**"This transcripts has not been edited or corrected, but appears as
received from the commercial transcribing service. Accordingly, the Food
and Drug Administration makes no representation to its accuracy\...."**

UNITED STATES OPF AMERICA

\+ + + + +

FOOD AND DRUG ADMINISTRATION

\+ + + + +

CENTER FOR BIOLOGICS EVALUATION AND RESEARCH

\+ + + + +

BIOLOGICAL RESPONSE MODIFIERS ADVISORY COMMITTEE

\+ + + + +

34th MEETING

\+ + + + +

FRIDAY,

FEBRUARY 28, 2003

\+ + + + +

The Advisory Committee was called to order at 8:01 a.m. in the Kennedy
Ballroom of the Holiday Inn- Silver Spring, 8777 Georgia Avenue, Silver
Spring, Maryland, **Dr. Daniel R. Salomon**, Chairman, presiding.

[PRESENT]{.underline}:

DANIEL R. SALOMON. M.D. Chairman

JONATHAN S. ALLAN, D.V.M. Member

BARBARA BALLARD Patient Representative

JOHN COFFIN, Ph.D. Temporary Voting Member

KENNETH CORNETTA, M.D. Temporary Voting Member

JOHN E. FRENCH, Ph.D. Temporary Voting Member

DAVID M. HARLAN, M.D. Member

KATHERINE A. HIGH, M.D. Member

JOANNE KURTZBERG, M.D. Member

ALISON F. LAWTON Industry Representative

WARREN LEONARD, M.D. Temporary Voting Member

CRYSTAL MACKALL, M.D. Temporary Voting Member

ABBEY S. MEYERS Temporary Voting Member

RICHARD C. MULLIGAN, Ph.D. Member

THOMAS MURRAY, Ph.D. Temporary Voting Member

PRESENT: (CONT.)

MAHENDRA S. RAO, M.D., Ph.D. Member

BRUCE E. TORBETT, Ph.D. Temporary Voting Member

ANASTASIOS A. TSIATIS, Ph.D. Member

LINDA WOLFF, Ph.D. Temporary Voting Member

ALICE J. WOLFSON, J.D. Consumer Representative

GAIL DAPOLITO Executive Secretary

[NIH REPRESENTATIVES]{.underline}:

STEPHEN M. ROSE, Ph.D.

[GUEST SPEAKERS]{.underline}:

CLAUDIO BORDIGNON, M.D.

MARINA CAVAZZANA-CALVO,M.D., Ph.D.

ADRIAN THRASHER, M.D., Ph.D.

[PRESENTERS FROM FDA]{.underline}:

PHILIP NOGUCHI, M.D.

RAJ K. PURI, M.D., Ph.D.

CYNTHIA A. RASK, M.D.

CAROLYN WILSON, Ph.D.

[PUBLIC SPEAKERS]{.underline}:

PAUL GELSINGER

RICHARD JUNGHANS, Ph.D., M.D.

CHRISTOF VON KALLE, M.D.

DONALD B.KOHN, M.D.

RACHEL SALZMAN, M.D.

**Morning Session**

Welcome and Introductory Remarks 4

Daniel Salomon, M.D., Chair

Meeting Statement 4

Gail Dapolito, Executive Secretary

Guest Presentations

Dr. Marina Cavazzana-Calvo 34

Dr. Claudio Bordignon 92

Dr. Adrian Thrasher 119

Discussion 132

Committee Discussion of Questions 166

Public Hearing

Donald Kohn 177

Rachel Salzman 187

Richard Junghans 191

Paul Gelsinger 197

Discussion and Voting 199

Adjourn 304

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

(8:01 a.m.)

CHAIRMAN SALOMON: I want to welcome everyone here to the second day of
Meeting Number 34 of the BRMAC, which of course doesn\'t mean anything
to anyone, including me.

What does mean something is the topic for today, which is to update the
Committee, and to provide advice to the FDA on retroviral gene
therapies, particularly focused obviously on the cases of severe
combined immunodeficiency disease. But certainly the discussions need to
range somewhat beyond that narrow focus at some point. The nature of the
topic is absolutely important and critical, and I think that does not
need any introduction, so I will spare you that.

The day is relatively compressed, just because it is Friday, and with
the snow and trying to get to airports, I would like to be done at 3:00.
Otherwise, I am not making it back to California this evening.

So you have got a Chair who is engaged in finishing on time, which is
usually a good thing. So without any other introduction at the moment.
We will pick up with the FDA\'s introduction in a moment.

I would like to turn to Gail Dapolito, our Executive Secretary, to read
a statement into the minutes.

MS. DAPOLITO: Good morning, everyone. This announcement is part of the
public record for the Biological Response Modifiers Advisory Committee
meeting on February 28, 2003. Pursuant to the authority granted under
the Committee charter, the Director of the FDA\'s Center for Biologic
Evaluation and Research has appointed Ms. Barbara Ballard and Ms. Abbey
Meyers, and Drs. John Coffin, Kenneth Cornetta, John French, Warren
Leonard, Stewart Orkin, Crystal Mackall, Thomas Murray, Bruce Torbett
and Linda Wolf as temporary voting members for today\'s discussions.

Based on the agenda, it was determined that there are no products being
approved at this meeting. The Committee participants were screened for
their financial interests to determine if any conflicts of interest
exist.

The Agency reviewed the submitted agenda and all financial interests
reported by the meeting participants. As a result of this review the
following disclosures are being made.

In accordance with [18 USC 208]{.underline}, Drs. John Coffin, Kenneth
Cornetta, and Warren Leonard were each granted a waiver that permits
them to participate in today\'s committee discussions.

Dr. Richard Mulligan was granted a limited waiver for today\'s
discussions that permits him to participate in the discussion without a
vote. We also note for the record that Ms. Alison Lawton serves as the
non-voting industry representative member acting on behalf of a
regulated industry.

She is employed by Genzyme, and thus has interests in her employer and
other similar firms. With regard to FDA\'s invited guest speakers and
guests, the agency has determined that the services of these speakers
and guests are essential.

The following interests are being made public to allow meeting
participants to objectively evaluate any presentation and/or comments
made by the speakers and guests. Dr. Claudio Bordignon is employed at
the Institute of Science in Milan, Italy. He is a researcher in gene
therapy clinical trials, especially ADA-SCID, and has associations with
firms involved with retroviral vectors.

Dr. Marina Cavazzana-Calvo is employed at the Necker Hospital in Paris,
France. She is involved in retroviral vector gene therapy studies to
treat patients with X-SCID.

Dr. Adrian Thrasher is employed at the University College in London,
England. He is a researcher in gene therapy clinical trials to treat
patients with SCID.

Dr. Cristof von Kalle is employed at the University of Cincinnati, and
is involved in gene therapy research. Drs. Amy Patterson and Stephen
Rose are employed with the Recombinant DNA Program, Office of
Biotechnology Activities, NIH. NIH funds gene therapy research.

Members and consultants are aware of the need to exclude themselves from
discussion involving specific products or firms for which they have not
been screened for conflict of interests. Their exclusion will be noted
for the public record.

With respect to all other meeting participants, we ask in the interest
of fairness that you state your name, affiliation, and address any
current or previous financial involvement with any firm whose product
you wish to comment upon.

Waivers are available by written request under the Freedom of
Information Act, and as a courtesy to the committee discussion and those
in the audience, and we ask that you silence your cell phones and
pagers. Thank you.

CHAIRMAN SALOMON: Before I turn to Phil and Carolyn to provide an FDA
introduction, I just wanted to share with you sort of a brief strategy
for today as far as I am concerned as Chair.

We have many of us sitting around the table right now, with a few
additions to increase the expertise here, but most of us have heard the
first round of this issue, with the first child that developed leukemia
from the retroviral insertion in the LMO-2 site just before the first of
the year.

And so I think it is very important that the focus of this meeting begin
solidly on the framework that the committee set at that time and ask the
major question; and that is, what has changed?

At the time, we talked about what would happen if a second case was
found. How would that change the risk/benefit ratio calculations that we
made? How does that serve the community and affect the stakeholders with
severe combined immune deficiency disease? How does that affect the
broader stakeholder community that now includes anyone who might benefit
from various kinds of retroviral gene therapy and the companies and
academia, et cetera, that are involved.

So I think the key thing here is to take the foundation of what we did
last time. It is perfectly appropriate to say, well, we were right about
this, and it incrementally changed in such and such a way, or that we
were wrong, and we need to see it.

But I\'d like to see the focus building on what we set up previously,
rather than starting all over again and taking everything apart and
taking a really long time to go over what I think \-- we already plowed
a lot of ground here, and I would like to see us go forward from this
point onward. Phil.

DR. NOGUCHI: Thank you, Dan, and I would like to thank everyone who is
participating today on behalf of the Center for Biologics. Our grateful
thanks for coming here.

This is extraordinarily difficult and is one of a number of things that
I would like to just introduce. I presented something like this at the
last meeting, but why are we here?

We are here to acknowledge that there continues to be extraordinarily
difficult diseases and the treatment of them remain hopeful, but are
always a problem in terms of balancing risks and benefits.

And we are here to affirm that the way to get at this ideal is to do
rigorous clinical trials. As we do this, and as we are seeing today,
this is not a static evaluation, but it is a continuous balancing of
risks and benefits.

We are here to further learn about adverse events as they occur, and as
they are scientifically researched, and I think some of our discussion
should be oriented towards taking what we now know and thinking of
strategies for mitigation and elimination of these particular side
effects, as well as strategies for side effects in general, where we
know more on a molecular basis than we did even just a few months ago.

And really we are here to confirm that this is exactly where we should
be, and we look forward to a very vigorous, a very timely and a very
important discussion.

Dr. Wilson will now follow this and really step us through a little bit
of the background from the last meeting and lay out the framework and
the pathway for our discussion today.

DR. WILSON: While they are getting it set up, I am just going to
introduce that what I will be doing today is to try to provide an update
for the committee since our last meeting in October.

And that update will include, actually, a revisiting of the discussion
that this committee had, so that analogous to what Dr. Salomon was just
saying, we can remind the committee what we said in October, and then
move forward from there.

(Brief pause.)

CHAIRMAN SALOMON: This is a new California thing where you kind of start
the meeting off with a Zen meditation. I hope you appreciate that.

DR. WILSON: Thank you, everyone, for your patience. And so, again, what
I am going to do for you this morning is to try to provide an update so
that you can have all the information at hand in terms of what has
happened since the October meeting, so that you can move forward in your
deliberations on these important safety issues regarding the clinical
use of retroviral vectors for gene therapy.

My update will include, as I mentioned, a review of the consensus points
from the discussion of the October meeting, subsequent FDA actions that
we have taken both in response to the October meeting as well as to the
subsequent notification in late December from Dr. Fischer\'s group of
the second child with the T-cell expansion.

I am going to provide a quick overview of active clinical trials that
are under U.S. IND that use retroviral vectors, and then provide some
information from other committees that have been deliberating on these
issues, in particular the recommendations from the Recombinant DNA
Advisory Committee that met earlier this month, as well as some of the
reports from various international bodies as well.

And then finish with just a quick read-through of the questions for the
committee so that you can have these in your mind as we move forward
with today\'s agenda.

So to start off, the one general consensus of the committee in October
was that the T-cell expansion seen in the X-SCID patient treated in
France was likely due to an insertional mutagenesis effect of the
retroviral vector used in the gene therapy.

With this as a premise in terms of a major conclusion, then you move
forward to address the following question which we asked you in October;
namely, are there additional data or measures that clinical
investigators need to provide before future and present clinical trials
in SCID patients should proceed in the U.S.?

Please consider in your discussion each of the following as they pertain
to X-SCID or other forms, such as ADA. And we asked you to discuss six
different issues: risk/benefit, informed consent, alterations to cell
dose or vector dose, mapping of vector insertion sites, and alterations
in vector design.

And what I would like to do in the next few minutes is just provide for
you, again, your committee consensus on each of these points so that you
know where you were in October.

So regarding risk/benefit, all agreed that, with HLA-identical donors
for SCID indications, the benefits of this particular treatment far
outweighed the potential risks of using gene therapy.

So the committee recommended that patients who have available
HLA-identical donors should be excluded from gene therapy clinical
trials. However, the case for haploidentical transplants was not as
clear-cut, in that you do get 90 percent survival if the transplant is
done in the newborn period.

Survival rates are lower, depending on the transplant center, when it is
done later in life. But in both cases, you don\'t seem to get B-cell
reconstitution requiring life-long administration of an IgIV.

And there was a general consensus that the quality of life for even
those patients, quote, \"who are surviving\" is suboptimal, with
recurring infectious episodes and other complications.

The other major point that was brought up in the discussion of
risk/benefit issues was the analogy to cancer treatments, which often
carry risk of secondary cancer, yet are very effective at treating
cancer and would not be thought of as being eliminated because of the
risk of secondary cancer.

As far as the risk of gene therapy, all acknowledged the obvious
statement that if you don\'t get gene transfer, then, of course, it is a
safe procedure. But in the case of the trial in France, clearly there is
gene transfer and it is having a therapeutic effect.

And there is actually 100-percent survival at this time, even now with
the second child having a leukemia-like illness. And the other important
point that was brought out was that the success of Dr. Fischer\'s trial
may be related to the fact that he treats patients de novo, and he is
not using patients who had failed haploidentical transplants.

So the committee felt it was important that gene therapy in this context
not be considered a salvage therapy but that families be given a choice
to have a haploidentical or gene therapy.

And so, essentially, in October the committee consensus was that trials
in SCID indications should proceed, but there were some caveats on that
conclusion; namely, that clearly changes to informed consent documents
needed to be made. You felt it was important that all retroviral vector
clinical trials should have these revisions to reflect this event.

The informed consent document should be written in clear language. It
should not include mitigating factors, such as issues regarding multiple
hits, or number of patients treated, and that it should be clear in
saying that gene therapy caused the leukemia, while still emphasizing
the unknown quality regarding the risk to an individual patient.

On the third part of this question regarding cell dose, there was some
information provided by the committee regarding, for example, use of
cord blood, that you may be able to reduce the numbers somewhat and
still maintain engraftment.

The number that was thrown out by the committee was one times ten to the
fifth CD34 positive cells per kilogram. I recognize that you had
extensive discussions of this yesterday, so you probably are much more
informed on this, at this point, than I am, and so I will just leave it
at that.

But, essentially, after going about this issue, the committee felt that
based on 30 years of experience that there are certain acknowledged
minimum cell doses that are required in order to get engraftment, and
that to go below those doses would provide \-- would put these children
at risk of additional infectious disease complications.

So, actually, the committee recommended moving forward on researching
how to better target the true hematopoietic stem cell, and that would be
a more effective way to reduce the cell dose.

Regarding vector dose, this was really felt to be a research question.
People also felt this wasn\'t a huge issue at that time because most
retroviral vectors hit about one copy per cell.

However, CBER does want to point out that we are starting to see novel
vector systems that reach significantly higher copy numbers per target
cell, and that this is an issue that the committee may need to revisit.

In terms of insertion site mapping, the way that we had phrased the
question was regarding lot release of ex vivo transduced cells. The
committee quickly pointed out that this was not scientifically or
technically feasible, and this was obviously rejected.

However, there was a strong recommendation from the committee that
patient samples should be monitored closely for outgrowth of single
clones, and that if a monoclonal integrant is observed, that it should
be sequenced, following with additional phenotypic analyses. And it was
pointed out that this information regarding the integration site may
inform clinical treatment, and it may allow earlier treatment.

The committee recommended that this type of monitoring be performed at
approximately a 3- to 6-months interval. It was thought that this should
be done on an active basis, rather than archiving of samples. And,
obviously, if there is no vector positive cells in the peripheral blood,
then there is no need to perform this monitoring. But the committee
recommended that each protocol needs to develop a monitoring plan,
including trigger points, for additional analyses.

And, finally, the committee left a caveat that if a particular sponsor
felt that it wasn\'t justified to do this monitoring in their clinical
trial, then the FDA should consider this, obviously on a case-by-case
basis.

Regarding vector design, the question here was whether or not you could
increase the safety of retroviral vectors by minimizing the effect of an
enhancer to activate neighboring or distal genes. And while everybody on
the committee felt this was an important research question and made the
recommendation that it should be further studied, nobody felt that this
was something that needed to be changed now for clinical trials to
proceed.

And, in addition to that, it was strongly recommended that preclinical
models be developed to assess the risk of vector insertion for new
vector designs.

Now, following the meeting in October, CBER then sent out letters to
sponsors requesting first of all that all sponsors using retroviral
vectors revise their informed consent, and we actually have specific
template language that we recommended in that letter.

In addition, we asked that, in a subset of those trials using CD34
cells, sponsors submit plans for monitoring for integration clonality,
and the interval that we recommended was every six months for the first
five years, and yearly thereafter for the next ten years.

And then when a predominant clone is identified, that there be a second
test within three months from the first, that the sequence be
determined, and that you monitor the subjects closely for signs of
malignancy.

So to summarize then, there were three sets of letters that were sent
subsequent to the October meeting. In the clinical trials in SCID, which
were the subset which were on hold at the time we met in October, we
required that they revise their informed consent and develop plans to
monitor clonality in order for those trials to proceed.

In indications that use hematopoietic stem cells or other stem cells,
these two conditions were recommended, but not a requirement. And in all
other retroviral vector clinical trials, we requested only that they
revise their informed consent, and at that time did not recommend
developing plans for monitoring clonality.

And we confined this to hematopoietic stem cells, this issue of looking
for clonality, based on the idea that stem cells are by their very
nature long-lived, with high proliferative capacities, and therefore
more at risk to the effects of vector integration mutagenesis.

Now, as you know, in late December, we received a second report from Dr.
Fischer that there was another subject in his X-SCID gene therapy
clinical trial that developed a leukemia-like illness at 34 months post
treatment.

And subsequent to that initial report, preliminary data was provided to
us by Dr. Fischer that there seemed to be, again, a monoclonal
retroviral vector integration 5\' to the LMO-2 locus, which I am sure
you recall is the same locus, but a slightly different site within that
locus, that was observed in Patient No. 4.

And so these preliminary data suggested that we were probably looking
again at an incident where retroviral vector integration was likely
playing a role in the T-cell expansion.

So in response to these data, we took the following actions: We again
sent three sets of letters to sponsors. In this case now, we changed the
issues of informed consent and clonality \-- monitoring clonality plans
to a requirement.

In other words, all clinical trials that used hematopoietic stem cells
as their target for ex vivo transduction were now put on hold until they
met these conditions.

Inactive trials that use hematopoietic stem cells were told that if they
ever wanted to resume their trial, that again they would need to meet
these conditions. And then all other retroviral vector clinical trials,
we didn\'t put these on hold, but we made a recommendation that they now
would also need to develop plans to monitor for clonality.

Now, what are the clinical trials that we are talking about? In terms of
target cells, you can see that really fully half of the current active
clinical trials are in either CD34 hematopoietic stem cells or bone
marrow cells.

The next largest category are in lymphocytes of various types. Then we
have a few in fibroblasts. The other category includes smooth muscle
cells as well as a number of different tumor cell types.

And then we have two each that are either direct administration of
vector producer cells, or of the retroviral vector itself. In terms of
indication, I have broken this down for you two ways. One by total
active clinical trials using retroviral vectors, and in the blue bars,
this shows that subset that are in the CD34 bone marrow target cells.

So in cancer, we have 8 out of 28 total trials using CD34 cells for the
ex vivo transduction, 8 out of 12 in HIV. The miscellaneous, these two
are osteogenesis imperfecta and multiple sclerosis.

And almost all of our trials in genetic disease target CD34 cells. And
these include, of course, the SCID indications, chronic granulomatous
disease, and Fanconi\'s anemia.

So at this juncture then, it is obviously prudent to ask whether or not
there are additional modifications that we need in order for these types
of clinical trials using retroviral vectors to proceed safely.

And what I would like to do for you now is to just outline some
considerations, some which are more theoretical and would require more
research before they could be immediately implemented in clinical
trials, and others which are potentially more practical and could be
implemented more directly.

So the first, which is a more practical solution, is again to revisit
the issue of dosing with the idea that if you reduce the total load of
vector integrants that this reduces the risk of integration into a
potentially, quote, \"bad locus\"; a locus that might be tumorigenic.

And one could envision doing this by reducing the dose of vector used in
the transduction, reduce the dose of cells given back to the patient, or
potentially changing the dose so it is based on a total number of vector
integrants.

In addition, as was recommended by the committee in October, we want to
consider whether or not we might need to have additional preclinical
studies to assess the carcinogenic potential of a particular vector
backbone-transgene target cell combination.

And there is one of two ways that one could envision doing this. One is
to perform traditional carcinogenicity testing at an earlier stage of
clinical development. This type of testing is usually done at the time a
sponsor gets to licensure.

And the reason for that is because these are multi-year, very expensive
studies. So we don\'t usually ask people to do this for a Phase I trial.

Alternatively, one might consider some of the newer accelerated models
of tumorigenesis, such as transgenic models carrying oncogenes or
knockout models of tumor suppressor genes. One might also consider a
complementary approach of both assays. One might consider doing these
concurrently with an early phase clinical trial.

In terms of cell target or culture conditions, again these are much more
on a theoretical, but again coming back to if we could identify what is
a true hematopoietic stem cell.

One issue that is acknowledged regarding retroviral vector or retroviral
integration in the genome is that it tends to occur in sites of
transcriptionally active genes.

So if you could identify a transduction protocol, for example, by
studying gene expression by gene or protein microarray that has a fewer
number of transcriptionally active genes, this might reduce the number
of integration targets.

And then, ideally, if you could actually identify cells with vector
integrants into known tumorigenic sites, this obviously would be nice to
be able to do, but clearly on the realm of way theoretical.

In terms of modifications of the vector, again, these are things that
are in the research phase. People are starting to look at the addition
of insulator sequences.

These have really been done more to look at the ability of these
sequences to insulate from the effect on the enhancer becoming silenced,
and it has not really been studied whether or not these elements would
also have the effect of blocking enhancer activation of neighboring
genes.

But that is something that probably should be studied. Deletion of
retroviral vector enhancer elements within the LTR would clearly reduce
the risk of enhancer activation of neighboring genes, and if you could
develop a vector with targeted integration, this would be ideal, but
again much more on the theoretical. And it is not known at this point
whether or not specific transgenes might also play a secondary role in
the tumorigenesis.

So I want to finish then with recommendations from other advisory
committees. The first is the NIH Recombinant DNA Advisory Committee.

They have had two meetings on this topic. The first was in December of
last year, and the second was just earlier this month on February 10.
And they made the following observations: The majority of children in
this X-linked SCID gene transfer study have had major clinical
improvement to date.

The gene transfer was a cause of both leukemias and the occurrence of
leukemia in this protocol is not a random event and constitutes an
inherent risk in this study.

So based on these observations, the RAC recommended the following two
main points: Pending further data or extenuating circumstances,
retroviral gene transfer studies for X-linked SCID should be limited to
patients who have failed identical or haploidentical stem cell
transplantation.

And then secondly, there are not sufficient data or reports of adverse
events directly attributable to the use of retroviral vectors at this
time to warrant cessation of other retroviral human gene transfer
studies.

Such studies may be justified contingent upon appropriate risk/benefit
analysis, accompanied by an implementation of appropriate informed
consent and monitoring plans.

The French gene therapy working group met at the end of January of this
year. They have recommended that the X-SCID clinical trial maintain its
clinical hold status pending additional scientific investigations of the
most recent event, and they also recommended that safety of retroviral
vectors should be improved by, for example, deletion of enhancers,
addition of insulators, and also by development of relevant and
predictable animal models.

Germany\'s Commission for Somatic Gene Therapy has also met twice to
consider these issues. In their most recent meeting, they went case by
case through the active clinical trials using retroviral vectors.

Based on that analysis, they recommended that one protocol using
hematopoietic stem cells for the treatment of chronic granulomatous
disease remain on hold pending additional data, while the other four
active protocols were recommended to proceed, obviously requiring
changes in informed consent to make patients and their families aware of
these events. And in some specific cases, additional protocol changes
were recommended regarding patient inclusion criteria and so on.

Italy\'s National Health Institute has recently come out with a
continued ban on all gene therapy for an additional four months, but
they do say that they may approve trials on a case-by-case basis.
Likewise, the U.K. Gene Therapy Advisory Committee is meeting in March
of this year. They are currently looking at trials on a case-by-case
basis, considering particular circumstances for each situation.

So, finally, I just want to quickly go through the questions for the
committee, and the first question is specific to the subset of trials in
SCID indications.

Please discuss under what conditions clinical trials using retroviral
vectors to transduce CD34+ hematopoietic stem cells for the treatment of
SCID may resume.

Currently, before sponsors of these trials may proceed with clinical
trials, they need to provide a revised informed consent document and
plans for monitoring of peripheral blood cells for the clonality of
vector integration.

So the specific question then we have, is this sufficient, or should
additional conditions be placed on these trials. We ask you to consider
whether dose should be altered, whether we need to include additional
pre-clinical studies, whether we need to look at the particular target
cells, or have alterations in the vector design.

The second question is identical to the first, so I won\'t read it, with
the notable exception that we are now asking you to consider really
these same issues in other clinical indications where retroviral vectors
are used to transduce CD34+ hematopoietic stem cells.

And then the third question regards the use of retroviral vectors for
marking studies where no direct therapeutic benefit is possible, whether
or not these should be allowed to proceed, again, considering issues
regarding risk/benefit, a particular vector design, or target cells.

And then the final question, if time permits, that we would like you to
consider is: Given the properties of lentiviral vectors to transduce and
integrate into non-dividing cells and their increased efficiency of
transduction, please compare the current requirements for clinical use
of gamma retroviral vectors to those that should be in place for use of
lentiviral vectors.

We currently are requesting that sponsors revise their informed consent
and monitor peripheral blood cells for the clonality of vector
integration. Is this sufficient or should additional conditions be
placed on these trials?

So, with that, I thank you for your attention. I am going to ask that
the committee hold questions after my talk so that we can continue with
our guest speakers, and there will be plenty of time in the afternoon to
ask myself or other members of the FDA questions about what we have
done. Thank you.

CHAIRMAN SALOMON: Thank you very much, Carolyn. That was excellent.
Before we start with the guest presentations this morning, I would like
to go around the room and have everyone briefly introduce themselves.

I apologize for not having done that earlier. It has just gotten a
little mixed up, as we were here yesterday in the same room, but it was
a different group. So, Rich, could you start us off.

DR. MULLIGAN: I am Rich Mulligan from Harvard and Children\'s Hospital,
and my expertise is in gene transfer and in stem cells.

DR. ALLAN: I am Jon Allan from the Southwest Foundation for Biomedical
Research, and my expertise is in retroviral pathogenesis in non-human
primates.

DR. KURTZBERG: I am Joanne Kurtzberg from Duke University. I direct the
Pediatric Bone Marrow Transplant Program, and my expertise is in stem
cell transplantation and cord blood transplantation.

DR. TSIATIS: I am Butch Tsiatis. I am from North Carolina State
University, and my expertise is biostatistics.

DR. MURRAY: I am Tom Murray. I am from The Hastings Center, and my
expertise is in the ethics of research with human subjects.

DR. MACKALL: I am Crystal Mackall, and I am from the Pediatric Oncology
Branch of the Intramural Program of the NCI. I practice pediatric
oncology and study transplantation immunology.

DR. COFFIN: I am John Coffin from Tufts University and the National
Cancer Institute. My research interest is in molecular retrovirology.

MS. LAWTON: I am Alison Lawton. I am the Industry Rep., and I am head of
regulatory affairs for Genzyme Corporation.

DR. RAO: I am Mahendra Rao from the National Institute on Aging, and my
interest is in stem cells.

CHAIRMAN SALOMON: Dan Salomon, from the Scripps Research Institute. I am
in organ and cell transplantation and xenotransplantation. We do gene
transfer studies as well.

MS. DAPOLITO: Gail Dapolito, FDA, Center

for Biologics, Executive Secretary for the committee.

DR. HARLAN: I am David Harlan. I am an intramural investigator with the
National Institute of Diabetes, Digestive and Kidney Diseases, and my
interest is in transplantation immunology in diabetes.

DR. HIGH: I am Kathy High. I\'m at the Children\'s Hospital of
Philadelphia, and my interests are in gene transfer for hematologic
disease.

MS. LEONARD: I am Warren Leonard in the National Heart, Lung, and Blood
Institute. My lab discovered the genetic defect in X-linked SCID, JAK-3
deficiency, and IL-7 receptor deficiency, and my expertise relates to
gamma-c-dependent cytokine interactions.

DR. ROSE: Stephen Rose. I am in charge of the recombinant DNA activities
in the Office of Biotechnology Activities in the Office of the Director
of NIH, and Executive Secretary of the NIH Recombinant DNA Advisory
Committee.

DR. RASK: Cynthia Rask from FDA, in the Clinical Evaluation and
Pharmacology/Toxicology Division, in the Office of Cellular Tissue and
Gene Therapies.

DR. WILSON: Carolyn Wilson in the Division of Cellular and Gene
Therapies.

DR. NOGUCHI: I am Phil Noguchi, Acting Director of the Office of
Cellular, Tissue and Gene Therapies.

DR. PURI: I am Raj Puri. I am the Acting Director of the Division of
Cellular and Gene Therapies.

DR. CORNETTA: I am Ken Cornetta from Indiana University. My interest is
in retroviral gene transfer, and I coordinate the National Gene Vector
Lab for the NCRR, and I am also a clinical bone marrow transplanter.

DR. FRENCH: Jeff French from the National Institute of Environmental
Health Sciences. My interest and expertise is in alternative models for
studying carcinogenicity.

DR. WOLFF: Linda Wolff from the National Cancer Institute. My expertise
is in retroviral pathogenesis in small animal models.

DR. TORBETT: Bruce Torbett from the Scripps Research Institute. My
interest is in HIV vector design as well as myeloid transcription
regulation.

MS. MEYERS: Abbey Meyers, President of the National Organization for
Rare Disorders. I am the Consumer Rep.

MS. BALLARD: I am Barbara Ballard. I am here to represent the SCID
families, and I am also on the Board of Trustees for the Immune
Deficiency Foundation.

CHAIRMAN SALOMON: Just a point for those of you who are not used to it:
when you are done speaking, if you will shut the mic off, it prevents
feedback from happening. Thanks. So if you see me doing something like
this, it is not, you know, be quiet, it\'s to shut your light off.

Okay. Let\'s get started then. It is my pleasure to introduce our first
guest speaker from the Hospital Necker, Marina Cavazzana-Calvo.

DR. CAVAZZANA-CALVO: Good morning, everybody. First of all, I would like
to thank Dr. Carolyn Wilson and Ms. Dapolito to give me this great
opportunity to share with you our updated results concerning all the
trials and the two side adverse events.

Nevertheless, I would like to just make one comment before I initiate my
talk. This protocol is under the authority of the French government, and
each public disclosure of this data must be made with our approval.
Thank you very much.

So let me remind you that X-linked severe combined immune deficiency is
characterized by the complete absence in the peripheral blood of natural
killer cells and T-cells. This is due to the fact that there is a gene
mutation on the gamma-common chain that is shared by IL-7 and IL-15.

The gamma-common vector, retrovirus vector, we used is described here.
The gamma-common cDNA is under the transcription counter of LTR of the
retrovirus, and we used an MFG vector kindly provided by Dr. Richard
Mulligan, and the classical psi-crip packaging cell line set up by
Olivier Danos.

The envelope of this retrovirus is an amphotrophic one, and no other
relevant characteristic of this retrovirus vector can be underlined.

So I resumed here the pre-clinical studies that we conducted in order to
obtain the approval through the clinical trial.

First of all, we have demonstrated as have two other groups in the
world, that the B-lymphocyte transformed by EBV, derived from the
patient and the gamma-c negative, can be efficiently transduced by our
retrovirus vector.

This demonstrates the feasibility of protein expression and the function
in terms of gamma-c transduction signaling and the stability of the
retrovirus expression over time. This cell line has been followed over
six months.

The second step was to demonstrate almost in vitro that the CD34
positive cells gamma-c negative, obtained from the patient at the time
of general anesthesia through the central line, can be efficiently
transduced in vitro and can restore, almost in vitro, NK and T-cell
differentiation.

In parallel, Gemmady Santos in our laboratory set up a knockout mouse
model without the gamma-common chain, and this model was indispensable
to demonstrate no toxicity. This is correction selective advantage.

Just some details on the animal model to implement the discussion. The
bone marrow site was derived from the donor gamma-c deficient animals.
The animals had been pre-treated by 5-FU and the whole bone marrow has
been transduced with a retrovirus vector very similar to that used in
the clinical trial, and for this model he carried a marking gene that is
the human CD2 molecules.

The recipient of the double transgenic \--double knockout mice gamma-c
deficient animals was low irradiated.

This is the survival curve of treated animals in comparison with
non-treated animals. Non-treated animals in the standard animal
facilities died within 15 weeks. Conversely, the treated animals are 100
long-term survival course.

How long have these animals been observed before sacrifice? For the
primary transplantation up to 47 weeks and the animals show no toxic
effect. The same cells have been used from the primary transplantation
of eight-weeks-old aged animals to transplant secondary mice to
demonstrate again the efficacy of the transduction of the stem cells,
and here again we obtained a correction of animal disease with no toxic
effect.

So on the basis of this preliminary design completed by the translation
medicine to make a scale-up study, we obtained the approval from the
French authorities to go to the clinical study with this protocol.

Patients were eligible for these trials when they have gamma-c gene
mutation, of course, and in the case where they have no HLA
gene-identical familial donors, and the presence of informed consent
from the family.

The protocol is the following one. Marrow is harvested under general
anesthesia and very small quantities of bone marrow cells are harvested,
around 50 up to 150 ml per child.

CD34 positive cells are selected by immunomagnetic microbeds, and
pre-activated in vitro for one day in the presence of the stem cell
factor FLT-3 ligand, MGDF and IL-3. I underline the fact that we used
very high doses of stem cell factor FLT-3 ligand following the protocol
described previously by Eve Sconis in the Vancouver laboratory, 300
milligram per milliliter.

MGDF was used at a nanogram per milliliter and IL-3 in very low doses.

After this 24 hours of preactivation, the cells are transduced with a
supernatant containing the vector in bags precoated with fragments of
fibronectin. And it is made each day for three consecutive days. At the
end of the treatment, which began on Monday morning and finished Friday
evening, the cells are extensively washed and transfused intravenously
into the patient without any additional therapy.

These are the 10 patients, the 10 newborn patients with classical SCID
form, that have been enrolled so far in this clinical trial. As you can
see the age is under one year, and the severe adverse event occurred in
two patients, the youngest. One was one month, and the three-months was
without any infection at the time of treatment. Conversely, all the
other patients had severe infection at the time of diagnosis

And I would just like to stress that these two patients \-- because I
think it is fruitful for discussion \-- these patients had been admitted
to the hospital with a disseminated varicella-zoster infection which
affected the central nervous system.

And we know there is no way to obtain a definition that this varicella
also disseminates infection with the classical haploidentical bone
marrow transplantation.

In the second case also there is lympthoproliferative disease with the
spleen and the lung affected, with a very, very poor prognosis for the
haploidentical bone marrow transplant.

Four patients had maternal T-cells at the time of diagnosis, with graft
vessels soft-like lesion on the skin: this patient, and this one, and
these two.

And two patients had an endogenous gamma-C process expression, and we
tested before gene therapy for the presence of transforming into a
negative effect.

This is the characteristic of infused cells for these nine patients, and
so this is the mean and the standard deviation.

Each patient received, except for one patient that I will describe in
detail, a huge number of CD34 positive cells, 24 million per kilogram
with a large variation between the patients.

The total gamma-C transfused cells is also very huge, with a mean of 17
million per patient with a huge standard deviation, and the
double-positive CD34 gamma-C per patient is 9 million plus-minus 7,
because there is one patient, Patient 6, that received a very low number
of CD34+ cells.

But you can see that the B cell reconstitution is less good and the
percent of CD34 gamma positive cells is finished one year after
transplantation. So a discussion of the dose of this patient can be very
interesting.

The proliferation rate for bone marrow cells is very high, and then you
have a fold increase in the number at the end of a manipulation of 6 up
to 10-fold. And in particular, I\'ll describe the two patients who
experienced the side effects, P4 and P5 patients.

And in these cases, the cells proliferated even more. The proliferation
rate was up to 8 and 9.5 for these two patients who were the youngest
ones, and I think that for these newborn patients, aged similar to these
ones, that the biological characteristics of stem cells are more close
to cord blood than to bone marrow cells. And it is important to stress
that for this discussion.

The number of CD34 positive cells that they received was very high: 44
million per kilogram for the first one, and the 42 million for the
second one. The total gamma-common positive cells was even more huge, 31
and 24. You can have here CD34 negative cells, but active lymphoid
precursor cells.

And the double-positive hematopoietic precursor cells is up to 20
million per kilogram for this patient, with a high proliferation rate.

What about the kinetics of lymphocyte T-cell reconstitution in this
different case? This is the patient that we followed actually, and this
is P4 and P5 patients that have experienced the side effects.

In this case, the kinetics of T-lymphocyte recovery is quite light, and
it begins 75 days after transplantation of the gene-modified stem cells.
And they grow within the first three months. They can recover a normal
number of T-cells that permitted the discharge of this patient from the
hospital.

Recovery increases for the first year, and then it goes down, as is
usual for patients of this age.

Strangely, for these two patients, the kinetics of the T-lymphocyte
recovery is quite different. First of all, the appearance of T-cells in
the peripheral blood is very fast. Within the first month, they
recovered a high number of T-cells, and the other difference is the
shape of the curve. This table remained high over the time, and at this
moment we have no worry about this.

And, abruptly, pretty much at the same time the number of T lymphocytes
goes up, and the patient is cured of the lymphoproliferation.

So the characteristics of the transduced T-cells for all the patients
enrolled in this trial are the following ones: normal count and subset
distribution; normal repertoire, analyzed by two technologies,
immunofluorescence and immunoscope; and normal phenotype. The T-cells
are the naive phenotype, not a memory one. This is normal for a new
appearance of a neurological system.

They present a good thymopoiesis, with the presence of recent thymic
emigrants in the same number as normal patients. This is another element
for discussion for the comparison between haploidentical bone marrow
transplantation and gene therapy.

They have a normal function, and by Southern blot analysis, they contain
one copy of a provirus per cell. NK cells after gamma gene transfer, you
know that this lymphocyte subset is missing in this population.

And we observed the correction for the first year after gene therapy,
and then we observed a decline over the time. And it is quite comparable
to that observed after haploidentical bone marrow transplantation.

So from a natural killer cells point of view, this result is very
similar to that obtained by bone marrow transplantation. The good news
from this clinical trial, and which was not expected at all, is the
correction of B cell compartment.

For these children, we had stopped at six months after gene therapy the
immunoglobulin substitution, and they recovered a normal level of serum
IgM ,IgG, and IgA antibodies.

This is the follow-up data as of February 1, 2003. These are the two
patients with the adverse effects. The other one, the follow-up, is
closer to four years for the first two patients treated.

This is the failure of gene therapy treatment. This patients never
restored a T-cell compartment. He has been grafted with a match
unrelated donor, and he is doing well. All the other patients, the
follow-up is variable between 1.7 years and down to less than one year
after gene therapy. All of them are doing well, with a complete
restoration of immunological function, and at the end of this talk I
will give you much more information about the immunological state of all
these patients.

Questions about the gene therapy are how many cells were efficiently
transduced to obtain a T-cell compartment, the characteristics of the
transduced cells, and the duration of the immunodeficiency correction.

For the first question, it is important for us to have a diverse
repertoire of T-cells because a restricted T-cell repertoire does not
permit these children to defend against infection. So the T-cell
repertoire after gamma gene transfer for all the children that restored
a T-cell compartment has been a diverse one, with no abnormalities
detected so far for the treated children, either by immunofluorescence
or immunoscope analysis of the CDR3 lengths.

The other point is the integration of the transgene more than one year
post gene therapy. You can observe here that we demonstrate once again
that there is a strong selective advantage for T-cells and NK cells over
the other hematopoietic cell lines.

One hundred percent of T-cells and NK cells have integrated and express
the transgene, and less than one percent, or around one percent of
B-cells, but this can be important for B cell reconstitution, and it is
variable between 1 percent and 5 percent, and less integration for
monocytes and polymorphonuclear cells.

I would like to stress that the polymorphonuclear cells that express the
gamma-common chain persist over the time at the same level that you can
detect a few months after gene therapy. So stated as a concept, probably
we have obtained a transduction of CD34 autorenewal of stem cells, or a
very primitive one in any case.

Worries about the T-cell reconstitution of these patients. This is a
magnetic resonance imaging of the P5 thymus one year after
transplantation, kindly provided by Dr. Sorensen.

And you can see, not very well, but there is a thymus, a sizeable thymus
that is of normal size. The other point is the function of the thymus
that we have studied by the investigation of the TREC. That is that an
episome drives it from the DDG recombination in the nucleus that can be
measured and tracked for the patient.

And all these patients have normal thymopoietic activities. This is in
contrast with the decline of thymopoiesis over the year for the patient
transplanted from a haploidentical donor.

About the duration of the correction of this immune deficiency, we have
performed some studies on the CD34 positive cells recovered one year
after transplantation for some of these children.

Here we see the LTC-IC frequency in P2 and P4 patients 22 months and 30
months after gene therapy. We have a normal frequency of CD34 immature
cells. And five weeks after long-term culture and limiting dilution
analysis, we have detected a high number of gamma-c expressing CFU-GM up
to five percent. This is another proof of the idea that we have
transduced some stem cells.

This is the study about this patient, realized thanks to the great
collaboration that we have with Christof von Kalle\'s group. We can see
here this mirror of the high number of integration sites for CD3 cells
at 13 months after gene therapy for the P4 patient, and he has been able
to track the same integration site in the CD3, CD15, and LTC-IC on the
basis of the diagram that I presented previously.

So we can say that in this trial we have transduced some T-cells,
polymorphonuclear cells, and the monocytes. So the idea is that we can
transduce the common lymphoid precursor cells with common myeloid
precursor cells.

And if we can track the same integration site, this can lead us to
conclude that we have transduced pluripotent progenitor cells.

The persistence of these effects up to two years after gene therapy and
the fact that Christof von Kalle has been able to detect the same
integration site permits us to conclude that we have transduced
hematopoietic stem cells with high proliferative capacity and probably
with self-renewing ones.

Limitations of gene therapy. We have had a failure in a child with an
enlarged spleen that received the VZV vaccination before diagnosis, and
the two side effects in two children.

This is the situation for the first patient up to month 30 after
transplantation. He showed rapid T-cell development with the polyclonal
repertoire, and the development of T and B cells immune responses,
including to varicella-zoster infection at month 30.

Christopher can detect about 40, up to 60, integration sites in T-cells,
and is doing well up to this date. What happened after? He showed an
increase in the T-cell count, overall for the gamma-delta T-cell
compartment and the TCR, this particular clone of gamma delta positive
cells, had a slight increase of 7,000 per microliter over the time and
overall after the chicken pox infection.

Nevertheless, after he cured this infection, the number of these clones
continued to grow during the summer, and at the end of August of last
year, they went up to 300,000 lymphocytes per milliliter with evident
clinical signs. At this moment we began the chemotherapy, the classical
one for high-risk acute lymphoblastic leukemia because we don\'t have
available at this moment the monoclonal actibodies against this clonal
proliferation, but now we have one for him.

The plan for this child is that he has been treated with a conventional
conditioning regimen this week, and he is to be transplanted next week
with a match unrelated donor, ten-out-of-ten antigen identical.

The analysis of this monoclonal proliferation \-- and you know some data
already \-- is that he is a monoclonal gamma-delta T-cell clone. And he
has a signature for the coming of this clone from the proliferation of
one single cell, because, both by immunoscope and by TCR sequences, all
the cells have the same TCR. The cells have the appearance of blast
cells. They are extremely mature because they have only the marker of
gamma-delta mature T-cells of a memory phenotype.

They are CD3, 5, 7, 28, and 45RO positive, and they all express gamma-c,
and they don\'t express any antigen for immature cells. In vitro, they
proliferate in the presence of IL-7 and IL-15. And these cells present
chromosomal abnormalities with a translocation of 6 and 13 at the time
of the treatment.

And the first question raised by the authorities and by everyone in the
scientific world of gene therapy was the detection of the replication of
competent retrovirus. There is a contamination. And we have performed
\-- these children are forwarded for six months for the detection in the
biological fluid of RCR, and all the detections made are negative, of
course.

And so we performed the classical mobilizing test on the master donee,
and Philippe Leboulch in Boston helped us with the match with other
tests because we were afraid that the test was not sensitive enough to
detect some competent retrovirus.

So he did a Southern blot analysis. This is the patient, the P4, and
this is the B cell count. We then entered a probe and an RT-IN probe,
and in all the cases, he was unable to detect any RCR.

And the question arose from our authorities and even in the first
meeting that we had with you about the possibility that at the time of
the production of a retrovirus some murine VL-30 retrotransposon are
packaged with the retrovirus.

So, again, Philippe LeBoulch in Boston helped us with this test. We sent
him the cells, and he was unable to detect VL30 in the blast cells of
this patient with this probe.

So these cells have one provirus integration site detected by LAM-PCR in
chromosome 11 in the short time within the LMO-2 locus. There is another
expression of LMO-2, and this integration site is detectable at least
from month 13 and it is not detectable at all in the CD34 positive
cells, but it is normal.

We have freed some of these CD34 positive cells just at the end of the
transduction protocol, and we have sent some cells to Christof. But
probably the technology is less sensitive, or is not sensitive enough to
detect this integration site on the CD34 positive cells. We can conclude
that the analysis, immediately after the transduction, is unable to
detect the \"dangerous\" integration sites.

This is the structure as it is known so far for the human LMO-2 gene,
and this is the integration site for the P4 patient in the first intron
in the reverse position.

So the question was: What is the mechanism of hyperexpression of the
LMO-2 gene? And before speaking about the aberrant expression of this
gene, this is the sequential immunoscope study of the TB delta one
population for this child.

And you can see here that for the SCID disease where we are required to
reconstitute or to restore the immunological compartment, you can follow
this patient, or this type of patient, by immunoscope.

You can see here the growth and distribution of the gamma-delta T-cell
repertoire for the control people. This is the situation of this patient
at month six, and you can see here that retrospectively, we can detect a
very, very mild incrementation of the size of these TCR, 11 percent.

But this clonal type increases much more between the 6th and 13th month
after gene therapy, up to 70 percent. But much more than an increase of
this clone, we can observe the decrease of polyclonality of the
gamma-delta T-cell population.

So the much more striking data is the loss of polyclonality, more than
the appearance of a clone. And over time this clone increases, at month
17 up to 52 percent, and you can follow this clone. This is the only one
at month 34 after gene therapy.

And these results by immunoscope are strictly concordant with the
analysis made by Christof von Kalle of this type of integration site. So
I think it could be alternate way to follow the immunological
reconstitution of this patient. And we can roughly build this type of
curve where we can see that this clone increases over time in a linear
way, and that it abruptly goes up after the chicken pox infection.

If you come back to the aberrant expression of this oncogene, we have
made a quantification of the LMO-2 RNA messenger transcript in the
patient\'s peripheral blood leukocytes by real time PCR.

The LMO-2 transcripts are ten times greater in patient cells versus
normal control cells. You have here the patient, and this is the normal
control industry standard. And as you can see, slight contamination by
monocytes in the peripheral blood leukocytes can give a positive result.

This is \-- the question was: Is LMO-2 hyperexpressed by the same allele
that has been integrated by the provirus? And the answer is yes. This is
the RNA-FISH study for the P4 patient, and there is a co-localization of
the gamma-c probe and the LMO-2 probe.

This is the gamma-c probe in the red, and this is the LMO-2 detected
with the green fluorescence probe, and there is a co-localization of the
two in the same cell.

The other question was: Is there an aberrant splice of the RNA messenger
from this integration? And the answer is no. Only one significant RNA
species of the respective size for the provirus on SCID is detected by
Northern blot analysis with two different probes.

And the reason for the normal splicing of the RNA messengers, despite
the integration of the provirus within Intron 1, is that in this site
there is the same splice locus that is present in the physiological
intron.

This study has been performed by Philippe Leboulch with our help.

We did help out with the greatest research in the world that has studied
the LMO-2 gene. He is permitted to us to be with him in the UK. We have
conducted a study on the LMO-2 protein expression by Western blot
analysis, and you can see here that we have a tremendously high
expression of this protein on the patient P4.

And it is equivalent to what we can detect in murine erthyroleukemic
cells and very comparable to that obtained in the CHO cell line,
transected with the LMO-2 plasmid.

So for the mechanism of LMO-2 activation by integrated provirus, we
arrived at this conclusion: RNA of the normal size contains both the
first and last exons and the correct junction.

LMO-2 RNA is monallelic. There is Cis-activation by provirus of a normal
endogenous LMO-2 promoter with a normal splicing of Intron 2. Two
possibilities still remain, but it is much more likely that the first
one is the correct one, that there is a Cis-activation by the proviral
LTR announcer.

And even if at this point we can\'t exclude it completely, there is a
disruption of a provirus LMO-2 silencer with normal slicing of Intron 1.

This second possibility is under study and in collaboration with Dr.
Kathleen Anderson at Cincinnati University.

So what about the overall interpretation of the side effects for Patient
4? The crucial point is insertional mutagenesis with the aberrant LMO-2
expression. But we are always looking for additional factors, such as
aberrant clonal gamma-c signaling, the role of varicella-zoster
infection, and genetic associativity to the cancer.

What about the gamma-c expression? This is the same as we obtained in
the knockout animals treated by gene therapy, and you can see here that
it has been deeply investigated by us that the expression of this
protein on T-cells, B lymphocytes, and the natural killer cells is
strictly normal.

And that there is no hyperexpression in the membrane of this protein.
What about \-- but we can have normal expression of the gamma-c chain
and the hyperactivation of the signaling pathway, but we have no JAK-3
phosphorylation detectable in vivo.

This is the control cells, and we can have the phosphorylation of the
JAK-3 tyrosine kinases exclusively after activation with the appropriate
cytokines IL-7 and IL-15. This is the control cells for the patient, and
if we have no activation in the steady state, just when we bring out of
the body the cells, and we have phosphorylation of the JAK-3 tyrosine
kinases after simulation. And this is the control.

So far we have no overexpression of gamma-c common chain. The sequence
of the provirus of the cDNA is strictly normal. We can\'t detect any
abnormal activation of JAK-3 Stat5 activation, and the study of Stat5,
that it could be much more sensitive than JAK-3, is pending. And in the
blast cells of this patient, apoptosis is strictly normal.

So at the first meeting that we had with you and with Alain Fischer, we
described to you the pedigree of these families. And something that
everyone around the table found very interesting was the fact that this
family has two cancers, and one sister and one cousin of the affected
child. And we investigated at least for this child the possibility that
there is a genetic associativity to the cancer.

So we sequenced the p53 protein, the complex interesting in reparation
of DNA as the MLH1 gene, and we sequenced thoroughly the ATM gene, and
everything is normal as expected.

What about the follow-up of Patient 4 because we are much more
interested in the clinical causes for this side effect. This is the bone
marrow of this patient at the end of January.

And we can consider that this bone marrow is in complete remission, even
if we can detect some cells in the bone marrow after Fikol that still
express the gamma-common chain. And we can detect a very low percentage,
0.1 percent, of the TCR gamma9. This is the TCR that is responsible for
the clonal expansion at the beginning.

We gave these samples to Christof von Kalle, and he provided us with
these extremely interesting results that show that this child recovered
a polyclonality between the few T-cells he has. He has no immunological
reconstitution, of course.

This child is now conditioned for his transplantation and he is doing
well, but we decided that theoretically the persistence of gamma-c
positive cells in bone marrow can be expected to restore or it could
restore an immunological system by these few cells.

But, naturally, everybody prefers not to run any risk for the clinical
status of this patient. And on the basis of the consideration that the
appearance of this lymphoproliferation with the characteristics of a
high-risk one, we recommended to be as cautious as possible and to
perform the bone marrow transplantation.

CHAIRMAN SALOMON: Was that the peripheral blood, the flow cytometry you
showed?

DR. CAVAZZANA-CALVO: It is the same, 0.1 percent of this TCR gamma-9
positive.

CHAIRMAN SALOMON: Is that a bone marrow sample?

DR. CAVAZZANA-CALVO: This is a bone marrow sample.

CHAIRMAN SALOMON: But it was the same?

DR. CAVAZZANA-CALVO: The same. We have some more details here. The
malignant characteristics for this patient are blastic appearance at the
time of diagnosis, the presence of translocation of 6 to 13, and the
detection of the hyperexpression of the LMO-2 protein.

This is all present at high levels at the time of the occurrence of this
disease. Two months later, after high-dose chemotherapy, we have a
complete disappearance of the blastic clone, the disappearance of the
translocation, but the persistence of a significant number of T-cells
that are hyperexpressing LMO-2 protein.

So we decided to reinforce the obtaining of a complete remission because
one month after, the blastic cells can appear again, and we can again
detect the translocation. So we reinforced the obtaining of complete
remission with three more months of chemotherapy.

Actually, we are in February, and this is 40 months after gene therapy
and six months after the occurrence of a leukemic effect, and we have no
blastic cells, no translocation either detected with a very accurate
method.

We have not done this exploration on the basis that we have 0.1 percent
of T-cells, and they are polyclonal in terms of the integration site. So
even if we think there is a very, very small quantity of gamma9 positive
cells, this is less than the residual leukemic cells normally detected
in a leukemic patient.

The therapeutic plan. You know we are at month 40, the patient is under
a conditioning regimen, and we have prepared over six months monoclonal
antibodies of a clinical grade in order to be able to treat the residual
leukemic cells eventually persisting in bone marrow.

We have obtained this clone through a very kind company in France, and
we have produced in real time monoclonal antibodies against the TCRV
delta-1. These antibodies are now finished, and we have enough quantity
to treat the patient in the next month.

We have approval that these monoclonal antibodies can target this
specific TCR, and we plan to inject it as soon as we have received the
test for eventually the viral contamination of these monoclonal
antibodies.

Patient 5 had gene therapy at three months of age, had a huge number of
CD34 positive cells infused, and is alive and well up to month 31 with
multiple integration sites. He came to the hospital at 34 months with
splenomegaly, an enlarged mediastinum, and a huge number of white blood
cells, 80 percent of blast.

And chemotherapy has been initiated by Ricardo Sorensen without any
delay. The marker for this Patient 5 is they are CD8 TCR alpha-beta
positive cells, gamma-c positive, no myeloid markers, and no NK or B
cell markers.

We have \-- and this is the greatest difference between the two patients
\-- 3 TCRV beta peaks, with only one integration site. No proliferation
is present with the gamma-c dependent cytokines, another difference with
the previous patient. And the chromosomal abnormalities appear at the
time of diagnosis at trisomy 10.

I would like to stress the fact that these chromosomal abnormalities are
not typical at all, even in the first cases, with the chromosomal
abnormalities that we can detect in typical ALL.

This is the repertoire of the beta chain for Patient 5 at month 34. The
peripheral blood still remains polyclonal, but we have the emergency of
three clones, Vbeta1, 15 percent of the total and Vbeta2, 64 percent,
and Vbeta23 that we can\'t detect at the surface is 70 percent.

So these three Vbeta clones make up the totality of the T-cell count in
the peripheral blood. And we have tracked this clone by immunoscope in
direct respective study, and you can see very easily that at month 30th
that we have a very diverse repertoire for these clones. Vbeta1 and
Vbeta2, there is no worry about.

At month 31, Vbeta2 is also polyclonal; no increase. Month 31 is
September. The leukemia occurred in December. And we just \-- this
alteration in the immunoscope analysis lost the polyclonality of the
beta-1 family.

And at month 34, we have 50 percent of this clone and 64 percent of this
one. And thanks to the analysis performed by the Funkel group we can
detect the presence of the provirus upstream of Exon 1 in sense
orientation in these cases.

So here again we have a normal hyperexpression of LMO-2 gene, with
exactly the same result in the P4 patient even. We did an RNA-FISH
study, where we can see merge between the probe for gamma-c and the
probe for LMO-2.

And the other red point that you see is the gamma-c physiological gene,
the two alleles.

The evolution of the P5 lymphoproliferation. It is blastic, there is a
trisomy 10, there is hyperexpression of an LMO messenger, and he has
three clones, two of them detectable by immunofluorescence.

Everything is present at month 34, and there is a disappearance just one
month after the chemotherapy. This is another difference with the P4
patient: this second case is much more sensitive to chemotherapy than
the first one.

And the medical doctor in charge of this child detected a disappearance
of the blastic cells, and a complete disappearance of the chromosomal
abnormalities. We can detect in significant quantity the clone involved
in this lymphoproliferation.

Now we are up to 36 months after gene therapy, two months after the
beginning of the treatment. There is the disappearance of the blasts and
the chromosomal abnormalities.

We can detect some Vbeta1 and Vbeta2 cells that have the same
integration site. There is a very significant decrease in terms of the
quantity of cells, but we can\'t formally conclude that this patient is
in complete remission but has a normal course for a child who is treated
for acute lymphoblastic leukemia.

Just to finish this talk, you have here the immunological analysis of
patients with T-lymphocytes, the other one that does well so far.

And you have the months of follow-up here. The first two patients are
more than four years after gene therapy, and this is the number of
T-lymphocytes for the first patient treated.

And the last determination was made yesterday, and he has 1,000
lymphocytes so strictly normal, probably slightly decreasing over the
time. This is the curve that you probably noticed in the first kinetic
T-cell reconstitution, that it dropped down much faster than the other
patient.

For the other patient the lymphocyte count is strictly normal. This
patient even \-- this is the patient with the sort of lymphoma
proliferation at the time of the diagnosis that I stressed to you at the
beginning, and he had a varicella infection two months ago.

We hospitalized him because we were very worried about the
varicella-zoster complication, taking into account the first cases, but
he was cured completely from his varicella-zoster without any
complication, and with a very mild increase of the gamma-delta T-cell
compartment that decreased over time after the resolution of the
infection.

And this is the blood cell count for the other patient. In terms of
activity, these cells proliferate normally to the T-cell stimuli, such
as the PHA anti-CD3 monoclonal antibodies, or antigens to the tetanus
toxoid and Candinine.

I think that there has been trouble with the patient called by Christof
Patient A, and some worries in the scientific journals. This is the
patient \-- the follow-up of this patient as of February 26th. He had a
normal physical examination, normal peripheral blood cell count, normal
subset distribution, and normal repertoire.

So to conclude this long talk, just two or three slides on
haploidentical hematopoietic stem cell transplantation versus gene
therapy for SCID-X1 patients.

Two points to consider from my point of view. Kinetics of immunological
reconstitution: twelve months to obtain a protective number of the CD3
positive cells versus three months for the gene therapy-treated patient.

This is extremely important, because in the case of a patient that
arrive at the time of the diagnosis with a severe infection disease,
this is the sort of run gain where we normally lose because of the viral
infection in comparison with that.

So a faster immunological reconstitution for CDF-6 patients is a very
important parameter to consider. The second one is the quality of the
immunofunction, and always a long term follow-up can permit us to
conclude about this.

I would like you to remember the European result of haploididentical
hematopoietic stem cell transplantation in an identical condition in a
SCID patient.

We have as each one in the world an extraordinary improvement in the
long-term survival curve for patients with a B plus SCID form over the
time, and this is the time of the first transplantation in Europe.

And we are now up to 18, and we can say 70 percent survival. All
patients are confused, and so even the patients that go at the time of
transplantation and the patients have a severe infection.

In any case, you can have a poor T-cell function in some case with a
partial T-cell reconstitution and as reported by Dr. Blakely, we have in
fact the same result, and a long-term decline in T-cell function, and
low NK cell count, and infrequent T-cell immunity.

The quality of the immunofunction, I feel we can make a comparison
between hematopoietic stem cell transportation and gene therapy. Or
regards of the T-cell function, the time created over 10 years is a
decline in this patient, and we don\'t know exactly why because we
don\'t observe, so far, any decline in T-cell reconstitution for SCID
treated patients, is probably leaked infection from one side, and
incompatability, allogenic response against chemokapithalium
thymopoiesis in the other cases.

This is the situation for gene therapy. The question is, are we able to
transduce stem cells to guarantee a long term restoration of
immunological function in this case.

And each case the restoration is the same in all the cases, and low for
hematopoietic stem cell transportation, and low for gene therapy.

In terms of B cells reconstitution, it is infrequent in this case, and
frequent, but, and as you know, we have a low figure.

This is the gamma-c transgene persistence in a patient with CD34
positive cells, at a different follow-up. For Patient 1, we have only
one data that amounts to six after gene therapy.

For Patient 2, we have a two determination in the bone marrow, and
positive at 5 months, and positive at 21 months after June 30.

Patient 4 is still positive in spite of the chemotherapy, and so I think
we have some doubt on the fact that we have transduced some stem cells,
and these doubts are now finished. He has sample cells detected at the
same extent after 6, 13, and 39 months after gene therapy.

For Patient 5, we have just one detection one year after gene therapy
and not evaluable at this time. We preferred to privilege the detection
of the malignant clone by integration site.

P6, this is a patient that had an extensive varicella infection at the
time of diagnosis. He was restored to complete immunologic function, but
the very cells that destroyed the \-- we know that what fights the
infection are very toxic for bone marrow, because of cells, and at the
time of the harvest of bone marrow, we can have very few CD34 positive
cells, in comparison to the other patients who are free of the virus
infection at the time at the time of diagnosis.

And in this case the kinetics of the immunologic reconstitution was very
slow, and the patient has a very slow increase in T-cell number, and the
CD34 detection up to one year after gene therapy is negative.

So in the debate on how many cells you must transfuse, these data can be
extremely important.

Patient 9, we only have one determination 5 months after gene therapy,
and the patient then is not evaluable because it is in Europe but not in
France. And why there is an apparently increased role of insertional
mutagenesis in a SCID patient, we can assess the gamma-c more than the
interaction of the gamma-c with LMO-2, and that the role of every block
in that T-cell differentiation pathway with the accumulation of immature
CD34 cells ready to go.

There is a massive proliferation of a transducer because of cells tend
to selective advantage, and probably we have an induction of gamma-c
expression of function in pre-CLP cells.

In all of age, I think it could be very important in these cases with a
distant pattern of hematopoiesis, and the accessability of active gene
loci. So different \-- gets a function of the disease and their agents.
So phenotyping of gama-c negative cells between CD34 positive cells
between 3 months and over 3 months is under investigation now in our
laboratory.

And gene inspection pattern is ongoing on the inspection of an
proto-oncogene as a function of the age, and integration sites as part
of a falling gamma-c transfer, and we are coming back to the gamma-c
negative murine mammal with new experiments in newborn mice.

This is the possible identification that everyone would like to know,
and lastly, I would like to thank the large quantity of people that are
studying in detail these two side effects, and the follow-up of the
patients treated.

First of all, at the Necker Hospital, with Peter Cooper, Alain Fischer,
Salima Hacein Bey, and Francoise Le Deist, who permitted us to sort the
immunological reconstitution of these patients.

Out of Paris, we have a great collaboration of LMO-2 expression studies
with Dr. Terry Rabit. And we have performed some experiments in
transgenic mice carrying this transgene; and Karen Osbourne and Peter
Fraser for the RNA-FISH analysis.

And Philippe Leboulch and Roberta Powlack in Boston for the study of
eventory presence of replication of recombinant retrovirus, and RNA
splicing of the LMO-2 protein.

And the VSV studies by Jeffrey Cohen in Bethesda, and Erika Avivi in
France. And we have made, but have no time, to explain all the data and
transcription for the phy-level gamma delta T-cell clone in relationship
to the gamma-delta control T-cell made by Francois Cigaud and Delain
Rigas in Paris.

And we make also the immunoscope analysis that doctor permitted to
follow very tightly, the patient treated by Annika Lim in Paris.

And all the medical doctors that followed up the patients that were
treated in Paris, the patients elsewhere in the world, especially at
Alexander in Melbourne, Australia; and at Winterstein in Munich. And
Ricardo Sorenson, that which the collaboration with whom is very
fruitful.

Of course, I would like to thank the group of Christof von Kalle and
Manfred Schmidt on the work on the integration site. And we are
performing some studies on the cell cycle of B-cells in Paris with
Papadapaluas involved in gene study and the reparation of genes. Thank
you very much for your attention.

(Applause.)

CHAIRMAN SALOMON: It is obviously impossible to cut discussion off at
this point and go on to a break, but what I would like to do is keep it
focused for 15 minutes, and then go to a break at 10:00.

Otherwise, we will not get to the important part of the discussion this
afternoon, and I feel responsible for that. So I would like to open this
very informative presentation on the patients for discussion. I had one
\-- just to start one question. Is it Patient One then that had the \--
is it the third patient with an LMO-2 integration site?

DR. CAVAZZANA-CALVO: Yes, I think it is Patient One in our service.

CHAIRMAN SALOMON: And that patient, if I remember right, is around 3 to
3.9 years?

DR. CAVAZZANA-CALVO: Four years.

CHAIRMAN SALOMON: Four years. Okay. John.

DR. COFFIN: A couple of things. I guess I just lost it as it went by,
but could you quickly indicate the relevant integration sites of the
vector in these three patients that have \--

DR. CAVAZZANA-CALVO: For the \-- I know in\-- the question is can I
indicate very precisely the integration site for the three patients, and
this is the question?

DR. COFFIN: Yes.

DR. CAVAZZANA-CALVO: This first patient, and I speak under the control
of Christof von Kalle, who performed the study, but for Patient 1, it is
within the intron, and in spite of this has a normal LMO splicing.

DR. COFFIN: That is a common feature in MLVs. It\'s not that unusual.

DR. CAVAZZANA-CALVO: But we have it two sites.

DR. COFFIN: Yes, of course.

DR. CAVAZZANA-CALVO: And for the P-5 patient, it is extreme, about 5 kb
before the first exon, and the third patient I know nothing in detail.

Dr. Von Kalle: Okay. Maybe I can briefly comment on this. As I have
stated previously, we have no indication that there is any
lymphoproliferation associated with LMO-2 integration in any other than
the two patients that Marina described.

The data that we have presented was with regards to the chance of an
LMO-2 integration into the vicinity of the LMO-2 locus and we have
specifically searched for such integrations, and we have found a couple
of instances.

One was located 40 kb upstream of the locus, and the other one was in
reverse orientation, about 2 kb upstream of the start codon of the
distal promoter.

And again we have no indication whatsoever that there is
lymphoproliferation from either of these clones. Of course, we are
looking closer with regards to patient safety in the other patients.

DR. CAVAZZANA-CALVO: But I have a comment. I think you can have one,
only one integration site near to the dangerous site. But the much more
important criteria is the clinical one; the physical examination of the
number of peripheral blood cell count, and immunoscope analysis, and the
other characteristics because if I remember correctly from the study of
Don Kohn for ADA patients, there is only one integration site, and there
is only one in one patient with an extremely large T-cell repertoire.

DR. COFFIN: Yes, I would completely agree with that point, but I think
it is important I think to get on the table exactly what we are seeing
in the total set right now, so that we can get the back of the envelope
calculations if nothing else.

CHAIRMAN SALOMON: Crystal.

DR. MACKALL: Two clarification questions. First off, I thought there
were 11 patients in the initial study.

DR. CAVAZZANA-CALVO: Which patient?

DR. MACKALL: I thought that there were 11 patients initially treated
that were discussed last fall.

DR. CAVAZZANA-CALVO: I think on the 11th patient there was a
compassionate treatment for a 15- year-old boy, because he had an
affected biology form, and he had a little T-cell repertoire that
permitted him to live in between a lot of virus, and parasitic
infection, and bacteria infection.

And we described this and discovered that he had a gamma-c mutation very
recently, two years ago or something like that. But the gene therapy
treatment has been a failure because the child has been largely
infected. So he has no restoration of T-cell function.

DR. MACKALL: Okay. So 9 out of the 11 patients that received the
treatment had initial benefit at this point?

DR. CAVAZZANA-CALVO: I think I prefer to consider the newborn infants as
a homogeneous group, and 9 of these were successful. And in one patient,
who was 15 years old, was also a failure.

DR. MACKALL: Okay. And a second question. When you were showing the
T-cell numbers on the two groups, separating out Patient 4 and 5 from
the others, it seemed to me that those patients from 10 months or so on
had about 10,000 circulating T-cells. Is it clear that they did not have
super-physiologic levels of T-cells before the development?

DR. CAVAZZANA-CALVO: It is very difficult to answer, because as you
probably know, a child less than one year has a physiological
lymphocytosis. So after to 10,000 lymphocytes, an upper airway infection
can determine lymphocytosis, and this is considered normal.

And even a small infection, a virus infection, upper airway infection
can determine a lymphocytosis. And these only after one year that they
showed the classical version of the cell hematological number, with an
increase in the neutrophil count and a decrease in lymphocyte.

This is \-- if you go see the identification tabs at 6 months late in
the treatment, you have a 12 months plus 6, and you can consider that
after or around 2 years, we can tolerate a number of lymphocytosis, mild
lymphocytosis, but it is normal in comparison to the age.

DR. MACKALL: But they certainly had higher lymphocyte counts than anyone
else in this study even early on looking back now?

DR. CAVAZZANA-CALVO: Well, looking back now, yes, you can say yes. But
if you have a newborn with 8,000 lymphocytes, what do you do with it.

CHAIRMAN SALOMON: Rich.

DR. MULLIGAN: Marina, two questions. On the kinetics of the T-cell
recovery, did I get that right; that those two patients, that they
recovered their T-cells much more quickly?

DR. CAVAZZANA-CALVO: Yes. This is impressive.

DR. MULLIGAN: And is that different than a person given a transplant, a
bone marrow transplant?

DR. CAVAZZANA-CALVO: Completely different.

DR. MULLIGAN: Okay.

DR. CAVAZZANA-CALVO: Never can we get two cervical \-- with
haploidentical bone marrow transplants.

DR. MULLIGAN: Okay. Secondly, the issue of \-- is there a different
target cell for infection? You mentioned potentially that there were
CD34 plus cells, quote, ready to go.

Can you tell us anything you now know about the CD34 plus cells from
those patients before infection, versus normal patients? Is there any
sense that they are more replicating CD34 plus cells?

Is there any strange characteristics? Do you have a sense that after
they are cultured under the conditions for infection that they give
different counts?

And particularly LMO-2, I think, is supposed to be pressed in primitive
hematopoietic stem cells. Is there any sense that these patients have
more LMO-2 expression in their CD34 plus cells?

DR. CAVAZZANA-CALVO: Yes, the question is crucial and very interesting,
but unluckily I have no clear answer to give you. Lastly, I can answer
that in this patient the number of CD34 positives out of a viral
infection is higher than other bone marrow cells.

And other bone marrow cells in the mononucleated fashion, and you have 3
percent of CD34 positive cells, and in newborns, we had upwards to 10
percent of CD34 positive cells. So this is the first great differences
without, and I can\'t underline any biological differences between the
two.

And the other one is the proliferative analysis, and for the scale-up
protocol, we have set up an experiment in cord blood. And roughly for
these two patients, the biological characteristics of the bone marrow is
much more closer to cord blood than the bone marrow cells.

And we can also say that to the other patients that are oldest have a
less proliferation during the transaction, but I am not sure that the
difference is significantly relevant.

I have no other data to share with you about LMO-2.

CHAIRMAN SALOMON: I need some help with two technical questions. The
first is, and it is just me being ignorant, but I don\'t understand this
proliferation rate that you referred to. It had no units, and so there
was a 7.7 and a 9.5 in two patients.

So, I apologize, but I just don\'t understand what that is.

DR. CAVAZZANA-CALVO: It is a stupid calculation, but you have 1 million
cells and you have 10 million at the end, and I say that you have a
10-fold incremental of the number itself.

CHAIRMAN SALOMON: And so that is over what period of time in culture?

DR. CAVAZZANA-CALVO: The five days. I explained that we began on Monday
morning to purify the cells and injected back the cells on Friday
evening, Friday afternoon. And so during this period you can from 5, up
to 10-fold expansion of the initial number of cells that are put in a
culture.

CHAIRMAN SALOMON: Okay. So maybe we will come back to that.

DR. CAVAZZANA-CALVO: CD34 positive.

CHAIRMAN SALOMON: Yes. And the other question that I had would be if I
\-- and again if I got this right, these two patients got 44 to 40
million CD34 per kilo? I realize that they are small, and that these
kids were infants, but that seems to me an extraordinary high CD34 dose.

DR. CAVAZZANA-CALVO: Yes, but per kilo. But we come from the experience
in identical bone marrow transportation, and you must remember that
during this period that we know nothing about gene cells. And all of the
clinical trial so far realizing that the world was negative in terms of
results.

And from the haplo condition we know that T-cell constitution is very
slow. And that even when we injected a mega dose of CD34 positive cells,
in some cases, although not in identical situations, you have a normal
constitution.

And so we were very worried about efficacy than toxicity at this time.
So this is the reason that in face of all of these proliferating cells
that we injected back everything without knowing anything about toxic
effect.

DR. COFFIN: Could I follow that up a little bit? So do these two
patients then get more? I mean, how do these two patients compare to the
others? Were they the ones that got the most cells?

DR. CAVAZZANA-CALVO: Yes, sir.

DR. COFFIN: And had the most rapid rates of cell reconstitution?

DR. CAVAZZANA-CALVO: Yes, sir. Correct.

DR. COFFIN: Did they also get \-- could you compare the numbers of
transduced cells?

DR. CAVAZZANA-CALVO: They are much higher.

DR. COFFIN: I\'m sorry?

DR. CAVAZZANA-CALVO: The higher \--

DR. COFFIN: These two were the two that had the highest?

DR. CAVAZZANA-CALVO: Yes.

DR. COFFIN: So quantitatively how many transduced cells were in these
two patients compared to what in general was in the others?

DR. CAVAZZANA-CALVO: I can say that they have two times the number of
the other patients roughly.

DR. COFFIN: So the average for the other patients \--

DR. CAVAZZANA-CALVO: Except for P6, because P6 is a strange patient \--
We know the toxicity of the various viruses on born marrow cells, and so
we could not have very few CD34 positive cells at the time of treatment.

And this patient received around 1 million of transduced 34CD positive
cells per kilogram. And so 10 times less than the other, and has a very
slow T-cell reconstitution probably. And we are looking attentively for
B cells because the level of immunoglobulin is going down, and it is not
perfect.

And they have no CD34 positive set transduced detectable today.

DR. COFFIN: I\'m sorry to keep hitting on this, but these numbers I
think are going to become very important in our discussions later on,
and so I wanted to make sure that we were very clear on them.

So you said before the average total number of transduced cells per
patient on average is 17 million per patient? I took that number.

DR. CAVAZZANA-CALVO: No. There is 10 patients, and so we have 8 million
and 20 million for P4 and P5, okay?

DR. COFFIN: Okay. Total transduced cells.

DR. CAVAZZANA-CALVO: Gamma-c transduced set cells. The total transduced
cells are much more. I think it is about double, about 40.

DR. COFFIN: But successfully transduced cells.

DR. CAVAZZANA-CALVO: CD34.

CHAIRMAN SALOMON: John, I calculated about 70 percent transduction.

DR. CAVAZZANA-CALVO: No, it is not 70 percent. It is 40 percent.

DR. COFFIN: I don\'t want twice as many. I want to know what the numbers
are. That\'s what I am trying to get at.

DR. CAVAZZANA-CALVO: But I think that your comment is right, because in
reality they received a huge number also of gamma-c positive cells, CD34
negative. And we don\'t know if they are committed for the precursor
cells that the other patients received less then.

DR. COFFIN: All right. So just for either patient, either Patient 4 or
Patient 5, once more, can we get the numbers. So the total for that
patient, the total number of gamma-c positive cells transduced in the
whole population of transduced cells was what? Was it 20 million, or \--

DR. CAVAZZANA-CALVO: Forty million.

DR. COFFIN: Forty million.

DR. CAVAZZANA-CALVO: The total number.

DR. COFFIN: The total number of gamma-c positive cells.

CHAIRMAN SALOMON: John, just for the interest of getting done here, can
we break on that, and then during the break, which is going to come in a
minute, can we make some calculations together.

DR. COFFIN: Yes.

CHAIRMAN SALOMON: And then present it to the group?

DR. COFFIN: That\'s fine.

CHAIRMAN SALOMON: So before the break, I would like \-- Joanne, did you
\-- and Warren, and Kathy, and Ken, you get the last. And can we keep
these kind of short and brief, because I don\'t want to completely lose
the track here, but I do certainly appreciate how important this part of
the discussion is.

DR. KURTZBERG: I have a couple of questions. One is did you change
anything about the separation of the marrow cells to select the 34 cells
between any of the patients?

DR. CAVAZZANA-CALVO: Nothing. Everything is reproducible and we have
made the same conditions, exactly the same for all of the patients
treated. And we obtained in term of a transaction of a CD34 positive
cell exactly the same results.

DR. KURTZBERG: Did you look for EBV infection in any of these patients?

DR. CAVAZZANA-CALVO: Yes, negative.

DR. KURTZBERG: Okay. And what happened to Patient 8? I lost track of
that.

DR. CAVAZZANA-CALVO: Patient 8?

DR. KURTZBERG: Yes.

DR. CAVAZZANA-CALVO: What is the problem that you have with Patient 8,
because I don\'t remember the all the patients in this way.

DR. KURTZBERG: I just thought that I saw Patient 8 missing from a lot of
the graphs, and maybe it was me. I can look after.

DR. CAVAZZANA-CALVO: It is narrow, but he is doing well. In the kinetics
\-- well, it is a patient that is not in France, and so it is impossible
for us to solely monitor the kinetic reconstitution.

CHAIRMAN SALOMON: Kathy.

DR. CAVAZZANA-CALVO: And also for Patient 5, the approximate kinetic
strength is not so precise as this patient does not live in France, and
we cannot follow at the same time period of the patient. This is the
reason. Kathy.

DR. HIGH: I wanted to ask you one question about gamma-c subunits. And
so I think you showed one slide where you showed that the levels of
expression, of protein expression, were essentially normal of gamma-c.
Is that right?

DR. CAVAZZANA-CALVO: Well, even knowing that for the other patients,
normal or low.

DR. HIGH: Normal or low for all patients.

DR. CAVAZZANA-CALVO: I decided that the best one is normal.

DR. HIGH: Okay. And is the gamma-c subunit usually limiting for assembly
of the cytokine receptor, or is it the other subunit?

DR. CAVAZZANA-CALVO: I have not performed the study of this type, and I
don\'t \--

CHAIRMAN SALOMON: Warren, why don\'t you answer that? You have the next
question.

DR. CAVAZZANA-CALVO: Well, just a second. In the EBV study, we
quantified the number of gamma-c receptor on each cell, and it was 150
gamma-c receptors present.

And the normal EBV cell line has up to 200 gamma-c receptors present. So
this is the only answer we can give you, and Dr. Leonard can give more
of an explanation.

DR. LEONARD: Yes. My question had also related to the level of gamma-c
expression, and whether perhaps Patients 4 and 5 had any more than the
other patients.

But related to the level of gamma-c versus the other cytokine receptor
chains, I don\'t think that anyone really adequately knows the answer to
that, because no one has ever done rigorous scat charts comparing with
mononuclear bodies comparing the level of each of the various
components.

And one of the underlying questions is whether gamma-c is overall
limiting or whether it is available in excess, and is there enough to go
around for all of the different cytokine receptors simultaneously, or is
it perhaps limiting some situations which would allow for competition?

And the answers are really not rigorously known for primary cells, and
particularly if you are considering thymic precursor cells or early
pre-genitor cells, and certainly no one has done any experiments on
those sorts of cells that would rigorously address that sort of
question.

DR. MULLIGAN: Can I just ask him something about this point, which is
that there is a point where gamma-c isn\'t normally on in the very
earliest cells I would assume, and so wouldn\'t this \-- there
definitely is a novel case here in principal, where the addition of the
gamma-chain to a cell that might be making or using another beta-chain
of these other cytokine receptors. Isn\'t that the case?

So you are introducing, you are having gamma-c at a point where it
wouldn\'t normally be.

DR. LEONARD: All I can really say is that when we were making our own
gamma-c knockout nest with Paul Love, and looked at early thymic
precursor from wild type mice, they made a Northern blot with
identifying thymic promordial cells at the earliest points they could
look at, gamma-c was expressed everywhere.

So we really never found in the thymus an early enough place where it
was not evident in the mouse.

DR. CAVAZZANA-CALVO: And just a piece of information. I don\'t know if
everyone knows that a transgenic mouse does exist for gamma-c that is
under a CD2 promoter. And that is a little bit later than ours, and the
mice did not develop any leukemia. That is information just to complete
your information.

CHAIRMAN SALOMON: Ken.

DR. CORNETTA: I actually have a question about the animal stuff that you
just presented earlier. You said that you had in your animal model study
out to 47 months.

DR. CAVAZZANA-CALVO: No, 47 weeks.

DR. CORNETTA: So, 47 weeks. Okay. 47 months, I wish. How many animals
and what kind of analysis was done at the end to have confidence that
there was not a leukemic process going on?

DR. CAVAZZANA-CALVO: How many animals we studied after the 47 weeks, I
don\'t remember, but I can check when I come back home. And conversely I
know what we studied extensively is the thymus, spleen, gastrointestinal
tract, and the peripheral lymph node for each animal after the necropsy.

And we studied these because as you know in gamma-c knockout mice, there
is \-- the gastrointestinal lymphoid compartment is depleted. And the
restoration of this compartment is a sign of good restoration. So it
permitted us to see very small histological modification for the mice.

DR. COFFIN: Just very quickly. The real question there would be how many
transduction events, how many integration events did you actually study
in total in those mice as compared to what you see in these patients?

It would be interesting, and you probably don\'t have that information,
but it would be interesting to dig that back out again and see how that
compares.

DR. CAVAZZANA-CALVO: Yes, but there is a gap in the sense that we
performed no study on the integration of profiles in the mice. I have no
information. When we performed the study on the mice, we didn\'t think
to look at the integration site. Sorry.

CHAIRMAN SALOMON: Okay. The last question before the break, and then we
are going to have a break.

DR. TORBETT: I just would like to ask Dr. Leonard a question. He
addressed the question of where gamma-c is expressed, but I would like
to know how early is it expressed, and is it expressed in hematopoietic
compartment? Getting back at Richard\'s question, because what you are
doing is transducing 34 cells at or in supposedly a very primitive
stage.

And what I would like to know, getting back at this question of
inappropriate expression, at a stage that might be critical to send it
on its way to an oncogenic event.

DR. LEONARD: We have not looked, and I am not sure that anyone has
looked really early in bone marrow derived cells. So I can\'t really
answer.

DR. MACKALL: I want to make a comment. I mean, early T-cell progenitors
in the bone marrow are known to be IL-7 receptor positive. And so I
presume that means that they are gamma-c now. Those are already somewhat
committed to a lymphocyte lineage.

DR. CAVAZZANA-CALVO: I know that \--

CHAIRMAN SALOMON: We will get back to this. This is kind of like holding
back a hundred thoroughbred horses. I mean, there is just a lot of
brainpower around the table, and I respect that.

And I wish that we just had hours and hours, but this is really where it
ought to go. I just think from the whole committee and everyone here
that I want to thank Marina for coming here.

I mean, you had an adverse event, and you really handled it well. That
is me speaking personally. You presented your data, and you shared it
with us in October, and you are sharing it with us now.

I hope that you hear directly from me, and I just have a lot of respect
for how well you have handled it, to me it has been an example. To the
whole world, how gene therapy ought to deal with its problems, as well
as its successes. Thank you for being here.

DR. CAVAZZANA-CALVO: Thank you.

(Applause.)

CHAIRMAN SALOMON: So, 10 minutes, guys.

(Whereupon, at 10:08 a.m., the meeting was recessed and resumed at 10:29
a.m.)

CHAIRMAN SALOMON: Okay. I would like to get started again. What we have
planned now are two 25 minute talks to further expand our database, and
then we will go into a Q&A period, and then an open public hearing.

My recommendations would be to everyone to stay hydrated. We have been
known to forego lunch, and I have sort of the sneaking suspicion that
may be necessary today as well.

So, getting started again, I would like to introduce Dr. Claudio
Bordignon from the Institute of Scientifico of Raffaele.

DR. BORDIGNON: Thank you. Thank you for this opportunity of sharing our
data. I have really preferred a talk that is more oriented to analyze
the overall data that we have available, rather than getting into the
scientific details.

Of course, all the scientific details are here, and so if there is time,
we can go back to the specifics during the questions. The scope of my
presentation is really to review all the data that are in our hands,
meaning my group and in collaboration with those that are directly
working on some of our projects; retroviral vectors, hematopoietic stem
cells, and peripheral blood lymphocytes.

And to share the results of the initial analysis of the integration
process and to take a look at whether or not this is meaningful, and how
much we need, and what kind of direction we should go.

I will be reviewing data from 21 independent groups, including
pre-clinical studies and clinical data. Two main fields, clinical trials
of gene therapy of ADA-deficient SCID. Our group, the collaborators in
Brescia, Luigi Notarangelo and others; and the collaborators in Israel,
Shimon Slavin and co-workers, and I have one slide from Fabio Candotti,
who has been so nice to give me one of the long term follow-up of the
lymphocyte ADA studies and making one of the points that I am trying to
make at the end.

The second set of group are pre-clinical and clinical studies of the use
of the suicide genes. This is an independent group and there is a large
European consortium founded by the European Union, and that is allowed
to study very similar parameters in different models and different
animal models for clinical and patients.

The reason why I decided to include this data, if there is time, of
course, is because it is probably the largest communitive experience in
the use of retroviral vectors in hematopoietic stem cells and
lymphocytes.

And in addition to the large European consortium, there were
collaborators from the U.S. and from Israel, and from Japan.

The first is ADA-deficient SCID. Of course, it is a different disease
than gamma-chain, but definitely we don\'t have the time to review all
the differences.

It is sufficient to say that probably that the selective event that is
described in this type of disorder is probably not as pressing, as
strong as it is in the gamma-chain deficiency. Here the defect is a
housekeeping enzyme adenosine deaminase.

Now, in order to have a reasonable evaluation of the risk benefits and
this was one of the points raised at the beginning of the presentation
today, and in the first discussion today, I would like very briefly to
come back to the point by Marina discussed in relation to the
gamma-chain study.

Here the available treatment are HLH matched transplant, and I will not
discuss this, but I will come back to this point.

Initially, no identical transplantation, and the range in Europe has
been updated fairly recently in the EBMT in 2002. And the results are
really not encouraging. Twenty-three percent overall survivor from the
long experience. Of course, this has improved over time, but in any
single selected center studies, you don\'t get higher than 60 to 70
percent. And if this is as a result of transplantation with
conditioning.

If you go to non-conditioning, without conditioning, then the largest
series comes from Dr. Buckley in this country, and it is about 53
percent.

Of course, there is PEG-ADA available, but this I think is also somehow
a misconception in the general perception, because PEG-ADA doesn\'t
really work in every patient, and does not offer the same level of
reconstitution.

And if you look at the last survey by Mike Herschfield, who presented
ESID in 2002 \-- 83 percent is the survival of this patient, and 73
percent if you include the patient with failing PEG-ADA, and then go on
to receive the transplant.

So these are the reference points, and what we are going to review as
quickly as possible is our ten, eleven years experience of gene therapy
and deficient bodies recombining immune deficiency, and this was mainly
down at our center in collaboration with the group in Brescia more
recently, and with Shimon Slavin in Jerusalem.

What were the main milestones of this research? In 1990, we published
the pre-clinical data for what was available at that time as animal
models, and I will not discuss any of those data today.

In 1992, we started a combination of stem cells, meaning total bone
marrow actually, and the peripheral blood lymphocytes transduction, and
this was published back in 1995.

And in \'99, we published the first discontinuation of PEG-ADA in one
patient. And in 2002, the more recent study based on CD34, and so when I
say stem cell here, it is selected CD34 in combination with
non-myeloblative conditioning, and this was also reported last year.

And these are the 12 patients that are enrolled in the study, and with a
different protocols \-- the PBL. There is not much that I want to make
in relation to this, with the exception of a couple of relevant points.

The patient who received the treatment of multiple injections, and we
don\'t have the total number here, but as Fabio conducted for this
patient, it is still a huge number of lymphocytes and a huge number of
integration. This is relevant and we will come back in a minute to the
analysis of integrations.

The patient discontinued PEG-ADA, and what happened in that sense went
from about 10 percent, less than 10 percent, to nearly a hundred percent
of the transduced lymphocytes, and the curve continued.

And together with this effect, the majority of the lymphocytes that were
present were transduced in increased numbers to increase the level of
ADA, and the ADA present in the transduced population and the
reconstitution of immune functions.

If you look at this, this is the first comparison of the response, and
if you take a vaccine in this patient, and you analyze the response, you
see that it is definitely better than the HLA mismatched transplant and
comparable to the HLA matched transplant.

And this the slide that I made and referenced several times. It is
important for the total number of lymphocytes that you see down here,
and for the people that are not close in the room, this is 10 to the
11th, and I am sure that Fabio will be happy to comment on the duration,
the number of integration and the survival of such cells for 13 or 14
years now.

Of course, please consider Patient 1 is on the original slide, and so
this is Patient 1 of the overall experience, and it is not Patient 1 in
our study.

Conclusions that I can draw at this point, and I apologize because I
only gave you a quick touch of what was studied, but all patients had a
total wealth of normal growth and development.

Gene therapy with PBL stands for safe and efficacious and optimal, as
compared to hematopoietic stem cell gene therapy. This is mostly due to
the failure of the total population of the peripheral blood lymphocytes
to toxify the whole system.

So although you have an immune constitution, you have a number of other
elements that are not optimal, at least if you compare to the data that
you will see with CD34 purified cells.

And you have the restoration of lymphocytes polyclonal repertoire, and
so it is included in the repertoire, the protection of infection is
pretty good.

A very large number of transduced lymphocytes have been injected and
have survived for more than a decade, both in the NIH study and in our
study. No apparent safety reasons are present to reduce or contain the
number of transduced lymphocytes that are injected into patients.

I wanted to make this point because the discussion on those integration
events and the total number of integration per cell and so on, came up
into the discussion, and if you look at the number, apparently for
lymphocytes there is no such concern.

The CD34 positive study is very, very similar to what you have seen from
Marina, and the protocol was inspired by their study. There are two main
differences. One is technical and it is related to how we do the
transplant, and the cell dose is much lower, the cell dose that is
injected.

And the patient \-- well, it is about one log less, between 1 and 2 logs
less, depending upon the patient. The patients are also conditioned with
non-myeloablative conditioning with Busulfan. You will see that this is
an ambitious definition, because actually one of the patients went into
myeloablation.

This is the story of the last four patients of the 12 that I indicated
in the summary slide. And here is present are the age of gene therapy,
in months, and so you see the patient, with the exception of the first
patient, is slightly older.

And this is the follow-up available as of today, or well, yesterday, or
the day before; 29, 23, 9, and 4 months. So the full follow-up is not as
long as the French study.

As you see, some of these patients had already failed after
transplantation. This is the total number of cells infused total. And
this is the dose per kilo, and so you can have your idea. This was
particularly low and it is important to keep in mind that this is
Patient 2 of the hematopoietic stem cell, and you will see that this
shows in integration a number of other issues.

So this is probably, I would say definitely the maximum dose. The
percent of transduction ranges around 13 and 40 percent, and the degree
of myeloablation.

As I said, essentially all patients were maintained on the same dose,
and at least we tried our best to maintain the same dose, but the level
of myeloablation, depending upon the condition of the patient, was very
different, and actually this patient received myeloablative treatment.
This is the patient, and you see here that there is a profound
difference.

The other patient actually recovered very quickly, and also this
patient, I have not updated the slides, but none of them needed to be
transfused for platelets, with the exception of these patient obviously.

I think we figured out what was the clinical reason for this, and it is
not too relevant for today. How about the correction of the immune
defect? Well, this has a level of a total account of lymphocytes, and
the different lineages, and as Marina described, in about 3 months you
see the reconstitution of lymphocytes.

Of course, all these studies, the hematopoietic stem cell studies are
done without PEG-ADA, and so only gene therapy is responsible for this
reconstitution.

This occured B-Cells and T-cells, NK-cells, the different sub-population
and so on, and I will not show any of the other patients, because the
story is essentially the same. Naive cells, thymic emigrants, and that
is an indication of thymic function, and you see there is nothing
before, and then you go into the range of the age-matched control.

The reconstitution is fairly convincing, and also the functionary
constitution, this is pre-gene therapy, and this is after gene therapy,
and in relation to the age-matched control, and that is the last \--

And you see that this is true for RPHA candidates, and so on and so
forth, and this is also for the correction of overall immunity, and you
see here a different type, and the level of IgG here, of course, the
patient was using IgG and so forth.

I refer to pre-clonal, and the complete correction that we get with the
hematopoietic stem cell also relates to the metabolic defect. This is
actually more relevant than if it was normal, and it was perceived
before gene therapy, and actually although we never reached the level of
normal individuals in the different cell lineage, this more than
sufficient to detoxify the system.

Again, not through normal levels, but to levels that are very similar to
the heterozygous parents, and therefore, influential for the health of
patient.

Now, let\'s take a quick look to the engraftment, because this is
probably in relation to the total number of cells and the integration
event. It is probably relevant to have a sense of how the different cell
doses are working for the patient.

This is Patient 1, and these are the days in the range for these
numbers. And T-cells are a hundred percent, and K, and so on, and so
forth. But also the other lineages are pretty good even at a relatively
long period after the procedure.

This is the second patient, and do you remember the patient who got the
0.9 dose, the lowest dose, despite this low dose, selective pressure was
sufficient to get nearly a hundred percent of transduced T-cells.

But in K-cells and B-cells, and all the other non-lymphoid lineages, are
very, very low. This patient, without the serious adverse events
reported probably was going to receive a second dose, but since he is
clinically well and doing fine, we decided to postpone a second
procedure.

Patient 3 is similar to Patient 1, and Patient 4 was actually receiving
gene therapy during the banned suspension that is ongoing in Italy, with
the specific permission to treat this patient on a single patient basis,
is now in the phase of reconstitution, and the numbers for the time look
pretty good.

This should not worry because we usually see the cells taking off after
3 months, and the patient is in Saudi Arabia, and so we cannot do the
controls all the time.

But the level of lymphocytes are climbing, and all the other patients
are predicted with the climbing of the level of lymphocytes to the
proportion of new cells should also go up.

Conclusion. A restoration of lymphocyte counts and corrections of
humoral and cellular response, and correction of the ADA and metabolic
defect, and this is what makes together with the full immune
reconstitution, and this was perceived better than the lymphocytes.

Multi-lineage stable engraftment of the new cells, no adverse effects.
Clinical benefit. PEG-ADA. How good is the clinical benefit. How does
this compare with allogenic bone marrow transportation. This data are
due to the courtesy of Shimon Slavin, and collaborators Memet Aker, and
Shoshana Morecki.

The have family that has obviously the same genetic background, a
Palestinian family, in which you can compare in that sense a normal
individual, and an ideal transplant, and gene therapy, because the
family has all three cases.

So this is Patient 1, and our Patient 1 from gene therapy, and the
second sibling is a healthy one, the blue one, and the middle is a
patient four years after umbilical cord blood with a full HLA match.

And you will see that I am not going to argue that this is a bit better
than this or this, but in essence, with the difference of K-cells, all
the different parameters, the gene therapy is either the same or better
than the transplant, and often very close to the normal individual.

And I am flipping very quickly for the second time through all the
different parameters, including the specific cell levels. So let\'s try
to conclude from this comparison and from the rest of the study.

All patients are doing clinically well with normal growth and
development. Gene therapy with CD34 cells, combined with mild
myeloblation, is safe and efficacious as a single therapy.

You have multilineage stable engraftment, and restoration of the
lymphocyte count, correction of humoral and cellular defect, correction
of ADA activity and metabolic defects, clearly superior to mismatched
transplantation, comparable, or at least comparable to matched
transplant.

These are all the people who participated in my group in San Raffaele in
Milano, and there are a number of external collaborators without whom
all the studies would not be possible.

These are the long term collaborators, with whom we started the
vectorology, and the initial studies. Now, let\'s go and take a look at
the preliminary data on the analysis of integration very, very quickly,
because these are definitely not complete data.

I am sure that everybody here is familiar with the reverse PCR, and you
can essentially cut out, and amplify, and sequence upstream and
downstream the regions that are close, adjacent to the integration site.

And you get this type of pattern. In T-cell patients receiving
hematopoietic stem cells, and this is Patient 1, and you remember the
good cell dose.

This is the T-cells and all the different times, and here and there if
you look carefully, you may find an event, and this is the level of
progression of transduced cells.

Patient 2, you will remember the very low cell dose, and I apologize, as
this is almost impossible to read, but this are from \-- two from the
same patient, and you see that there is some level of clonality.

Patient 3, again, is similar, and Patient 4, it has some level of
clonality, but certainly after reconstitution as we saw in every
patient. So you can clone and sequence in a number of different ways.

First of all, you can clone the T-cells, and then you will produce a
number of clones, and then they are either single integration or at most
a couple of integrations and that would be related to the fact that they
are not really clone.

But it is a clone with two integrations, but you can cut out and
sequence the whole thing. This is the study on integration in peripheral
blood granulocytes, and so this is the myeloid compartment.

Here in all patients you see a limited number of clones, and that makes
it easy because you can cut out any one of these and sequence them all.
So for this patient, I will show you that they have the analysis on all
the clones.

And these are again in peripheral blood, and in bone marrow in different
lineages. And again you see fully cloned, oligoclonal integration. This
is the patient who received \-- and this is the only one I am going to
show, the patient who received peripheral blood gene therapy.

And as you see, this is 25 months after the last infusion, and 90
percent of the cells are vector positive, and again you see a big smear
with many, many integrational doses, and a few of those are predominant.

If you analyze this at different times, actually some of these switch,
and so you don\'t find the same immediately. How can we do this, and how
can we analyze integration. It is relatively simple.

You have two possibilities. If you have these discrete bands as you have
seen in the granulacyte, then with the bands you do direct sequencing,
and with an algorithm that was prepared by our bioinformatic people, you
can go directly and analyze where it is on the genome, if the region is
known obviously. But this is the case for the majority as you will see.

If you are not in this situation, you can make a mini-library clone
directly in plasmid sequence, pick the positive one sequence and map the
same way, and this can be done with rubber, if that\'s justified, of
course.

So this is the preliminary analysis of 25 integration sites that for one
reason or another were selected because of the clinical predominance,
because they were appearing as more clonal in some patients, or in some
phases of life in the clinical follow-up of the patient.

These are the number, the location of flanking regions and so on. So not
containing genes are 11, and inside known are predicted genes 70 introns
and 20 exons.

The draft genome region one, highly repetitive sequence, one; short
non-conformative sequences. We are redoing the analysis of these four.

This is the analysis that I mentioned for the granulocyte. This is in
essence the full feature of Patient 1 at a given stage.

These are the number of identical clones identified, and this is the
length of the region, and this is the chromosome location, whether it is
outside the gene, inside the gene.

And we are continuing with this analysis for all the other patients, and
for the different lineages. What can we conclude after this? Not much
really. Integration are highly pre-clonal in circulating T-cells of
three ADA SCID patients, Patient 1, Patient 3, and Patient 4, and there
is a single exception of Patient 2, but you remember Patient 2 really
got very, very few cells.

Several different integrations are detected in granulocytes and other
subsets, and cloning of integration site and differentation to different
subpopulation is in progress. I will come back at the very end of this.

Now, in the last few minutes I will review the suicide gene therapy in
hematopoietic stem cell transplantation, and I apologize for those of
you who are not directly in the field of gene therapy, because at the
speed I will be presenting this data and the clinical protocol will
probably not mean too much.

But the purpose is to tell you that this is probably the largest study,
both pre-clinical and clinical levels, and therefore, I will show you
the data from the safety point of view.

Well, why was this done? For the simple reason that in allogenic bone
marrow transplantation, T-cells that are present in the graft really
determine the outcome of the transplant in many ways.

If you take the lymphocytes out, you get no graft-versus-host disease,
no immune reaction from the graft to the patient. Unfortunately, when
this was extensively utilized in the clinical setting, this increased
the risk of relapse, demonstrating that actually the T-cells in the
transplant to take care of the minimal residual leukemia disease, or
lymphoma, or other tumor.

When you were doing the transplant, or we were going the transplant in a
conventional way, the idea was to find the balance between
graft-versus-host disease and relapse. This was done with a total cell
dose, but also with immune-suppressive agents: cyclosporine,
methotrexate, and others.

Now, it is so true that the lymphocytes are taking care of the leukemia
that from the middle 90s actually, the lymphocytes were extensively used
to treat relapse after transplantation in order to obtain maximum
anti-leukemia activity, unfortunately this was associated with
significant graft-versus-host disease, at least 11.

In essence what you can do and what we did is to insert the gene in here
so that you can switch them off if the graft versus host disease runs
out of control.

How do you put it in and how do you select the cells through a
transgene, truncated form of the deltaLNGFR affinity receptor for the
non-growth factor, and so that you have the untransduced cells, and the
transduced cells with a mixed population, and these also contains the
Swiss Ig, the thymidine kinase.

But you cannot inject this, because you will only be able to kill those
cells, and this would still leave graft versus host disease. So thanks
to the cell surface marker, you can fish out all the cells and see how
the protocol works. The protocol is fairly simple I believe.

If the patient relapses, you bring the donor of the bone marrow back to
the clinic, and you do a leukopheresis, and you get all the lymphocytes,
and you transfuse those, the transduced cells, and the little flag on
the subsurface marker with a monoclonal antibodies, and you select them
all out, and then you can give it for transplantation.

If the patient goes into complete remission, great. If the patient goes
into complete remission and develops graft-versus-host disease, you can
kill out all those cells by grancyclovir. This is the technology that is
fairly established, and was published in 1997 for the first time.

And there are a number of groups throughout the world who are working on
this. Now, you don\'t need to read all the names and all the
affiliations. Of course, the majority of these as I mentioned is a
consortium founded by the European Union to demonstrate that this really
actually works at the clinical level.

What is important is that there are some collaborators from outside the
consortium, again Shimon Slavin, and Phil Greenberg in this country, and
Steve Kornblau from MD Anderson, and a few others.

These groups have been utilizing these tools both for pre-clinical
models and for marking studies, and for clinical studies altogether.
Now, where are we in relation to numbers.

I will not show you how efficacious this is. This was not my point. The
point was not to find the right risk balance in this study, but to show
you the size of the study and what we can try to conclude out of this.

These are pre-clinical studies all done in mice, utilizing human cells,
human-mouse chimera, so murine cells. And this is the number of mice
treated, 140; in the human chimera, 206; a total of 368, and these are
the total cell doses that have been reached.

This is the follow-up in weeks, with several secondary and tertiary
transplant recipients. This is the total accumulated time. The outcome
after or at the end of the study, all the animals were specifically
controlled to check whether there was anything abnormal in the
hematopoiesis, and all the animals appear to have a normal
hematopoiesis.

So the cumulative data on over 300 animals transplanted with the
hematopoietic stem cell, and transduced with delta-LNGFR-coding vector,
revealed no adverse event, with normal engraftment, persistence of
differentiation of transduced cells, secondary and tertiary successful
transplants.

More than a hundred of these mice were maintained for more than 20
weeks, and more than 70 animals, including 16 recipients of secondary,
were sacrificed over 28 weeks.

Risk of oncogenic transgenic transformation by transduction with this
vector system is less than 1 in 10 to the 9th events is what we can say
so far. What is happening in pre-clinical studies supporting the safety
of marking of T-lymphocytes with deltaLNGFR.

So this summary was on hematopoietic and I hope I didn\'t confuse you.
Hematopoietic, first, and lymphocytes after. These are all done with
lymphocytes. This again is human into mouse, 20 animals, mouse in mouse,
rat in rat, and three long term dogs.

This again are the total number of cells infused with the total
cumulative dose, and this is the follow-up in weeks, with a significant
range for the dog. Of course, these are very precious experiments, with
a total cumulative follow-up.

Again, the same condition. All animals were analyzed for lymphopoiesis,
and in this case it is written hematopoietic and it should be
lymphoiesis and no abnormality was observed.

So no other toxic events related to the gene transfer procedure of the
transgene expression or differences in the ability to induce donor
chimerism associated with graft versus host disease were observed with
this transduction system in T-cells in 356 mice, 200 rats, and 3 dogs.

So, let\'s try to again accumulate everything. Studies supporting the
safety of gene marking with a delta-LNGFR, a total of 905 animals, 7,169
10 to the 6th for the number of transduced positive cells, and the
accumulative follow-up in weeks is 12,000 or so weeks.

And the number of animals that were followed for over 20 weeks is 151;
and for over 28 weeks, 74. In every single animal, whether an
hematopoietic stem cell was transduced for marking, or lymphocytes were
transduced for the graft versus leukemia approach, the hematopoiesis and
leukopheresis was normal.

The analysis of 93 independent studies of human T-cells revealed no
change in the expression of markers of lineage activation of additional
proliferative capacity.

The analysis of 102 independent consecutive transduction of human
T-cells with two different vectors, and a variation of the same
construct, revealed that all the cells remained strictly dependent on
IL-2 for growth and survival.

These are the clinical data. Twenty-three patients treated with HLA
identical sibling, so this is the graft versus leukemia, these are
lymphocytes only. Eight are identical family donors, and these are the
total number of cells that have been injected, again you see here that
we are in the 10th to the 9th range, 105 times 10 to the 9, and the dose
here is lower obviously because the risk of graft-versus-host disease is
much higher for this kind of transplant.

Survival of cells in patient months calculation. The longest survival of
the cells, the peak frequency that you see is significant for the
immediately post-transplantation period. And here are the cumulative
numbers.

Again, in the clinical study, not a single adverse toxic event, acute
and chronic related to the gene transfer procedure, or through transgene
expression that was observed during this trial, which involved the
infusion of more than a hundred-million cells generated by more than 15
independent in vitro transductions.

What do these data suggest? The data are available to suggest that PBL
gene therapy does not carry an increased risk of tumor transformation.

Of course, these are done, these studies are done with a limited number
of transgenes, and we were discussing the issue of gamma-chain before,
but this could be true for any gene.

Here I am arguing on the issue of insertion on mutagenesis if you can
call it this way. So in that regard, for the ADA gene, the TK gene, and
the truncated form of the LNGFR apparently there is no reason today to
say we should limit the total dose of lymphocytes.

The available data on hematopoietic stem cell gene therapy for
ADA-deficient SCID do not show an expansion of dangerous clonal
integration. We have monitored the change over time there is no
expansion.

We are sequencing, and we have not found anything. The analysis will
continue. The analysis will continue in my mind doesn\'t mean that this
is really useful. I am just giving you my opinion. We are doing it.

And whether or not we will get out anything I don\'t know, but I think
that some of the groups that have the possibility because of the size of
the study of the patient should do it, but whether this should really be
mandatory for each study at this stage for the data that we have in hand
I am not really sure.

But of course I am in a different position related to the one of this
committee. Instead of transgene-specific risk, the discussion that has
already started, it is not my position to fuel the discussion also
because as the Chairman already said, this is fueling it enough.

How extensive should be the monitoring of the integration sites, I
don\'t know. We will definitely go on to analyze the different
technology, probably a few thousand sites, and hopefully it will make
for a nice paper, but if it will make for anything more, I don\'t know.
Thank you very much.

(Applause.)

CHAIRMAN SALOMON: We will return to this for questions, Claudio, after
Dr. Thrasher has given his presentation. So the second speaker is Dr.
Adrian Thrasher, from the Center for Gene Therapy and Childhood Diseases
in the U.K. Is it the Imperial Cancer Centre in London?

DR. THRASHER: I am actually an immunologist at the Greater Ormond Street
Hospital in London. We have one of the biggest immune deficiency
services in Europe.

Okay. So we have several Phase-I clinical gene therapy trials which were
open and I am going to talk to you today a little bit about our X-SCID
study. Marina actually introduced X-SCID and has given you most of the
background excellently earlier, and so I can be relatively brief.

I will say that the other two studies that we have is for X-linked
chronic granulomatous disease, and in this study we have treated one
patient, and the ADA study is approved by our G-type, but we have not
treated any patients yet in that study.

I just want to reinforce what Marina first said and Claudio said with
the importance of reference points, because when we are trying to devise
a new therapy, we need to compare that with the existing therapies.

Now, the European study has been extensively collected since 1968 and
has been recently published in [The Lancet]{.underline} as Claudio has
said, and I just want to show you a couple of slides. The first one is
the probability of survival after a mismatched transplant in SCID
patients according to conditioning regime.

And many of you will know that the preference treatment of SCID in
Europe and in most centers in the U.S., I believe, is to use
conditioning in the mismatch setting. And since 1968 in the transplants
the survival rate has been measured at about 50 percent.

Now, of course, we have gotten a lot better at transplanting these
patients, and this is not accurate data for today\'s transplants. Now,
we can also break down these transplants into subcategories of SCID, and
we can definitely say that the outcome for the positive forms of SCID,
such as JAK-3 deficiency or gamma-c SCID, is a lot better than, for
example, ADA-SCID.

And currently as I said the survival rate across Europe and in our
center for mismatched transplanting ADA SCID remains at about 30 center
at one year. So it is very poor.

So this slide Marina showed earlier, and this indicates the improval in
outcome for transplants in SCID and B-positive SCID for mismatched
grafting.

And we counsel our patients now about an 80 percent one-year survival
rate. Now, this does not take into account the patients who don\'t make
it through the transplant center. We know that several of those or many
of those occurring over time.

The other thing that we have to remember is that to achieve efficient or
improve the B cell engraftment and T-cell engraftment that we certainly
believe in Europe that you need to use some form of preferative
chemotherapy.

And when you are considering risks and benefits, you have to build in
the effects of the chemotherapy into the equation, and there are
certainly long term effects related to chemotherapy employed in infancy,
and the chemotherapy usually or has been until very recently been using
alkylating agents, such a busulfan.

And there are clear effects documented on growth, fertility, possible
developments of secondary malignancies later in life, and also
neuropsychological effects, which may in-part at least be related to the
use of chemotherapy.

And, of course, in many of these cases there is incomplete immunity
reconstitution. And I would just show this, because I think this is a
graphic example of how brutal using chemotherapy is in children, and so
these are dental x-rays of a normal seven year old, and a seven year old
treated in infancy for SCID by condition transplants.

And the normal seven year old is showing secondary teeth, and this child
has no secondary teeth. Now, for a seven year old child, this is a big
deal both very psychologically and physically, and we see dental
abnormalities in most of our conditioned transplants.

So really these are the drivers to try and develop less toxic both in
the short term, and in the long term treatments, and more effective
treatments in terms of immuno-reconstitution.

Now, Marina set the case for this type of study and our gene therapy
study for X-SCID is very, very similar to the study conducted in Paris.
So what I will do is highlight some differences.

The entry criteria are the same and so there is no matched sibling
donor. The vector we use is also an MFG based vector, and it doesn\'t
have the BT mutation, and whether that is relevant or not I doubt.

There is a single gamma change, cDNA, and so this is virtually identical
to the vector used in the Paris study. One significant difference
perhaps is that all vectors are produced in PG13 cells, and so it has a
different envelope. It has the gibbon ape leukemia virus envelope.

The transduction cycle is the same, and we started them on Monday
morning and we finished on Friday evening when the cells are reinfused
back into the patients.

The CD34 positive cells are purified by the CliniMACS system, so it is
magnetic bead selection system. The cells are preactivated for 40 hours
in the presence of high dose cytokines, stem cell factor, FLT-3 ligands,
thrombopoietin, and a slightly lower dose of IL-3 than used in the Paris
study.

And another difference is that we actually use serum-free conditions to
culture our cells, as opposed to using some fetal calf serum. So there
are three cycles of transduction over three days on Retronectin-coated
surfaces. So this is in a closed system, and the back to the bag type
system, which many of you would be familiar with.

And as I said, these cells are reinfused without any preconditioning for
the patients. So the only procedure that the patient goes through is a
bone marrow harvest, where we take probably around a hundred mls of bone
marrow under general anesthetic for about an hour.

And so these are the details of the patients who we treated to date, and
as I said, a follow-up is \-- the maximum follow-up is 18 months for
Patient 1, and they all present with classical features of SCID.

The age at therapy is 10 months, and 10 months, and 4 months, which is
our youngest patients, and this patient was diagnosed early because of a
previously affected family member.

And then the final two patients are slightly atypical, and this is a 20
year old patient with a failed graft, and this is a patient who has an
unconditioned haploidentical transplant in infancy, and who has had
waning immunological function, and consequently has developed end-organ
damage in the form of bronchiectasis, liver disease, and gut disease.

And the fifth patient is a rather unusual patient, also from Denmark,
who has classical SCID and expresses no gamma-chain, and presented with
PCP at the age of 10 to 12 months, but survived at home with
prophylactic antibiotics and immunoglobin cover until the age three
years, and at the time of treatment he in fact was completely well and
free from infections, and that is unusual.

So this is total cells infused times 10 to the 6th, and 180 million, 180
million, 78 million, 150 million, and 115 million. This is our
transduction procedure, and you look at CD34 along here, and gamma-chain
here, and we start off with virtually pure CD34 populations, and through
the week we lose CD34 positivity on our cells, which is a side effect if
you like of the culture conditions that we are using.

And so at the end of the culture we would say that approximately 60
percent of our cells are transduced for gamma-chain, and that 30 percent
of the population retains CD34 positivity.

This is the data on the first three patients, and I will show you a bit
more on Patient 1 because this is the longest follow-up. The first thing
that we noticed, and the same as in the Paris study, is that we see many
NK cells emerging very consistently between or after four weeks of
infusion of cells.

And these rise and then tend to fall a little bit, and then stabilize at
or just below the normal range for an age match control. At 10 to 12
weeks, we begin to see new lymphocytes appearing, and these gradually
rise over time, and then stabilize, and at 18 months in Patient 1, we
see normal numbers of lymphocytes, normal CD34 and CD8 ratios and
slightly low numbers of NK cells.

Patient 3 is a Saudi patient, and again the follow-up is shorter on him,
and he is in Saudi at the moment, and from the information that we have
his immune reconstitution continues to be very good.

Patient 2 had an arrest of immune reconstitution of about 12 weeks. Now,
this coincided with the time when he developed severe gastrointestinal
bleeding, and we believe that this is a consequence of immune
reconstitution. It is not a side effect of gene therapy, per se.

He then underwent radical surgery to remove part of his bowel, and
developed nutritional problems afterwards, and so we believe that these
factors in combination caused this delay or this plateau of immune
reconstitution.

Now, around about here we managed to correct his nutritional problems,
and we corrected the stoma that was produced at the time of surgery
here, and so his gut was linked back up again.

And his immune reconstitution appears to be running back on track. So I
think that is interesting, because it may be saying that at this point
in time that we are reconstituting his T-cells from cells that have been
engrafted in the bone marrow, rather than cells that are in the initial
graft going into the patients, but that is speculation at this point.

And this is an interesting point. This is Patient 3, and at the time of
T-cell emergence, he also developed this rash on his hands and feet, and
in fact all over his body, and which really is indistinguishable from a
mild cutaneous graft versus host disease. Now, this responded very well
to topical steroids, and has not reoccurred subsequently.

Now, this is Patient 1, and this just shows you in a different way the
emergence of naive T-cells, and so if we look at CD27 and CD45RO, and
the 27 positive RO population are naive cells, and so you begin to see
them at 10 weeks, and these gradually increase in number over time here.

And we know that if we take these cells out and we stimulate them with
mitogens, or antibodies to CD03, that they will proliferate entirely
normally.

We can also use the V-D-J recombination process to measure the diversity
of the immune reconstitution as you see earlier, and so both by
immunofluorescence studies we can show that the TCRVbeta families are
represented entirely normally, and with a normal distribution.

And we can also measure by a spectral-type analysis by that diversity of
CD03 links, and so again this is in Patient 1, and look at the total
peripheral blood mononuclear cells between weeks 12 and 16, and you can
see that this is week 12 and this is week 16, and you can see at the
beginning that there is an oligoclonal pattern, and this is very
typical, whether it be in the gene therapy setting or in the transplant
setting.

The reconstitution is always oligoclonal to start with, and in fact some
of these clones you can see from quite a distance after or for quite a
time after engraftment, and they do persist.

But because there is a clone there doesn\'t mean that it is a
pathological thing. So by week 16, you can see some normalization of
these distributions, and then by week 24, when he has enough cells, you
can separate the CD34s and CD8s, and see again a highly complex Gaussian
distribution in those representative families. And again at week 52, the
same.

So this is the follow-up on these patients, and the first patient was
followed up at 18 months, 13 months, and 9 months, 6 months, and 2
months. The first three patients are alive and well, and at home, and
this patient is off all therapy and off antibiotics and immunoglobulin.

The third patient is about to discontinue the immunoglobulin therapy and
has normal levels of IgA and M. And Patient 3 at the moment remains on
immunoglobulin therapy and prophylactic antibodies, but again is well
and thriving.

Patient 4, which is the 20 year old patient, we can see no evidence for
change in his immunological function or diversity by an immunoscope or
spectral-type analysis, although we do see a positive signal for
transgene CD34 positive cells.

And again Patient 5 is a three year old patient that was treated just
before Christmas, and the follow-up is 2 months, and he has NK cells,
and he also has small numbers, just detectable now of naive T cells, and
he remains alive and well at home.

The copy number in our cells is very similar to that seen in Marina\'s
study. We have seen approximately one transgene copy number per T-cell,
and we also see markings of B cells between 1 and 5 percent, and in
myeloid cells between .1 and 1 percent.

This is a LAM-PCR analysis, which we are all familiar with, and this was
very kindly done for us by Christof von Kalle, and Manfred Schmidt, and
again you see a very familiar pattern in these two patients of
polyclonal smears in the CD3 populations in these two patients.

We were also interested in perhaps more bands, more polyclonality in the
B cell lineage, and monocyte and granulocyte image than seen in the
Paris study, and that may be a reflection of the different envelope that
we have used for this study.

And we believe that also may be important for the robustness of the
immune reconstitution, because if you can keep applying gamma-c
transduced cells that contribute to the thymopoiesis, then the longevity
of reconstitution may be more robust.

Okay. So the monitoring that we are undergoing or undertaking at the
moment is conventional, in terms of spectral-type analysis. Obviously
lymphocyte counts and mitogen responses.

Christof was very kind to do the integration profiles for us. We have
performed RT-PCR for LMO-2, and have found in sorted T-cell populations,
and have found low levels of LMO-2 transcription in some of the
patients, but then we have also seen low levels of LMO-2 transcription
in some of our normal controls.

So I am not sure that is a useful test to do, except that if you can
clearly see hyperexpression of LMO-2, and then it may be useful. We are
performing microarray analysis on all sorts of populations at the moment
to look at global gene expression of cells, but I don\'t have any data
on that.

And finally we have also looked for the presence of VL-30 sequences in
our patients, and I can say that in one of the patients by PCR we can
see the very low level in CD-3 cells. But it has been under textbook in
4 out of the 5 patients.

So as you know, our current trial status, which is this is a restriction
imposed by our GTAC and our Medicines Control Agency, is that the X-SCID
study at least is reviewed on a case by case basis. Okay. I will stop
there and take any questions that are necessary. Thank you.

(Applause.)

CHAIRMAN SALOMON: Thank you very much, Adrian. If I can have Claudio
join you, then what I would like to do is turn these two speakers to the
questions.

To start, I wanted to make sure that I was really clear on how exactly
similar, Adrian, your studies in the X-SCID children were to Marina\'s
studies at the Hospital Necker.

So I guess the key question, and you didn\'t give us kilograms of the
children, but I was trying to figure out that even if they were 10 kilos
or more, they were getting more like 10 to \-- somewhere around 10
million per kilo.

DR. THRASHER: Yes.

CHAIRMAN SALOMON: So, the number one question was can you give us some
range of CD34 cells per kilo. The preconditioning, there was no
preconditioning in your studies. And I apologize to Marina, because I
don\'t remember whether there was any preconditioning in yours?

DR. CAVAZZANA-CALVO: No.

CHAIRMAN SALOMON: So that was similar.

DR. CAVAZZANA-CALVO: Yes, it was identical.

CHAIRMAN SALOMON: Identical. Anyway, if you can help me with any other
\--

DR. THRASHER: So the differences are our vector is serotyped with the
gibbon ape leukemia virus envelope, okay? One difference. And the second
difference, which may or may not be important, is that we don\'t use
fetal calf serum in our culture process, and that may alter the
distributions. So we don\'t know.

I mean, we have no data on that. And the expansion of total cells we see
is probably a little bit less than what Marina sees. We see about a 4 to
5-fold expansion in total cell number, but we also see a big loss in
CD34 positivity.

So our expansion in CD34 positive cells is probably only two-fold or
three-fold maybe, or something like that. I can\'t actually give you the
exact numbers as I don\'t happen to have them.

CHAIRMAN SALOMON: Yes. If you will just forgive the Chair\'s prerogative
for a moment. I just wanted to track that down, and so the one thing is
that when you \-- you got a 60 percent transduction if I remember right,
but about 10 percent of the cells were CD34 at the end of the \--

DR. THRASHER: No, 30 percent.

CHAIRMAN SALOMON: Thirty percent. Okay. Marina, can you \--

DR. CAVAZZANA-CALVO: Similar. With the total cells transduced.

CHAIRMAN SALOMON: Just so it is on the transcribed record, if you could
come to the mike.

DR. CAVAZZANA-CALVO: In terms of the total number of transduced cells, I
think Adrian is highest than me, because he mentioned 60 percent of the
total cells transduced, and we never reached this level. It is around 40
percent for us.

And in terms of CD34, that positive cell for the gamma-chain is the
same, around 30 percent from 25, up to 40 percent. This is the range
limit we had.

CHAIRMAN SALOMON: So you gave 40 million \-- 40 to 44 million in the two
patients, and CD34 cells per kilo.

DR. CAVAZZANA-CALVO: No. For P4/P5, the question is related to the two
severe adverse events, they received, at maximum, 20 million per
kilogram of CD34 positive cells, gamma-c positive.

CHAIRMAN SALOMON: Okay. Right. About 50 percent of the total, they got.
Okay. Now, that was CD34 \--

DR. CAVAZZANA-CALVO: Positive.

CHAIRMAN SALOMON: \-- positive. So that would be 30 percent of what you
infused, right?

DR. THRASHER: Right. Well, before finding those, we would have to sit
down and do it accurately.

DR. MULLIGAN: Can I make a suggestion? This is going to haunt us unless
we \-- are we always going to do per kilogram, total cells CD-34? I
think the simplest thing is the total number of cells that you put in a
patient.

DR. THRASHER: Yes, I agree.

DR. MULLIGAN: Okay. So what is the difference between that? Which is
going to be comparable.

DR. THRASHER: Yes.

CHAIRMAN SALOMON: That\'s fine, and thank you for that. So how many \--

DR. THRASHER: Well, that is the total number of cells that we are
putting into the patient is between 80 and 200 million.

DR. MULLIGAN: And how many per kilo?

DR. THRASHER: No, no, that is total cells.

DR. CAVAZZANA-CALVO: Yes, if you can permit a comment. In terms of a
bone marrow transplantation, the cells given to the cell must be
expressed per kilogram and not in total number, and there is no sense,
because all comparison with the hematopoietic stem transplantation is
based on the kilogram basis.

DR. THRASHER: Yes, I would agree with that, but I think that in terms of
measuring or trying to determine the number of integration events you
are putting into the cell, I should change that slide to put in the
total number of cells, okay?

The other thing that I think you may want to consider, I know you were
talking about cord blood earlier, is that the CD34 positive cells you
are putting into the patient here are different than the CD34 positive
cells you get out from fresh cord blood.

So that way you can directly compare your numbers if it comes to that.

CHAIRMAN SALOMON: Right. Now, just one last question. So this is to
Claudio. So when you did the ADA-SCID children, how many \-- can you
give us a sense of how many transduced hematopoietic stem cells you were
putting in?

DR. BORDIGNON: It is about one log less, and the reason \-- and also
there is a significant range, from 0.9 to 20 or 15, and so even inside
the study there is some difference. The reason for that is \-- and in
that regard ADA is different and would probably not be so informative.

So depending upon the level of toxicity that the patient gets there, you
get or you don\'t get any expansion of the CD34. You start with the cell
dose, and you finish with the same cell dose.

You don\'t get any expansion, and sometimes even the harvest of the CD34
is worse. One of the patients, the patient from 0.9 dose, was actually
going through some myelotoxicity due to a previous viral infection.

So I think ADA is a very different story in this regard, and it would be
difficult to compare, except for what is concerning the total dose of
transduced cells, because that would give you an indication of the
transduction events in vivo, and therefore, a comparison on whether or
not that carrier is associated.

But this study is definitely at the low range compared to the X-linked
studies.

CHAIRMAN SALOMON: Okay. John.

DR. COFFIN: Okay. For the sake of the back of the envelope calculations,
which is by far the best we could possibly hope to achieve here, could
we agree that the total number of transduced cells was somewhere \-- and
in the case of the X-linked SCID, was somewhere up to around 10 to the
8th per patient in total dose of integration events in these cells, and
probably that level, and down to about 10-fold less, in that range.

Would that be sort of a fair range that we are thinking of? And that the
two patients with the adverse outcomes were the two that were at the
high end of that range. And I am not talking about per kilogram.

(Discussion off the record.)

DR. COFFIN: Well, they were still at the 10 to the 8th range.

DR. CAVAZZANA-CALVO: Yes.

CHAIRMAN SALOMON: Just as \-- just a minute, John.

DR. BORDIGNON: I think \--

CHAIRMAN SALOMON: One of the things that you have to do here is keep the
comments on the mic, which is hard. I screwed up earlier on that, and so
if you have a comment, I will do my best to recognize everybody, but you
have to be on the mic, or otherwise the transcript will have holes in it
and it won\'t work. I\'m sorry.

DR. BORDIGNON: I think the three of us can sit down and give you a table
and exact the numbers, per kilos, per total, and everything else,
probably in 10 minutes.

DR. COFFIN: I think that would be great.

CHAIRMAN SALOMON: Then what I would like to do is to continue the
discussions, and move towards when the first wave of the discussion is
over, take a 10 minute break, and then let them do that, because I think
that is really important to me, and I am getting some nods. Is that a
good idea?

Because I am trying to square all these numbers and am having trouble
with it, and so let\'s continue with the discussion that doesn\'t
involve the numbers.

If there is any question that someone has about the numbers, they will
hold it until we move up to a 10 minute break, okay? Mahendra and then
Rich.

DR. RAO: Well, this is sort of a general question to anybody who can
answer it, but it seemed to me that when everybody talked about having
no adverse events, the time period was too short given what was
reported.

So that if you had reported at that time on that study, you would have
also said that there were no adverse events. Is that a fair statement?

DR. BORDIGNON: Definitely not for the ADA. I may have confused you
there. The initial study, the first bone marrow studies, were done in
1992. So this is true. However, if you look \--

DR. RAO: For the stem cells?

DR. BORDIGNON: Well, that was bone marrow stem cells transduction. It is
true if you compare similar studies, and so if you compare the last
study for CD34 purified, with the same cytokine combination. So the
study that is comparative, and the ADA that is comparable to the gamma
chain, then we are in that range.

With one relevant difference, I believe, that having looked at the
analysis of clonal expansion, I think that at least the first two
patients would have been already informative.

CHAIRMAN SALOMON: Let\'s do this. Richard, Barbara, Crystal, and Tom.

DR. MULLIGAN: Well, just on Mahendra\'s point, I want to echo that I
think that this is key. I think when we go off and do our calculations
that we should also do a calculation just on simply how many, what
number of patients does Claudio have that are on the 3 year period.

Let\'s just say that is some magic period, and how many patients are in
your collection of patients that have actually gone past 3 years and
have had some demonstrable gene transfer.

CHAIRMAN SALOMON: We will put you on the numbers subcommittee.

DR. MULLIGAN: I am not finished, and so the second thing is comparison
of Adrian\'s protocol with Marina\'s. During the in vitro
pre-stimulation cocktail period, what was the total of A of growth of
your cells in culture, versus \-- and were they comparable factors? It
looks like they were comparable factors, except you had calf serum I
think, she didn\'t have calf serum.

Because I think that an issue \-- if one hypothesis is that there is
some abnormal target cell that is diseased specifically, then those in
vitro culture conditions could be very important.

For instance, you may have differentiated out the cells that otherwise
could be dangerous cells if they were preserved in the culture. So it
would be very important to see if they are comparable.

DR. THRASHER: Yes, I would agree with that. We don\'t use fetal calf
serum, fetal calf serum is not popular in the U.K. for various reasons.
But I think that is probably the only significant difference in the
culture conditions; that we are serum free.

And I agree with you. I think that made a big difference in the types of
cells proliferating, or maybe different regions of the chromosomes that
are susceptible to integration, but we have no data on that.

And we do plan to compare very closely the two transduction protocols to
see if there are significant differences.

CHAIRMAN SALOMON: Barbara.

MS. BALLARD: Yes. My question is very \-- actually kind of an extension
of his, but you talked about a different vector envelope.

DR. BORDIGNON: I\'m sorry, it may not even matter, but I didn\'t answer
Rich\'s question. Did you ask how many patients were over the years \--

CHAIRMAN SALOMON: Yes, but we will get to that in the 10 minute break.
Sorry.

DR. BORDIGNON: Okay.

MS. BALLARD: Somewhat an extension of his, in that you mentioned a
different vector envelope was used in your study from the Paris study,
and I was curious if there is any way to know how much difference that
made in how the insertions occurred?

DR. THRASHER: Well, Christof may want to comment on this, but just
looking superficially at the LAM-PCR data, the number of integrations in
CD3 are probably similar, but I have not looked at the comparative data.
I mean, I think Christof should maybe comment on that.

DR. Von KALLE: The thing that we think is a little different

CHAIRMAN SALOMON: I\'m sorry, but this is Christof von Kalle.

DR. VON KALLE: I\'m sorry. The thing that may be a little different
between the Paris and the London trial is that the amount of insertion
sites we tend to find per given number of myeloid cells is higher in the
trial from London.

I don\'t think that we can say anything firm about the number of
insertion T-cells.

CHAIRMAN SALOMON: Let me just try to clarify. You kind of trailed off.
It is higher in the French trial, or higher in the British trial?

DR. VON KALLE: In the British trial. The number of integrations as
defined per nanogram DNA of myeloid cells seems to be higher in the
British trial.

CHAIRMAN SALOMON: Is it still an average of one copy per cell?

DR. VON KALLE: Oh, yes. Oh, yes. Well, actually in myeloid cells it is a
lot lower on average than one copy per cell.

DR. MULLIGAN: Can I just address her question technically? The GALV
versus the ampho, shouldn\'t infect the types of integrations that
occur, I think you might have been asking would it go into different
locations, and there is no sense that would occur.

But in fact the kinds of cells that could be infected could be
different. And so there was a weird target cell population and it might
be more infectable by ampho than by GALV, or less infectable?

CHAIRMAN SALOMON: And remember that by the premise that we have on the
table here, which we will get to later, if integration is not completely
random, or if integration is affected by which genes\' chromatins are
open at a given time, then the possibility that different packaging
envelopes would target different populations of cells could also affect
the spectrum of the genes that might see the integration event.

And so it is not totally \-- it is an interesting question, but I don\'t
have any answers for you. Crystal, and then Tom.

DR. MACKALL: The first question is for Dr. Bordignon. It would seem that
the combination of LMO-2 integration or around there, and gamma-c is a
bad combo. I mean, a very simplistic interpretation. And you have listed
for us thousands of integration events that have been accomplished in
mouse and human models without adverse events.

But do you know if any of those were in or around LMO-2?

DR. BORDIGNON: Yes. That is a very good point. We have not found any so
far, and we are trying to do \-- to have a quicker way to answer
specifically only that question, rather than analyzing zillions, how
many go to the LMO-2, and I don\'t have an answer at this stage.

My impression is that from what we have analyzed so far, is that it is
not a hot spot. It is not something that happens because it is more
susceptible in the same transaction conditions, because essentially the
transaction conditions are the same.

So from here down it is all speculation, of course. You can imagine that
it occurs at exactly the same frequency, but it does not pop up, also
that the inverse PCR system is also related to the efficiency.

You know, if you get the right amplfication size and the right primers
and so on, they will come out more frequently. I am convinced that you
will be able to give a definitive answer to this in a matter of probably
a few months, but at this stage it is just my impression.

DR. MACKALL: And I think it is critical with what we are going to be
charged with now to try to decide, which is whether the insertion of
another gene around LMO-2 is going to be just as dangerous, and until we
know whether there is any data to that effect, it is going to be very
hard to know how critical the gamm-c component is here.

The second point, just in terms of distinguishing the British from the
French studies, I still an struck by the post-gene therapy data that
looks different.

In other words, the two patients that got leukemia had this dramatic
immune reconstitution that was at an increased rate, and so that within
a month and in an increased amount.

I mean, they were up to 10,000 T-cells, and I didn\'t see any of your
patients doing that. Is that true?

DR. THRASHER: Yes, that\'s true. I mean, those patients are exceptional,
and in Marina\'s study as well, and they stand out as the patients who
reconstitute the quickest.

DR. MACKALL: It would be certainly nice if we had an earlier marker for
those patients that were going to develop, rather than having to wait 3
years for them, and if you go back and look, in one year they certainly
looked different.

DR. THRASHER: Yes, in hindsight, I think that is true, but as Marina
pointed out, those parameters remain within the normal range for
age-match controls.

DR. MACKALL: We are only setting the normals now and they are standing
out now.

DR. THRASHER: Yes.

DR. MURRAY: This is for Adrian. I noticed that you had quite a broad
range in age of treatment of your patients, and the youngest was 4
months to 2 years.

And I want to focus on in particular the two youngest patients, at four
and 10 months, I believe it was.

DR. THRASHER: Two at 10 months, and one at 4 months.

DR. MURRAY: Okay. There is also the two patients in the French trial
were the two youngest patients also who have the immune response. I
noted or remembered you saying that Patient 3, who is 4 months old at
treatment.

But what I don\'t remember was which patient did have \-- I thought one
patient in one of your graphs did have an earlier immune reconstitution
than the others.

DR. THRASHER: Actually, the scales are different in total number of
lymphocytes, the actual initial reconstitution rates are virtually
identical in all of them.

DR. MURRAY: They are, and so you didn\'t have one with a more
significant response before the 3 month period?

DR. THRASHER: No.

DR. MURRAY: Okay. And which patient was it that had \-- I can\'t
remember the patient number of the one who needed the bowel surgery.

DR. THRASHER: Two.

DR. MURRAY: That was two, and so how long was that patient in treatment?

DR. THRASHER: Ten months.

DR. MURRAY: Thank you.

CHAIRMAN SALOMON: Phil.

DR. NOGUCHI: It is to follow up on some of those questions, and Patient
Number 4, Adrian, was that the patient that appeared to be a very mild
GVHD?

DR. THRASHER: That was Patient 3.

DR. NOGUCHI: I\'m sorry, Patient 3, and that was the youngest patient;
is that correct?

DR. THRASHER: Yes.

DR. NOGUCHI: And do you think that might be any indication that perhaps
the cells that are being transduced might be somewhat different than if
they are transduced at an older age.

DR. THRASHER: It is impossible to say. I mean, the numbers are so small.
GVHD type phenomenon in autologous transplants is well recognized. What
the stimulating antigens are we don\'t know. It could be maternal cells,
and it could be infection on board at the time of the graft. We don\'t
know. We believe that it may be a cytokine-driven, CD4-mediated event.

DR. NOGUCHI: Just a couple of other trivial questions. Do you have any
information yet on this Patient 3, in terms of integrants? I think you
presented, I think, Patients 2 and 5.

DR. THRASHER: They actually all look pretty similar in terms of the
distribution of integration.

DR. NOGUCHI: Okay. And was Patient 3 or which patient \-- how old was
the patient that had this very preliminary evidence of a VL-30 sequence?

DR. THRASHER: How old was he \-- well, 10 months at the time of
treatment.

DR. NOGUCHI: No, you mentioned one of the five had evidence of PCR
positive ?-

DR. THRASHER: Yes, VL-30 sequences. We can detect that in Patient 2 a
year after treatment, and at a very low level, you know, between 1 and a
thousand, and 1 and a hundred T-Cells, compared to one transgene of
T-cells.

DR. NOGUCHI: Thank you.

CHAIRMAN SALOMON: Kathy.

DR. HIGH: I know that Marina is looking at this question, but just to
the group, are there any data that suggest that CD34 positive cells from
infants less than 3 months of age are somehow different from those of
older ones?

CHAIRMAN SALOMON: Marina, you might want \-- I think she is running
away.

DR. CAVAZZANA-CALVO: I think nobody knows, because for a practical
reason none of these can harvest the bone marrow sensor from children
without any diseases. So the studies were conducted on cord blood, but
we don\'t know when there is a switch of proliferation capacity between
cord blood and newborn.

The cord blood proliferates up to 10-fold when you make the same
protocol in the transaction rate and is much higher in bone marrow, and
the 3 months patient who had very similar to cord blood, and 11 months,
and the 8 month patient, are much more similar to bone marrow.

But the figures are so low that you can\'t make a statistical test.

CHAIRMAN SALOMON: And sort of following on that theme, Claudio, you
answered me at one point that the expansion potential, or the expansion
seen in the early activation of your stem cells was one or two using
Marina\'s view.

And your statement to me was, oh, because ADA-SCIDs are very different.
So can we go back to that? A), are you saying that you used the exact
same protocol; and, B), are they really different even if you match for
age?

In other words, is a 4 month old ADA-SCID really acting differently than
a 4 month old gamma-SCID in terms of their proliferation in these ex
vivo things?

DR. BORDIGNON: What I was trying to say that they are less homogeneous
in that regard, and therefore it is much more difficult to extract the
same type of information.

And they tend to be from a metabolic point of view much more prone to
toxicity. Now, the study will probably be different if you would do the
same study in PEG-ADA patients when they are detoxified.

But the plans and protocol is designed for patients who do not have
access to PEG-ADA, and that was what was requested initially, and that
is what we are doing.

So under those conditions, you have patients that have significant
metabolic toxicity, and therefore they proliferate relatively little,
they harvest poorly, you have a low number of cells and low growth.

On the other hand, you have patients that respond absolutely normally,
and they grow 5 to 10 times during that transduction phase as the
patient described by Marina. Maybe a comment from Don Kohn on this.

CHAIRMAN SALOMON: All right. Don.

DR. KOHN: Don Kohn, Children\'s Hospital, Los Angeles. We are doing a
trial for ADA gene therapy with Fabio Candotti, Cynthia Dunbar, and
myself, and we have harvested marrow from four of those patients on
PEG-ADA; a 4 year old, a 5 year old, a 15 year old, and a 20 year old.

It mirrors all the coments that have been made. We get much less cells
as they get older, and they tend to transduce less, and so even by four
years old, you are over the hill to some extent. And I think it is a big
factor that these very young patients just have a lot of cells that
transduce very efficiently.

And the disease setting may also be different in ADA, and we have also
done children with HIV, and get again lower numbers, like 1 to 2 million
per kilo, and not 20 or 30, or 40 per kilo.

CHAIRMAN SALOMON: So I think an interesting thing here is \-- and an
interesting theme here that we could return to later is that assuming
that age is this obviously very powerful biological determinant, there
seems also to be the influence of the diseases, and I thought that
Claudio\'s comments are well taken about the toxicity that occurs from
the primary gene defect in the ADA kids.

So that may be another factor, that if you take that away, you may level
the playing field there to be more of the age. The activation protocols
and the level of activation are felt at this point to be necessary to
get good transduction efficiency.

But in the context of all of the things that we have begun to talk
about, one wonders when we get back to safety whether we should
carefully consider how much activation is necessary in a given protocol
to achieve a reasonable amount of vector integration.

And certainly one could then go from there to argue for less is better
if you can get a sufficient amount of transduction. So, Claudio, lining
that up is, what were your transduction efficiencies despite the fact
that your proliferative activities were significantly less?

DR. BORDIGNON: Between 10 and 40.

CHAIRMAN SALOMON: Joanne.

DR. KURTZBERG: I think it is also important to notice that the ADA kids
are different because if they are detoxified early, they can have their
own host cells proliferate without transfection. So their immune
regulation may really be different of the cells that are transfected.

And so I think they should be evaluated as a completely different
patient subset.

CHAIRMAN SALOMON: I didn\'t mean to imply that these diseases should be
collapsed in any way. I was just trying to talk about the biology of the
stem cells. John.

DR. ALLAN: This is probably a naive question, but in your Patient Number
2, Adrian, that had gastrointestinal problems, it made me start to think
that is it possible that you could actually either constituitively
express genes that are not directed towards uncontrolled growth, but
could actually home to specific tissues.

And so you get \-- you may get some sort of diseases arising because of
the nature of the cells that have been transduced. So did you do a
histopathology on the intestines?

DR. THRASHER: Well, actually, the gastrointestinal problems also
pre-dated the gene therapy. So you had some GI hemorrhages from
macroscopically inflamed lesions prior to the gene therapy.

The histology was pretty unexciting to be honest, and we never found
histological microbiologic reasons for those lesions. But the same
lesions bled after gene therapy.

DR. ALLAN: I just sort of wondered if you may get other types of
diseases besides cancers that you might want to think about. I don\'t
know if that is even a real possibility, but I would like to throw that
around at some point.

CHAIRMAN SALOMON: Ken.

DR. CORNETTA: I am interested to hear what these numbers will be around
CD34, but I just sort of give in prospective that we are talking
probably an order of magnitude more CD34 in these very young children
than we would normally think about per kilogram in adult
transplantation.

But when you then factor in that often adults may be two orders of
magnitude bigger than these children, if we are looking at actual
integration sites, if the Committee is to try to find a number that sort
of sets the bar, I think that is going to be very hard to do.

And I think we are ignoring a lot of the other factors that may be here.
So I just sort of would have the Committee think about as we do this
that this may be a bar that we really are never going to be able to try
to set.

CHAIRMAN SALOMON: Mahendra, and then Dave.

DR. RAO: One thing that I wanted to do was just try and get a general
comment either from the Committee or one of the speakers about this full
integration site issue. I mean, you made the point that perhaps it is
gamma-c, along with LMO-2, which might be the important thing.

Maybe it is not gamma-c at all, because when you look at the
over-expressing mice, you don\'t see that kind of procreative response
at all, and so it is not the gamma-c.

And when you looked at the integration sites in the inverse PCR
experiments, I thought that the number that you saw within genes, you
know within the intronic sound boundaries was significant, as a number
from the total number that you analyzed, a third, and was that not
surprising, or is that not a cause for thinking that you can interrupt
genes or do something?

DR. BORDIGNON: Well, I think that will have to be a bit better defined
than what you mean around genes. We have been choosing some sort of
distance, but whether or not this is meaningful in the sense that the
distances are appropriate, and really results in amplification of the
gene that is upstream or downstream.

It is an additional part of the work that will need to be done.

DR. RAO: If you look at your table to ask if they were in the intron or
exon.

DR. BORDIGNON: No, no, sure. Despite the consideration that it is not
really the siting itself there that would matter, but whether or not it
is affecting the expression of the gene, and where the gene is and so
on.

There is apparently, but I think it is too early to say from this data,
but there are data on the HIV integration that a famous science paper by
Bushman and co-workers that suggests that there is a skewing towards a
transcription active sites for integration, by a factor of two, which is
not much.

And which for this type of concern for this type of study will probably
not matter at all. I think that I will have to wait for a bigger number.

CHAIRMAN SALOMON: David, and then John.

DR. HARLAN: When the numbers committee meets, I would ask that they put
together for us not only total cell number and CD34 positive cell
numbers, because the point that I wish to make is that CD34 is not a
clear binary definition as Adrian, I think, you showed.

You start off with CD34 bright, and then they get dimmer, and dimmer,
and dimmer, and it gets to be an increasingly fuzzy number.

CHAIRMAN SALOMON: John.

DR. COFFIN: I wanted to address two things that came up before, which I
probably forget the second part by the time that I get to it. The first
thing is that there was discussion about setting a bar for numbers and
so on. I don\'t think we will be able to do that.

But I think it should be in our purview to try to do some back of the
envelope calculations to see, sort of, \"what if things.\" And I think
at some time in the future somebody is going to have to sit down and try
to do the best job they can with that in a format design exclusively for
that purpose, which this is not appropriate, and so we might be thinking
about that as we go forward.

The second point regards both the distribution of integration sites and
their relationship with integration sites to turn on a gene expression.
Our analyses have found that integration sites are very, very widely
distributed in cells as far as regions are concerned, with very, very
strong, and very local preferences.

The Rick Bushman paper that was referred to uses a somewhat different
method, but it came to the conclusion that there was a skewing towards
regions that had been identified in genes and in HIV integration in
human cells.

But the scaling was a factor of two, and about a third of the genome by
their definition was genes, and those contained about 60 percent of the
integration event.

So that number is small relative to the other levels of uncertainty that
we are discussing, and that is actually sort of a small error, or a
small correction, if that is the number that holds up.

And finally the experience with MLV systems in particular, and ALV
systems, where lots and lots of integration sites activating genes have
been looked at, has revealed that the rules for whether an integration
site can activate a gene are probably extremely complex, and
case-by-case, because in some cases their integration is more than a
hundred KB away from a gene that are known to activate it.

But that doesn\'t mean that the target for that gene is a hundred KB. It
may well be that anything closer to a hundred KB won\'t work. We just
don\'t know. It all depends on how the chromosomes fall and everything
else.

So we really can\'t know that. We can only make real guesses as to what
in any given case might be the sensitive target region. I usually use
the figure of somewhere between 1 and 10 KB for the sake of the back of
the envelope calculations.

But it is certainly at least 1 KB I would say on average per gene would
be the sort of region that you could imagine the targeting to occur in.

DR. BORDIGNON: Can I ask a question?

CHAIRMAN SALOMON: Right now? Hang on a bit. What I would like to do is
\-- Carolyn, you had a question, and then maybe Don, and then I would
like to go to the break, where we can get some of these numbers, and
then come back if that is okay. And, Claudio, you will be the last
question.

DR. WILSON: This is on a completely different topic, but Dr. Bordignon,
you summarized very quickly for us a vast amount of preclinical data
regarding the use of the LNGFR marker gene, and made a case for the
safety of that gene.

And I wanted to just clarify for my own purposes in contrast to the data
from Christopher Bounds\' group. All of those studies were using
transduced lymphocytes, as opposed to hematopoietic stem cells? Is that
the difference?

DR. BORDIGNON: No, no, I presented \-- I went very fast I realize, and I
probably also made some confusion myself. But there are two sets of
data. The first half was all related to hematopoietic stem cells. The
second half was a lymphocyte study. So the numbers are fairly equal in
the two studies.

DR. WILSON: Thank you.

DR. CORNETTA: Again, maybe something else that people can consider as
people are working through the numbers. I think this insertional
mutagenesis, we sort of fixate on, that these vectors will just go in
and knock out genes.

But I think something that is very telling here is that in all of these
patients there has only been two occurrences, and it is both in the same
locus.

So I think again focusing rather from how many CD34 cells are at risk or
whatever, and also taking into big consideration that presumably some
interaction, whether it is the LPR enhancer or something else that is
really playing a major role here, I think that needs to be considered in
these.

And the second point is I think that not only do we need to think about
how many CD-34 cells have been transduced, but there have been many
other T-cell studies that we have not talked about, and these are mature
T-cells that have been transduced and had many more integrations, if you
tried to put in how many have occurred over these trials that have not
seen this event.

So again I think that this is a pretty complex issue and just to make
sure that we are thinking about all of those.

CHAIRMAN SALOMON: The last question.

DR. BORDIGNON: Yes. There was a very interesting piece of information in
what Christof von Kalle and Marina said about the existence of another
couple of \-- I probably understood another couple of LMO-02 related
integration observed in the analysis.

Do you know anything about whether or not this is affecting the
expression of the LMO-2 in those circumstances? Because probably if
there was an increased expression or not an increased expression, and
will analysis in the other one. I hope that I didn\'t ask the wrong
question.

DR. VON KALLE: No, I think you didn\'t ask the wrong question at all.
One of the clones that we looked at that have occurred in the patients
earlier, and we have tried to track it, and that was the one that was
about 40 KB away, and apparently it has not led to any
lympho-proliferation.

The other one that we are looking at that is closer, we also don\'t have
any evidence yet that is proliferating, but we have not done as much
tracking on this clone.

CHAIRMAN SALOMON: But I think \-- well, maybe I am interpreting, but
what I thought what Claudio was asking you was that in the T-cells
themselves that have that insertion, is there any evidence that they are
expressing an excessive amount of LMO-2 message, for example?

DR. BORDIGNON: We cannot answer that question because if we do not find
it as a clone that we can separate, that is not a question that we can
technically answer at this point.

CHAIRMAN SALOMON: Okay. We can talk about that later. You could get at
it perhaps. I said that was the last one, but Linda had her hand up. So,
I\'m sorry, you will be the last question.

DR. WOLFF: Carolyn brought up about the pre-clinical studies, and I just
wanted to clarify something. I thought I heard you say that the longest
time period was 6 to 8 months, would that be correct for the
pre-clinical studies in mice? What was the longest period of time that
these mice were analyzed or monitored?

DR. BORDIGNON: In essence, the majority of the animals, and there are a
few animals that went to almost through the entire life span, and were
analyzed over 28 weeks. Sorry. Yes, 28 weeks.

And this also includes secondary and tertiary transplants, however, and
so it is probably more than the life span of the animal.

DR. WOLFF: Okay. Thank you.

CHAIRMAN SALOMON: Then I would like to take a 10 minute break. If I can
have Rich, Ken, and Marina. I am deputizing you as the subcommittee
here, and if anyone else really wants to be a part of this, they are
welcome to come up and join us.

(Whereupon, at 12:04 p.m., the meeting was recessed.)

A-F-T-E-R-N-O-O-N S-E-S-S-I-O-N

(12:18 p.m.)

CHAIRMAN SALOMON: Welcome everybody back. What we are going to do is \--
I am going to be the fall guy on this one, but we just are not going to
get to lunch. I can see that. So for the panel, they are going to bring
some cookies, and some drinks and stuff, and I will try and work on
that.

But I apologize, on the other hand, I just think that the time is
constrained, and the topic is so important that I think a couple of
hungry scientists and other advisors is probably a reasonable price to
pay for what we need to get accomplished.

But you can blame me for it. I don\'t know why I am getting blamed for
it, but I suppose that is the true nature of blame.

DR. NOGUCHI: We will support this and say that the FDA actually feels
that lunch is not necessary today.

CHAIRMAN SALOMON: I have worked so hard to get out of the evil empire at
the FDA that you just set it back a couple of years. Anyway, what we are
going to start with is that we had a kind of a little impromptu
subcommittee of numbers, and grappled with the issue of what numbers
could be put together that that had value.

And obviously the speakers didn\'t come here with every detail in their
databases. So, Rich, can you give us just kind of a quick rundown on
this.

DR. MULLIGAN: Yes. The only numbers that we could really get three
different values for were the total and estimate, a real estimate, of
the total number of transduced cells that are put into the patients.

And that appears to be for the Paris and Milan groups of about a
hundred-million. So that is the total numbers, whether they are CD34
plus, or deficient, that are infected.

And it appears that Paris and London were about a hundred, and the Milan
had about a tenth. Okay.

CHAIRMAN SALOMON: And the two children that developed leukemia?

DR. MULLIGAN: Had about two times that.

CHAIRMAN SALOMON: About 200 million?

DR. MULLIGAN: Yes.

CHAIRMAN SALOMON: Okay. So the difficult point \--

DR. MULLIGAN: Two times for one, 1.5 for the second. Okay. So that there
is a 10-fold difference, and one other little discussion that we had was
just that the manipulations of these cells in vitro are such that by
certainly mouse marrow transplantation they can have a major effect on
the reconstitution potential.

And so easily a 10-fold effect. So we are clearly I think where judgment
I think would be by the individual investigator about what kind of
things their protocols will do to take hits on the reconstitution
potential.

DR. JUNGHANS: Just a question on that.

CHAIRMAN SALOMON: Could you give you name.

DR. JUNGHANS: Richard Junghans, Harvard Medical School. One question on
that. Was that compensated for the fact that you infect on maybe day
two, and you expand? In France, they had a 10-fold expansion; whereas,
in the other groups they may have only had a two-fold.

So it is really on the number of integration events prior to expansion
that you want to count?

DR. MULLIGAN: No. This is the literal \-- and this is a rough number,
but this is the literal number of cells that were put back into the
patient that were determined to be transduced.

DR. JUNGHANS: Right, but if there \-- okay. So that is a separate
question, as the number of integration events which may be more
equivalent or the \--

DR. MULLIGAN: Yes, I think what you are getting at is whether or not you
have fewer integration events, but that is going to be too complicated.

DR. JUNGHANS: I can provide a little bit of information on this because
I had \-- no, it is not 10-fold. I had a discussion earlier that the \--
that apparently as they tracked the number of integrants the infection
was ongoing I believe in these protocols through the entire expansion
process.

And it looked like the vast bulk of the integrations occurred in the
last day. So at most I think the correction that you are after is
probably a factor of two, and that is sort of the guesstimate that I put
on that.

Is that there may be half as many unique integrations as total
integrations in the population, because the expansion was ongoing, but
there is only a fairly small number of integration events that occurred
early on, and most of them appeared to have occurred late in the
expansion.

DR. COFFIN: So they are reinfecting on a daily basis through the whole
expansion period?

DR. JUNGHANS: Through the last three days, I believe, the protocol is.
The first two days are getting ready and then the last three days are
infecting all the time.

CHAIRMAN SALOMON: Okay. Thank you to everyone on the subcommittee. So I
guess one of the things that came out of that before we go on was that
there are some \-- let me see how to put this.

So yesterday we spent a lot of time with some really lovely data from
the International Bone Marrow Transplant Registry, and Cord Blood
Registry, and the New York Blood Bank Registry, talking about the
numbers of bone marrow stem cells and peripheral blood stem cells, and
cord blood, umbilical cord blood cells, that were required for
engraftment and doing comparisons.

Today we are talking about a very different kind of situation, and it is
a very interesting highlight, and a challenge I think to the field,
which is what Rich referred to.

And that is that if you take CD34 stem cells that have been in many ways
processed identical to the types of stem cells that I just got through
mentioning, but then put them through these transduction protocols of
activation with a cocktail of hematopoietic activating factors, and
manipulations, such as growing them on fibronectin or rectonectin, which
is a recombinant fibronectin fragment, that the question then becomes
\-- and then there is this range of proliferation, which is a whole
question in and of itself.

And there is a big question as to how much reconstitution potential for
a human patient is left in the context then of how one would calculate
what was an appropriate CD34 dose.

And all I am saying here is that I think it was clear to the
subcommittee in talking about it that we really don\'t have the kinds of
information yet to absolutely understand that.

However, I think that we also felt that based on the preclinical models
that the idea of about a 10-fold loss of reconstituting capability would
be a reasonable estimate.

So that the idea of giving 20 million CD34 per kilo, which is something
that I brought up, or 40 million per kilo, as I brought up in Marina\'s
talk, may not be such an unreasonable guess in this situation.

But it is a really interesting and important topic to get back to in
further investigations. I don\'t know if anyone wants to make any
comment on that, but that kind of came out of our discussions. Rich.

DR. MULLIGAN: And I think that there are many different groups that
think that they are have better or worse protocols along these lines and
there are controversies. So I think it is going to be very, very
difficult to come up with any sort of number.

In the mouse case, where there has been all this pre-clinical
information, there is very, very few, if any, reports where they
directly assess the reconstitution potential in the hit after the
infection.

But there is cytokine cocktails in vitro culture where they assess the
hit, and in the mouse system you can test this by a competitive
repopulation test, which is a really good quantitative test.

But in human, there is a tremendous controversy whether there is any in
vitro assay, any SCID-NOD mouse system that accurately assesses that,
and I am certainly on one end of the controversy thinking that there
definitely isnt \-- that these SCID-NOD systems are not appropriate for
trying to make such an assessment.

CHAIRMAN SALOMON: Ken, do you want to have any additional comment? I
know that you referred to some data that you had.

DR. CORNETTA: I guess I feel like we are getting off-track again with
CD34. I mean, I am sure that you had \-- I was not here yesterday for
the discussion, but I have been involved in bone marrow transplants for
about 15 years, and the regime that you used to prepare the patient and
everybody else is such a big number that I am not sure that is really
relevant to what is going on here.

I think it is not necessarily how many cells you are having. If you
think back to what happens in mice who get below the LTR in a virus,
they get T-cell lymphoma.

When monkeys got exposed to this virus, they got lymphoma, and now we
have patients who have been exposed to this LTR, and for some unique
reason that we have not figured out, they have gotten T-cell leukemia,
too.

It is associated with the same gene in two different patients, and I
think that is where we should be focusing our biology and discussions
about those kinds of issues, rather than how many CD34.

Because the calculations that I made earlier looking at our adult
patients who got a very relatively similar transduction process over
fibronectin probably had very similar numbers of cells transduced.

They didn\'t have this issue, but again they were not genetic disease
patients. They were cancer patients, but they are out now 5-plus years,
and we have not seen this event. So I think we probably need to refocus
what we think is the major problems here.

CHAIRMAN SALOMON: So I am comfortable with that as a statement to end
the discussion on numbers. Is there anyone who \-- Claudio?

DR. BORDIGNON: Yes. I would like very much to support this point on the
basis with two observations. First, as you probably remember, we have
one patient with a relatively low dose who didn\'t engraft, meaning that
there is no marking outside T-cells.

But T-cells are a hundred percent transduced. So we have to keep in mind
that these are very specific biological situations in which the
selective advantage for cells that can grow a bit better to the next
cell, it is enormous.

And it is even probably stronger in the gamma-chain than in the ADA form
because of the mechanism of the selection. So I would like to share with
you a comment that actually came out during the European gene therapy
meeting a few months ago on calculating the total number of the
reconstitution, and the number of events, and so on and so forth.

And one of the speculations that came from the floor was actually that
if you give a relatively low number of cells, but you have a very strong
selective advantage, you are going to fish out and give the maximum
pressure to the cell that has a growth advantage.

So you are actually putting yourself in the situation in which
potentially you are favoring a transformation event. Of course, this is
just a speculation, but in a way I want to agree with Ken. I think that
we have to look at the biology of the system.

Otherwise, we can argue one way or the other, and we really don\'t know.

CHAIRMAN SALOMON: Just to put this in the context, John, the point here
isn\'t to argue about anything. The point is just to have as clear an
idea of the different kinds of facts.

And one fact set here is numbers, okay? And the issue is how many cells
are infusing, and how many cells were transduced, and how you activated
them, and those are very relevant.

Now, I agree that the discussion has to go on now and talk about the
vector, and talk about the gamma chain, and talk about the disease, and
that is where we are going to go.

But just as you say, Claudio, the numbers are there, and you have got to
put them in a context and then set them aside clearly and move on. And I
am okay with doing that, but I want to make sure that it does not keep
coming back in the discussion to haunt it the way that it did for the
first hour. John.

DR. COFFIN: Let me make one hopefully last response to that. You can\'t
select for something that isn\'t there. So in my mind as I think about
this right now, the only way that this problem can be overcome is to try
to arrange things so that that integration is not in the population of
cells that you put in.

And I suspect that I will come down with the idea that only if we can do
that can we \-- if only we can do that can we \-- only if we can come up
with a strategies that have a good chance of doing that can these things
be considered safe enough to go forward with. That is my position right
now and that may change at the end of the day.

CHAIRMAN SALOMON: Well, we will see where we are at the end of the day I
guess that is the point. Okay. Thank you, John. So I would like to go on
to the public hearing part of the morning, which should be brief. But we
have three speakers.

The first is Dr. Donald Kohn. Is Joe Glorioso here as well? No? Okay.
Don is representing the American Society of Gene Therapy, and is going
to present some data that the ASGT came up with.

DR. KOHN: Which hopefully will shed some light, but maybe not. The
American Society of Gene Therapy is a scientific society that was
founded in 1996, and it has over 2,500 active members, 71 percent of
which are in the U.S., and 38 other countries are represented.

And the purpose is to engage exclusively in scientific and educational
activities, including promoting professional and public education in all
areas of gene therapy. Next slide.

And so in response to the news of this second adverse event, we
discussed what our response should be and could we do anything to help.
And before even the second LMO-2 integration site was formed or was
identified, we discussed forming a subcommittee to help inform the
debate on the causes, risks, and solutions to leukemogenesis.

In other words, as it was discussed at the last BRMAC meeting, to help
to find the denominator. What is the \-- what are all the data that
these cases are divided by, and so we developed a plan to collect all
the relevant literature and as much available unpublished data as we
could.

And so we are in the process of accumulating data in three areas; in
gene transfer studies in mice, and especially focusing on immune
deficient mice in gene knockout models; and in large animal studies of
retroviral-mediated gene transfer of hematopoietic stem cells.

And the clinical trials involving human subjects. And our plan then, is
that once this is accumulated to publicly post it at the ASTG website,
www.astg.org. Next slide.

And so a subcommittee was formed with three main groups, as well as some
other people just to give overall guidance. And Michel Sadelain and
David Bodine have gathered a large volume of data on all the relevant
murine studies.

I will just give you in my talk just a little introduction of some of
the findings. Cynthia Dunbar and Hans-Peter Kiem have accumulated as
much of the world\'s information on large animal studies, a group of us
are attempting to collect as much clinical data as possible. Next slide.

And so I just want to tell you a little bit about some of the murine
data, and this is has already been written up by Michel and Dave in a
really scholarly overview of all of the studies that we will post. Next
slide.

And so they focused in six areas looking at studies that have been done
in murine models of SCID, both natural pathogenesis, as well as gene
correction. And looked at marketing studies in murine and hematopoietic
chimera, and in non-lymphoid murine disease models. Looked at questions
of tumorigenesis and transgenic in naturally occurring immune-deficient
mice.

Tony Blau wrote a subsection focusing on what is known in studies
related to efforts to expend stem cells or select them to get at the
issue that Claudio was just addressing.

They have looked at murine models of insertional mutagenesis that lead
to hematologic malignancies and try to ask what can we learn from those
to understand these cases.

And they have looked at the studies where leukemogenesis or
lymphomogenesis have occurred in transgenic mice where either oncogenes
or fusion genes were inserted as transgenes and what do they tell us
about these cases. Next slide.

And just a few of the highlights from the study. This group, including
Fabio Candotti, have identified at least 80 X-SCID mice that have been
transplanted with retroviral-medicated gene transfer, and that have been
published in at least another 53 or more from unpublished series.

And what stands out in all these animals is as you have heard to some
extent from the previous speakers, there were no serious adverse events,
like leukemogenesis. And in their discussion, they talk about the
benefits and limits of this model for predicting the human disease.

Brian Sorrentino reviewed the JAK-3 kinase deficient SCID mouse model,
and in fact reported that there is a high incidence of spontaneous
T-cell leukemia even in untreated or non-vector just transplanted
animals, and the rate did not seem to be increased with retrovirus
vectors.

And in a review of some of the insertional oncogenesis literature, there
is actually LMO-2 is a rare target for insertional leukemogenesis. I
believe they spoke with Dr. Neal Copeland, who has had several hundred
integration sites that have been analyzed, and LMO-2 was seen in only
one of them.

And so again it is a rare target, and I think that may be informative.
Next slide.

The large animal data, there is a large amount of this, and Cindy and
Hans-Peter have again accumulated this data into tabular form, as well
as text that sort of comments on it. Next slide.

And so there have been gene transfer studies done in non-human primates,
dogs, cats, sheep, and pigs, both gene transfer, hematopoietic stem
cells, or lymphocytes, as well as direct vector injection.

And these models I think have great relevance to the human experience,
and their comparable life expectancies unlike the short life span of
mice; similar hematopoietic demands, the reagents are cross-reactive,
and the gene transfer efficiencies are similar to those seen in clinical
trials. Next slide.

And so their method was to, first of all, go through PubMed to identify
and review all the published articles and then to directly query all
investigators known to operate large animal facilities, able to perform
gene transfer and transplantation regarding questions of long term
follow-up in unpublished toxicity that they may have observed.

And then there was a detailed analysis of cohorts that have been
followed the longest times, so multiple animals followed more than one
year, with blood counts, gene transfer levels, LAM-PCR in some of them.

And this is primarily sets of rhesus animals at the NIH, and baboons and
dogs at Seattle. Next slide. And again just a couple of the highlights.

From this they were able to ascertain at least 46 rhesus mecaques, with
a mean follow-up of 3 years after a gene transfer by retroviruses. The
median number of CD34 cells was 82 million, and the animals have all had
normal CBCs and are healthy, except for transplant related
complications.

And the clone number in 20 animals has been a median of 30. That
analysis is still ongoing. At the Hutch in Seattle, 21 baboons have been
followed for a mean of 2.3 years, and receiving a median of 60 million
infused cells, and again these animals have been healthy; as well as
another 12 dogs have been followed for a median of 2 years, receiving
170 million CD34 cells, and again no adverse events have been seen. Next
slide.

From the clinical trials, this is a little more difficult to get the
data, so far we have obtained data on 38 clinical trials in which
hematopoietic cells were targeted, with at least 218 subjects that we
have ascertained existing.

Thirty-one of these were in the U.S. and six were non-U.S., and I
believe that there are more outside the United States that we don\'t
have. Six of these were gene marking studies in the setting of
autologous bone marrow transplant for a variety of malignancies.

And six of these were chemotherapy resistance genes, and again in the
setting of autologous transplants for malignancies. Six of the trials
were for HIV or AIDS, and 17 were in genetic diseases, and eight I guess
were for SCID, and then other genetic diseases. Next slide.

And again just to sort of summarize what has been seen from all of these
studies, there have been no serious adverse events observed related to
the vector other than the two cases in the X-SCID study.

However, there are a number of caveats. Most yielded quite low level of
marking for a short duration, and in many of the oncology patients were
done at an advanced disease stage.

And the one number \-- the one finding that sort of sticks out is what
has been discussed extensively, is that the absolute number of cells
given to the X-SCID patients are within the range given to many adult
patients.

So that if you look at a insertional oncogenesis model, it would not be
consistent with that, but the cells per kilo were higher, which really
suggests that there is something about the biology of these patients\'
marrow that may be a factor. And such as disease status, age, or bone
marrow. Next slide.

And so for the clinical data, most of the relevant published data have
been assembled, and accrual of the unpublished data is somewhat slower
due to one element is that some groups have expressed, IRB concerns
about releasing the data.

So we are asking for a minimum of just of the number of subjects that
were treated, or referral to published abstracts. We need to collate the
data with the non-U.S. data, and we have made contact with the European
Society of Gene Therapy, who are undergoing a similar effort to obtain
this data.

I have spoken with Armand Keating at the International Bone Marrow
Transplant Registry, which I guess you heard about yesterday, and they
have formed a working group to begin prospective collection of data from
clinical trials involving gene transfer to hematopoietic stem cells.

And so hopefully what we have done can be turned over to them to sort of
form a nucleus of this effort to collect these data in a prospective
manner.

And this will be an ongoing effort by ASGT, with a goal of completing it
by our annual meeting in June of 2003, although we hope to have the
material posted on the website within the next few weeks of what we have
so far. Next slide.

And so just one slide of recommendations, and that would be important to
standardize data capture as we try and get data from the different
trials. Different data have been recorded in different studies, and so
not everyone has CD34 cells per kilo, and transduced CD34 cells per
kilo, et cetera.

And the specific questions need to be asked for specific vectors, cell
targets, and routes. And I know that the RAC is developing a database,
and at the present time it does not have this kind of information in it,
and this may be useful to help them formulate their later stages of the
database.

And that finally we would recommend a continued need by the NIH and
other funding agencies to support cores for clinical trial monitoring if
it is now going to be a mandate for the studies, and support will need
to be done for these studies, which are expensive, despite the ease that
they seem to be done by Dr. Von Kalle, and in fact they are a lot of
work.

We need to also support long term observation of experimental animals
for late events, especially large animals. Keeping these animals alive
after the study are very expensive, and so often they are euthanized 6
months to a year after the gene transfer study is complete.

And with the events occurring later, we need to specifically support
that. And we need to support basic science studies to look on the risks
of integrating vectors, and the role played by specific transgene
products, stem cells in different disease states, as well as developing
safer methods, such as non-integrating the persisting vectors, site
specific integration, insulators, suicide genes, et cetera. Thank you.

(Applause.)

CHAIRMAN SALOMON: Thank you, Don. The next speaker in the public record
will be Dr. Rachel Salzman of the Stop Adrenoleukodystrophy Foundation.
Rachel.

DR. SALZMAN: Hi. Good afternoon. I would like to thank everybody for
giving me a couple of minutes here. I just wanted to make a couple of
comments. The first one is adverse events.

Obviously this is what started this whole thing is addressing these
recent serious adverse events, and I just wanted to comment that in the
whole modern history of experimental medicine, we have always
encountered serious adverse events, and over the years there have been
methods developed of analyzing them.

And the reason that I am bringing this up here is because there has been
sort of this chatter in the professional gene therapy community, and in
the research gene therapy community, about concern of maybe the
potential for over-reaction more globally to one particular category of
adverse events.

That has not come out of this committee at all, but I just wanted to
make the committee aware of that. I know that in the history of cancer
that there has always been adverse events, and that led to the
development of the NCI toxicity index, and so there is a paradigm or
methodology for handling that.

Another example is they have been doing some clinical trials with
erythropoietin, and one form was found to be causing aplastic anemia,
which is obviously quite serious.

And so that form of Epo was addressed. However, it didn\'t really have a
significant impact on other Epos or other growth factors. So it didn\'t
really radiate out that widely.

And when we talk about retroviral vector in the way that the questions
were designed by the FDA, retroviral vector is not a generic term. I
mean, it depends on whether there is an LTR, and when you say retroviral
vector, there is many versions of it.

And they don\'t all behave identically at all.

And so I think that also should be remembered. My second area of comment
is on the importance for this committee to devise guidelines or
recommendations for groups that are interested in moving forward.

Fortunately, there is a lot of preclinical work ongoing with many
different groups and institutions around the world, and that is very
positive.

But the only way that all of that preclinical data can be useful to
patients is if it gets translated to a clinical trial. Now, clinical
trials are very expensive, and for rare diseases clinical trials even
become more rare.

I know personally of a case where a group of Canavan\'s patients wanted
to have a gene therapy trial, and I know at least one family had to
remortgage their house to pay for it.

And I don\'t think that is the way that we want to go. That just is not
where we want to be. So it is very important that we have industry
participation and a willingness for them to be part of these types of
efforts, and that also academia gets a perception of support from the
regulatory community.

And when these parties here blanket limiting recommendations or
comments, again not necessarily in this forum, but they come out of
other forums, it has a very chilling effect on them, and makes everybody
want to put on their breaks.

And it stops also some very brilliant and thoughtful investigators from
thinking about moving forward, and investing their time and their brain
power into trying to advance a clinical trial that they might believe
in.

So I would like to respectfully request that the BRMAC issue
recommendations in particular to Item Number 4, which I know is on the
end of the list, and you have time constraints, because we need to think
about these disenfranchised patients that may benefit from these more
novel constructs, these more novel approaches, because they have got
fatal, rare diseases.

And the risk benefit ratio is sort of easy to calculate for them, and
they really need all the help that they can get. And I would like to
hear the Agency be able to promote a climate that industry and academia
will then find encouraging, and they are going to want to participate in
clinical trials, and invest in them moving forward.

No matter what, I think that clinical trials need to be conducted in a
safe and rational fashion, and we have to consider like we are
discussing today what disease we are talking about, the age of the
patients, certain numbers that I am not going to get into; vector
constructs, the transgene product, and risk versus benefit for each
particular disease, and obviously a program or protocol for patient
monitoring.

Nevertheless we really think that future gene therapy clinical trials
should be conducted, and that is a message that we would like to hear,
and we would like to have everybody else hear that also.

Because the bottom reason and the bottom line is that there is a lot of
sick and affected patients out there that are counting on you to make
these opportunities available to them.

And their outlook right now is very, very dismal and poor for many
people. So they are counting on you. I think that is about it, and I
would just like to thank you very much for your time.

(Applause.)

CHAIRMAN SALOMON: The third scheduled speaker is Dr. Richard Junghans
from the Beth Israel Deaconess, Harvard Med School. Dr. Junghans.

DR. JUNGHANS: I will have three minutes of slides and two minutes of
comments. This follows very well upon the prior speaker\'s comments,
where we want to be sure that other areas get represented in a way which
balances their risk, versus the potential benefits.

So today most of the conversations obviously have been about genetic
diseases, and the use of stem cells. There is a large group of
investigators now who are going into the cancer area, and using mature
T-cells as targets for modification in directing the immune system
against T-cells.

This is one protocol which I just want to briefly give you an overview
about, and then some comments that I would just like to follow up with.
We chose as an antigen for targeting the CEA antigen, which is on colon
and rectal cancers, as well as breast and lung cancers, and you can see
here a high expression in tumor versus low expression in normal colonic
epithelium.

And so to target this our approach is that we take an antibody directed
against the CEA antigen, and graft it on to the zeta-chain of the T-cell
receptor, and we use the MFG retrovirus kindly provided by Dr. Mulligan,
to package this product, and then express it in patient T-cells.

So the idea here is that we have a patient with a tumor, who takes their
T-cells out, or the normal TCR repertoire, and we do ex vivo gene
therapy, and modify as many as 10 to the 9th T-cells, and expanding them
up to the 10 to the 11th cells, and infusing them into the patient.

And then hopefully the tumor is targeted and eliminated. In our first
generation product we ran a Phase I study and this represents a patient
who had metastatic rectal cancer, with mets to liver, lung, and a large
pre-sacral mass was extremely painful, and his serum CEA was rising from
800 to 1,300 over the time that we prepared his cells prior to infusion.
Normally it is below five.

And at the time that we infused these T-cells, he was bedridden on
narcotics, and nausea and vomiting, and very bad protoplasm. A week
later after T-cells were infused, his CEA dropped by 50 percent, and he
was up and ambulatory, and pain free, and off of narcotics.

And for a period of about a month he had an improved performance status.
His life was better, but this highlights the potential of this approach,
but also a limitation of it. That it was time limited in efficacy,
whereas, a good immune response, which we use every day in fighting
viral infections, will persist and amplify in accord with the threat.

So we had here this chimeric immunoglobulin TCR cell receptor delivering
signal one to the modified T-cell through antigen recognition on a tumor
cell.

We knew that this led to the activation of cell death in the absence of
signaling the CD28 molecule, and this is a stimulation and
post-stimulation.

And what we did is that we have since prepared a molecule which
incorporates CD28 and the T-cell receptor into one molecule so an
antigen is recognized. We get signal one and two, and we have shown that
this leads to actual T-cell proliferation in contact with tumor cells,
as opposed to activation and new cell death.

And this is what we want to be in a complete immune response in vivo
against a tumor, and that is done by taking this molecule and inserting
CD28 signaling domains here.

In an animal model, we are looking at tumor growth here with a CEA
positive tumor in mice for a certain number of days after tumor
injection. We inject T-cells, which are either untransduced are first
generation without the signal two, and then a tandem, which is signal
one plus signal two.

The untransduced T-cells have no effect on tumor growth, the first
generation slows the tumor, but the they all grow; whereas, we have no
tumor growth whatsoever in the second generation designer T-cell treated
animals.

CHAIRMAN SALOMON: You\'re getting pretty close to the end of your three
minutes of slides.

DR. JUNGHANS: Yes, this is it. Okay. So in an established model, we have
CEA negative and CEA positive tumors. And you can see after 10 days in
the untransduced T-cells they grow.

And 10 days with the \-- you get a partial remission with tandem
T-cells, whereas, a CEA negative tumor continues \-- is growing, and in
other mice, they did not have the CEA negative tumor, and at 70 days,
you can have complete tumor elimination.

So that is the end of the slides, and we now have a Phase I study set up
for doing second generation designer T-cells in colon and rectal cancer
with possible extensions of applications.

This will be the vector that will be produced by Ken Cornetta at the
National Gene Vector Lab. So three points I want to make. One is that we
are working with mature T-cells.

We have heard from prior speakers that there is a reason to believe that
these mature T-cells could be at less risk for leading to leukemia when
these are transformed.

We don\'t know that for sure. We need more data. But at least there is a
reason to believe that. Also, these T-cells do not survive, except if
you maintain IL-2 present in the patient, and if you don\'t, the T-cells
die off within a week.

So that gives us a little bit of a safety margin. The second point is
extremely important. There are no instances in which a metastatic rectal
or colon cancer, or breast cancer patient, has been cured. They all die,
100 percent.

They may die in 3 months, and they may die in a year, or even 2 years,
but they will all die. This is a group of people who are highly
motivated to participate in some kind of rationally designed study.

And the final point, which is almost the important one, is that we
don\'t want to be \-- echoing the prior speaker\'s comments. It would be
a misfortune if we were so to regulate this area as to prevent these
patients from having the right to decide, as you said to disenfranchise
them.

In other words, these are adult patients, and they are fully competent.
We can even tell them that there is a 20 percent chance that you will
get leukemia in 3 years.

These patients aren\'t going to live that long, and if they were, they
would be willing to take that chance. And that is all that I have to
say. Thank you.

(Applause.)

CHAIRMAN SALOMON: The fourth speaker scheduled for the public session is
Mr. Paul Gelsinger. Paul.

MR. GELSINGER: Thank you, Dr. Salomon. I am here representing CIRCARE,
Citizens for Responsible Care in Research; and my son, Jesse Gelsinger.
CIRCARE is about accountability in research.

In that regard, I would like to compliment the FDA and all the
scientists here from all around the world working together to try to
unravel this mystery that has cropped up.

I would like to second the patient advocate\'s stance on taking care of
these patients. This is about people. But I would also like to temper
her remarks in unqualified support for ambitious researchers is not
necessarily a good thing.

Be careful. Ambitious men may paint a great picture, but the reality may
be something altogether different. And I am waiting with bated breath to
see how you guys focus in on the age-related aspects of this.

It is something that just jumped out at me early in this meeting, and in
that regard, I would like to ask a question related to the animal
studies that have been done.

It is my understanding that they don\'t treat very young animals. So how
relevant is that data in relation to what you see in these very young
patients? Thank you.

(Applause.)

CHAIRMAN SALOMON: In keeping with the policy of these open public
hearings, is there anyone in the audience who would like to step up? It
is not just the scheduled. I think, as you already know, my strategy or
attitude as Chair is always to try and make the audience feel as welcome
at the mic as the participants within reason so we can get our job done.

And so if there are those of you out there who still feel later that
they have something pertinent, then please step up to a mic and just
remember to identify yourself, and I will do my best to keep track of
the surrounding mics that are outside the table area.

I would like to now \-- if there is anyone on the panel who has a
comment. I know that Abbey \-- I am sorry for putting you off just a
little bit, but go ahead.

MS. MEYERS: I just want to say that I have not heard any discussion at
all about the ethical aspects of this whole thing. I know that we are
focusing in on the science, but when I hear people talking about gene
therapy as if it is their last chance for themselves or for their child,
I am bothered by it, because actually in the 11 years of gene therapy
experiments the only ones that have been proven effective are these
studies on gene therapy.

And, of course, in the cases of the X-linked SCID, we traded one
terrible disease for another terrible disease. Now, the goal of human
research, of course, is to come out with a product, whether it is a
surgery or a drug, or a device, or whatever, that hopefully will be safe
and effective and get on the market.

We have some drugs, for example, that are not safe, like thalidomide,
but it is on the market because there was a way to control that terrible
side effect. If we don\'t let pregnant women take it, it is a good drug.

In this case here, I can\'t think of any company in the world that would
want to commercialize gene therapy when they know that there is a
likelihood that a percentage of those people who take this gene therapy
are going to come down with leukemia.

They would not face the liability insurance problem in that.

And so when I look at this whole thing, we are going down a road, and we
are looking at future clinical research on this, and I am wondering
whether it should all go back to the laboratory, and instead of using
people, we should go back to the mice.

And the most disturbing thing that I heard this morning was the first or
second speaker who said, you see, they tried it in baboons, and they
tried it in monkeys, but it is very expensive to keep them alive. So we
only followed them to 6 months or a year.

Well, what was the cost of saving the money and not following those
animals for a longer period to see whether they came down with leukemia.

So I am really disturbed, because I don\'t know whether human beings
should be put in this position, especially when a parent makes a
decision for a child who does not have the capacity to say what he wants
and what he needs and who can later grow up, like the babies from the
DES mothers, and sue everybody. I just want to put that out on the
table.

CHAIRMAN SALOMON: Well, I think we acknowledged last time, in October
when we met, that part of the responsibility of the committee in
considering this was to relate as scientists to something that for some
of us is a potentially extremely important insight into oncogenesis.

It is an important step in deciding the direction of different kinds of
gene therapies, all pieces of which you have heard. But at the same time
we acknowledged in October how important it was to keep the ethical
issues, which as we now think about it, between the public comments and
your comments, represents a bit of a \-\-- represents two sides of a
coin.

And I am not going to try and resolve it, but certainly on one hand you
have patients who are grievously ill or dying or have almost basically
zero hope of being alive in two years.

And you have patients who \-- or you have a community or a public that
has other interests. As you point out, Abbey, should this stop now and
not go forward into the clinical trials, and go back into the lab.

And I think that these are very important for us to think about. One way
we deal with it is in informed consent. So I think that we need to make
sure that we spend a few minutes on that.

So I guess all I can say is that I am going to try and manage the next
two hours well. That is not going to be easy I know, but to try and get
through the science. And I think that a lot of us in the field feel that
there is a lot at stake here about directions, and there has got to be
some sort of statement in that regard.

But we are going to leave some time to try and maybe end on some of the
ethical issues. Okay. So we are going to let it go a little bit loose
for a few minutes just because people have a right to say what they want
to say to start, and then I want to go into the questions as shortly as
possible. Joanne.

DR. KURTZBERG: I have two comments for the last two speakers. One is
that SCID is a disease that affects babies, and if you don\'t treat them
as babies, they often don\'t live to have access to other therapies.

So you don\'t have the luxury of waiting until they are older, and that
in and of itself can cause harm. So treating younger children is an
obligation because of the diagnosis, not because of the safety of the
situation.

And the second is that I think if you think of developing drug therapies
and devices in terms of the marketing and the commercial companies, that
you do a great disservice to patients with orphan diseases, because they
are not a big market.

And they will never have these therapies developed for them because,
safe or not, they are not money-making propositions, and a lot of what
drives our industry of drug therapies and other therapies does not serve
those populations.

So I don\'t think that marketing or liabilities, et cetera, should be
the reason that we make decisions about drugs. I think that\'s why
government oversight is important.

That is why the NIH is important because it takes some of that out of
the situation and allows these orphan populations access to developments
of new therapy.

CHAIRMAN SALOMON: Linda, do you still have a comment? Then Tom and then
David.

DR. WOLFF: I wanted to make a comment that is related somewhat to the
ethics and to the informed consent. I noticed at the end of our last
meeting in October it was concluded that the informed consent should be
more potent and direct.

And I was just reading the other night again what it said, and in the
very beginning of it, it says \"expected to cause no harm.\" And even
though there were statements made after that about how a patient had
gotten leukemia, if I were a parent looking at that and didn\'t have
much knowledge, I would almost stop at the \"expected to cause no
harm,\" which was at the beginning.

And I just think that it should be a little bit more straightforward and
realistic.

CHAIRMAN SALOMON: I am not certain exactly what wording you are
referring to, but the message from the committee in October was that it
should be very straightforward and not mince words about the fact that
gene therapy caused leukemia.

And so I don\'t know. I would have to defer to my FDA colleagues on that
one. Tom, and then David.

DR. MURRAY: Thanks. And I want to take particular note of the comments
made by Abbey Meyers and by Paul Gelsinger and by the person whose name
I did not get.

CHAIRMAN SALOMON: Rachel Salzman.

DR. MURRAY: Rachel Salzman. Thank you. It is not easy striking the right
balance here. People who are dying or whose children are dying of
disease are desperate for a cure in many cases.

Certainly many of the people, adults and children, who participate in
first line clinical trials will receive no benefit, and may even be
harmed by their participation, and that needs to be made abundantly
clear to anybody who will enroll in a subject trial.

And I think that we need to make sure by the end of today that we give
clear instructions to the FDA, which I think is welcoming of these
instructions, and to be as firm and as clear as we can on that. On the
other hand, if there aren\'t any human trials, no progress would be
made.

I do think having been involved in, among other things, a reexamination
of NIH\'s role in oversight of gene transfer research, that there seems
to me to be a world of difference between the way that we are dealing
with this, and the way that we dealt with \-- or what was done prior to
Jesse Gelsinger\'s death.

I think that the openness of the investigators, and the candor, and the
extensive pre-clinical work that was done \-- of very high quality
\--seem to me to mark a very substantial difference in the
responsibility that is being shown by the scientists involved in this,
and I just wanted to go on the record to say that.

CHAIRMAN SALOMON: Thank you. David.

DR. HARLAN: I wanted to applaud the first presenter this afternoon,
representing the American Society of Gene Therapy, Dr. Kohn. I thought
the way that was put together was exactly the kind of information that I
would like to see.

But then in the public comment, several points were made that I wanted
to make sure registered with that group and that analysis. And that is
that age of animals be considered \-- and that was Mr. Gelsinger\'s
point \-- when the gene therapy was administered, and that the duration
of follow-up be especially paid attention to.

But then in the clinical studies part, I find almost counter to the
argument any study that says that we have done this in 300 people, if
the follow-up is only a month or two. It is completely uninformative.

And I would argue \-- I heard the point mentioned, but I would really
emphasize that you not even consider in the denominator gene therapy
trials, or the duration of follow-up, or the duration of gene therapy
labeling, as uninformative.

And that the committee come up with criteria before they even consider
in the analysis whether that is relevant data.

CHAIRMAN SALOMON: Don, did you want to \-- where is Don? He\'s hiding.
Oh, there you are. I saw you go that way at the end of your talk.

DR. KOHN: I had to check out. In terms of the age of the animals, in
fact most mice typically are transplanted at 6 weeks of age, which is
young, although for a mouse, that is probably an early teenager or
something.

So there are now groups that are transmitting newborn mice, which might
be the most relevant time to get those kind of data. In terms of the
follow-up, what we were tempted to do is get all the data with as much
information about time-to-follow-up, extent of marking so that it can be
assessed.

So this was just sort of a summation of how many studies we have gotten
data on. It wasn\'t a comment on the quality of the data. And I did make
one comment that in fact in many of them, or the majority of them, the
marking was very low and short term, not much beyond 3 to 6 months.

And so they are part of a denominator, but maybe not the most relevant
denominator.

DR. HARLAN: Just a comment. When you presented the clinical data, I
didn\'t hear you say that the committee was looking to identify criteria
that would decide whether or not a clinical study was informative for
the safety question.

DR. KOHN: At this point, we are just trying to get the data as much as
possible, and then once it\'s assembled, at the annual meeting there is
going to be a presentation of it in a symposium, followed by a workshop
to discuss it to maybe come up with some methods of what to do with it.
But the first step is just to try and get it.

CHAIRMAN SALOMON: Dr. Cindy Dunbar.

DR. DUNBAR: Yes. I just wanted to make a couple of comments about the
large animal models. They are unbelievably expensive. Ms. Meyers already
alluded to the horror that we were not following animals long term, but
the program, just for the infrastructure, is over a million dollars a
year. And that is not buying the animals, and that\'s not talking about
any of the reagents.

I am sort of amazed that I actually did have 46 animals that we followed
for a median of 3 years, and the only reason we were keeping those
animals was because of some other scientific studies that were not even
related to gene therapy, in terms of stem cell cycling, and I am very
glad we kept them.

But my facility has recently been told that we have to cut half our
space, and just simply in the current budget, NIH budget in 2004, there
is just no money for non-hypothesis driven non-investigator \-- I mean,
this is not something that we follow the animals for ten years and were
going to publish papers about it if nothing happens. The FDA was
wonderful about following a group of animals that French Anderson had
transplanted and given vector to ten years ago. I mean, he had given
replication competent viruses to these animals and said, you know, they
didn\'t get the disease, so that is good. It is not toxic. But those
animals turned out not to be very useful because the immune system
cleared the virus right away.

More relevant were animals that got help for virus by mistake, more or
less, and did get lymphomas. Those studies we finally shut down because
it was felt that we had not learned anything from them ten years after
they had started, and I took the animals and used them for something
else.

But I seriously don\'t know if we are going to be able to continue to
follow these animals. We had our breeding programs shut down, so the
whole issue of looking at young animals is going to be much more
difficult.

It is very hard to buy \-- you can\'t buy any new animals. They have to
stay with their mother, you know, and we no longer have a breeding
program and neither does Seattle.

And so these are big issues, but there is going to have to be creative
funding mechanisms through NIH or the FDA that is not your typical
investigator-sponsored RO1 grants or intramural investigator-sponsored
things because it is not possible in the current climate to do that.

And the magnitude of expenses is horrifying, and that\'s why it was easy
for me to gather all the data because I know the 4 or 5 people in the
world who have these programs, and we are all holding on by our
fingertips.

CHAIRMAN SALOMON: Well, my comment to Abbey about that is that you are
doing good. I mean, one of the roles that we can play here for the field
in general \-- we have people here from the NIH, and certainly we have
the FDA staff here, and we do have people listening in industry as well
to what we are saying. So you made your point.

MS. MEYERS: The NIH got a 15 percent raise for 5 years in a row, way
above anybody\'s inflation, and I cannot believe that they have cut back
on their animal money. It is unbelievable when they have gotten such
huge raises.

CHAIRMAN SALOMON: Well, in the two hours that are left, we are not going
to solve the NIH\'s budget woes. That much I am sure of. Dr. Bordignon.

DR. BORDIGNON: Yes, thank you. Actually, I would like to make sure that
one of the aspects, the technical aspects related to the duration and
level of marking in relation to the safety studies is not overlooked.

I sensed a couple of times through the discussion either public or
during the breaks that the threshold for considering a given animal or
patient valuable has to have a upper peak level of marking, and that
level of marking has to stay for three years, four years, or whatever
was the crucial and critical time in the gamma-chain study.

I personally disagree on this point. I completely agree with the
statement that was made on this issue, that if there is no marking,
there is no toxicity to study.

But if there is marking in the first place, the marking disappears, and
the patient or the animals is alive for evaluation, that marking
disappearing means that that cell that was tested was transduced. It is
just doing whatever biologically it is supposed to do.

Therefore, it is dying at the end of its expected life. I think that
those data could be of different value, that long-term marking and
long-term expression, and long-term function, but they can be extremely
valuable, and I would caution against discarding them.

CHAIRMAN SALOMON: Ken.

DR. CORNETTA: I guess going through a number of things that were said,
one of the things that was brought up was that the climate seems to be
different than it had been with \-- or at least the climate currently is
that the investigators are really trying to cooperate and find this.

And I think that is a credit to the folks in the field, and I have been
contributing my data to that also. I think in regards to a follow-up of
the ethical issues, while this formation of leukemia is something that,
you know, has been a sort of shock to the field, in some ways it hasn\'t
been.

And I think that most investigators, including myself, have always
included this possibility on informed consents. And the problem is that
we have not known when it is going to occur. I think the thing to keep
in mind is that, with the committee and the other folks in the room, we
have been doing trials in this type of gene therapy for ten-plus years
now.

There is a tremendous amount of animal work, and I think there are some
questions about how long to keep animals, but probably every medical
school in the country now has some investigator doing retroviral gene
transfer in some model system, and this is not something that has been
predicted with all of that work.

I think the real challenge for the committee today is why, with all of
the work that has been done and all the patients that have been treated,
why in this trial have we seen this, and how does that impact on the
rest of the people doing work.

CHAIRMAN SALOMON: Cynthia.

DR. RASK: Yes. I would just like to make a comment with regard to the
informed consent recommendations that we had sent out recently. We
recommended that the investigators insert a section entitled, \"Risk of
Cancer.\"

And there is a statement that says that most integration is not expected
\-- or, is expected to cause no harm. However, it is followed by two
paragraphs describing the potential risks and the events that have
occurred.

And I would submit that, if patients stop at the point of that sentence
and there is no further discussion with the investigators and the
treating physicians, they are not really being informed fully as they
should be.

CHAIRMAN SALOMON: Well, I think that this whole issue isn\'t one to run
away from. I mean, the strong recommendations of the committee in
October were that there should not be any equivocation in the informed
consent.

I think at the same time it was the intention of the FDA, in crafting
that particular language, not to create a situation in which it sounds
like every time you do gene therapy that you are going to get an
integration event causing cancer. And I think that was responsible.

However, certainly your comment, Linda, is reasonable, and we shouldn\'t
run from that immediately. I mean, if you feel that it still is not
unequivocal, when we come back at the end to talk about the informed
consent, you might want to readdress it.

DR. WOLFF: Just a quick comment. In reading the two paragraphs, there
was no estimate of risk, which I realized was because we ended that
session saying that you could not estimate a risk, and that\'s why it
was put in that way.

But I was just trying to look at it as a parent, instead of a scientist,
and how I would interpret that.

CHAIRMAN SALOMON: And I would just reiterate, the intention is that we
think that the people that are reading this that need to get the message
get the message. So if you don\'t think that that was crafted properly,
that is on the table then. Alice.

MS. WOLFSON: Yes. I am here on this committee as a consumer
representative, but I am also the mother of a child who died from
leukemia following a bone marrow transplant, and one of the things that
I hear missing from a lot of the scientific discussions is the physical
costs.

I don\'t mean monetarily, but I mean the extraordinarily rigorous and
physical pain that not only, in my case, the child but an entire family
and an entire community endured for a bone marrow transplant which was
really entered into without sufficient informed consent, exactly what
Linda is talking about.

As a desperate parent, you are not going to notice the second paragraph,
because you are already thinking that you know you are doing something
that is desperate. And people talk to you about statistics, Well,
somebody makes it. Statistics are meaningless.

Well, they are really not meaningless, and I think putting that section
second in that way makes the argument that statistics are meaningless,
and I don\'t think that parents and children should be put in that
position.

CHAIRMAN SALOMON: Abbey.

MS. MEYERS: I have had an 11-year argument with Phil Noguchi on this
problem, because Phil says in public \-- and if you go back to the
minutes of RAC meetings ten years ago, eight years ago, five years ago,
you will see this argument in the minutes. Phil says that the FDA has no
governance over informed consent documents. He cannot force \-- the FDA
cannot force a university to change them. You can advise them, but you
can\'t force them; is that correct, Phil, or has it changed?

DR. NOGUCHI: Legally, the jurisdiction over the status and the form of
the informed consent is the jurisdiction and approval by the local IRB.
That\'s correct.

MS. WOLFSON: I will just answer that a little bit. It is not an answer,
but I can tell you that if the FDA has a very, very strong informed
consent requirement, then beware if you are an institution that doesn\'t
enforce it, because legally you open yourself to exactly the kind of
lawsuits that you were talking about from DES daughters, where in fact
the reason they won those lawsuits and are winning them is that the drug
companies knew what they were doing and did it anyway.

CHAIRMAN SALOMON: Crystal.

MS. MEYERS: But each university has its own IRB and does it the way that
they want to do it, and we don\'t have a federal law that requires some
kind of punishment if you don\'t do it that way. And the FDA is not
legally empowered to do it.

CHAIRMAN SALOMON: Abbey, again, we are not going to solve that either.
That is the American way right now, and it is more now than it was a few
years ago. Crystal.

DR. MACKALL: Yes. I guess to echo this informed consent, we could talk
about this all day and more, but I am a pediatric oncologist who deals
with lethal cancers of childhood on a daily basis and go through the
informed consent process firsthand with my families. And our IRB at the
NCI is very strong and insists that every possible negative event that
this child can go through is there in black and white staring these
families in the face.

And the fact of the matter is that under most circumstances the families
don\'t have a lot of options. That is part of having one of these
terrible diseases. So in some ways I think we overestimate what the
informed consent can do for our families.

I think the goal of this session here is to decide whether we think that
first sentence is true, that we expect that the likelihood of this is
that there will be no harm.

If we don\'t think that is the case, then all the informed consent in
the world really does not matter. We have to believe that sentence is
true, or else we don\'t go forward.

CHAIRMAN SALOMON: So my view here is that we are kind of, in a natural
way which is good, coming back to what we need to do now, which is to
discuss the questions. And I promise, Abbey, that we will come back.

And the only thing that I am not going to try and do is solve problems
that are way outside this advisory committee, not when we have such
limited time. Rich, is this relevant to getting to the questions?

DR. MULLIGAN: No, but it wasn\'t as irrelevant as the last ones.

(Laughter.)

CHAIRMAN SALOMON: I assume that includes my comments.

DR. MULLIGAN: Definitely. This is about Dr. Fischer. You know, we were
talking about how the field has shifted, and I want to make sure that
people have a sense of the impact that his forthcoming has had on the
field.

I would say that if there is a single person over the last couple of
years that has influenced the course of the field, it is him. And I want
to make sure that everyone is very aware of how upset he has been very
recently about the circumstances of the release of the information about
his patients.

Now, I don\'t want to argue about it, because I know that there are a
lot of issues of getting the information out to people, but I would just
make the point that, had he not been as forthcoming and had he not led a
very open transparent analysis of what has happened, we would be so far
behind.

And I think that \-- I mean, I can think of many other situations and
other places where this could have happened, where we would be so far in
the dark that it is not even funny.

So it is just a pitch to everyone to be thinking about this issue of how
unique his contributions have been, and the issues that he will face in
the future if there is a third case or a fourth case.

I just know because I have talked to him personally that he is very,
very concerned about how he makes public information. He is not under
jurisdiction with the FDA. So I hope that people can just \-- the
respective bodies can think about this issue because he is a very, very
valuable and important resource for us to have.

(Applause.)

CHAIRMAN SALOMON: Agreed. Okay. The first question is to \-- Carolyn, do
you want to project those?

\"Please discuss under what conditions clinical trials using retroviral
vectors to transduce CD34 positive hematopoietic stem cells for the
treatment of SCID\" \-- this is for the treatment of SCID, not X-SCID
specifically, but SCID \-- \"may resume.

\"Currently before sponsors of these trials may proceed with clinical
trials, they need to provide a revised informed consent document and
plans for monitoring peripheral blood cells for the clonality of vector
integration. Is this sufficient or should additional conditions be
placed on these trials?\"

And then there are a couple of things that they want us to consider. Let
me throw it to the group.

And, again, remember that we want to move forward from where we were in
October and not go over all the old ground. So we all remember what
happened in October. Is it sufficient to open up the SCID trials that a
revised informed document \-- well, we all agree with that, right? I
mean, I don\'t think we need to waste any time on that.

Any revision of the informed consent document that captures the
integrity of what we were trying to do in October \-- and I have heard
very clearly now \-- is okay; right?

So how about clonality of vector integration? How feasible is this? How
accurate is it? Should they do it? Is that enough? Rich.

DR. MULLIGAN: Well, I think it would be helpful if we just first
addressed the kind of philosophical question about what is different at
this meeting than was at the previous, because otherwise we are going to
redo \-- I thought we had actually an organized discussion previously,
we had good consensus, and everyone felt very happy about most
everything.

And unless we kind of understand what is different and how that will
influence the decisions on these points, I am not sure that we are not
going to be doing a worse job this time just by the randomness of it.

And I was going to say that what I think is different is that there
obviously is a second case. We now know that. Before we could have said
that this would never happen again and that it was a random thing, but
it has happened another time.

There is much more information scientifically about the characteristics
of the disease. We obviously have addressed a lot of points about cell
dose. But I think it is very key to also address this issue of safety. I
know that John made some comment earlier, that I don\'t know that I can
support his, you know.

I mean, I think that is very important for people to be thinking about,
now there are two cases of leukemia, is a point of view that there
can\'t be a third case, as opposed to the issues about how to judge risk
and benefit.

And I would just like some discussion by people on the issue of what is
different.

CHAIRMAN SALOMON: Bruce, and then John.

DR. TORBETT: I tend to agree with Rich. I mean, I think what we heard
today is that we have very little, other than perhaps culture
conditions, to base what is different.

We do know that, unfortunately, another individual came down with that
debilitating disease. However, trying to set a bar or readjust a bar I
think is going to be very, very difficult.

And I guess I would again like to echo the point that Rich made, that
until we have some idea or a discussion of what the differences
potentially could be, I am not sure that we are not \-- I think we are
moving, if anything, backwards.

CHAIRMAN SALOMON: John.

DR. COFFIN: In the last discussion we had a fairly long discourse on
denominators. When you have one out of nine that the real denominator
could be a thousand or a million, and it could be a fluke; when you have
two out of nine, the real denominator is nine.

And that is a hundred-fold, thousand-fold, change in one\'s thinking in
a way. Because I think we can have some confidence that if this protocol
were to be repeated exactly this way in another similar group of
patients, we would be looking at exactly the same thing going forward.

And so I have a lot of trouble seeing \-- I\'m wrestling with that.
Before, I was quite enthusiastic about continuing these studies because
of the likelihood that it really was a flukish experience.

But now I think we really have to come to grips with what we need to do
and what steps need to be taken to try to prevent this from happening in
the future.

You know, we are not going to send the space shuttles back up until we
figure out what went on with the Columbia, and I don\'t \-- I think we
would be derelict in our duty if we didn\'t make a real effort to come
to grips with some technical way to deal with this, rather than just
saying we should keep going along as we are.

I don\'t think we can afford to do that at this point, with these kinds
of studies at least. I mean, there are other kinds of studies we can
consider.

CHAIRMAN SALOMON: Okay. There are hands going up. Usually, in all other
BRMAC meetings \-- it sounds like Passover for those of you who get that
joke \-- but in all our other meetings, we obsess about how we have got
to get to the questions.

I am actually okay with this little more freewheeling discussion, and
since this is my last meeting, you guys can fire me anyway.

(Laughter.)

CHAIRMAN SALOMON: So we may not get to your exact questions, but maybe
we will. So let\'s try something a little bit different, because I think
that there are some points here. There is so much that is important
here.

So I have Ken, and Alison, and then Barbara, and then I think Bruce was
waiting.

DR. CORNETTA: I guess I was trying to get to the question, at least for
me, where we branch off and to start making some decisions. Do I think
that the integrations that we have seen and the leukemia that has
developed is this a single hit that everyone who gets a gene transfer is
at risk to?

Or is there something unique about, for example, the transgene, in
combination with this, that really makes a very big difference on where
we go? Because it also \-- even the first question, of what does this do
for SCID, actually you might want to rephrase that.

If this is \-- if the transgene is playing a dominant role here, then
actually even non-X-linked SCID trials may not be at risk for this type
of problem. So, for me, that is a real crucial point.

CHAIRMAN SALOMON: Well, let\'s just try and \-- just since there is a
lot to go through, let\'s try and keep key points. So Ken\'s key points
now are vector and transgene. Okay. And Bruce seconds that. Alison.

MS. LAWSON: I was going to say exactly the same thing, but I would add a
couple of more things into that. Because what John said was 2 out of 9,
and I think what we have to discuss is: Is it 2 out of 9, or is it 2 out
of 2? Because we also talked about age, and we talked about dose, and so
we don\'t know if those other factors as well may be part of that.

CHAIRMAN SALOMON: So as we evolve it now, the question would be is there
enough information, at least inferentially, allowing us to say that
there are specific groups within the group of X-SCIDs that might be at
higher risk.

And age, dose \-- well, no, that is on the table, and you can shake your
head. But age and dose, and other issues. Barbara.

MS. BALLARD: I was looking at much the same question, and whether or not
the first question looked at all of SCID, versus X-linked, and breaking
X-linked out from the other types.

DR. LEONARD: A couple of the same related ideas, but the one thing is
that JAK-3 deficiency is clinically and immunologically so
indistinguishable from X-linked SCID that I think a JAK-3 deficiency
must be considered in the same context as X-SCID.

IL-7 receptor deficiency, as far as I know, no one is doing gene therapy
is related to that, but it would also fall within the spectrum of SCID.

So that one question is to consider all SCID or X-SCID. But if X-SCID is
a breakout, then I think that JAK-3 deficiency and IL-7 receptor
deficiency should necessarily go with it.

And the age issue is very important. I suspect that there are not that
many here who would be enthusiastic tomorrow transducing more children
one or three months of age; whereas, if the question is older children,
there might be more room for discussion and greater thoughts related to
that.

CHAIRMAN SALOMON: David, and then Jeff.

DR. HARLAN: I am going to propose coming at this from a completely
opposite angle; and that is, I would be in favor of a trial as long as
there is nothing else to offer.

I mean, if there is really nothing else to offer, then I don\'t see \--
then the risk/benefit ratio for me is easy, and this is where we did
discuss this last time, and I know at the DNA RAC, this is how it was
approached.

If there is no other therapy, then it is pretty hard to argue that the
risk/benefit ratio isn\'t \-- even if it is infinitesimally greater
benefit, then it is greater than nothing.

CHAIRMAN SALOMON: That\'s fine. Jeff.

DR. FRENCH: It is inherently difficult to extrapolate from mouse models
to humans, but I wanted to go ahead and factor in both dose that is the
vector cell integration into pre-clinical studies, because you don\'t
seem to have any other options at this stage to proceed, because you
can\'t wait for any other preclinical studies to be done.

But in the future, if you consider pre-clinical studies, I would want to
give you the benefit of what we have experienced over the past ten years
in trying to deal with safety assessments in both pharmaceuticals, as
well as environmental chemicals.

But I was struck by Baum and von Kalle paper in terms of the potential
rates of integrants that could have an adverse event in a case, and it
is very similar to the spontaneous mutation rate in both the mouse and
the human genome. It\'s not different, so something else is obviously
happening that drives that progress forward.

In terms of what we have experienced, in terms of how do you define a
model or a battery of models that can help you actually address
pre-clinical safety issues, historically the carcinogenistic potential
of a given chemical is dealt with by looking at long-term studies in
rats and mice, which is very time consuming and very expensive, and
probably not applicable to here, where you have to address something
very quickly.

I have not seen anything today thus far that really shows that those
studies in mice that tried to address safety were done to the extent
where you could come to a conclusion about the actual safety.

But there are a lot of models that are available, and we have seen the
papers from the Jenkins-Copeland lab using retroviral targeting that can
identify potential cancer genes, more oncogenes, and tumor suppressor
genes. But they obviously do occur at some rate because those were
determined by pulling out tumor DNAs and identifying them.

So there are obviously a lot of animal models that are available. So how
do you do that? I would suggest that you actually need a working group
of people to define it.

And we had a partnership between academia, industry, and government over
the past six years that sort of addressed that. You have to build a
consensus on how that is going to be done.

And the more models that you bring into it \-- and I am referring back
now to the list of models that we saw with the presentation from the
Gene Therapy Association \-- you can inundate yourself.

We spent six years and about \$50 million to try just to find three
models. I am not trying to equate the two, but the point is that you
have to be very circumspect and very direct by what you want to get out
of the outcome if you are going to use animal models to try to determine
a pre-clinical safety assessment.

CHAIRMAN SALOMON: Okay. But again we have lost the thread of the
questions. We said that was okay, but I am trying to make sure that we
do have a thread.

So the thread so far is we have talked about the vector, and we have
talked about the transgene. We have talked about the disease, and we
have talked a little bit about whether there were \-- you know, how you
would make the cuts. I mean, SCID as a big group, versus type X SCIDs,
versus types of SCIDs, okay? We have got to get to some place at the end
of this. Joanne.

DR. KURTZBERG: You know, I think when people are trying to figure out is
if there is something different about these two kids that led them to be
more vulnerable to this problem, I don\'t think the problem is two out
of nine. I think the number right now is three out of four.

Because you have five kids, and the first one has the insertion, even
though he or she is not sick. I think the third one didn\'t engraft, and
then the other two have it. So time-wise you really only really have
four children out the same amount of time in which the event occurred.

And then you have three or four more who could still be under
observation, but have not necessarily fulfilled the time for observation
that this might happen within. So I think you have to think of it from
that perspective when you start trying to figure out what the incidence
might really be.

I think that first patient is going to be very important, because age is
a factor and if that patient does not end up with leukemia, that is a
very positive observation. But we don\'t have the time yet to know that.

So I think if this was an oncology study, you would say we have met a
stopping rule. We need to sit down and figure out if we can make this
safer and have a hypothesis about how to do that and then reopen the
study with whatever that change may need to be.

And it may need to be that we have more time to observe the kids already
treated before you can make that hypothesis.

But I think that that is the direction that people ought to take, rather
than some of the discussions that we have had so far.

DR. MACKALL: Let me just comment, Joanne. I agree with you that I can\'t
imagine that we can go from here today without saying that there has to
be at least some hold on this trial, because we don\'t have that many
person-years.

We need the individual patients to accumulate enough time post-transfer
to really know what the incidence is, but in the meantime, you know, you
are going to be faced with some kids that don\'t have other options. So
you as a transplanter \-- I mean, what are you going to do with that?

DR. KURTZBERG: Well, that was the other part of my comment. There are
other options for these kids. You could argue about qualitative risks
and benefits, but these kids could have haploidentical transfers, and
they could have ablative transplants. They could have cord blood
transplants. There are donors available now to transplant these kids.

And those are not necessarily less risky procedures, depending upon what
the incidence of this event really turns out to be. But there are
options, and that should not get lost in the discussion.

CHAIRMAN SALOMON: Tom and Butch.

DR. MURRAY: The last point gives me pause. Of the ten children treated,
if we had seven positive responses and three non-responses, we would not
be here talking about it. In fact, what we have is seven children at
this point who I guess have responded positively at this time, or at
least no occurrence of leukemia, and one not responding, and two with
leukemia.

And we need to be mindful of what the options are, both in terms of the
percentage of success, but also in terms of what it does to quality of
life of the child and the family. That point was made, and it is an
extremely important point.

These are not data points on a chart. These are children who have
parents who are worried about the children and caring for the children,
and children and parents can suffer together.

And some of the alternative treatment modalities can be fairly harsh I
understand. So we just need to weigh that in the balance with whatever
recommendations we make.

CHAIRMAN SALOMON: I think we are actually getting there. So, Jon,
Richard, and John Coffin.

DR. ALLAN: I don\'t know that I have anything different. I will maybe
just phrase it a little bit differently. I mean, when you talk about all
of these variables \-- and they are all variables. You can say
transgenes, and you can say dose, and you can say cells and you can say
age, and you can say vector, and you can say the target cells.

And you can say all of these things, but at the end of the day these are
all variables, and they are not easy to separate, and so I think you are
sort of stuck in these SCID trials, in terms of trying to sort that out.

I don\'t know that pre-clinical animal models are going to be able to
give you that information the way I think you want. But what strikes me
is the fact that even when you looked at one of the studies \-- I think
it was Adrian\'s study, that compared umbilical cord blood \-- well, I
don\'t know if it was Adrian or whose study it was. But they said it was
equivalent, that the gene therapy was equivalent to the umbilical cord
blood.

And so that makes me sort of, like, pause and say, well, we keep hearing
all this other stuff that says the bone marrow transplants are 50
percent or 60 percent, or whatever, but some of those are
non-conditioned kids.

And if you threw in umbilical cord blood, maybe you would get 80 or 90
percent, and the quality might not be any worse than the gene therapy
trials. So that suggests to me, then, that there are alternatives at the
present moment, which would mean that, with the fact that you have got
at least two leukemias, it is a no-brainer to me.

But then you sort of have to break it down into what it is that you are
\-- if you are going to keep a hold or put a hold on a trial, how much
do you define it?

And someone else suggested that, well, maybe we shouldn\'t include these
SCIDs. Just these SCIDs. I don\'t know where to stop there, but I can
tell you that if there are alternative therapies, it is just common
sense.

CHAIRMAN SALOMON: Well, that is a good piece, and we will come back to
that in a couple of minutes. I think we are almost there. So, Rich, and
then John Coffin.

DR. MULLIGAN: Yes. I look at the breakdown between the scientific advice
and the clinical advice that we have in this case. And at the previous
session, I was just very impressed by Rebecca (sic) Buckley and all the
clinical discussion of the risk/benefit, and also a little bit about the
differences in the options, and Joanne just entered that.

I mean, in the previous talks that we had, there clearly was not a
consensus among the people that there were other options. It was clearly
not put that way. And so I think there is going to be a difference among
excellent clinicians about what those options might be.

Now, I think what is different at this point, and I think we mentioned
this at the previous meeting, too. I think I may have mentioned it
specifically that I wouldn\'t be surprised if this never happened again
in other patient populations even if it happened to every one of the
children that was treated for this disease.

So I think the scientific judgment that is different is that I think
that the message that we would get across is, based on what we see here,
this is not a random thing, and indeed it might happen to every one of
the patients.

And then I think we break that and separate that from essentially what
is the clinical judgment. I think there will be variations. And with
regard to the FDA, I think from a scientific point of view, is it
irresponsible at this point for us to recommend that, scientifically in
a way, you go ahead.

And I think from the vector issues that will all surface at some point,
we are in no position to get there quickly, okay, for a lot of reasons,
some of which we talked about before.

So that is not going to happen, and we need to let that happen, we want
to encourage that to happen, and then once there are vectors that have
these properties, as we have seen in the past, people gravitate towards
these, and there will be a consensus, just like the discussion about
packaging cells and old fashioned ones, and people tend to go to new
things.

So here I think the message that is very clear is that this could likely
happen, all ten. I think Joanne pointed out that there is people that
have LMO-2 in this trial, and that is not a good thing to see.

But all of that being said, I am not sure that necessarily interferes
with a clinical decision about how to go ahead with these patients. That
is very different. I think it is simple to say that we have no
information from the disease that we are seeing in these kids to really
suggest that it will happen in other diseases.

We just don\'t have information, and I think we will come to that.

CHAIRMAN SALOMON: So hold that. I mean, I think that one of the things
that I would like to try and do is like sort ripples in a pond. So
let\'s deal with this and then see how far the ripples go out, which is
where you are starting to go now. John, do you have a comment?

DR. COFFIN: I have a couple, actually. In terms of where we cut our
decisions, I have a lot of trouble just because of our complete lack of
knowledge of any other system other than X-linked SCID really. Cutting
on SCID versus non-SCID, or X-linked versus ADA deficiency, the cut that
I would be willing \-- or that I think we should consider more is
perhaps between stem cells and non-stem cells.

And I think there we might be able to come to some agreement.

CHAIRMAN SALOMON: That is a good way of looking at this ripple approach,
so now you have rippled it all the way out to hematopoietic stem cells
and that\'s fine.

DR. COFFIN: So that is one point. The other point is that as far as this
particular outcome is concerned, I think we would all be extremely upset
if we allowed trials in other diseases or in these to go forward, and
this event happened again.

And the only way I can see that trials could go forward and that this
would not happen, that we could reduce the probability to something that
we might be able to live with is if the trials were allowed to go
forward only with doses of unique integration events that were small
enough that the probability of there being an integration next to LMO-2
or other oncogenes was low enough that we could comfortably live with
it.

And I will just lay that on the table right now. That may not be a
wonderful option, and it needs a lot of research to sort of come to a
consensus on what those levels would be, but it is perhaps better than
putting indefinite holds on these trials, waiting for very large amounts
of sort of very basic research to be done.

And we are talking about extensive research projects whose designs are
going to be difficult, if they are going to be really tightly designed
to answer the sorts of questions that we have. And so I will just lay
that on the table for the moment.

CHAIRMAN SALOMON: Ken and Steve Rose.

DR. CORNETTA: I guess, as you said, we are wrapping up, and I guess I am
ready to put out what I am thinking. In terms of X-linked SCID and JAK
and the Il-7 receptor, I think it would be very hard for me to enter
someone in who had other options at this point. And, again, those are
sometimes left to the clinician.

But I think what I am hearing is really a consensus here, and that is
really what we need to do. We have to realize that there will always be
extenuating circumstances, and that we need to let the FDA know that
there are going to be that.

But I think what I am hearing from the committee, and at least where I
am coming to is for these \-- you know, we have a disease that is
somewhat unique, and there are other good similar diseases.

But at least my recommendation right now would be that, if there is an
alternate therapy, those should be explored now.

CHAIRMAN SALOMON: Yes, that\'s perfect. If the circle of this
conversation is getting us to the right spot, then it is working.
Barbara, and then Steve Rose, and then Warren.

MS. BALLARD: One thing that I want to bring up, though, is Dr. Kurtzberg
brings up alternative therapies, but the thing that you are dealing with
at this point in time is a child who has already failed one type of
standard therapy, whether it is haploidentical, PEG-ADA, whatever. They
failed the therapy.

And so you are dealing with a child, who is not a healthy child, with a
cellular defect. You are dealing with a child who has possible
infections that you can\'t clear, and a child who probably has organ
damage, maybe multiple organ damage, and your optional therapy is to
give him chemotherapy.

DR. KURTZBERG: First of all, the current trial enrolls these kids as
frontline therapy. And one of the proposals on the table was, until the
safety is better defined \-- and I think it should just be limited to
the X-linked and the IL-7s, et cetera \--to say that it is not frontline
therapy. It is salvage therapy or second-line therapy.

But what is going on right now is that it is the frontline therapy. And
at the very least it is now equivalently risky as other frontline
therapies. And I think that should be on the table for families that
have to make a decision about treatment.

MS. BALLARD: I just did not want to lose the idea of it being a salvage
therapy, too, because the alternative options on salvage therapies
aren\'t a hundred percent and are not great options, either.

DR. KURTZBERG: And I agree with you, and that may be the solution, to
say \--

CHAIRMAN SALOMON: And that is a good example of how these are circles. I
mean, you can go to saying it maybe is not the primary therapy and we
ought to consider options.

But that doesn\'t \-- and I think Barbara is right \-- preclude that
under the right circumstances, it can be salvage therapy, and that is a
circle that we should follow. Steve, and then Warren.

DR. LEONARD: Just a brief comment related to John, and Christof could
speak to this. At the RAC meeting, he estimated that the target window
for the LMO-2 gene was one per ten to the fifth.

So that really is a low enough frequency so that, although limiting the
number of integrations would be desirable, you may not really be able to
get the number of integrations down to a sufficient level, if that
calculation, is true to really avoid the LMO-2 integrations.

That is to say that lowering the number of integrations might not be
desirable.

DR. COFFIN: My calculation was one in a million on that, so maybe we
should talk to the RAC \--

CHAIRMAN SALOMON: It\'s one times ten to the fifth, and then there are
people arguing for first hits and second hits and third hits. And to be
honest with you, I would like to just cut that off. We are never going
to get there.

I am actually totally with you as a scientist, so we should put our
heads together afterwards and talk about this. But I don\'t think that,
as a regulatory principle or as an advice principle, it is going to work
at this point, and we will just drive each other nuts.

DR. COFFIN: Before we take it off the table, could we just consider
advising that a committee of some kind be put together to specifically
investigate this issue?

CHAIRMAN SALOMON: I don\'t know if I am \-- well, sure, you can put that
on the table. No, I shouldn\'t do the Chair thing and cut that off. Does
anyone think that there should be a committee to investigate this? I
just am not certain what you \--

DR. TORBETT: I guess it should be tabled until we make some of these
other decisions first, but I do agree with John that there should be a
concerted effort, and it looks like the American Society of Gene Therapy
has taken the lead in that. But there needs to be something done.

CHAIRMAN SALOMON: I think we all agree that this is really where the
science is, and that is good. I think if we don\'t advise also in the
context of where the science should go, then we have not done the full
job today either. Bruce.

DR. TORBETT: I guess I would weigh in with X-linked SCID. I think what I
have been convinced of, at least for the data here, is that it is as
equally risky or more risky than current conventional therapies.

And so given that, I guess I would weigh in for it being, at best, a
salvage therapy at this point. This is not the general SCID, but at
least the specific X-linked SCID.

CHAIRMAN SALOMON: So let\'s see if we can get some traction on the first
part of the circle, the inner-most circle, if you will, by the end of
the day. We have only got an hour to torture this metaphor, and so I
guess we can probably get away with it.

The X-SCID. And let\'s go with Dr. Leonard\'s comment that within X-SCID
there may be a couple of critical types that I guess are a little
outside the actual X-SCID group, like the IL-7 and the JAK-3, that would
be in the same way, where there would be such a powerful potential
selection element that a transgene would contribute.

Do we agree that those right now should not be primary therapies for
these children? Is that a consensus? Are we voting actually today or
just achieving some sort of consensus?

DR. NOGUCHI: I think the importance of this discussion would warrant a
vote on how people think about this. It is not meant to be binding in
any sense, but where we at the FDA want to be very clear is that we get
the advice, and we know the strengths of the arguments about it. So a
vote would be helpful, at least a vote for the sense of where people
would be going.

CHAIRMAN SALOMON: I am trying to focus us down just for the moment now
on a clear statement from the committee about X-SCID, with a little bit
of a ripple out into a couple of other very similar molecularly
mechanistic types of severe combined immunodeficiency. David.

DR. HARLAN: I want to make one last stab at not going down that path, if
I can, by challenging Joanne for her opinion. You said that there are
always alternative therapies, and you know that, in clinical medicine,
you never say \"always\".

You know, let\'s say that there is no umbilical cord blood donor and
that the parent is CMV positive. You know, it seems to me that you
don\'t want to limit it to a specific disease if there really is no
other therapy available.

CHAIRMAN SALOMON: But, David, I think what we are saying here \-- and it
is important what you are bringing out \-- is that we are not trying to
preclude someone who has got no other options and is going to die. We
are just trying to get at a primary therapy. A kid \--

DR. KURTZBERG: I mean, a protocol can be written with an algorithm.
It\'s done in transplantation all the time. If you don\'t have a
six-of-six match sibling, and you don\'t have a this, and if you don\'t
have a that, then you are eligible.

DR. HARLAN: Then why try to limit it further? I mean, why split it? It
seems to me that is the critical place where these should move forward.

CHAIRMAN SALOMON: Well, we need to give a clear message to the FDA, if
we can. We can say that we can\'t give you a clear message, and that is
a message, too. But I think if we can give them a clear message, then
there are people \-- there are sponsors who are stepping up to do these
trials, and the FDA can\'t avoid the need to regulate them.

So they are going to have to say, we are going to give you an idea or
not. And we have to give them something here. Marina.

DR. CAVAZZANA-CALVO: I have just a comment on the definition of a
salvage therapy or firstline or second-line. I think that it is a
decision that can be made by the clinician on a case- by-case basis.
Because we can think that we can avoid in the future \-- and this is a
reflection that we have had in France \-- that we can avoid using gene
therapy for a newborn child of the age of the two with side effects that
we have had, less than 3 months, for example, and in good health because
the two cases had no infection at the time of the gene therapy. So in
this case probably even haploidentical bone marrow transplantation is
good enough to hope to cure the patient.

In the cases that you have, all these newborns, more than 6 months and
severely affected with multiple virus infections, herpes viral
infection, and bacterial infections. That is, pneumocystis carinii at
the time of the diagnosis is a common feature, and herpes virus
infection.

In this case, haploidentical is not really a choice. We lose the child
before you have the option of gene therapy.

CHAIRMAN SALOMON: Well, I think that this is really important. I mean,
you are right at this point on how you define salvage therapy. But can
we just get through the idea that it isn\'t salvage, then define
salvage?

DR. CORNETTA: Well, I actually made the suggestion that \"if there is no
alternative therapy,\" and I think that is the word that you want, not
salvage versus primary, because there are going to be cases where it
would be primary therapy, but, because of other clinical indications, it
would be inappropriate to take that patient to transplant.

And there may be other times where there may be other salvage therapy.
So that\'s why it should be \"if there is no alternative therapy.\"

DR. CAVAZZANA-CALVO: This is the definition. Because in the case of
varicella-zoster, I can assure you that with haploidentical you lose the
patient before any alternative treatment can be made.

CHAIRMAN SALOMON: Did you want to comment?

DR. HIGH: I just wanted to say that before I came here today, based on
what I read in the provided documents, I had made a decision. But based
on the discussions that took place, at least it seems to me that there
is a possibility that there may be something about the CD34 cells of
very young children, of infants, that would make a difference.

So that I am not sure that it isn\'t correct what Alison said, that
maybe this is two out of two. And if I had one wish for one more piece
of data, it would be to fast-forward 18 months.

So my point is that I would be willing to agree to what we are talking
about now, with the caveat that I get to reverse my decision in 18
months if it turns out that no other children develop this sort of
complication.

CHAIRMAN SALOMON: Well, I would think that is a good point, and clearly
the premise is that you can only do what you know now. My personal view
of this is right now with what we know about using this particular
vector with this particular transgene, in this particular disease, with
this particular induction protocol, is that we know that at least two of
seven or eight, depending on how you cut these numbers, got leukemia.

And I don\'t know whether that leukemia is going to kill these children.
I really don\'t. So one thing that I would love to fast-forward to is
three or four years from now and find out that these kids\' leukemia
wasn\'t as serious as a T-cell leukemia in a kid.

DR. KURTZBERG: But one of them is already going to a transplant, the
dreaded therapy that everybody is trying to avoid.

CHAIRMAN SALOMON: Right. Where I am going here is that I don\'t know how
many more of these children are going to get leukemia in the next 18
months, which echoes something that Rich said, and something that you
said, Kathy.

So I must say that from my point of view, not trying to be the chairman
but just a part of the committee, I am not comfortable at this point
going forward with these cases anymore, with using gene therapy.

I am okay with doing it if you can convince me that there is no
alternative therapy. I am okay with that caveat. I am always going to be
that. I have done enough medicine, and I have cried enough at patient
bedsides to be there with you.

But other than that, I just am not comfortable with it in this
particular, very narrowly defined group of people, only because \-- and
here is what is driving that decision for me.

I can, based on the data that we heard in October and the data that we
heard in the last day, say something about the risk of haploidentical
transplantation, and HLA identical transplantation, et cetera.

At this point, I don\'t know anymore what the risk of gene therapy is in
these kids. I really don\'t know today. And based on \-- knowing that it
is serious and not knowing whether there are going to be two or three
more kids, given the data that you all know, then to me it is moving off
the table unless there is no alternative. So that is kind of where I am
at right now.

DR. MULLIGAN: I think the way that Joanne put it was perfect, that it is
now clear that, weighing this relative to the other risky approaches or
last-ditch approaches, it is clear \-- the information that we have is
that it now clearly is a question whether these other things are more
risky.

So that is a big difference.

I guess I would ask Joanne about this issue of clinical judgment and
whether there is any alternative therapy in the eyes of the beholder.

DR. KURTZBERG: I mean, there is a lot of criticism in that decision, but
if you really think about it, when we talk about haploidentical
transplant in SCID patients, we are not talking about conditioning. We
are talking about taking the risk that (a) they don\'t engraft, or (b)
that they partially engraft.

And there is a small risk of GVH, but the biggest risk is that it
didn\'t work, and not that the child is worse off than they would have
been without that procedure.

If you talk about the risk of cord blood or match related donor or
whatever transplant with appropriate regimen, then you have the inherent
risk of the chemotherapy, which is somewhat age- and clinical
status-dependent, but can range between 5 percent to 30 percent,
depending on where the child fits in that category.

But I think the people who believe that haploidentical transplant has a
role would say that everybody has a parent, and everybody has that
option.

Certainly that option carries no more risk than what we are talking
about now, which is a 20 or 30 percent risk at least, of a leukemic
transformation. And again I think the risk of an ablative transplant is
equivalent at this stage.

So I think that everybody has a haplo donor. Ninety-five percent of
people will have a cord blood donor. We have an 80 percent event-free
survival with full T- and B cell reconstitution in our immune-deficient
population who get cord blood.

But I am just saying that these things are equivalent, and there are
options for everybody. And gene therapy should be an equivalent option
in that cascade, but not a superior option in that cascade.

CHAIRMAN SALOMON: Okay. You were going along okay, which I would define
as following the discussion, until that last little zinger. If it is at
all an even playing field, that is real different from saying we don\'t
know whether there is now going to be, in 18 months, two, three of four
more kids, which now you would have to say there was a 60 percent
incidence of leukemia, versus a 20 percent incidence of GVH for the cord
blood or something. I don\'t know, but that is the problem that I am
having.

DR. MACKALL: I think that we do have to keep in mind Joanne hails from
Duke, and this is the center of the universe when it comes to
transplanting SCIDs. So it may not be the same everywhere that you are,
and I think that Marina has alluded to that.

You have situations where you do not see haploidentical transplant as
any kind of a real option at all for your patient, even though they have
a parent who is a haploidentical donor.

So I respect Joanne, and I believe what she is saying, but it may not be
the same in every center with differing levels of expertise with that
therapy.

DR. KURTZBERG: But we have data to fall back on. I mean, I am not a
haploidentical transplanter, but the data with the haploidentical
transplant is \--

DR. MACKALL: But it is single-institution data, Joanne. It has not been
replicated everywhere.

DR. CORNETTA: These are also done under IND. So the FDA does have an
input here of what are going to be the eligibility criteria. So I think
we have to give them some credit to be able to look at these protocols.

So it is not like we are sending it back to a local IRB, and it is only
one institution that is making these decisions. The FDA is going to have
input here, so hopefully they will take our advice.

CHAIRMAN SALOMON: Okay. So one thing that I sort of see us coming around
to is \-- the difficult thing is deciding for a given place, a given
part of the world \-- in this case we have to deal with the United
States, but the United States is pretty large and diverse \-- what it
means for an alternative not to be available.

And that I don\'t think the committee is going to get through defining
for the FDA, nor frankly do I think we would be very good at it, since
it is going to be very individual.

So I think that, in general, could we agree that every sponsor has the
right in coming forward with the design of their trial and their
inclusion and exclusion criteria to make the case to the FDA that this
is the definition of when a patient is eligible for our study, based on
the precept that there is no alternative available.

And that might be a concept that this committee can agree to, and I
think we will get lost in the details of, well, if they are not at
Duke\... That\'s more like an exclusion criteria.

DR. PUCK: I just wanted to make a quick clinical point.

CHAIRMAN SALOMON: Can you identify yourself, please?

DR. PUCK: I am Jennifer Puck from NIH and the Genome Institute. And
there is something of a watershed in the presentation of babies with
SCID now that we are able to do prenatal diagnosis, or if there are
patients with a positive family history, so that you know right at birth
that a baby is infected before infections have set in and the
complications have set in.

That is a very different baby from the one who was unsuspected, who
presents with months of failure to thrive and infections and is already
in a very tenuous situation.

And so those eight-, nine- and ten-month patients are really a different
group from that very young group who had to be picked up because of
their genetics, not their infections.

And I think that the low-risk transplant could be applied to those very
young babies who aren\'t so ill, fortunately, because those may be the
babies who you would least like to do gene therapy on because of
leukemia risk.

CHAIRMAN SALOMON: David.

DR. HARLAN: So I just want to strongly endorse this
no-alternative-therapy concept at the jurisdiction of the local level,
as you just proposed, with the final arbiter being, as it always is, the
court of public opinion.

If somebody does something and the patient does poorly, and there was an
alternative therapy, we will all agree on it. Because the last point
that I want to make is that this same rule can apply to gene therapy, as
far as I am concerned, across the board. It doesn\'t have to be SCID at
this point. I think the same rule could apply to retroviral gene
therapy, regardless of the indication.

CHAIRMAN SALOMON: Well, I mean, the concept is there. Let\'s ripple out
there in a minute. I am still trying to get us to a point where we could
vote on something that we will try and craft in a moment. Now, Jon, does
this have to do with getting us to the vote?

DR. ALLAN: It is just that when you are talking about alternative
therapy, I am getting concerned. Because if a researcher goes and says,
well, gee, I can\'t find whatever, or there is some reason to push, if
the agenda of that researcher is to do gene therapy, then they are not
going to be as diligent about alternatives, because they are thinking
about gene therapy. And so I am worried about that.

DR. KURTZBERG: But the FDA could help with that if they put together an
informative document that says here is the state of the art for this
disease. Gene therapy is one of the options, and here are the risks and
benefits of this, as well as the other therapies that you are
considering for yourself or your child. So it would be a generic
document that would not have been prepared by the local investigator.

CHAIRMAN SALOMON: So if you think about the dynamics that have evolved
here, it really is encapsulating the major issues. The public comments
and the comments that followed point out that there are people dying who
are grievously ill, and who could potentially benefit from gene therapy,
right? We all get it.

On the other hand, one of our roles is to protect human subjects from
therapies that are insufficiently safe. And then we have gone into all
of these mitigating factors. How do you responsively respect the
potential future and in this case the tremendous benefit that these
children got from their gene therapy, and at the same time responsibly
fulfill our role to protect subjects and protect safety?

Now, in this particular case, I am saying that we need about two more
years before I can say how safe this therapy is. And until then,
regardless of its incredible benefit which I acknowledge to everyone, I
am not comfortable supporting it any longer, unless there is no
alternative.

So could we vote on that? Okay. All of those in favor \--

DR. ALLAN: Can I just \-- I\'m sorry. That \"alternative\" still bothers
me, because the thing is that there are alternatives as far as I can
tell with these SCID patients. It may not be the best alternative, but
it sounds like there are alternatives.

CHAIRMAN SALOMON: Well, I think we are giving a pretty clear message,
Jon, that any sponsor who wants to do these studies better have a darn
good line of reasoning for \"no alternative\" at this point, and that
that could change 18 to 36 months from now when hopefully there are no
more children with leukemia, and these two kids have had complete
remissions, and everything is good again. That is all that I am saying.

DR. KURTZBERG: I mean, you could follow the pediatric oncology model
right now and just say that kids will be eligible for this if they
failed or were ineligible for the other therapies that are available.

And that way it could still be a salvage there therapy, and you could
still learn about it. The informed consent would have to be incredibly
clear, but it would be like Phase I studies in kids who are dying of
leukemia, where we say to the parents that we are testing a new drug, we
don\'t expect it to help your child, but we hope that it will help other
children. We\'re learning about the safety of this drug.

CHAIRMAN SALOMON: Can we get a vote on this then? Is there anybody
confused about what we are voting on?

DR. NOGUCHI: Please articulate exactly what you are voting on.

CHAIRMAN SALOMON: I knew you were going to say that. Well, we don\'t \--
I don\'t want to go into motions and seconding and all of that. We have
never done that in the BRMAC.

But the concept here is that for the moment, given the evidence, that
gene therapy trials in X-SCID children using the retroviral vector with
the gamma-chain transgene and X-SCIDs with the JAK-3 deficiency, and the
IL-7 \-- just SCID.

Okay. I want the ripple to go next to the ADA, because there is a lot at
stake here, and I am not sure the ADA is the same game. That in that
situation, until new data is available in 18 to 36 months, that these
are not going to be allowed in children unless there is no alternative
therapy available for those children under these hematopoietic stem
cells. Is anyone opposed to that?

(No response.)

CHAIRMAN SALOMON: Does anyone want to abstain?

(No response.)

CHAIRMAN SALOMON: So then it is a unanimous vote of the voting members,
and then I don\'t have to count. Okay. So the next issue, following this
analogy, is \-- I\'m sorry, Phil?

DR. NOGUCHI: I would like to thank the committee for being very clear
about this. Just a comment about going beyond the X-SCID and the SCID
with JAK-3 and SCID IL-7.

I do think that one needs to consider when we are talking about other
models, such as pediatric oncology, I would just say part of that is not
similar because here we have evidence from a different country of
benefit. We have evidence from a different country of adverse events.

Typically in a pediatric oncology, you do not start with a presumption
of effectiveness. It is try this since you have no other alternatives,
but it probably won\'t work.

I don\'t think that is really the same concept that we have for the
X-SCID, but when we get beyond X-SCID to the other small populations,
then I think that model is actually closer to what we are talking about.

But for X-SCID it is a different kind of calculus that everybody has
struggled with and gone through.

DR. KURTZBERG: I don\'t know about that. Because it works, but it causes
an equally serious illness. That is not a home run.

DR. NOGUCHI: No, it is not a home run, but in pediatric oncology if you
are testing an experimental drug, you don\'t even have that first
assurance that in fact in some cases, in some clinical study there is
necessarily effectiveness. I am just saying that it\'s a different
perspective.

DR. KURTZBERG: But you are not trying it in frontline patients when you
are at that level. You are trying it in patients who failed the
effective therapy.

DR. NOGUCHI: And that is what we have talked about for X-SCID, yes.

CHAIRMAN SALOMON: So what I would like to do now is see how far can the
ripple go next. I mean, the next group of trials is obviously there, as
described by Dr. Bordignon, but I know that there are at least two or
three in the United States, right, for ADA-SCIDs, and what do we think
about that?

I would start by saying that I think that is a very different group, and
I am not convinced by anything that I have heard that we should continue
a hold on ADA-SCID trials. But that is my statement. Abbey.

MS. MEYERS: ADA-SCID has an FDA-approved drug on the market. It is an
enzyme replacement therapy. It seems to me that all of the figures that
I have seen say 80 to 90 percent of the children do well.

And it should only be, I think, the people or children who don\'t do
well on that FDA-approved drug who should be considered for this.

CHAIRMAN SALOMON: So that is an important statement. There is a drug
available for these children, and should that be considered in the trial
designs. John.

DR. COFFIN: To take the other extreme on this, the only fundamental
differences I see, if I got them right from what we have been presented,
is the dose that was given and the follow-up time.

Otherwise, I have no good faith basis for thinking that there is any
fundamental biological difference in what is being done in ADA-SCID
versus this that will impact this kind of outcome in that disease.

We have just basically an anecdote, that we have two patients here and
none there, but in my opinion that is only an anecdote at this point of
the level of evidence that we have.

CHAIRMAN SALOMON: I think we should discuss that because I think it is
really different. But let other people deal with it.

DR. COFFIN: It is a matter of one\'s feeling about the underlying
biology, but I think it is only a feeling because we do not know what
the important biological parameters that underlie these events are.

And until we do, all we can offer I think is gut feelings regarding
differences in the diseases. I mean, I can understand what the
rationales are, but they are just rationales right now. There are no
data that support them.

CHAIRMAN SALOMON: I would like more discussion on this, but again this
is really important. What we are dealing with now is how far our
anxieties and uncertainties now can drive regulation or inhibition of
progress in trials to treat sick people based on \-- in other words, it
is just as irrational for you to say, well, I am concerned because of
these X-SCID kids that it is going to happen to these kids.

DR. COFFIN: I would argue about levels of irrationality, but if it is
irrational, that is the level of rationality that the FDA aspires to.

CHAIRMAN SALOMON: Right. So let\'s see where that goes. Crystal.

DR. MACKALL: Well, I mean, we didn\'t talk a lot about it today, because
I think that there were other more pressing issues, but we had an
extensive discussion at the last BRMAC meeting about the second hit and
then the potential critical role of the second hit being a gamma-c
signal, a growth signal.

And certainly when you are looking at IL-15 transgenic animals or IL-7
transgenic animals \-- animals that have a constitutive on through the
common gamma-chain \-- there is plenty of precedent that that is
oncogenic in and of itself; whereas, the ADA is simply a metabolic
pathway. So at the scientific level, they seem like, really, apples and
oranges to me.

So I think that there is a lot of rationale for believing, if you
believe in a second hit, that these are two different things.

CHAIRMAN SALOMON: Rich, and then Mahendra, and then Jon.

DR. MULLIGAN: Yes. I agree with John Coffin on this point, but I come to
a different conclusion. That is, I think it is a gut feeling. This
person just had a gut feeling, and maybe that is my gut feeling, too,
that it is different. But there are not sufficient facts.

CHAIRMAN SALOMON: Right.

DR. MULLIGAN: And the fact that we have is that there is not yet an ADA
kid who has this, and when the first one gets this, if someone gets
this, then I am sure that we will be right back here recounting the
conversation.

But I fall in differently, although I think that the reasoning is sound.
I don\'t think that you can prevent these things. I think that this is
the way that the course of clinical research has to actually move ahead.

CHAIRMAN SALOMON: Mahendra.

DR. RAO: I was just going to echo what you, Dan, and Richard have said.
Basically, I don\'t think we have data on the ADA in sufficient numbers
to be able to try and make a judgment call either way. And so we
shouldn\'t until we have data.

DR. KURTZBERG: I agree with that, but I also want to say that ADA is a
different disease, because these kids have the potential for endogenous
immune recovery with PEG-ADA or with gene therapy, because it is a
different kind of defect.

They don\'t have a preemptive defect at the level of an immune cell, and
that may be enough of a safeguard to prevent this kind of event from
transforming.

So I think it is very different, and it should be approached very
differently.

DR. ALLAN: Okay. I don\'t know that we have any data that says that a
transgene is responsible for the leukemia or even a second hit. We
don\'t have any information; it\'s a guess. It is. It is a guess. It is
probably a pretty good damn guess, but it is still a guess.

And for me, like Abbey was saying, you have got some treatment already,
so it is not a last-resort therapy. So if it was your kid and your kid
was on this pegylated-ADA and the kid was doing fairly well, but you
wanted to try something different because you didn\'t want this kid to
be on this thing, and you gave him the gene therapy, and the kid got
leukemia, that would be awful.

So I am a little concerned when you say, well, wait until we get a
leukemic kid. If it was my kid, I don\'t want him to come in here with
leukemia.

CHAIRMAN SALOMON: So you read the informed consent, and you don\'t agree
to your kid having the trial. But I think we have got to be careful
here. The retroviral \-- I mean, if you want to go there, Jon, and you
are welcome to do that here, then you get to the point where you stop
all retroviral gene therapy. Because this is just going to reverberate
out to any sort of integrating gene therapy.

DR. ALLAN: No. This is a hematopoietic stem cell in a SCID.

CHAIRMAN SALOMON: Okay. Then you draw the line at hematopoietic stem
cells. Okay. Warren, and then David.

DR. LEONARD: I was just going to say that I am really not convinced that
the transgene is having an effect, and I know that we have no way of
knowing definitively one way or the other.

But the fact is that the gamma-chain, to the extent that we know, is
constitutively expressed, and there is no evidence of JAK-3 activation.
I think that the IL-15 and IL-7, et cetera, transgenes are different
because then you are constituitively providing growth factors that are
normally not constitutively present.

And without the constitutive presence of the growth factors, there is
not necessarily a reason to think that the receptors are going to
respond when the gamma-chain is presumably there anyway in the wild-type
situation.

So I am just throwing that out for food for thought, that I am not
convinced that the gamma-chain gene transduction is contributing. I
don\'t want to rule out that it is not, because I can\'t know.

So I think ADA deficiency is in fact quite different. Nevertheless, you
know, there is a possibility of integration of the ADA transgene, for
example, in the LMO-2 locus or elsewhere. So I think that there is a
finite whatever-the-risk-is associated with that type of therapy as
well.

CHAIRMAN SALOMON: David, and then Barbara.

DR. HARLAN: I am going to be a broken record here, but I am going to
fall in with Jonathan Allan, Abbey, and what Warren just said. Because
what we are saying is whether or not we should let informed consent be
the arbiter or regulatory guidelines be the arbiter. And I think the
latter should be on this alternative therapy rule.

Because if we see a \-- number one, informed consent. Patients, no
matter what \-- and our ethicists I think will back this up. If it is
allowed, there is an implicit statement that doctors wouldn\'t even let
me do this if they really thought that it was dangerous, or they didn\'t
have some pretty good idea. No matter how you word it, there is that
implicit communication.

So if a kid does get leukemia, someone will say, What were you guys
thinking? You knew that this was a risk, and you allowed this to proceed
when there was an alternative therapy.

It seems to me that we have to do it only for those where there is no
alternative therapy.

CHAIRMAN SALOMON: I have no problem with that, and that is well said.
Just as a point of context though, that is what we said in October. One
of the major messages we made in October was that the risk/benefit
analysis has to be in favor of the therapy.

So what that means to me, Abbey, is that if you have a drug, in this
case pegylated ADA, that is part of your risk/benefit analysis. And,
again, if a sponsor can make adequate case that the risk/benefit
analysis is such, then I think that works.

And so I don\'t think that we need to reinvent risk/benefit analysis at
this point. I think that we affirmed that in October, and that is one of
the things that I think we did well. Claudio, do you have a comment?

DR. BORDIGNON: Yes. I must apologize, because probably during my rush in
my presentation, I was not very clear about the data on the PEG-ADA.

I think that everybody can assess this, but about 80 percent of the
patients were on PEG-ADA and alive, which means that the other ones were
not.

Of those patients, the ones that failed PEG-ADA and had to go to bone
marrow transplantation, overall 73 percent are alive, which means that
the others are not.

Of all the patients who went into gene therapy \-- there are over 20,
but I am not sure about the numbers right now \-- they are all alive. I
cannot say that they are all well.

All the patients that are in gene therapy without PEG-ADA are alive and
well. I think that the numbers speak for themselves. Of course they are
not big numbers, and of course the follow-up is not at the same level as
the gamma-chain. It is a different disease and a different condition,
and a different age.

But how do I deal with parents asking me about the choice between the
two treatments, and having to say that a treatment with 30 percent risk
of dying is better than a treatment so far that has zero percent dying.

CHAIRMAN SALOMON: So the question would be: Can we focus this discussion
enough to now vote on whether we would take a position as a committee on
the trials on ADA?

And, again, this is not an academic question here. There are three
trials. My thinking here, my intuition is that there is two ADA trials
and one other trial that is not an ADA; is that right? Because they were
both put on hold the last time in October.

DR. NOGUCHI: There is just one ADA trial. But there is an ongoing study
that is not accruing patients.

CHAIRMAN SALOMON: But my point is that it is not academic, right? I
mean, there are people waiting to find out whether they can go forward
with an ADA trial in the U.S.?

DR. NOGUCHI: That\'s correct.

CHAIRMAN SALOMON: So I think that the community has got to grapple with
this one. Whether we can successfully or not, we will figure out in a
second.

But I would like to propose that, for the moment, provided an
appropriate risk/benefit analysis \-- a principle that was articulated
in October \-- and an appropriate informed consent principle that was
articulated in October, I don\'t believe that there is enough data on
the table right now that justifies this committee stopping retroviral
gene therapy for the other forms of SCIDs that we have not already
targeted.

And I don\'t want to see that happen, and that is my personal opinion.
Alison.

MS. WOLFSON: I need to say something about the appropriate risk/benefit
analysis. We just heard a risk/benefit analysis, and I asked David,
because I am a non-scientist, do the kids, the 20 percent who die, do
they die from the medication, or do they die because the medication has
not worked and then the disease kills them. And he said, the latter.

Well, that is a whole different way of looking at what a risk/benefit
analysis is. Here you have a drug and there is a 20 percent chance that
you are going to die, and a hundred percent chance that you won\'t if
you do this. But that is not really true.

CHAIRMAN SALOMON: John.

DR. COFFIN: I, too, hate to sound like a broken record, but the only
thing that gives me some optimism that we won\'t see the same kind of
adverse events in the ADA case is that the dose of cells is smaller, and
that really is the only thing that I think we could hang some biological
difference on.

And I think somehow we should get that idea out there, that less can be
more in these cases.

CHAIRMAN SALOMON: Butch.

DR. TSIATIS: I have gotten very confused with the numbers that are being
thrown around. I heard before that there is an FDA-approved therapy that
has a 90 percent success rate.

And then I hear that there is only a 70 percent success rate. Then I
hear there is a hundred percent, with very limited follow-up. So I am
getting very confused what is what.

Again, I feel very uncomfortable given that we have a problem that
children that are eligible for an FDA-approved therapy that is
beneficial, that they be eligible for a trial that we know right now is
a problem, at least for the time being.

CHAIRMAN SALOMON: As long as, Butch, what you are saying now \-- it is
fine to say it that way \--but what you are saying then is that any
retroviral gene therapy or lentiviral gene therapy, for that matter, in
hematopoietic stem cell, you don\'t feel comfortable with right now.

DR. TSIATIS: As long as there is no alterative therapy.

DR. ALLAN: So let me get this straight for me. If the child can take
pegylated ADA, why not put him on pegylated ADA? If he fails, then you
are basically in that mode where there is no alternative. And then you
could have gene therapy. So that is how I would look at it.

CHAIRMAN SALOMON: I think the important thing here is \-- well, sure, I
agree. But the point here is that I don\'t think that it is our job to
design the trial. Our job is just to deal with the principle that, under
the right circumstances, it can go forward.

DR. ALLAN: But it is the same principle that we just did with the X-SCID
kids. So I am just saying that we are using the same principle, which is
if you have got an alternative therapy that works well, then the
firstline should not be gene therapy.

CHAIRMAN SALOMON: And my point to David was, Exactly. That\'s the
risk/benefit analysis, right? I mean, obviously there are individuals
that are not getting full benefit from replacement therapy with
pegylated ADA.

It is extremely expensive, and it is in short supply. There have been
different times that it has not been available. It isn\'t perfect. It
requires a constant, umbilical cord attachment to medical care.

So there is a lot of reasons that these sort of intermittent infusion
replacement therapies are not ideal. So it is okay to see that they have
got their good and bad points.

DR. ALLAN: I just do not want to be responsible if the kid is given gene
therapy and isn\'t being offered \-- or the way it is being offered
makes him jump for gene therapy, instead of PEG-ADA, and he gets
leukemia. I am going to feel responsible for the fact that that kid got
leukemia.

CHAIRMAN SALOMON: Joanne and then Ken.

DR. KURTZBERG: One thing in defense of gene therapy for ADA that has not
been said is that children on PEG have a selective disadvantage to
benefit from gene therapy because you take away the selective advantage
for the gene-altered cells to work.

So it is actually a more complicated situation than we have been able to
talk about today. Because, although PEG does have such efficacy, it has
only had short-term observation, and it undermines other types of
therapy that might be based on selective advantage. So it is just
something to put on the table.

CHAIRMAN SALOMON: The field agrees that if you are going to do this, you
are going to have to remove the pegylated ADA to allow selective
advantage to work. Ken.

DR. CORNETTA: Well, maybe just to remind the committee, because I know
you said three o\'clock, but we have talked about X-SCID for a long
time, and there have not been any U.S. trials, I think, that have
entered any patients. This is a still low number, and if you look at
Carolyn\'s slide, the ones that we have not talked about are really the
largest number of studies, and we should make sure that we discuss that.

But I think to follow up, what probably what we are struggling again
with is something that we consider firstline therapy, or in the case
where there is no alternate therapy.

And I still am not sure that there is a consensus here, but it seems to
be that is what we are trying to move towards.

DR. MACKALL: We have not mentioned bone marrow transplant for this
either. We have only talked about the PEG.

DR. CORNETTA: Again, that is an alternate therapy.

DR. MACKALL: Exactly. Would we have to have worked through bone marrow
transplant? That is the question.

CHAIRMAN SALOMON: Okay. So I am sitting here, and what is going through
my head is that, for people who want to talk, there is 20 minutes left,
and if we don\'t push this to the next logical ripple, which is
hematopoietic stem cells or not, then we have not done our job today.

So if you will forgive me, I am just going to temporarily push past this
for a second and not force a vote on this ADA thing yet, but hopefully
we can come back to it. I may be in la-la land now.

But how far do you guys want to ripple this out? Retroviral gene therapy
for a hematopoietic stem cells is on the table, and that is the next
concentric circle that I see.

DR. WILSON: And as Dr. Cornetta pointed out, we currently have
approximately 27 trials that are on hold using hematopoietic stem cells,
so that is an important issue that the committee needs to discuss.

CHAIRMAN SALOMON: So everybody keep their comments real short here so
that we can get everybody\'s comments, but just that we get them.

MS. MEYER: I just want to ask a question of the FDA, which is that I
think at the last meeting we asked that you have all of the gene therapy
scientists report to you on any clinical trials underway and test the
blood to see if there had been any of this insertion problem. What did
you find?

More than half of gene therapy is on cancer. So if a patient died of
cancer, nobody is even going to think about this. Did you find any of
this other insertion problem in those?

DR. RASK: Well, we have only gotten limited data since that meeting in
October. And we were only asking them to monitor that periodically, but
we have not obtained any information of concern.

CHAIRMAN SALOMON: Abbey, we are not going to get this data. I mean,
let\'s go on. With all due respect, you are not going to get an answer
to your question. It is not anyone\'s fault. It is just that it is
really complicated to do those kinds of studies, and no one is doing
them yet. David.

DR. HARLAN: So if we start from the point of using this
no-alternative-therapy standard, there must be hundreds of people in
this room who have arguments on why not to use that. I would like to
hear what do we lose by using that as the standard.

It will continue because there are going to be patients for whom there
is no alternative therapy. I don\'t see what we lose by adopting that
safety standard.

CHAIRMAN SALOMON: Be brief.

DR. JUNGHANS: I think with oncology, you have got a real problem because
we always have another chemotherapy that we can give. So there is
alternative therapies. There may not be alternative curative therapies,
but when you are giving PEG-ADA, you are not giving a curative therapy
either.

So I think you have to be careful how you phrase that.

DR. HARLAN: But I would say that jurisdiction should be at the IRB
level. An IRB would recognize that an alternative anti-cancer agent is
really not an effective alternative therapy, and that we should leave
that at the local jurisdiction.

DR. JUNGHANS: You have to be careful how you phrase that because IRBs
can be very nervous when they hear someone say, \"no alternative,\" and
they hear \"gene therapy\" on the other side. Believe me.

CHAIRMAN SALOMON: Okay. Hematopoietic stem cells. John.

DR. COFFIN: Again, I will express the conservative position, which is
that I don\'t see right now any evidence that the same kind of event
will not happen or should not be considered as a significant risk with
any hematopoietic stem cell therapies, so long as adequate numbers of
transduced cells are infused.

That is not to say that in any given case it should not go forward, but
in the risk/benefit balance, I think this should be the risk. Clearly if
somebody is going to be \-- if we are talking about terminal cancer
patients, it is an insignificant risk.

But this is what I think should be on a risk side of a risk equation
like that.

CHAIRMAN SALOMON: Okay. Rich.

DR. MULLIGAN: I always go after John and say that I agree, but I still
draw the opposite conclusion. So I think that is true that these other
things are hunches. I say that ADA is no different than any other stem
cell, and certainly there is some reason to think that insertions will
cause difficulties.

Nevertheless, I still harp on the lack of any data suggesting in
patients that bad things will happen in other diseases. There is no
direct evidence. And I just happen to think that is the way that one
ought to look at this.

CHAIRMAN SALOMON: I would reiterate that. I mean, what we are faced
with, factually, is two tragic complications in an otherwise successful
gene therapy trial in a disease called X-SCID.

And that really to me is no different than a leukemia trial that someone
got then lymphoma 12 years later or something. And we have got to be
really careful that we suddenly abandon all existing principles of
informed consent, and risk/benefit analysis because theoretically \--
which we have known all along, John \-- a retroviral vector with an
integration \-- I mean, I know that I don\'t need to tell you of all
people. Ken.

DR. CORNETTA: I think the risk is significant. I don\'t know how
frequent it is, and that\'s what we are, again, still struggling with. I
do think that for Phase I that these studies are generally done in
populations where there is either no alternative therapy or no therapy
at all.

I think the one thing that we can, again, try to advise the FDA, which
they probably thought of already, is that as they look at the process of
going from Phase I to Phase II to Phase III agents, there is more
characterization and validation of that process.

But, in addition, to make sure that they are telling the investigators
that they now need to be thinking about their vector construct, what is
the enhancer there, and all the things that we have talked about today
so that the FDA is also communicating that to investigators, that as
they are moving beyond Phase I they need to be considering this in the
development of their product.

CHAIRMAN SALOMON: Present and future. Cindy.

DR. DUNBAR: Well, I do think that we do have some data from the large
animals. I mean, those animals\' median cell dose was 65 million. That
is not that far. There are 46 animals with, if you add up the follow-up
years, 250 follow-up years, and I calculated it to be like 5,000
insertions that we know about so far. I mean, they have not all been
sequenced obviously.

I believe that there is something unique about the selective expansion
of the cells, potentially the transgene may be less likely. I think
it\'s the age. I mean, I don\'t think we know yet.

But when you say \"no alternative therapy,\" there is no way that you
can even think of developing HIV \-- many genetic diseases, like CJD,
thalassemia, sickle cell, et cetera, where there are certainly
alternative therapies, but they are just not necessarily very good ones.

And I don\'t think that the risk in the other group \-- I think we have
data that would suggest that we are not going to suddenly see 20
leukemias with a neovector or a globin vector. We don\'t know.

But we do have a lot of experience, and I think we need to figure out
what it is about the bone marrow or the transgene in that particular
clinical situation that may have led to second hits.

CHAIRMAN SALOMON: David. And, again, let\'s keep it very brief because I
want to get to a vote in a minute.

DR. HARLAN: So I don\'t think that anybody said, \"no alternative
therapy.\" The words that people have used are \"failure\" or \"no
effective alternative therapy.\" And the second point is imagine a
situation where a treatment was available for Disease A, and two of
eleven of those patients got a serious complication.

And then we are asking about using that same therapy for Disease B, and
saying because there is no proof that it causes that complication, we
should let it proceed. That is not where the safety equation falls for
me.

It seems to me we should say its absence of proof does not mean proof of
absence.

CHAIRMAN SALOMON: Kathy and then Bruce.

DR. HIGH: Okay. I just want to point out that they are not the
equivalent therapy. When the transgene is different, the therapy is
different. And to me, I think it is being too liberal, not too
conservative, but too liberal to take adverse event data from one trial
and extrapolate it to everything that uses the same vector and the same
target cell.

Because if the transgene is different, then the therapy is different.

CHAIRMAN SALOMON: Well, the transgene is different, but the disease is
different, the ages are different, the co-existing comorbidities are
different. So that is the issue.

DR. RAO: That is like taking one chemotherapy drug and saying it is like
another chemotherapy drug and we can generalize across all of them. I
mean, we don\'t do it, so we shouldn\'t do it because it is a gene
therapy.

CHAIRMAN SALOMON: Okay. Bruce. Again, be brief.

DR. TORBETT: I tend to agree with the analogy to cancer. I think we are
trying to lump everything together and draw large conclusions based on
very little data at all, and I guess I would err on the side \-- and
perhaps in six months I hopefully won\'t be back here\-- err on the side
of being more cautious, and trying to keep the bar at a reasonable level
to proceed in this area, and not kill it off completely.

So I guess I would agree with what Kathy was saying, that I think that
without any data \-- and there has been history with Cindy Dunbar\'s
work and others, that it has been fairly safe so far. And I use
\"fairly.\"

CHAIRMAN SALOMON: Ken and then Barbara.

DR. CORNETTA: Well, I guess to put it in an analogy that we are getting
used to, I think with the X-linked SCID that we are sort of at Code Red
or whatever, Yellow, and I think \--

CHAIRMAN SALOMON: That is worse than my ripple metaphor.

DR. CORNETTA: But in a sense I think that there are so many different
diseases that we are talking about \-- it\'s oncology patients, it\'s
HIV patients \-- that it is going to be very hard for us to get a
consensus on what the risk is for each of those.

But in a sense I think what direction we can give the FDA is that we are
not considering the risk that we see with the X-linked SCID to be the
same risk currently with these other trials.

There is certainly room for concern. We are not down to Code White or
whatever, but we are probably somewhere in the middle. But I think the
recommendation that we can give currently is that there is enough
difference to say that these are not equivalent risks.

CHAIRMAN SALOMON: Barbara.

MS. BALLARD: Another thing that I was going to say is that I think we
are kind of working semantics of language here in the difference between
whether there is a failure of standard treatment versus no optional
treatment, or alternative therapies.

Do we want to specifically say that there has to be no alternative
therapy? And I don\'t think that is what anybody is trying to do. So I
think the language that we are using is a little bit of a misnomer.

We need to present it to the FDA in a way where if there has been a
failure of standard therapy, then a risk/benefit analysis needs to be
done on a case-by-case basis.

CHAIRMAN SALOMON: I would even go a little further and say that as far
as I am concerned, when you get out to just all retroviral gene
therapies and hematopoietic stem cells, as long as the informed consent
is unequivocally clear about what has happened, I would not touch those
trials at all.

And I would not try and craft language today to change them. I am very
comfortable with those trials. I don\'t think anything that we have
heard today changes those trials.

I know that everybody does not agree with that, but I am just saying
that I don\'t think we have to get hung up right now on that language. I
thought that was important for the X-SCID statements and your points are
well taken on that. But I don\'t think that is important now.

DR. NOGUCHI: To try to cut to the chase here, I will say that the FDA
already has a policy for the 27 trials outside the SCID, and X-SCID, and
ADA- SCID, and that would be on a case-by-case basis. We will have and
have entertained on a case-by-case basis taking people off, given all
the caveats that we have from the October 10 meeting.

What we are simply asking here in the sense of that larger scale is:
What is the sense of the committee regarding risk? And we have already
made a determination that we are prepared to move forward in specific
cases where there are no alternative therapies or where the therapies
are inadequate.

CHAIRMAN SALOMON: I would like to, just for times sake here, we have got
two important questions that we need to vote on. I think we have
articulated all the sides, and we don\'t all have to agree.

AUDIENCE MEMBER: Can I say one thing about the patient side?

CHAIRMAN SALOMON: If it is really quick.

AUDIENCE MEMBER: I just think that you are in a unique position here,
where everyone has been saying that informed consent is for desperate
parents, and therefore it is like less legitimate.

Well, now you have a perfect opportunity where informed consent is not a
desperate situation. It can be used as a situation to really empower the
patients or the parents to make a more informed balanced decision.

So you have an opportunity here to make informed consent part of it, and
I think that is powerful.

CHAIRMAN SALOMON: I think we all agree, and I think this informed
consent issue is really good. I just think that \-- everybody is always
ready to beat us up with this informed consent when it suits them, and
then they are always ready, like you, to tell us, oh, you know, informed
consent is such a great tool.

We are not trying to get rid of informed consent. But I think you have
got to realize that this has been used against us and used with us, and
it is not as clear to me. We really think we can do better informed
consent, and we are really trying our best to do it. I guess that is
what I am trying to say.

So can we have a vote now on should we advise the FDA that there should
be a hold on retroviral gene therapy trials continued that use
retroviral vectors for hematopoietic stem cells.

DR. ALLAN: Dan, that is not what he is saying.

CHAIRMAN SALOMON: That is the vote that I want to hear though. What is
different?

DR. ALLAN: This is on a case-by-case basis when there are not other
therapies, either no alternative therapies or what was the other?

DR. CORNETTA: Inadequate. I mean, it is the responsibility of the
sponsor to really justify to us why this should proceed.

DR. ALLAN: So it is not a question of putting a hold on all therapies
because that is not what is going on, right?

CHAIRMAN SALOMON: Right now they are all on hold, Jon. So I am asking
the committee whether they can vote to take the trials off hold. That\'s
all I am trying to get at. I am not trying to stipulate what the basis
of the off-hold is, just that we would advise the FDA that they can now
review the 27 trials on a case-by-case basis to take them off the hold

Or do we want to go with the opposite feeling that I think John has
articulated very clearly, that this is a risk of this class of vectors,
and it is not acceptable, and they should all stay on hold.

DR. COFFIN: That wasn\'t exactly it.

CHAIRMAN SALOMON: I was just taking your articulated ideas as the other
thesis. So can we vote? How many would agree to advise the FDA to go
back and take a reevaluation of all 27 cases on a case-by-case basis
because we feel that they don\'t have to be on hold any longer just
based on the fact that that they are using retroviral vectors and
hematopoietic stem cells? How many would agree to that?

DR. HARLAN: I will agree to that, but that is where I thought you said
you were right now.,

CHAIRMAN SALOMON: No, it\'s not. Everything is on hold right now.

DR. HARLAN: The FDA doesn\'t even have the prerogative to release them?

CHAIRMAN SALOMON: Well, the FDA can, but we are trying to advise the
FDA. They want to know our advice on this.

DR. NOGUCHI: We are, on a case-by-case basis, entertaining proposals
from sponsors where they can demonstrate to us satisfactorily that there
is no adequate therapy or inadequate therapy for life- threatening
diseases.

And we have implemented for those conditions the advice of October 10,
and that has been updated with the evidence of the new adverse event. In
that sense, I think this vote would be saying in general, given \--
rather than wait for people to come to us, we should actively work with
sponsors on this.

It is sort of, where is the burden placed to take people now off
clinical hold in this subset.

CHAIRMAN SALOMON: How many vote aye? I am trying to articulate what Phil
said. Basically, can we advise the FDA that it is time for them to
remove the blanket hold on all retroviral gene therapy trials in
hematopoietic stem cells and review them case by case, and where
appropriate risk/benefit is there, and where appropriate consent form
documents are given, and where there is an appropriate balance in this
concept of risk/benefit of alternative therapies that have been
considered, that they can take them off hold and let them go forward.

DR. TSIATIS: Just a point of clarification. How is this different from
our motion with the SCID?

CHAIRMAN SALOMON: It\'s not. We are just following the ripples, Butch,
because there are now 27 trials waiting to hear what we have to say.

DR. MACKALL: With the SCID, we said that this shouldn\'t happen.

DR. ALLAN: To me, it is just wording because it sounds to me like you
are saying that we are going to take everything off hold, and it sounds
like we are giving the green light to go forward with all these trials,
and that is not what you are saying.

CHAIRMAN SALOMON: No. I am definitely not saying that. I am trying to
capture what the committee was saying, which is that we have concerns
about consent forms, and we have concerns about risk/ benefit, and we
have concerns about a careful consideration of alternative therapies.

So I am trying to say that given that you don\'t want to review all 27
trials before they can go forward, we ought to advise, if you can get
yourself to that point, the FDA that they should do it.

DR. COFFIN: Dan, I would support this if the FDA at the same time when
they went back over these asked the sponsors to give an incisive
analysis as to whether or not these events \-- what the probability,
based on what they can tell now, of these kinds of events occurring in
their trial is.

CHAIRMAN SALOMON: Can we vote first, and I will come back to you. But
can we just vote on what I said first? So how many people vote aye?

(Vote taken.)

CHAIRMAN SALOMON: It is not unanimous. How many people vote nay?

MS. DAPOLITO: Dr. Salomon, can we take a poll by individual?

CHAIRMAN SALOMON: Well, I thought the nays would be easy.

MS. DAPOLITO: But we are required to have on record your vote.

CHAIRMAN SALOMON: Okay.

(Vote off microphone.)

DR. HARLAN: If I understand it, aye.

DR. HIGH: Aye.

DR. FRENCH: Aye.

DR. CORNETTA: Aye.

DR. WOLFF: Aye.

DR. TORBETT: Aye.

MS. MEYERS: Aye.

CHAIRMAN SALOMON: And Barbara. Thank you, guys. Now, if I can just back
you up. How about ADA-SCIDs? One way we could deal with this is to say
we just dealt with it. I am happy with that. I like it. Now, the last
thing here would be that John suggested is there something else that the
committee would feel.

Now, I have to say to you that with the world looking at us like, Did
you do the right thing in October and did you do the right thing in
February, I personally would like to see at a website somewhere at some
point in the near future where I could tell people go to the website and
all 27 trials have a couple of paragraphs about how they dealt with
these issues.

I feel like all of us feel a lot of responsibility, and I feel like we
have done a really hard job here for you to give you support, and that
gives us as a whole field an integrated answer to a tough issue.

You know, sick and dying patients and safety issues and trials gone
array and the whole thing. But I sure as heck would like to be able to
point people who start hassling me six months from now to just go to
such-and-such a website and see what we really did.

DR. NOGUCHI: I think we would take that under advisement and strive to
do that. As you know, though, each case is individual and we may not be
able to necessarily make public each response.

We may be able to in a better sense be able to give you both the general
feeling, as well as some of the outliers. I just think that on a case by
case basis we would be not in a good position at FDA to completely
specify all the responses.

But the point is absolutely well taken, and part of the discussion and
part of the minutes for this particular meeting will be reflecting these
concerns.

CHAIRMAN SALOMON: I guess to be really specific, what I am saying and
the committee can agree and support it or not, but I guess the message
that I am giving you after this experience of doing this thing in
October and being back here in February to do it, and then listening to
Bruce say, gee, I wonder what I am going to say six months from now, and
I think we heard that from Kathy and from others as well, is \-- I mean,
we need or you need to do this.

I mean, you guys really need to go through all of these cases, and it
had better be clean if we are back here again in September.

DR. MULLIGAN: I want to emphasize that all the things that we didn\'t
get to, like the cell dose, and actually implementing that. I think it
is very, very important that our concerns are really emphasized, in
terms of we think that \-- I certainly think that things like suicide
vectors, insulator vectors, all those things are incredibly important.

And it is not that we don\'t think that they are important. And it would
be fantastic if, although we have not implemented any of these issues,
people got the message that we do think \-- many of us think the cell
dose is key.

That the number of integration sites is key, and it would be wonderful
if new clinical trials were \--

CHAIRMAN SALOMON: I didn\'t shut you off. Ken. I would just say that Ken
sort of captured that, you know, sort of present and future. But, Ken,

your comment.

DR. CORNETTA: Another comment, and maybe I\'m sorry that I am sitting so
close to the FDA folks here. One of the things in line with this is the
clonality that has been asked for by investigators. And to be able to
analyze what that data is, there is going to have to be some consistency
in what that analysis is going to be.

And I would ask the committee to maybe \-- if they agree with me \-- to
sort of make the recommendation that at least some type of paper or
guidance comes out on what that analysis \-- you know, what are the
expectations and sensitivity, or is there some common or agreed-upon
assays that would be done.

But really some specific guidance for investigators because I think
that\'s going to be key to collecting that data and having compliance.

CHAIRMAN SALOMON: And I would just point out that we made a decision two
hours ago to go a little different direction, and to the FDA\'s credit,
those very specific kinds of questions were spelled out in their
questions.

So we didn\'t get to those, but I think that everyone can agree that
those are the next big steps, and there may be another BRMAC meeting
that needs to happen in 6 to 12 months to do that. Bruce.

DR. TORBETT: I think, with the whole world watching on this decisions, I
think that some type of website or some type of information and profile
similar to what Rich and Ken said is needed, and I think that it needs
to be updated, because if this is a recurring theme, I think the public
needs to know what is going on, and I think it is imperative for the
committee to decide something along these lines.

CHAIRMAN SALOMON: Abbey and then Linda.

DR. WOLFF: I just want to say that if there are animal studies going on
right now, preclinical studies, that those animals should be kept longer
if possible.

CHAIRMAN SALOMON: Write your Congressman, Kathy.

MS. MEYERS: On the informed consent argument thing, I want to agree with
what somebody said before that there should be some piece of paper
written by the FDA that is required to be attached to the informed
consent document so that every patient, no matter where they are in the
country, who is considering gene therapy, would have, like, a patient
package insert.

CHAIRMAN SALOMON: Abbey, in fact, if you go back to the website around
October, we specifically said there should be standard language drafted
by the FDA for the informed consent, and indeed they did that, and that
was what they were reading from for all retroviral gene therapy trials.
Tom.

DR. MURRAY: Also on informed consent, which is going to be made to bear
an enormous amount of moral weight in these trials, there is a growing
and significant body of empirical information about when informed
consent \-- how and when informed consent can be made meaningful and not
merely a pro forma exercise.

And everything from the cognitive errors that people commonly make in
judging risks, including ways of presenting information, not just \-- I
guess I was getting distressed by this notion that somehow we are going
to have a magic paragraph that is going to solve all of our problems.
That is not the way it is going to work.

And, in fact, I think I would recommend to the FDA that it recommend to
any group that wishes to do these trials that they should familiarity
with this empirical literature about informed consent, and that in fact
it is in conformance with best practices of informed consent.

CHAIRMAN SALOMON: Well, I don\'t know about your institution, but every
year I have to recertify the fact that I am exhaustively aware of
everything that happened in the last 12 months, and that is the point
there. David, a last comment.

DR. HARLAN: So if I understood what I just voted for, it was to move the
onus of responsibility from the IRBs to the FDA, and then you \-- well,
sort of, but \-- well, no?

CHAIRMAN SALOMON: Remember these programs are on IND, these programs are
now on hold. We are telling the FDA to go back, review them, and let
them go. The IRBs can make their own decisions after that.

DR. HARLAN: Right. Yes, that is what I meant to say. And then you had
asked could we have on a website some short paragraph from each center
and Dr. Noguchi\'s response was maybe yes and maybe no. I would just say
for those instances, where there isn\'t explicit wording as to that
analysis, that some generic wording to that effect be placed on the
website. That is my only suggestion.

CHAIRMAN SALOMON: Well, again, I think that the best thing the FDA does
now is publicly demonstrate that these 27 trials, and any other trial
after that, address the principles that we have articulated for you in
October and February.

I mean, I think that is really important, because the public is going to
come to it and the public is going to demand it, particular if the
you-know-what hits the fan in another six months from now.

DR. NOGUCHI: Obviously, we will work to implement all the advice. We may
be getting back to the committee for help on some of the details, but we
greatly appreciate all the advice that is being given and continues to
be given.

This is a difficult area and I thank the committee in its entirety, and
including the public here, for helping us move through these very
difficult issues.

CHAIRMAN SALOMON: So with that, I am closing this meeting, the last of
my chairmanship of the BRMAC, and to tell you just \--

(Applause.)

CHAIRMAN SALOMON: And in keeping with my idea of staying brief, it has
been an extraordinary experience with extraordinary people. Thank you.

(Whereupon, the Advisory Committee meeting was concluded at 3:08 p.m.)