that

9 with the introduction of testing and more knowledge

10 about HIV, this is a requirement that doesn\'t make

11 a lot of sense.

12 So, FDA changed that, however, it is still

13 in the inspection protocols when centers are being

14 inspected and what happens now is that if you have

15 a donor that has a deviation in weight of 10 lbs or

16 more, you need to do an enormous amount of

17 investigation. Well, look at me. I would like to

18 lose 10 lbs. It doesn\'t mean I am not healthy; I

19 am maybe even healthier. So, I think this is a

20 kind of requirement that we should consider, and I

21 think that it would make sense if we could come

22 together with a group of experts, collection

242

1 experts, industry experts, FDA experts to see

2 whether we can make an analysis and find these kind

3 of requirements that don\'t really add a lot of

4 safety.

5 If you look at team biologics, I think FDA

6 and team biologics do a tremendous job going in to

7 make sure that companies are in compliance, and I

8 don\'t have to repeat the past but I think that we

9 have all learned a lesson and I honestly can say

10 that where we are today with quality and safety is

11 enormous if you compare that to ten years ago.

12 Maybe it is time to reconsider what needs to be

13 done, whether there are some redundancies in

14 systems that can be removed as well.

15 Then, when we talk about clinical trial

16 requirements, the difficulty is that because we

17 have a small number of patients, to set up the real

18 big trials is very difficult. Sometimes we see a

19 discrepancy between products that are already

20 approved in Europe and are not approved in the

21 States because the requirements are different, or

22 vice versa. The way the information is submitted

243

1 is different. There is no consistency in format.

2 I understand from a conversation earlier today that

3 this may be subject to see whether there is any

4 room for harmonization. These are the kind of

5 things that we need to look at.

6 \[Slide\]

7 So, what we need to do is we need to

8 continue with having a clear monitoring system, as

9 I explained in the beginning, while we continue to

10 measure inventory and distribution. We do have an

11 emergency plan for supply in place. In 1998 we

12 made a commitment. If you look at the data you

13 will see that every month there is an emergency

14 supply available. In case patients need it

15 immediately, there is always a quantity made

16 available by the industry to make it available for

17 patients, but also healthcare professionals because

18 we are not dealing with patients alone. Healthcare

19 professional organizations are very important.

20 Then what we do, we have regular

21 communications with all stake holders. We have

22 four meetings per year, here in the United States,

244

1 where we meet with consumers; where we meet with

2 physicians; where we meet with regulators; where we

3 have open dialogue about all these developments and

4 in case we see a deviation that requires attention

5 we have to form to do so.

6 \[Slide\]

7 In conclusion, we do not see a near-term

8 threat to the availability of plasma therapies. I

9 think that is a most important message. We believe

10 that the current inventories and also the change

11 through technology that allows us to use higher

12 yields will most likely offset reductions in the

13 throughput that we have seen earlier from Dr.

14 Weinstein.

15 We will remain vigilant because it is our

16 task to make sure that this industry is healthy.

17 The health of the patients and the health of the

18 industry go together. We can\'t do it without each

19 other, and we cannot afford to continue to

20 manufacture products and lose money. That is not

21 in the interest of the industry but, most

22 importantly, not in the interest of the patients.

245

1 We will make sure, as an industry group, that we

2 make corrections. If we do that, then we can

3 guarantee further access, choice and continue with

4 the profits that are necessary to continue to work

5 on innovation. Thank you very much for your

6 attention.

7 DR. NELSON: Thank you. Any comments or

8 questions?

9 DR. DIMICHELE: Thank you for that. That

10 was very informative. I wanted to ask a question

11 about the difference in the sort of profit margin

12 structure between biologics and pharmaceuticals.

13 My concern is that many of the plasma industry

14 companies or the plasma manufacturers are now part

15 of conglomerates that include pharmaceuticals. To

16 what extent will the economics of the

17 pharmaceutical industry threaten the companies or

18 the parts of the companies that produce plasma

19 products?

20 MR. BULT: It is very difficult to go into

21 company specific situations but, again, going back

22 to 1998 where we had a situation in the United

246

1 States where basically the market was supplied by

2 four companies and the American Red Cross, three of

3 those four companies no longer exist. One is gone,

4 another is taken over, another is in the process of

5 divesting. So, I believe we have gone through a

6 process of adjustments.

7 What I do see is that companies are very

8 aware of the economic situation and the corrections

9 that need to be made, and one of the things is that

10 as a result of the commitment that we made in \'98

11 to produce more and more and more, which was good,

12 now we have a situation where on some occasion you

13 may even talk about over-supply, and if we have

14 over-supply that is not really helpful. So, I can

15 see the point of some of the companies, in order to

16 make these economic adjustments, will tighten

17 supply to balance demand and supply. I think that

18 is what is going to happen.

19 DR. ALLEN: Looking at the series of

20 slides you showed on the cost to manufacturer and

21 then the revenue generated by the different

22 products, I was a little surprised to see the

247

1 immune globulins right at the bottom. I would not

2 have predicted that. In terms of the cost to the

3 manufacturers, is there a significant difference

4 between the intravenous immune globulin products

5 and the injectable immune globulins?

6 MR. BULT: You should not draw any

7 conclusion about the order of the therapies. The

8 only conclusion that you should draw is that if you

9 talk about fractionated plasma that is needed the

10 driver is immune globulin and, from that point of

11 view, the place in that graph is absolutely the

12 correct place. The vertical access is absolutely

13 not an indicator of what the true revenue is

14 because that differs from company to company. What

15 was important to me is to share with you the

16 concept and the model to help everybody understand

17 how it works and how complex it is.

18 DR. KLEIN: I always worry a little bit

19 when I see fractionation plants closing down in

20 terms of response time. I pretty much have a good

21 idea of how long it takes to put collection sites

22 and license them but if you could give us an idea,

248

1 first of all, of how long it takes to build and

2 qualify a fractionation plant, and where we stand

3 right now in terms of fractionation capacity

4 worldwide.

5 MR. BULT: The numbers that we have always

6 used in the past are that in order to get a plant

7 in function after going from the drawing board is

8 about five years, building it up and going through

9 the validation processes, etc., etc. When you talk

10 about collection, yes, of course it is true that

11 when you close your centers, and if a situation

12 occurs where you need to have more plasma, well, I

13 haven\'t spoken to the individual companies but I

14 would expect that they have not closed the most

15 efficient centers. I would expect that they have

16 closed centers where there were some questions

17 about efficiency. In case we need more plasma it

18 is easier to work with efficient centers to improve

19 that and increase it than start all over again.

20 The other thing is that if you look at the

21 technology that is being used, and I mentioned that

22 in the presentation, most of the companies that I

249

1 know use the technology that obtains higher yields,

2 which means that you use less plasma. So, that is

3 another important contributing factor.

4 DR. KLEIN: Do you have an idea about the

5 fractionation capacity worldwide in terms of

6 current needs and what there is in reserve?

7 MR. BULT: I don\'t have those numbers in

8 my head but maybe there is someone in the audience

9 that could help me out here and give me a number,

10 if that is available, but I don\'t have it at hand

11 here.

12 DR. KLEIN: I guess what I am asking is if

13 we needed a ton of anthrax immune globulin or a

14 whole host of other things that one could guess at,

15 would we be in a position to manufacture it?

16 MR. BULT: Well, I think if we start

17 talking about the anthrax issue, I mean that opens

18 up a whole\--

19 DR. KLEIN: I was only using that as an

20 example.

21 MR. BULT: Yes. I do believe that if we

22 talk about existing products where you need to

250

1 expand capacity, that is easier than to develop new

2 products where you have to go through the whole

3 process. So, if we talk about existing products,

4 that is easier to do. But, again, I have no

5 indication that there is a near-term threat to

6 supply or availability. I think that is the most

7 important message.

8 DR. KUEHNERT: Looking at your slides on

9 supply trends and also distribution in the

10 handout\--and maybe this is more of a question for

11 FDA also, but how are not only supply but demand

12 trends followed? I mean, what system is there to

13 determine sort of what the supply is in relation to

14 demand in the United States on this products?

15 MR. BULT: Let me make a couple of

16 comments about the slide that you have seen. The

17 numbers that you have seen on the slide are what we

18 call a true supply into the market. Let\'s take one

19 example if you go to the first dot on the slide,

20 which is January, \'98, the way this was constructed

21 with the help of experts on economics, they have

22 taken the production in the month of January; they

251

1 looked at the inventory on February 1st, and

2 deducted the inventory of January 1st. So, what

3 that means is that you have the true supply in the

4 market.

5 Now, what you have seen cannot be a true

6 amount because there are too many fluctuations,

7 especially when you look on a month to month basis.

8 What we do is we provide this information to FDA so

9 FDA has full insight on all the information company

10 by company and what you see here is aggregated

11 information. But if you combine that information

12 we believe we can say, with a high degree of

13 confidence, that the annual gross of immune

14 globulins is somewhere between 4-6 percent per

15 year.

16 DR. HOLLINGER: What is the expiration

17 time of IVIG, for example, how long?

18 MR. BULT: Sorry, I couldn\'t hear the

19 question.

20 DR. HOLLINGER: The expiration time for

21 IVIG? How long?

22 MR. BULT: I think I see a sign in the

252

1 back, three years. That is the shelf life.

2 DR. HOLLINGER: Three years?

3 MR. BULT: Yes.

4 DR. HOLLINGER: How about specialty IVIG

5 products, like HcIG, HbIG, new bioterrorism

6 products and so on that might be manufactured for

7 the military, and things of that nature? And

8 albumin? I didn\'t see the numbers for albumin but

9 I can tell you it seems like albumin is being used

10 a lot more than it has in the past, medically.

11 MR. BULT: Yes. Coming back to your

12 question, it is a while since I, myself, was

13 working in the industry but I recall from those

14 days that there was no difference between the

15 shelf-life of hyper-immunes and polyvalent immune

16 globulins. What you do see is that it is dependent

17 on the regulations of the country where you

18 distribute. Sometimes you can have an expiry data

19 that goes for months and you have 36 months. There

20 are other countries where it is only twice a year.

21 So, you may have a difference of 6 months but that

22 is just a technical detail. When it comes to

253

1 albumin, I think albumin goes up to 5 years, if i

2 am correct but I have seen different stability

3 numbers.

4 DR. STRONG: I was interested in your

5 comment about harmonization. Those of us who

6 provide plasma for recovered plasma, we are

7 noticing an increasing conflict between European

8 standards and American standards. Even within

9 Europe there are country to country variations, for

10 example, a requirement for ALT testing in some and

11 not others. What is your forecast for how

12 harmonization is going, and do you think that there

13 is a role here for us to do more?

14 MR. BULT: You know, if you would have

15 asked medication that question two years ago I

16 would have said everybody wants to harmonize if you

17 do what I do. But today I would say I see much

18 more willingness among regulators to really start

19 to realize what the differences are. I already

20 mentioned before that in a conversation with Dr.

21 Weinstein we spoke about a potential workshop on

22 clinical trial requirements. We have a dialogue

254

1 with regulators all over the world, from the United

2 States, from Europe, from Australia, to identify

3 those issues to see how we can help each other to

4 understand and work together to create better

5 harmonization.

6 A part of the problem that we have is that

7 this sector is not part of the ICH process, the

8 International Conference of Harmonization. This is

9 true for the pharmaceutical sector. Because of the

10 specific nature, we were excluded. But I see far

11 more willingness of regulators to work with us and

12 to find ways to harmonize.

13 DR. WEINSTEIN: I should mention that we

14 are having actually a workshop on that very topic

15 to study standards for recovered plasma that will

16 be held on August 31, September 1st at the NIH. We

17 have invited speakers from Europe, from Australia,

18 from Canada to get international perspective on it.

19 We are looking for the scientific basis of these

20 standards. We are looking for practicality and the

21 need for adopting certain standards. So, we are

22 moving ahead on that.

255

1 DR. ALLEN: Two questions, building on the

2 harmonization issue and also looking at what I

3 anticipate will increasingly become an enhanced

4 global demand for these kind of products, much of

5 it supplied by the plasma, I would assume,

6 collected in the United States and European

7 countries or certainly in North American and

8 Europe. What is the anticipation in the industry

9 for the growth of global market sales, and are they

10 going to be able to meet that both in terms of

11 plasma collection as well as in terms of

12 manufacturing tank capacity?

13 MR. BULT: If you look at the global

14 numbers, what I do know is that if you listen to

15 the consumer organizations you know that there is

16 an enormous amount of patients in the world who are

17 diagnosed. For example, hemophilia patients, only

18 25 percent of the world population receive any form

19 of treatment. If you look at immunodeficiency as

20 an example, here in the United States it is very

21 well developed but there are other parts of the

22 world where the awareness is not as high and the

256

1 diagnostic ability is not as high as here in the

2 States. The same is true for alpha-1 for example.

3 It all depends on other factors such as

4 the economic situation in a country. There are

5 certain countries that are crying for help but

6 there is no funding available to make that

7 available. But if you look worldwide, as I

8 mentioned, for immune globulins worldwide there is

9 about a 4-6 percent increase for those countries

10 where immune globulins are being used. For the

11 rest, it is dependent on individual companies and I

12 cannot talk about these issues with individual

13 companies because of the anti-trust laws.

14 DR. ALLEN: The second question I have is

15 what percentage of the Factor VIII concentrate used

16 in the United States and Europe today is

17 recombinant? You mentioned new technologies making

18 allowing more efficient extraction of fractionation

19 products from plasma. To what extent do you

20 visualize that new technologies in other arenas,

21 particularly recombinant products perhaps, will

22 replace the need for plasma-derived products?

257

1 MR. BULT: Well, I originally had a slide

2 for this presentation which identified which

3 therapies could be replaced with alternative

4 technology, like recombinants and currently it is

5 Factor VIII, Factor IX and Factor VII. If I focus

6 on Factor VIII, I would say that in the United

7 States the last number I have seen is about 75

8 percent, 80 percent use for recombinant Factor

9 VIII. When I go to Europe it is about 50 percent.

10 If I go to Japan it is about 50 percent. If I go

11 to less developed countries there is a high use of

12 plasma-derived, mainly for cost reasons.

13 DR. DIMICHELE: Just to say, yes, indeed,

14 most of the product that is used, or a large

15 proportion of it for hemophilia A and B is

16 currently recombinant. But one of the things that

17 has become really apparent to those of us who treat

18 people with bleeding disorders is that there is a

19 vast array, you know, of other bleeding disorders,

20 most of which are more rare for which there is not

21 adequate therapy, and any therapy that is

22 potentially available, maybe with the exclusion of

258

1 Factor VII, has pretty much been plasma derived.

2 Also, within hemophilia A and B there are several

3 reasons to still need plasma-derived products with

4 respect to bypassing agents and certain

5 therapeutics.

6 So, one of the concerns that we have

7 certainly in the bleeding disorders field is that

8 the plasma industry continue to produce sufficient

9 supply and that we work with regulators and the

10 plasma industry to develop new technologies, new

11 treatments for the rare disorders. And, you know,

12 with respect to modifications of clinical trials,

13 requirements, orphan drugs are the sort of things

14 that would sort of make these therapies accessible.

15 So, there is a lot more that we have to do. The

16 whole problem of clotting disorders hasn\'t been

17 solved by recombinant technology and we have a lot

18 more work to do, and it still involves

19 plasma-derived therapies.

20 Open Public Hearing

21 DR. NELSON: In the open public hearing

22 Mr. Patrick Schmidt wanted to comment.

259

1 MR. SCHMIDT: Good afternoon. I will

2 speak very quickly because I want to make sure I

3 don\'t make me miss my plane. Good afternoon,

4 distinguished ladies and gentlemen of BPAC. My

5 name is Patrick M. Schmidt and I am the president

6 and CEO of FFF Enterprises. We are the nation\'s

7 largest distributor of intravenous immune globulin

8 and human serum albumin. Approximately 70-80

9 percent of the hospitals in the U.S. rely on the

10 distribution and management expertise of our

11 company as the primary source for these critical

12 care products. Countless other physician offices,

13 home care companies and patients rely on us as

14 well.

15 From this unique perspective we see a new

16 marketplace reality unfolding. The new marketplace

17 reality is characterized by rising prices,

18 declining inventories and a necessity to increase

19 vigilance on our industry\'s ongoing ability to meet

20 the needs of the patients we serve.

21 The plasma derivative market is very

22 complex. It is characterized by steadily growing

260

1 demand for most products, met by the challenges of

2 a very difficult, highly regulated and

3 capital-intensive manufacturing environment. We

4 encourage all participants in the marketplace to

5 recognize and understand this dynamic nature. We

6 have a saying within FFF once you think you

7 understand the marketplace, you end up realizing

8 you don\'t because it changes so rapidly.

9 The economics of plasma fractionation is a

10 study of supply and demand. An example, just in

11 the past five short years, the price of albumin has

12 declined from the mid-50s to the mid-teens. During

13 the same period of time IVIG has vaccinated from

14 the low-30s to the upper-50\'s and back again.

15 While tremendous savings have been enjoyed by the

16 healthcare provider, those who understand the

17 financials associated with running a plasma

18 derivative business knew that in the long-term not

19 all manufacturers would survive this downward

20 spiral.

21 If you remember back to 1988, the two

22 largest group purchasing organizations in the

261

1 United States, Premier and Novation, each had

2 contracts with seven different suppliers of IVIG

3 and albumin. They were Alpha, Baxter, Centeon,

4 ARC, Bayer, Immuno and Novartis. Four of those

5 seven suppliers no longer exist. They have been

6 replaced by new business combinations or new market

7 entrants like ZLB-Behring, Grifols or Octapharma,

8 as has been discussed before. Sort through this

9 myriad of changes, mergers and acquisitions,

10 consolidations and plasma collection center

11 closures, and you are left with a new marketplace

12 reality\--fewer suppliers.

13 The new look of today\'s marketplace will

14 feature three meta-suppliers that have global

15 reach, as was touched on earlier. They have the

16 complete portfolio of products from the precious

17 alpha-1 therapies to the workhorse albumin

18 products. Today\'s marketplace economics dictate

19 that the necessity that the manufacturers generate

20 revenue from multiple products per liter. I

21 believe the days that manufacturers fractionate

22 plasma for the purpose of producing a single

262

1 product, like IVIG, are gone. It just doesn\'t make

2 economic sense any longer.

3 Worldwide cuts are necessary from my

4 perspective and will result in a tightened supply

5 situation that will ultimately lead to shortages in

6 the IVIG marketplace and perhaps albumin market,

7 which is far less conceivable at this time.

8 This environment demands a supply solution

9 and distribution model that can manage rapidly

10 changing dynamics, a distribution model that

11 provides stability for both supply and pricing. We

12 must provide consumers a responsible distribution

13 channel that delivers the most reliable IVIG and

14 albumin supply in the United States today

15 regardless of the manufacturing changes.

16 In anticipation of a tightened supply, we,

17 at FFF, have already place four lyophilized IVIG

18 products on supply guideline status. That means we

19 have put filters in our internal ordering systems

20 that prevent customers from ordering quantities

21 that far exceed their previous utilization

22 patterns.

263

1 But please be aware\--it is very important

2 to emphasize this\--there is plenty of IVIG on the

3 marketplace today to meet the needs of the current

4 patient demand. Please also be aware that this

5 situation is highly likely to change in the future

6 and a great deal of collaboration that currently

7 exists between the manufacturers and distributors

8 of these products must continue to avoid 1998-like

9 shortages. Of course, the FDA is proactively

10 seeking to understand and mange this industry\'s

11 complex challenges and that is why we are here

12 today.

13 What role can the FDA assume to help

14 manage the transitioning marketplace and protect

15 the continuity of care? We have three brief

16 suggestions we wish to make to help accomplish

17 that. They are, first, prioritize or expedite any

18 manufacturing process change applications that

19 improve yields. Second, engage in discussions with

20 other federal agencies, like CMS\--and I realize

21 that may not be the purview of this committee, to

22 ensure that the appropriate reimbursement rates for

264

1 these critical products exist. Often the greatest

2 barrier to access to products is economic. Lastly,

3 consider implementing a pedigree requirement for

4 certain plasma products. Six different IVIG

5 preparations exist on nationally published lists of

6 the 31 drugs most susceptible to counterfeiting.

7 IVIG products have been counterfeited, diverted and

8 subject to the voracious pricing policies of the

9 secondary grade markets. Whatever you decide, I

10 encourage you to consider that the only ongoing,

11 viable solution must require the utmost in

12 distribution channel responsibility and

13 collaboration, managing the plasma product supply,

14 and necessitates the collective commitment of the

15 manufacturer, the distributor and the public

16 representatives, yourselves.

17 As our company has been involved in past

18 challenging marketplaces and markets surrounding

19 plasma derivatives, we remain ready and willing to

20 share data and perspective as the new market

21 reality crystallizes. So, thank you very much for

22 the important work you do for our industry and for

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1 the opportunity to address the committee today.

2 Thank you very much.

3 DR. NELSON: Thank you. Are there any

4 questions or comments? Harvey?

5 DR. KLEIN: I am not quite sure I

6 understood one of your statements. If there is

7 plenty of IVIG why would you have filters in your

8 distribution system not to sell people as much as

9 they either want or need?

10 MR. SCHMIDT: Well, because we are seeing

11 our ability to replenish at the same rate we were

12 purchasing before, and we are seeing declining

13 inventory so our ability to replenish is going

14 down.

15 DR. KLEIN: So, I guess there isn\'t plenty

16 of IVIG. Is that not correct?

17 MR. SCHMIDT: At this time there is plenty

18 of IVIG. I think the question that hasn\'t been

19 answered is what is the near-term, how long is the

20 near-term. While we have plenty of IVIG, we are

21 beginning to proactively monitor the situation so

22 we don\'t get into an exacerbated situation of what

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1 has happened in the past with decentralized, if you

2 will, management of these products. We have 6,000

3 hospitals in the U.S. and if they believe there is

4 going to be a shortage, they train management to

5 increase their levels and possibly exacerbate

6 shortages.

7 DR. NELSON: Jay?

8 DR. EPSTEIN: Thank you, Patrick.

9 MR. SCHMIDT: Thank you very much.

10 DR. EPSTEIN: Could you just comment why

11 do you think that IVIG products have been more

12 susceptible to counterfeiting than some other

13 products? What is the driver?

14 MR. SCHMIDT: I believe the driver, and

15 the criteria for being included in the list, is the

16 fact that one or two of the drivers have already

17 been counterfeited. There was an issue of gamunin

18 \[?\] that was counterfeited. Then, IVIG at times

19 has been highly sought after and people will do

20 almost anything to get their hands on IVIG in a

21 real tight marketplace because it is a critical

22 care drug and people, unfortunately, die if they

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1 don\'t have it. We have experienced times in our

2 business where people call and order IVIG without

3 any consideration of cost. I would also like to

4 say we have never taken advantage of that situation

5 but there people who have.

6 DR. GOLDSMITH: I probably should make

7 this statement from there because I put my IDF hat

8 on for a minute. I guess from the perspective of

9 the Immune Deficiency Foundation, I would like to

10 recognize the members of industry for being so

11 frank today, coming forward and speaking about what

12 they are doing, what their plans are. I think I

13 heard some promises there that they would maintain

14 supply that was kind of laced into all the bad

15 news.

16 I want to also recognize the fine work

17 that has been done by the FDA in terms of bringing

18 three new IVIG products to the U.S. market in the

19 last year, which is really an outstanding

20 accomplishment and shows that regulatory wheels can

21 grind fast when they need to, to respond to this.

22 I guess I would like everybody to

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1 recognize the fact that IVIG is a life-saving drug

2 for people with immune deficiency and it must be

3 available on the U.S. market.

4 DR. NELSON: Thank you. Dr. Carol Lee

5 Koski, University of Maryland?

6 DR. KOSKI: Thank you. I am actually a

7 neurologist that heads the Neuromuscular Division

8 at the University of Maryland. I also am on the

9 medical advisory board for the Guillain-Barre

10 Foundation. Although certainly immunodeficiency I

11 think is a significant indication for intravenous

12 immunoglobulin, I think it is also important to

13 remember that there are actually other neurological

14 patients, including those with Guillain-Barre

15 syndrome, chronic inflammatory demyelinating

16 polyneuritis and also myasthenia gravis where

17 immunoglobulin is actually used to prevent and

18 limit their paralysis. It allows these patients to

19 not only survive but to actually go on being

20 productive members of society, able to support

21 their families and do their daily activities of

22 living. So, don\'t forget the patients that may not

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1 have an FDA indication for that particular disease.

2 DR. NELSON: Harvey?

3 DR. KLEIN: I just want to know are you

4 getting all of the IVIG that you need for your

5 patients at the University of Maryland?

6 DR. KOSKI: Yes, we do. But one of the

7 things that I will also tell you is that during the

8 shortage I did not have any problems in getting

9 intravenous immunoglobulin, but that was partially

10 because of the fact that our hospital pharmacy was

11 able to buy very large lots and was one of the

12 major suppliers. But I very frequently had

13 patients that were referred to me from community

14 hospitals, that probably would have been treated in

15 that community hospital, because they simply didn\'t

16 have the intravenous immunoglobulin.

17 DR. GOLDSMITH: May I make a quick

18 comment? One of the things we need to watch\--I

19 agree that there are certain neurological diseases

20 that are have clearly benefitted from IVIG and I

21 think the FDA, when it responded to the crisis, did

22 point out that there was a large amount of the IVIG

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1 that was going for off-label use and it was up to

2 60 percent. These are estimates made by large

3 medical centers, and part of the way we dealt with

4 the crisis was by interacting with practitioners at

5 big medical centers and indicating to them that

6 they need to form some kind of filter for how they

7 were using immune globulins. We did not want to

8 curtail use for patients that had legitimate

9 diseases where there is a consensus that they

10 respond to IVIG. But we identify, the community at

11 large identified a large number of patients or

12 patient groups that were being treated for causes

13 for which there was no evidence\--so, something we

14 need to watch in the future in terms of

15 availability is off-label use, and make sure that

16 that off-label use is based on evidence that the

17 IVIG works for those patients.

18 DR. NELSON: That is an important issue.

19 It is a therapy that could be, and I guess has

20 been, abused to some extent. Yes, Dr. Koski?

21 DR. KOSKI: Just to really reaffirm that

22 the particular indications that I was talking about

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1 actually are really supported very heavily,

2 particularly Guillain-Barre syndrome, with

3 absolutely outstanding trials that comprise almost

4 600 patients, that were done in multicenters across

5 really Europe and North America.

6 I agree with you that there are perhaps

7 very, very rare disorders where some of the

8 randomized, controlled trials, such as stiff person

9 syndrome, comprise only about 15 patients. But

10 some of those trials are really still extremely

11 good, with very high efficacy.

12 DR. NELSON: But there have been some

13 proposed used for which the data were pretty shaky.

14 At one point they consumed a fair amount of the

15 supply, as I recall. So, I think the point is well

16 taken that this is an important commodity,

17 particularly if it is in short supply its use

18 should be supported by good scientific data.

19 Well, thanks. I guess that is the end of

20 the session. I guess October 21 and 22 will be the

21 next meeting. Thanks.

22 \[Whereupon, at 3:10 p.m., the proceedings

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1 were adjourned.\]

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