1
DEPARTMENT OF HEALTH AND HUMAN SERVICES
FOOD AND DRUG ADMINISTRATION
CENTER FOR DRUG EVALUATION AND RESEARCH
ONCOLOGIC DRUGS ADVISORY COMMITTEE
Wednesday, December 1, 2004
8:00 a.m.
Holiday Inn, Silver Spring
8777 Georgia Avenue
Silver Spring, Maryland
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PARTICIPANTS
Victor Santana, M.D., Acting Chair (a.m. session)
Silvana Martino, D.O., Acting Chair (p.m. session)
Johanna Clifford, M.S., RN, Executive Secretary
MEMBERS
Otis W. Brawley, M.D.
Ronald M. Bukowski, M.D.
Bruce D. Cheson, M.D.
Stephen L. George, Ph.D.
Pamela J. Haylock, RN
Maha H.A. Hussain, M.D.
Silvana Martino, D.O.
Joanne E. Mortimer, M.D.
Michael C. Perry, M.D.
Gregory H. Reaman, M.D.
Maria Rodriguez, M.D.
INDUSTRY REPRESENTATIVE (NON-VOTING)
Samuel Maldonado, M.D.
CONSULTANTS (VOTING)
For clofarabine
Joanne Kurtzberg, M.D.
David Poplack, M.D.
Victor Santana, M.D.
Alan Wayne, M.D.
For Marqibo
Michael Bishop, M.D.
Wyndam Wilson, M.D., Ph.D.
PATIENT REPRESENTATIVES (VOTING)
Ruth Hoffman - for clofarabine
Susan Krivacic - for Marqibo
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PARTICIPANTS (Continued)
FDA
Martin Cohen, M.D.
Ramzi Dagher, M.D.
Ann Farrell, M.D.
Maitreyee Hazarika, M.D.
Steven Hershfeld, M.D.
Richard Pazdur, M.D.
Robert Temple, M.D.
Grant Williams, M.D.
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C O N T E N T S
Page
Morning Session
Call to Order:
Victor Santana, M.D. 6
Introductions 7
Conflict of Interest Statement
Johanna Clifford, M.S., RN 9
Opening Remarks
Richard Pazdur, M.D. 11
NDA-21-673 Clolar (clofarabine)
ILEX Products, Inc.
Sponsor Presentation
Introduction
Steve Weitman, M.D., Ph.D. 19
Pediatric Leukemia
Bob Arceci, M.D., Ph.D. 21
Clofarabine Pivotal Studies
Steve Weitman, M.D., Ph.D. 26
Clinician's Perspective
Steve Sallan, M.D. 49
Clofarabine Development Plan
Steve Weitman, M.D., Ph.D. 54
FDA Presentation
Martin Cohen, M.D. 60
Questions from the Committee 83
Open Public Hearing 139
Committee Discussion 163
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C O N T E N T S (Continued)
Afternoon Session
Call to Order
Silvana Martino, D.O. 221
Introductions 221
Conflict of Interest Statement
Johanna Clifford, M.S., RN 223
Opening Remarks
Richard Pazdur, M.D. 226
NDA 21-600 Marqibo (vincristine sulfate
liposome injection)
Inex Pharmaceuticals
Sponsor Presentation
Introduction
Alexandra Mancini, MSc. 234
Overview
Fernando Cabanillas, M.D. 236
Pharmacology
Tom Madden, Ph.D. 245
Efficacy and Safety
Alexandra Mancini, MSc. 251
Clinical Benefit
Fernando Cabanillas, M.D. 284
FDA Presentation
Maitreyee Hazarika, M.D. 292
Questions from the Committee 309
Open Public Hearing 347
Committee Discussion 358
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P R O C E E D I N G S
Call to Order
DR. SANTANA: This is a meeting of the
Oncology Drugs Advisory Committee for the FDA with
additional pediatric oncology representation this
morning because we are going to discuss a new drug
application for the proposed drug clofarabine.
With that brief introduction, I want to
make two comments. First of all, I really want to
keep the agenda on schedule. We will allow all the
presentations to occur both from the sponsor and
from the FDA, and then we will proceed with a
period of discussion and comments, have our break,
and then come back and deal with questions and the
advice to the Agency.
So, I really want to keep on schedule as
much as possible, because there is another schedule
this afternoon that the Committee has to abide to,
and I want to make sure that they get their
opportunity this afternoon, too.
Secondly, I want to go ahead and do a very
brief introduction of all the members of the
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Committee, since we have additional pediatric
oncology representation today. So, if we could go
around the table starting with Dr. Poplack on the
left corner, introduce by name and affiliation.
Introductions
DR. POPLACK: David Poplack from Baylor
College of Medicine.
DR. KURTZBERG: Joanne Kurtzberg from Duke
University Medical Center.
DR. WAYNE: Alan Wayne from the National
Cancer Institute, Pediatric Oncology Branch.
MS. HOFFMAN: Ruth Hoffman, Patient Rep.,
Candlelighters Childhood Cancer Foundation.
DR. MALDONADO: Samuel Maldonado from
Johnson & Johnson, Industry Representative to this
Advisory Committee.
DR. GEORGE: Stephen George, Duke
University.
MS. HAYLOCK: Pamela Haylock, Oncology
Nurse, Consumer Representative.
DR. HUSSAIN: Maha Hussain, University of
Michigan.
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DR. PERRY: Michael Perry, University of
Missouri, Ellis Fischel Cancer Center.
DR. MORTIMER: Joanne Mortimer, University
of California, San Diego.
DR. SANTANA: Victor Santana, St. Jude
Children's Research Hospital in Memphis.
MS. CLIFFORD: Johanna Clifford, Executive
Secretary to the ODAC.
DR. MARTINO: Silvana Martino from the
John Wayne Cancer Institute.
DR. BRAWLEY: Otis Brawley from Emory
University.
DR. CHESON: Bruce Cheson, Georgetown
University, Lombardi Comprehensive Cancer Center.
DR. BUKOWSKI: Ronald Bukowski, Cleveland
Clinic Foundation, Cleveland, Ohio.
DR. COHEN: Martin Cohen, FDA.
DR. DAGHER: Ramzi Dagher, Pediatric
Oncologist and team leader in the Division of
Oncology Drug Products, FDA.
DR. WILLIAMS: Grant Williams, FDA.
DR. PAZDUR: Richard Pazdur, FDA.
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DR. SANTANA: With that, I will hand it
over to Johanna. She needs to read the Conflict of
Interest Statement.
Conflict of Interest Statement
MS. CLIFFORD: The following announcement
addresses the issue of conflict of interest and is
made a part of the record to preclude even the
appearance of such at this meeting.
Based on the submitted agenda and the
financial interests reported by the committee
participants, it has been determined that all
interests in firms regulated by the Center for Drug
Evaluation and Research present no potential for an
appearance of conflict of interest at this meeting
with the following exceptions:
Dr. Victor Santana has been granted a
waiver under 21 USC 355(n) for owning stock in a
competitor. The stock is valued from $5,001 to
$25,000. A waiver under 18 USC 208(b)(3) is not
required because of the de minimis exception
2640(b)(2) applies.
Dr. Stephen George has been granted a
10
waiver under 18 USC 208(b)(3) for serving as a
consultant to the competitor on an unrelated
matter. He receives less than $10,000 per year.
Ms. Ruth Hoffman has been granted a waiver
under 18 USC 208(b)(3) because her husband serves
as a consultant to two competitors on unrelated
matters. He receives less than $10,001 per year.
A copy of the waiver statements may be
obtained by submitting a written request to the
Agency's Freedom of Information Office, Room 12A-30
of the Parklawn Building.
We would also like to note that Dr. Samuel
Maldonado has been invited to participate as the
Non-Voting Industry Representative acting on behalf
of all regulated industry. Dr. Maldonado is
employed by Johnson & Johnson Pharmaceutical
Research and Development.
In the event that the discussions involve
any other products or firms not already on the
agenda for which am FDA participant has a financial
interest, the participants are aware of the need to
exclude themselves from such involvement and their
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exclusion will be noted for the record.
With respect to all other participants, we
ask in the interest of fairness that they address
any current or previous financial involvement with
any firm whose products they may wish to comment
upon.
Thank you.
DR. SANTANA: Thank you, Johanna. Any
other Committee member want to disclose any
conflict at this moment?
[No response.]
DR. SANTANA: Thank you. We will go ahead
and have Dr. Pazdur give us the introduction from
the FDA perspective.
Opening Remarks
DR. PAZDUR: Good morning. The sponsor of
the application in this morning's session requests
marketing approval of clofarabine for the proposed
indication of the treatment of pediatric patients
with refractory or relapsed acute leukemia.
The presentations will focus on one
single-arm trial conducted in 35 patients with
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relapsed, refractory AML and a second single-arm
trial in 49 patients with relapsed, refractory ALL.
A Phase I study was also conducted in 25 patients
with relapsed or refractory acute leukemia.
For the treatment of acute leukemia, the
Division has recommended the use of improved
survival or a complete response rate of a
sufficient magnitude and duration to ensure the
demonstration of clinical benefit.
Complete response rates of sufficient
duration are considered clinical benefit, because
they are usually associated with reductions in
infection rates and blood product transfusions, and
may be considered established surrogates for
survival in this disease.
Response duration is usually measured from
the time of initial response until documented tumor
progression. One problem encountered in this
application is the introduction of bone marrow
transplantation in patients who have received
clofarabine, but have not had documented disease
progression.
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The addition of transplantation prior to
the documentation of disease progression confounds
any interpretation of clofarabine's response
duration. No consistent prospective criteria were
used to determine patient selection for
transplantation. Some patients went to
transplantation with only a clofarabine partial
response or even without a response in these
single-arm trials.
A clofarabine induction response may
simply indicate a chemosensitive-leukemia and the
patient might do as well with transplantation
without clofarabine induction.
In patients who did not go on to
transplantation and, hence, response duration, can
be measured. These response durations were
generally short and many of these responses were of
uncertain duration because they were not confirmed
by a repeat marrow aspirate.
These results are presented in the
preamble to your ODAC questions. In 35 patients
with AML, there were no complete responses, only 1
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complete response without complete platelet
recovery, a so-called CRp, and 8 partial responses.
Of the 9 responding patients, 2 patients
did not go on transplantation prior to disease
progression. These patients had PR's. Their
response duration was short, 12 and 34 days.
Of the 49 patients with ALL, there were 6
CR's, 4 CRp's, and 5 PR's. In this population,
response duration was not confounded by
transplantation in only 9 patients. The 5 patients
with CR's had response durations of 43, 50, 82,
93+, and 160+ days. Only 3 of these 5 CR's had a
confirmed response. As in AML, PR's had a very
short duration of only 7, 16, and 21 days.
As stated previously, the Agency has
recommended a substantial complete response rate
and duration at endpoints for regular approval in
hematological malignancies denoting clinical
benefit.
In 1992, the accelerated approval
regulations allowed the use of additional endpoints
for the approval of drugs that are intended to
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treat serious and life-threatening disease and that
either demonstrate improvement over available
therapy or provide therapy where none exists.
The FDA may grant accelerated approval
based on the effect of a surrogate endpoint that is
"reasonably likely" to predict clinical benefit.
A drug is approved under accelerated
approval on the condition that the manufacturer
conduct studies to verify and describe clinical
benefit. The regulations stated an expectation
that post-marketing studies would usually be
underway prior to accelerated approval, however,
this is not a requirement.
At a March 2003 ODAC meeting, the ODAC
reinforced the Agency's view that these
confirmatory trials should be ongoing at the time
of accelerated approval is granted. Approval with
subsequent commercial availability of the drug may
interfere with subsequent enrollment to the
confirmatory trial.
We, the Division, are asking your opinion
regarding the accelerated approval of clofarabine
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based on the data presented. The ALL indication
should be considered separately from the AML
indication. There exists uncertainty regarding the
response duration because of the lack of subsequent
bone marrow biopsies to confirm a response and the
introduction of transplantation prior to the
documentation of disease progression.
Where durations can be measured, the
Division considers, with some exceptions, these
response durations to be limited. We have asked
the sponsor to present ongoing planned trials in
both pediatric and adult leukemia. Presently, we
have not identified any study that has been
designated as a confirmatory trial for the
subsequent demonstration of clofarabine clinical
benefit.
For our Division, this is the first time
we are considering a pediatric application for
accelerated approval. Pediatric drug development
in the treatment of pediatric malignancies differs
from adult drug development, therefore, we have
supplemented this ODAC membership with voting
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members from the pediatric oncology community.
Pediatric drug development has been
blessed by an exceptionally high rate of patient
enrollment compared to enrollment in adult studies.
Great strides have been made in curing and
prolonging the survival of children in the past
decades. Most children, especially with the
diseases under consideration this morning, are
treated on protocols at referral centers rather
than in the community.
Your discussions should consider the
ramifications of accelerated approval for the
pediatric development of clofarabine. Approval of
the drug for a pediatric indication should not be
at a lesser standard than that expected for an
adult indication.
Approval decisions should be based on a
risk-benefit determination. A reasonable question
is whether the necessary information regarding this
risk-benefit relationship can be derived from a
single-arm study where the primary endpoint is
confounded by the introduction of a subsequent
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therapy, specifically bone marrow transplantation.
Your decision regarding the approval
status of this drug should be based on the above
scientific decision, not simply a desire to provide
drug access to patients. Access to a yet approved
drug, especially with a limited patient population
encountered in these applications, can be
accomplished through additional registration trials
and expanded access programs.
We are interested in your discussion on
the impact of this drug's accelerated approval at
this time, and the timely completion of any
confirmatory trials in pediatric oncology. An
appropriate question is whether the drug approval
at this time, especially since the designated
confirmatory trial is not underway, may interfere
with the conduct and completion of confirmatory
trials.
Discussions may focus on whether approval
of this drug, with its response rate and
uncertainties regarding response duration, is
appropriate, or whether additional data should be
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available before a definitive approval decision is
made.
Thank you.
DR. SANTANA: Thank you, Dr. Pazdur.
I want to note for the record that Dr.
Temple has joined the table. If you would briefly
introduce yourself, Dr. Temple.
DR. TEMPLE: Good morning, everyone, sorry
I am late. I am Dr. Robert Temple. I am the
office director of the office in which oncology
lives.
DR. SANTANA: Thanks. We will go ahead
with the sponsor presentations, and I would ask the
sponsor to go ahead and follow the schedule, and
after each speaker, the next speaker can get up and
follow with their presentation.
Thank you.
Dr. Weitman.
NDA 21-673, Clolar (clofarabine)
ILEX Products, Inc.
Sponsor Presentation
Introduction
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DR. WEITMAN: Good morning. I am Dr.
Steve Weitman, Chief Medical Officer for ILEX
Oncology. I am also a pediatric oncologist.
I would like to start by thanking the ODAC
panel members, as well as the FDA today, for the
opportunity to be here today to present the results
of our clofarabine studies in pediatric patients
with acute leukemia.
[Slide.]
I would also like to start by just
recognizing some of the pediatric leukemia experts
that are here with us today, as well as the
investigators in a number of our trials that are
also here, that may help present and also answer
any questions that may come up during later parts
of this discussion today.
[Slide.]
Following my brief introduction, I am
going to introduce Dr. Robert Arceci, who is here
today to talk about pediatric leukemia and the need
for new treatments. I will then return to the
podium and talk about the results from our two
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pivotal studies in pediatric patients with acute
leukemias.
Then, Dr. Steve Sallan will come up to the
podium. Again, he was not an investigator on any of
our studies, but will provide his perspective as a
pediatric oncologist and caregiver regarding what
clofarabine means to him.
Then, I will return, as Dr. Pazdur alluded
to, to talk about our plans moving forward with
clofarabine both in the pediatric population, as
well as in adults with acute leukemias.
With that, let me introduce Dr. Robert
Arceci.
Pediatric Leukemia: Need for New Treatment Options
DR. ARCECI: Thank you, Steve, and thank
you, Dr. Santana and the Committee for allowing us
to present these data. I am a pediatric oncologist
and was an investigator on the clofarabine trials.
[Slide.]
What I want to try to do is to give you an
overview of the situation that we deal with in
pediatric oncology particularly with regard to
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pediatric acute leukemias.
Currently, treatments for newly diagnosed
patients with acute lymphoblastic and acute
myelogenous leukemia all use very aggressive
combination chemotherapies, quite intensive and
have been become increasingly intensive over the
past 10 years.
The overall survival for pediatric
patients with ALL and AML has improved
significantly, but over the past 5 to 10 years, has
started to approach plateaus. This is in spite of
a maximum intensification that we are using, so new
drugs clearly and new approaches are needed in this
group. Despite that intensification, 20 percent of
patients with acute lymphoblastic and possibly a
little more than 50 percent of patients with
myelogenous leukemia will have disease recurrence.
[Slide.]
Those numbers lead to the following
conclusion, that that is, relapsed acute leukemia
represents the third most common cancer that we
deal with in pediatric oncology, so although an
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orphan disease, this is a major problem for those
of us treating patients in pediatric oncology.
[Slide.]
Now, the challenge to approach that group
is immense. We know that at relapse and even at
diagnosis, these relapsed leukemias represent a
very heterogeneous group of diseases. At the time
of relapse, they are usually multi-drug resistant,
and that resistance crosses most of our
conventional drugs, so it is a major problem and
multifactorial.
Dose intensification with combination
chemotherapies, as I mentioned to you, for newly
diagnosed patients often leads to much more heavily
treated patients than we did 10 or 15 or 20 years
ago, so this group of patients have highly
resistant disease, and they often have
co-morbidities in terms of organ toxicities when
they relapse.
In many respects, transplantation is not
only the best, it is possibly the only curative
therapy we have for these children. So, getting
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them to transplant in a state of what we would
expect to be minimal residual disease is a vital
and important component of how pediatric
oncologists approach these children.
[Slide.]
This just shows you some data. Although
from 1997, the fact of the matter is the data have
not changed significantly since these data were
published. These are patients and their outcomes
who had relapsed and refractory pediatric leukemia
treated with chemotherapy only, and this is
primarily data from pediatric oncology group
studies, Phase II studies. In 2004, these results
are really no different.
Transplantation, I should note can improve
the outcome of those patients somewhat.
[Slide.]
Now, in spite of what I have told you, few
agents have been approved for pediatric leukemia.
The most commonly used agents that have been
approved, have been approved many years ago, 1950s
onward.
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The development of new agents that are
well tolerated and more effective becomes an
increasingly important part of what we are trying
to accomplish in our field in pediatric oncology.
[Slide.]
So, to conclude, and I hope this gives you
a bit of a feeling for what we are dealing with, is
that relapsed leukemia is the third most common
cancer we deal with. Successful treatment for
relapsed and refractory pediatric leukemias remains
an enormous challenge for us.
These are children who often don't have
very much time because of the progression and rapid
rate of growth of their leukemias. Patients with
these multi-drug resistant leukemias also have
these co-morbidities because of prior
intensification therapies, therefore, we conclude
at least that we need well tolerated, new, and
effective agents to induce minimal residual disease
states, to get responses, so we can then move
towards a more curative approach.
Thank you very much.
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Clofarabine Pivotal Studies
DR. WEITMAN: Thank you, Dr. Arceci.
What I would like to do now is tell a
little bit of a story, really a story of how we got
to this podium today to present the results of our
pediatric studies in acute leukemia.
I think, as most pharmaceutical companies
do, we started our adult Phase I study back in
1999, and that was followed shortly thereafter,
approximately 18 months later, by our Pediatric
Phase I study.
For those of you who are familiar with
pediatric oncology, I think most of us would
recognize it is becoming a more and more
traditional pathway in which new agents are
introduced into the pediatric environment.
The results that we saw of this study,
though, were very striking as regards to the Phase
I study, and particularly in a very heavily
pretreated population of patients and with an
acceptable profile.
The results of these studies, though, were
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extremely impressive and really propelled the
studies and the program in pediatric oncology
forward at a much faster rate than otherwise would
be expected.
In addition, because of the fact that
there was a lack of other opportunities in other
protocols for these patients, because many of these
patients would not qualify for other studies, we
saw an increase in demand for access to this drug
by pediatric oncologists.
Because of this, we also opened up an
expanded access program that was focused almost
exclusively on the pediatric population.
[Slide.]
This next slide shows somewhat of a
timeline of our program to date, and if I can just
walk you through this. As you can see on the top
of the slide, the adult studies are in blue. On
the bottom of the timeline, the yellow represents
the pediatric studies.
As you can see here, again, the Phase I
study in adults was started back in 1999. This was
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followed 18 months later by the pediatric Phase I
program. Subsequent to this, two adults Phase II
programs were started with a predominant focus on
patients with AML.
We then started our two pediatric
programs, one in AML and one in ALL in 2002.
Again, following that was the Phase I/Phase II
combination studies with clofarabine and ara-C in
adult patients, again predominantly with AML.
You can see, moving forward, our plan is
to do a Phase II study with clofarabine and ara-C
in patients with AML, but there has also been
interest in the same study in patients with ALL
through the Children's Oncology Group.
But I think this slide shows you again the
stepwise approach that we have taken where the
adult studies preceded the pediatric program, but
it was really the results of the Phase I study in
the highly refractory-resistant population of
patients that propelled our program in pediatrics
forward at a much faster rate than what otherwise
may have happened.
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What I would like to do now is to talk a
little bit about that Phase I program because again
I think it was pivotal in our decision to move
forward with this program.
[Slide.]
As you can see here, and as Dr. Pazdur
noted, 25 patients were enrolled in this program.
Dose levels ranging from 11 to 70 mg/m
2 with MTD or
recommended Phase II dose being 52 mg/m
2 for 5
days. The dose-limiting toxicities of this study
were increases in bilirubin, as well as skin rash.
Now, most Phase I studies are not designed
to really characterize the response rate in this
population of patients. However, again, I have
conducted a number of studies in both solid tumors
and pediatric patients with leukemia, and what
really struck us was an over, really impressive
response that we are seeing in this patient
population. There were 5 CR's noted in this
patient population.
I should note that 4 of these CRs lasted
more than 50 weeks. One of these CRs was in a
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patient with AML that had failed fludarabine and
ara-C before coming onto the clofarabine study.
Following this, this patient refused to go
on to transplant and stayed on clofarabine for 8
cycles, and then stayed in remission for 43 weeks
after clofarabine treatment. Again, that was a
patient with AML.
As you can see here, we also had 3
patients who had a PR, and 7 of these 25 patients
went on to a bone marrow transplant or stem cell
transplant.
[Slide.]
Because of these results, we again moved
forward with 2 studies, one in acute myelogenous
leukemia, the other one in ALL. The primary
endpoint for both of these studies was overall
response rate defined as complete remission, as
well as complete remission without full platelet
recovery.
A Fleming 2 stage design was used in these
studies. However, we began to see very early on in
this program that patients much more heavily
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pretreated than we had ever anticipated began
coming on to study. In fact, most of the patients
that were being enrolled had undergone a bone
marrow transplant, in come cases 2 transplants,
before coming on study.
In addition, as you can see here, some of
the patients had up to 6 prior regimens before
being treated with clofarabine. In addition, one
other confounding factor, that has already been
alluded to, many of these patients were being taken
off study very quickly to move to transplant, and I
will talk about that a little bit later on.
Again, a lot of these patients were PR in
which they had 0 to 5 percent blasts, but did not
have full ANC recovery, so because of that, they
were still considered a PR, but were going to
transplant.
In addition, a lot of these patients did
not go on to second or third cycles of treatment
because they had a donor that was identified and
wanted to move to transplant.
Following discussion with our external
32
thought leaders, and well as the FDA, we decided to
expand these studies to get a better determination
of the response rate in this highly refractory
patient population.
What I would like to do now is just walk
you through a couple slides that I think again
highlight how heavily pretreated this patient
population is.
[Slide.]
This slide shows the number of unique
agents that these patients were exposed to prior to
coming onto the clofarabine study. As you can see
here on the left-hand axis, this is the number of
unique agents, and across the bottom is the patient
number.
This first slide is for patients with ALL.
This first patient had 12 unique agents before
coming on to clofarabine, and then had also a bone
marrow transplant.
[Slide.]
The next patient, patient 7, I just want
to highlight had 9 unique agents, a bone marrow
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transplant that included total body irradiation.
As you can see here, for the rest of the patients,
again, this was an extremely heavily pretreated
patient population. In most cases, the patients
received anywhere from 9 to 12 unique agents.
Some of the patients received up to 16
unique agents before coming on the study. Many of
them also had bone marrow transplant and many of
them have also had total body irradiation.
[Slide.]
This patient here, that had 16 unique
prior agents, also had two prior transplants, as
well as total body irradiation as part of the
conditioning regimen for the transplant. This
patient went on to achieve a CRp after treatment
with clofarabine.
[Slide.]
This next slide again is a very similar
presentation of the number of unique agents that
these patients had been exposed to prior to coming
onto the clofarabine study.
As you can see here, again, your first
34
impression, or at least my first impression, was
the fact that these were patients who were less
heavily pretreated than those with ALL. In fact,
they were probably more heavily pretreated than the
patients with ALL.
Both sets of diseases, ALL and AML, the
patients had been exposed to a median of 3 prior
regimens before coming on study. It appears that
there are a fewer number of unique agents that
these patients were exposed to, where, in fact, I
think that represents two important findings.
Number one, that there are fewer options
for patients with AML particularly at the time of
relapse. In addition, many of these patients
received the same agent over and over and over
again during their treatment courses, so again,
they appear to be less heavily pretreated, but, in
fact, I think again they were just as heavily
pretreated and likely just did not have many
options as far as new agents to be used.
[Slide.]
What I would like to highlight is one
35
patient in particular, just because I think this
again shows how heavily pretreated this patient
population was, and it also points out a number of
other key findings.
This is a 4-year-old with AML that was, as
you can see here, treated with multiple regimens
before coming on to this study. This patient I
think was most notably exposed to a number of
nucleoside analogues including cytarabine,
thioguanine, gemcitabine, fludarabine before being
treated with clofarabine.
I think again it is important to note that
this patient received cytarabine 4 times in
different treatment regimens during the course of
his disease. Regimen 3, asparaginase/cytarabine,
this patient was refractory to that treatment, and
then went on to receive a multi-agent regimen,
again was refractory to that treatment. Then, went
on to receive cytarabine and idarubicin.
This patient did go into remission in
October of 2001, and again as it very commonly seen
when there is a donor available, this patient moved
36
very quickly to transplant. So, in December,
approximately two months later, this patient went
into transplant, being conditioned with TBI,
thiotepa, and fludarabine, and then underwent a
stem cell transplant.
This patient stayed in remission until
July of 2002, approximately 30 weeks from the very
start of cytarabine/idarubicin until relapsing. In
July, this patient underwent clofarabine treatment,
received 1 cycle, and then went into complete
remission.
This patient went on to receive 5
additional cycles of clofarabine before undergoing
a bone marrow transplant, and as data cutoff, this
patient is alive with no evidence of disease.
The period of remission from the start of
clofarabine to the date of cutoff was over 70
weeks, nearly twice as long as the period of
remission from the start of the cytarabine regimen
until relapse.
I think this slide also shows again the
fact that this patient had been exposed to a number
37
of nucleoside analogues in the past, as well as
cytarabine multiple times before coming onto the
clofarabine study, also had been proven to be
refractory to a number of the best agents that we
have available right now in pediatric AML.
[Slide.]
What I would like to do now is focus a
little bit on the efficacy results from our two
studies.
[Slide.]
Before I talk about the two studies, I do
want to highlight the database that was used in our
analysis. As was noted earlier by Dr. Pazdur, we
did analyze patients with ALL separately from those
with AML.
However, for safety analysis, we did
combine these two patient populations together, and
we also included the patients from the Phase I
study. So, that is why there is a little bit
difference in the patient numbers for the database
size for these two analyses.
[Slide.]
38
Key endpoints of the study were overall
response rate, again CR and CRp. It should be
noted that an Independent Review Panel reviewed all
patients enrolled in the study, and their
determination of response was used in all
determinations of efficacy moving forward.
In addition, at the time that they
determined that a response occurred, that was then
used to determine duration of remission.
We also looked at post-transplants,
survival, and obviously, the safety profile.
[Slide.]
Now, with regards to patients with ALL.
[Slide.]
Again, I will focus initially on the
efficacy results of this study.
Forty-nine patients were enrolled in this
study with a median age in years of 12, ranging
from 1 to 20. These patients received a median of
3 prior treatment regimens before coming onto the
study with a range of from 2 to 6.
Approximately, two-thirds of the patients
39
were refractory to their last therapy before coming
on study, and most of these last therapies again
were multi-agent regimens. Whenever there was an
evidence, for the most part, of palliative therapy,
such as oral etoposide, we would go back to the
previous regimen before that.
As you can see here, approximately a third
of the patients had bone marrow transplant with ALL
before coming onto this study.
[Slide.]
The Independent Review Panel found that 20
percent of the patients enrolled in the study had
either a complete response or complete response
without full platelet recovery with confidence
intervals ranging from 10 to 34 percent.
Patients with at least a PR had a 31
percent response rate, again with confidence
intervals ranging from 18 up to 45 percent.
The patients that were deemed refractory
to their most recent prior therapy had a response
rate of 17 percent. Again, this was for CR and CRp.
[Slide.]
40
This next slide shows a duration of
remission for patients enrolled in this study. As
you can see, for patients with at least a PR, the
duration of remission was approximately 10 weeks.
For patients with a CR and a CRp, the duration of
remission was 20.2 weeks.
[Slide.]
Of these patients, again, one of the
critical next steps in a curative approach is to
try to take these patients to transplant. As you
can see here, 14 percent of these patients went on
to transplant, 2 with CR, 2 with CRp, and 1 with
PR.
The median time to transplant was 32 days,
but as you can see here, again, they moved very
quickly to transplant in many cases, where in as
little as 16 days, the patient would go to
transplant, and this was after following remission
induction.
The median number of cycles before
transplant was 2, and 5 of 7 patients are alive
post-transplant.
41
[Slide.]
This slide represents the overall survival
of patients enrolled in the ALL study. The bottom
green line represents overall survival for patients
enrolled in the study of 11.7 weeks. If you look
at the top line, this is for patients with a CR or
a CRp where the overall survival was a little bit
over 1 year.
[Slide.]
Now, to move on to our studies in patients
with AML.
[Slide.]
Thirty-five patients were included in this
study. The median age was 12 with a range of from 2
to 22. Again, as I noted earlier, the number of
median regimens was 3 prior to coming onto this
study. Sixty-three percent of these patients were
refractory to prior therapy, and over half of these
patients had some form of bone marrow transplant
before coming onto this study.
[Slide.]
The Independent Review Panel found that 1
42
patient had a CRp and that there were 26 percent of
patients who had at least a PR. Again, as has been
noted, PR's are not typically viewed in hematologic
malignancies as a benefit, however, this PR allowed
many of these patients to move on to transplant
that may not have otherwise had that opportunity.
Four of the patients that were refractory
to prior therapy did have a PR. It should be noted
that 3 of these patients went on to transplant and
2 of these 4 patients are still in remission today
following clofarabine and transplant. One of these
patients had failed cladribine and idarubicin
before coming onto the study.
Again, this was a patient with AML,
received 1 cycle of clofarabine and went into
remission, and that he had zero percent blasts in
this bone marrow, his ANC was increasing, however,
it did not reach the threshold of 1,000, which was
needed for a CR. Before reaching that threshold,
the patient went on to transplant, and is now in
remission 58 weeks since undergoing clofarabine and
bone marrow transplant.
43
[Slide.]
This slide shows the duration of remission
for all patients that had either CR, CRp, or a PR
in the AML study. The median duration was 16.2
weeks.
[Slide.]
Again, one of the key endpoints for any
patient at this stage is to get to transplant,
particularly in patients with AML where a PR may be
more meaningful than certainly in patients with
ALL.
As you can see here, over a third of the
patients went on to transplant, 1 patient with a
CRp, 6 patients with a PR. As has been noted in
your briefing document and some of the questions
that you received, 2 of the patients had treatment
failure, still went on to transplant.
I think these 2 patients are worth noting
and explaining in a little bit more detail.
The first patient had 98 percent blasts at
study entry. After a cycle of clofarabine, this
patient dropped down to 2 percent blasts in the
44
bone marrow. However, when the IRP looked at that
patient's report and smear, they noted that there
were still some myelomonocytic cells present, so
they considered that patient a treatment failure.
However, this patient still went on to transplant
because the treating investigator felt that the 98
percent blast at entry down to 2 percent was
substantial cytoreduction to allow this patient to
go on to transplant.
The other treatment failure that is listed
on this slide is a patient with monosomy 7. Again,
I think most of the pediatric oncologists would
recognize that as a fairly resistant to leukemia.
This patient came on study with 68 percent blasts
at study entry, went down to zero percent blasts
after 1 treatment, and was proceeding to transplant
when this patient did, in fact, have a relapse.
However, because of that substantial cytoreduction
that was still present, and the fact that there was
a haplo-identical donor available, the treating
investigator still wanted to go to transplant, so
while both patients were deemed as treatment
45
failures by the IRP, there were still significant
cytoreduction and benefit afforded these patients,
so they could move on to transplant.
I do want to mention just a couple others
really quick. Again, the median time to transplant
for these patients was 38 days, again, as little as
21 days after remission induction, they would go to
transplant.
The median number of cycles was 2, but
particularly in AML, they were very interested in
going to transplant as soon as possible, because
this disease is so difficult to treat.
As you can see at the bottom of the slide,
7 of the 12 patients are alive post-transplant, and
4 of these patients are still in remission.
[Slide.]
This slide shows the overall survival
curve for patients with AML enrolled in this study.
As you can see, the bottom line is for all patients
where the median survival was 21 weeks. The top
line represents those patients who had at least a
PR where the median survival was 39 weeks.
46
So, at this point, in summary, as far as
the efficacy results, again, recurrent pediatric
acute leukemia is a substantial unmet medical need
especially for patients with AML where new agents
are desperately needed.
We saw impressive response rates for
clofarabine in pediatric patients with ALL and AML
that had become cross-resistant to most standardly
available agents. The duration of remission was
long enough and sufficient enough to allow these
patients the opportunities for those with donors to
be able to proceed to transplant. Long-term
survival was observed in patients with both ALL and
AML who responded to clofarabine.
[Slide.]
Now, I would like to touch on the
integrated safety analysis. Just as a reminder,
again, this was combined data from both patients
with ALL and AML into one database, as well as
those patients from the Phase I study.
[Slide.]
This slide shows all Grade 3 and Grade 4
47
adverse events that occurred in greater than 10
percent of the patient population regardless of
causality. As you can see here, the most common
Grade 3/Grade 4 adverse event was fever and
neutropenia. This was followed by nausea, fever,
epistaxis, hypotension, sepsis, and anorexia.
A couple of factors should be noted here.
Number one, most of these patients had been in
relapse many times, weeks, if not months, before
coming onto this study. If you look at the list of
concurrent conditions, many of these events were
present at the time of study entry.
[Slide.]
This slide shows the drug-related adverse
events as determined by the investigators. Again,
these are Grade 3 and Grade 4 events only, that
occurred in greater than 5 percent of the patient
population.
As you can see here again, fever
neutropenia was the most common event, nausea,
fever, diarrhea, neutropenia, vomiting, and
dermatitis. In almost all cases, Grade 3 was much
48
more common than Grade 4.
[Slide.]
We also looked at the laboratory
abnormalities that were observed in this study.
Again, this represents Grade 3 and Grade 4
hepatobiliary and renal abnormalities that were
observed.
By far the most common were elevations in
transaminases, both ALT and AST. In almost all
cases, these tended to occur very early,
approximately one week after starting drug, and
then would resolve over the next week or two back
to baseline. We also saw increases in bilirubin,
creatinine, and alkaline phosphatase, but again, in
almost all cases, Grade 3 was much more common than
Grade 4.
[Slide.]
Deaths during study were fairly equally
divided between those from disease progression, as
well as those from non-drug or drug related AEs. A
couple of factors really stand out when you look at
these patients.
49
Number one, they were extremely heavily
pretreated patients before coming on study, many
with a variety of concomitant conditions and on a
variety of different medications before coming on
study. Many of them also had persistent disease or
progressive disease, as well as bacterial and
fungal infections. We also saw a number of cases
of capillary leak in this patient population.
[Slide.]
In summary, again, this study was
conducted with extremely heavily pretreated
patients. Most of the adverse events were
consistent with the underlying leukemia, and the
events were not unexpected particularly for a
cytotoxic agent, and most adverse events were
reversible, and not again unexpected.
At this point, I would like to introduce
Dr. Steve Sallan. Again, he was not an
investigator on these studies, but he is here today
to provide his perspective on clofarabine as a
pediatric oncologist and caregiver.
Clinician's Perspective
50
DR. SALLAN: Thank you very much. Good
morning.
[Slide.]
My name is Stephen Sallan and I have been
a pediatric oncologist for over 30 years, and have
been treating this patient population nearly every
working day of my life during that time, and have
been very blessed, as have been all the other
members of the pediatric oncology community, to
watch huge success being made in the 20th century
and getting to a point where childhood acute
lymphoblastic leukemia is really cured in 75 to 80
percent of children using multidrug chemotherapy,
multidrug chemotherapy that you have all seen
already, all of which was developed before the
1970s.
In AML, the cure rates are in the 40 to 50
percent range, again principally with multidrug
chemotherapy and enhanced by bone marrow
transplantation. Clearly, for us, the successful
treatment of relapsed and refractory pediatric
leukemias is our major challenge.
51
[Slide.]
Shown on these curves is really a picture
of the success story that I have alluded to, and
mostly from my medical oncology colleagues at the
table, I would like to reiterate that while we are
justly proud of these accomplishments, if one looks
at the curves, these really end in the '90s.
If one looks at what has happened in the
last decade, there has been incremental-only
increases, and as Dr. Arceci already alluded to,
these are approaching plateaus of about 80 percent
in ALL and somewhere between 45 to 50 percent in
AML.
[Slide.]
Now, there is no child on those curves who
has been cured who probably has not received 6 MP
and methotrexate if they had ALL, or cytarabine if
they had AML. Interestingly, when we look at these
data today, the question is what is the expectation
of a single active antileukemic agent, in this
case, against de novo ALL, so for this, we really
have to look at historic data, and I have adapted
52
this table from a textbook from 1974.
What you can see is that the workhorses in
these diseases, when they are tested against de
novo ALL as single agents, gave complete remissions
in this 20 to 25 to 30 percent range. I might also
say that the stringency of that definition of
complete remission, as you look at the old
literature, is highly variable.
So, when one sees a population of today's
relapsed, refractory patients, it is very difficult
to have any comparative population, and, in
addition, what impressed me when looking at the
clofarabine data, was that we saw a CR and CRp rate
that was really in the similar ballpark as
effective drugs are against de novo disease.
I think, although I am showing this for
ALL, you saw similar results with clofarabine
generating principally a CRp and PR's in that
population.
[Slide.]
What impressed me about the availability
of a new drug again as you have heard, in part, is
53
that 1 in 5 children with multiple drug resistant
ALL achieved a clinical response--sorry for the
CR--principally, the majority of those who went to
transplant had CR's or CRp's, and as you saw, some
PR's, as well, and similarly, for this relapsed,
refractory AML population, 1 in 3 children with
again multiple drug resistant disease was able to
come to transplant.
We strongly believe, as a community, that
transplantation is the curative therapeutic option
in the early 21st century for children with
drug-resistant childhood AML.
[Slide.]
So, in closing, what really impresses me,
as a clinician, is that we have a drug,
clofarabine, which is well tolerated, very
importantly, the absence of overlapping toxicities,
so that we can treat these children without
additive cardiac, renal, or other organ toxicities
permitting them to be good candidates when they get
into the transplant setting; that the drug provides
a clinical benefit, as shown in our responses, in a
54
very heterogeneous population, which right now, in
2004, is critically important.
I mean we are all focused in part on
targeted therapies, very few, none of which have
really come to this population, so the fact that we
have a drug that gives a clinical benefit in a very
heterogeneous population is extremely helpful, and
most importantly, for these children, there are no
meaningful alternatives.
I would say it is the last point that
really causes me to feel very positive and
enthusiastic and really desire to have something
that is well tolerated, that is beneficial, and is
available now, and that is why this data is
important to me.
Thank you very much.
Clofarabine Development Plan
DR. WEITMAN: Thank you, Dr. Sallan. We
feel that in some ways, we have embarked on really
a historical approach, an approach that is
different than what has been in the past when it
comes to pediatric oncology patients.
55
[Slide.]
The approach that we have taken
potentially is a new paradigm for getting access to
pediatric new agents into the pediatric community.
The sponsor, moving forward, commits to
several factors including the further development
of this agent in the pediatric oncology population.
Number 1. To continue to follow these
patients that are enrolled in these two studies for
long-term follow-up data. We also have a
commitment to move to less heavily pretreated
patients, both patients with ALL and AML, and to
ultimately, at some point, proceed to a randomized
study with clofarabine in newly diagnosed patients.
This commitment includes a very close
working relationship particularly with the
Children's Oncology Group, but also through CTEP.
[Slide.]
Just to highlight the program through the
Children's Oncology Group, we have two studies
moving forward there. One is in AML, and again
this is a combination study with ara-C and
56
clofarabine. This is actually a Phase II study in
patients with first relapsed AML.
The study chairs for this are Dr. Razzouk
from St. Jude, as well as Dr. Cooper from the
University of Alabama.
Again, in ALL, the parallel companion
study is a combination of cytoxan with clofarabine,
but there has also been interest from the
Children's Oncology Group to look at clofarabine in
combination, not only with etoposide, but also with
ara-C.
Again, this is a different population of
patients that we have studied in this submission.
In these follow-up studies, we are looking at less
heavily pretreated patients, in this case, second
relapsed patients.
Again, many of the patients enrolled in
our study would not have been eligible, and
certainly would not have been eligible for these
follow-up studies.
[Slide.]
To bring it full circle, our program in
57
the adult community is also moving forward,
although it has a little bit different focus. The
focus in the adult oncology community is
particularly focused on AML, because that is where
most of the activity has been seen.
Combination studies, particularly with
ara-C are moving forward, and there has been an
interest in the elderly population of patients
again because of some of the early pilot studies in
adults that have shown considerable activity in
this group of patients.
One study that I would like to highlight
is a CLO-141 study. Again, this was the
combination study of clofarabine with ara-C. This
study has met full accrual, but is still open.
Interim results of this study were just
recently published in Blood where the overall
response rate was 40 percent, again in a refractory
population of patients with leukemia, and the
overall response rate was defined as complete
remission and complete remission without full
platelet recovery.
58
Because of these results, our plans are to
move forward, and we have already discussed this in
brief with the FDA, as far as two potential
randomized studies, one with clofarabine and ara-C
in elderly patients newly diagnosed, as well as
clofarabine with ara-C in recurrent or refractory
adult patients with AML.
[Slide.]
At this point, I just want to return again
to the fact that we are here today presenting the
results of our pediatric studies in acute leukemia.
We found that clofarabine had an acceptable profile
particularly in this extremely heavily pretreated
population of patients, that impressive benefits
were observed including meaningful clinical
responses, such as CR, CRp, and even PR's and again
in this highly refractory patient population, that
allowed many of these patients to move on to
transplant.
As you can see here, 23 percent of the
patients were able to proceed to transplant, 14
percent of the patients with ALL, 34 percent of the
59
patients with AML. At data cutoff, 22 percent of
the patients with ALL, and 26 with AML are alive.
So, in conclusion, we believe that
clofarabine does meet an urgent unmet medical need
in a population of patients that frequently has not
been included in many other current protocol
opportunities, and the fact that activity has been
seen in a very highly resistant and refractory
group of patients.
[Slide.]
Again, I would like to thank the ODAC
panel members, as well as the FDA, today for the
opportunity to present the results of our pediatric
studies with clofarabine in patients with acute
leukemias.
Thank you.
DR. SANTANA: Thanks also to Drs. Weitman,
Sallan, and Arceci.
I want to recognize for the Committee, and
ask the individual to introduce himself by name and
affiliation, Dr. Hershfeld has joined the meeting.
DR. HERSHFELD: Steven Hershfeld, Food and
60
Drug Administration.
DR. SANTANA: Thank you.
With that, we will proceed with the FDA
presentation. Dr. Cohen, please.
FDA Presentation
DR. COHEN: Good morning. My name is
Martin Cohen, and the NDA being presented today is
No. 21-673. The study drug is clofarabine, which
structurally is chloro-fluoro-Ara-A. The sponsor
is ILEX Products, Incorporated.
Clofarabine is a second-generation purine
nucleoside analogue. It is a prodrug that must be
metabolized to its triphosphate conjugate by
deoxycytidine kinase within tumor cells.
Clofarabine has a greater affinity for this enzyme
than does other purine nucleoside analogues.
[Slide.]
The proposed indication for this NDA is
that clofarabine is indicated for the treatment of
pediatric patients 1 to 21 years old with
refractory or relapsed adult leukemias including
both pediatric acute myelogenous leukemia and acute
61
lymphoblastic leukemia.
[Slide.]
Regarding clofarabine dose and schedule, a
Phase I study in pediatric acute leukemia patients
indicated that when a daily times 5 schedule was
used, the selected dose was 52 mg/m
2. Clofarabine
treatment cycles are repeated every 2 to 6 weeks
following recovery to acceptable organ function.
[Slide.]
The pertinent clinical trials in this NDA
submission are summarized on this slide. There
were two, Phase II trials conducted by the sponsor,
one in pediatric AML, the other in pediatric ALL.
In addition, there was a pediatric Phase I study
conducted at M.D. Anderson Hospital.
[Slide.]
For both of the Phase II studies, the
primary efficacy objective was to determine the
complete response rate and the complete response
rate in the absence of platelet recovery, that is,
the CRp rate.
Secondary objectives were to document the
62
partial remission rate and also to document time to
event parameters including remission duration and
overall survival.
[Slide.]
Study inclusion criteria for both the AML
and ALL studies included an age less than or equal
to 21 and the presence of greater than or equal to
25 percent bone marrow blasts.
Eligible AML patients were in their first
or subsequent relapse and/or they were refractory,
having failed to achieve remission following one or
more different regimens.
Eligible ALL patients were in their second
or subsequent relapse and/or they were refractory,
having failed to achieve a remission following two
or more different regimens.
Patients had an ambulatory performance
status and had adequate bone marrow, liver, and
renal function.
[Slide.]
Response definitions are listed on this
slide. A complete response, or CR, required no
63
circulating blasts, no extramedullary disease, and
an M1 bone marrow defined as having less than 5
percent myeloblasts or lymphoblasts.
There also had to be recovery of
peripheral blood cell counts to a level of greater
than or equal to 100,000 platelets/microliter, and
an absolute neutrophil count greater than or equal
to 1,000/microliter.
A complete response in the absence of
platelet recovery meets all the criteria of a CR
except that the peripheral blood platelet count has
not recovered to 100,000/microliter.
A partial response is defined as no
circulating blasts along with an M2 bone marrow
defined as having 5 percent to 25 percent blasts
accompanied by the presence of normal progenitor
cells.
In addition, an M1 marrow without
peripheral blood count recovery would be classified
as a PR.
[Slide.]
A total of 18 Unites States sites
64
participated in the two, Phase II pediatric acute
leukemia studies. Thirteen of these sites enrolled
patients in the acute myelogenous leukemia study or
CLO-222, and 14 sites enrolled patients in the
acute lymphoblastic leukemia study, CLO-212. As
mentioned previously, an independent response
review panel was established to confirm response to
therapy for each patient. Independent pathology
review was also available.
[Slide.]
Demographics and Karnofsky Performance
Status of patients participating in the acute
myelogenous leukemia study are shown on this slide.
A total of 35 patients were enrolled and treated.
As indicated, the median age was 12, and ranged
between 1 and 22.
Approximately, one-third of patients were
female, and two-thirds were male. The majority of
patients were Caucasian. Despite the fact that
patients had relapsed and/or were refractory to one
or more prior regimens, performance status was good
with 89 percent of patients having a Karnofsky
65
Performance Status of 80 or better.
[Slide.]
Therapy is administered prior to entry
into the clofarabine AML study are listed on this
slide. The median number of prior induction
regimens was 3 with a range of 1 to 5. Five
patients received one prior regimens, 12 patients
received two, and the remaining 18 received three
or more prior regimens.
A total of 18 of the 35 patients, or 51
percent, received at least one transplant before
study entry, 13 of 35, or 37 percent, having
received one prior transplant and 5 of the 35, or
14 percent, having received two prior transplants.
[Slide.]
As previously indicated, the rate of
complete response and complete response without
platelet recovery were the primary efficacy
endpoints. Responses were determined by an
independent response review panel and confirmed by
FDA.
There were no complete responders and only
66
1 CRp. There were 8, or 23 percent, partial
responses. Seven of the 35 study patients were not
evaluable for reasons listed on the slide.
[Slide.]
This slide shows pediatric AML patients
who received a transplant after initial clofarabine
treatment. Because stem cell or marrow transplant
in pediatric AML may be associated with durable
remissions, there is pressure to proceed with a
transplant if a suitable donor is available.
In the clofarabine AML study, 12 of the 35
study patients underwent transplant including the 1
CRp patient, 6 of the PR patients, 2 of the 7
non-evaluable patients, and 2 of the 19 treatment
failures.
Transplants were performed after patients
had received 1 to 5 cycles of clofarabine
treatment. Because of the transplants, it was not
possible to determine duration of remission after
clofarabine treatments alone.
[Slide.]
This slide indicates some of the
67
difficulties encountered when evaluating this
application. As listed and as mentioned by Dr.
Pazdur earlier today, the traditional endpoints for
evaluating acute leukemia studies include the
confirmed complete response rate, complete response
duration, and overall survival.
Confounding factors in evaluating this NDA
submission were that some patients were
transplanted early, either before clofarabine
response could be confirmed or response duration
determined.
Further, some study patients received 1 or
more transplants prior to entering the clofarabine
study, and some did not. Whether these groups can
be compared must be considered today by the ODAC
Committee.
Because of the above difficulties, I chose
to evaluate an exploratory endpoint, namely, longer
time to progression with clofarabine treatment with
or without transplant, then, with the therapy
immediately preceding clofarabine, whether or not
it also included the transplant.
68
[Slide.]
This slide summarizes 4 pediatric AML
patients with a longer time to progression with
clofarabine plus transplant, then, with the therapy
that immediately preceded clofarabine.
One of these patients also had a longer
response duration to clofarabine plus transplant
than he had with his prior transplant.
Reviewing each of these patients
individually, Patient 14-03 had a time to
progression of 270 days for the treatment regimen
preceding clofarabine study entry. He had received
a prior transplant with a time to progression of
150 days. He received 5 cycles of clofarabine and
was a CRp. His clofarabine plus transplant time to
progression was 519+ days.
Patient 15-17 had a time to progression of
60 days for the treatment regimen preceding
clofarabine study entry. He had not received a
prior transplant. He received 1 cycle of
clofarabine and was a partial response. His
clofarabine plus transplant time to progression was
69
465+ days.
Patient 06-36 had a time to progression of
30 days each for the 2 treatment regimens preceding
clofarabine study entry. He had earlier received 2
prior transplants with response durations of 365
and 485 days, respectively. He received 5 courses
of clofarabine and was a partial response. His
clofarabine plus transplant time to progression was
130+ days.
Patient 14-31 had a time to progression of
30 days each for the 2 treatment regimens preceding
clofarabine study entry. She had not received a
prior transplant. She received 2 cycles of
clofarabine and was a partial response. Her
clofarabine plus transplant time to progression was
93+ days.
[Slide.]
Turning now to Study CLO-212, the acute
lymphoblastic leukemia study, this slide summarizes
the demographics and Karnofsky Performance Status
of participating patients.
A total of 49 patients were enrolled and
70
treated. As indicated, the median age was 12 and
ranged between 1 and 20. Approximately 40 percent
of patients were female and 60 percent male.
Hispanic and Caucasian patients comprised the bulk
of the study population.
Despite the fact that patients had
relapsed and all were refractory to 2 or more prior
regimens, performance status was good with 31
percent of patients having a Karnofsky Performance
Status of 100, and 39 percent a Karnofsky
Performance Status of 90-80.
[Slide.]
Therapies administered prior to entry into
the clofarabine ALL study are listed on this slide.
The median number of prior induction regimens was
3, with a range of 2 to 6. A total of 15 of 49
patients, or 31 percent, had received at least 1
transplant prior to study entry, 13 of the 49, or
27 percent, having received 1 prior transplant and
2 of 49, or 4 percent, having received 2 prior
transplants.
[Slide.]
71
Best response to therapy as judged by the
independent response review panel and confirmed by
the FDA for the pediatric ALL study is shown on
this slide. There were 6 complete responders and 4
complete responders in the absence of platelet
recovery. There were 5 partial responses and 8 of
the 49 study patients were not evaluable for
response.
[Slide.]
This slide shows pediatric ALL patients
who received a transplant after initial clofarabine
treatment. As previously noted in the AML study,
marrow transplant in pediatric ALL may be
associated with durable remissions, thus, marrow
transplant is often recommended if a suitable donor
is available.
In the clofarabine ALL study, 7 of the 49,
or 14 percent, of study patients underwent
transplant including 1 of the 6 CR's, 3 of the 4
CRp's, 2 of the 5 PR patients, and 1 patient who
was non-evaluable because of a poor quality bone
marrow.
72
Transplants were performed after 2 cycles
of clofarabine treatment in 5 patients and after 3
cycles of clofarabine treatment in 2 patients.
[Slide.]
In the pediatric ALL study, it was
possible to evaluate complete response duration in
patients who did not receive a transplant. As
previously indicated, 6 patients achieved a
complete response and 5 did not have a transplant.
The 2 CR's listed on this slide had a longer time
to progression with clofarabine treatment than was
achieved with their immediate prior therapies.
Another 2 of the 5 non-transplanted
complete responders remained in remission, but
follow-up is brief. As seen on this slide, Patient
07-18 had a time to progression of 60 and 30 days
for the 2 treatment regimens preceding clofarabine
study entry. She had not received a prior
transplant. She received 3 cycles of clofarabine
and was a complete response. Her clofarabine time
to progression was 143 days.
Patient 6-47 had a time to progression of
73
30 days each from the 2 treatment regimens
preceding clofarabine study entry. He had not
received a prior transplant. He received 2 cycles
of clofarabine and was a complete response. His
clofarabine time to progression was 76 days.
[Slide.]
As shown in this slide, 3 of the 4 CRp
patients, 2 with a transplant, 1 without, had a
longer time to progression with clofarabine with or
without transplant than with immediate prior
therapy.
Reviewing each patient individually,
Patient 09-24 had a time to progression of 120 days
for the treatment regimens preceding clofarabine
study entry. He had received a prior transplant
with a time to progression of 60 days. He received
3 cycles of clofarabine and was a CRp. His
clofarabine plus transplant time to progression was
259 days.
Patient 12-14 had a time to progression of
30 days for the treatment regimen preceding
clofarabine study entry. He had not received a
74
prior transplant. He received 2 cycles of
clofarabine, was a CRp. His clofarabine plus
transplant time to progression was 168+ days.
Patient 14-40 had time to progression of
30 days for the treatment regimen preceding
clofarabine study entry. He had not received a
prior transplant, nor did he receive a transplant
after clofarabine. He received 2 courses of
clofarabine, was a CRp. His clofarabine time to
progression was 64 days.
[Slide.]
Turning now to the supporting trial in
this application, the CLO Phase I study performed
at M.D. Anderson Cancer Center is summarized on
this slide.
In this study, patients 21 years or
younger with refractory leukemia or lymphoma, who
had a Zubrod Performance Status no greater than 2,
and who had adequate organ function were eligible
for enrollment.
There were 25 acute leukemia patients
entered, 17 with ALL, 8 with AML. Using M.D.
75
Anderson response criteria, complete response were
noted in 5 of the 25 patients 4 with ALL and 1 with
AML. In addition, there were 3 PR's.
ILEX convened an independent response
review panel to review the 5 M.D. Anderson complete
responses using the same modified COG review
criteria that were used in the sponsor's Phase II
studies. The independent response review panel
reclassified the 5 CR's to 2 CR's, both in ALL
patients, 1 CRp in the AML patient, and 2 PR's.
[Slide.]
Turning now to safety, this slide
summarizes clofarabine exposure by cycle. The
database includes 113 patients derived from the
sponsor's Phase II studies, the M.D. Anderson
study, and from adult trials that included
pediatric patients.
As indicated, all 113 patients received at
least 1 cycle of clofarabine, 68 received 2 cycles,
and 24 received at least 3 cycles. Dose reductions
were necessary as is expected for heavily
pretreated patient population.
76
[Slide.]
Some of the clinically more important
baseline conditions present in the 113
clofarabine-treated patients are listed on this
slide. Despite ambulatory performance status, the
patients appeared to be relatively fragile with CTC
Grade 3 to 4 baseline toxicities including
tachycardia, pyrexia, nausea, and anorexia.
[Slide.]
An overview of adverse event occurrence is
shown on this slide. Ninety-nine percent of
patients had 1 or more adverse events, and 83
percent had 1 or more serious adverse events. Four
percent of patients discontinued therapy because of
an AE. Fifty-three percent of patients had at
least a Grade 3 AE, 23 percent a Grade 4 AE, and 20
percent a Grade 5 AE.
[Slide.]
Frequent adverse events are summarized on
this slide. Gastrointestinal toxicity in the form
of vomiting, nausea, and diarrhea occurred
commonly. Grade 3-4 vomiting occurred in 10
77
percent, Grade 3-4 nausea in 16 percent, and Grade
3-4 diarrhea in 10 percent of patients. Grade 3-4
febrile neutropenia occurred in 58 percent.
Constitutional symptoms, such as headache,
pyrexia, rigors, fatigue, and anorexia were also
common and occurred in 30 percent to 48 percent of
patients.
[Slide.]
Other adverse events noted during
treatment are listed on this slide. Infections
were an important adverse event because of
prolonged immunosuppression and myelosuppression
from both current and prior therapies. SIRS, or
systemic inflammatory response syndrome, capillary
leak syndrome manifested by the rapid onset of
respiratory distress, hypotension, and multi-organ
failure occurred in 10 patients. It most often
occurred in conjunction with rapid tumor lysis.
Renal insufficiency was multifactorial in
etiology included nephrotoxic antibiotics,
hyperuricemia from tumor lysis, and hypovolemia and
hypotension. Hypotension was a component of SIRS,
78
but was also associated with sepsis and
dehydration.
Hepatobiliary toxicities were frequently
observed as the liver is a known target organ of
clofarabine toxicity. Approximately one-third to
one-half of study patients had Grade 3 elevations
of transaminases during study.
Left ventricular systolic dysfunction was
noted in 15 study patients. This might have been a
direct cardiotoxic effect of clofarabine as
clofarabine cardiac toxicity has been seen in
preclinical rat studies.
Numerous contributing factors were
present, however, including sepsis, prior
anthracyclines, and prior whole body radiation
therapy. Hand-foot syndrome was noted in 12
percent of treated patients.
[Slide.]
To summarize standard efficacy results for
the study population of relapsed, refractory
pediatric acute myelogenous leukemia patients,
there was 1 CRp, or 3 percent, and 8 PR's, or 23
79
percent, among the 35 treated patients.
Remission duration could not be determined
because 12 patients went on to transplant.
[Slide.]
To summarize exploratory efficacy results
for the study population of relapsed, refractory
acute myelogenous leukemia patients, 4 clofarabine
plus transplant AML pediatric patients had a longer
time to progression of clofarabine plus transplant
to time to progression of immediate prior therapy
with or without transplant.
One of 2 patients with a prior transplant
also had a longer time to progression with
clofarabine plus transplant than with his preceding
transplant. The other is too early to evaluate.
[Slide.]
To summarize the standard efficacy results
for the study population of relapsed, refractory
pediatric acute lymphoblastic leukemia patients,
there were 6 CR's, 4 CRp's, and 5 PR's among 49
treated patients.
Two CR's who did not have a transplant had
80
a longer time to progression than was achieved with
their immediate prior therapies. Another 2 of the
5 non-transplanted CR's remain in remission, but
follow-up is brief.
One CRp who did not have a transplant also
had a longer time to progression than was achieved
with his immediate prior therapy.
[Slide.]
To summarize exploratory efficacy results
of the study population of relapsed, refractory
pediatric acute lymphoblastic leukemia patients, 2
CRp patients had a longer time to progression with
clofarabine plus transplant than with the treatment
immediately preceding clofarabine.
One of the 2 above patients had a
pre-clofarabine transplant. This patient also had
a longer time to progression with clofarabine plus
transplant than with his previous transplant
regimen.
[Slide.]
As to safety conclusions, toxicity was as
expected for a heavily pretreated relapsed,
81
refractory acute leukemia population. Principal
toxicities were gastrointestinal including nausea,
vomiting, and diarrhea. As expected, there was
significant hematologic toxicity, fever and febrile
neutropenia, hepatobiliary toxicity, infections,
and renal toxicity.
SIRS, tumor lysis syndrome, multi-organ
failure, hypotension, renal insufficiency, and left
ventricular systolic dysfunction also occurred.
With attentive patient care, however, the drug
appeared to be tolerable.
[Slide.]
To conclude, I would like to come back to
a slide that I showed earlier. This slide
indicates some of the difficulties encountered when
evaluating this application.
As listed, the traditional endpoints for
evaluating acute leukemia studies include confirmed
complete response rate, complete response duration,
and overall survival.
Confounding factors in evaluating this NDA
submission were that some patients were
82
transplanted early either before clofarabine
response could be confirmed or response duration
determined.
Further, some study patients received one
or more transplants prior to entering the
clofarabine study, and some did not. Whether these
groups can be compared must be considered by ODAC.
Because of the above difficulties, I chose
to evaluate an exploratory endpoint, namely, longer
time to progression with clofarabine treatment with
or without transplant, then, with the therapy
immediately preceding clofarabine, whether or not
it also included the transplant. Whether this
appropriate must also be considered by ODAC.
Thank you for your attention.
DR. SANTANA: Thank you, Dr. Cohen, if you
would remain on the podium, there may be some
issues of clarification or questions for you.
I want to go ahead and open up the session
for questions, and I want to reiterate to the
Committee, it is primarily to ask clarifications or
questions related to the presentations, comments
83
that have been made, or anything that is in your
briefing document. I really don't want to get into
the issues or the questions for discussion later in
the morning.
Questions from the Committee
DR. SANTANA: I will go ahead and get
started with one question. I want to focus a
little bit on the issue of toxicity as it may help
me define clinical benefit for these patients.
When you looked at toxicity across the
board, then specifically at those patients that did
not go to transplant, but had either a CR or a PR,
did you notice any difference in toxicity rates,
particularly serious infections, hospitalizations,
that nature, that would help me assess whether
those patients that did not have transplant really
benefited?
DR. COHEN: Well, I think all of the
toxicity data was gathered before patients went to
transplant. It represented the effects of
clofarabine treatment--
DR. SANTANA: Could you point to patients
84
that were not transplanted? I believe there were 9
ALL patients and a few AML patients.
DR. COHEN: I did not break it down that
way, I did not look specifically.
DR. SANTANA: Maybe the sponsor can
comment on that later, if they have looked at the
data that way.
Kind of a follow up to that toxicity
issue, this theme of hepatobiliary toxicity and its
resolution, were you able to assess whether that
required dose modifications in subsequent courses
or even extending it a little bit, did it impact
those patients that went on to transplant?
DR. COHEN: Well, the protocol, depending
on the level of hepatobiliary toxicity, the
protocol called for dose modifications, and those
modifications were followed.
DR. SANTANA: Yes.
DR. MARTINO: A question to the sponsors.
Within the protocol, can I assume that there were
some guidelines as to when a patient might be taken
to transplant? How was that decision made, by whom
85
was it made, did the protocol restrict or simply
allow judgment truly to the individual clinician?
DR. WEITMAN: The protocol did allow
patients to go to transplant, and again, as in many
of these studies, if they had available donor, that
was pretty much the primary requirement. There
wasn't a requirement for number of cycles or
anything else before going to transplant.
DR. SANTANA: Dr. Cheson, did you have a
question?
DR. CHESON: Yes, actually, I have three
questions for the sponsor.
Number one, if you could please flash
Slide 26 of your slide kit, and while you are doing
that, let me ask my other one while he is taking
time to do this.
You included the Phase I patients in your
toxicity analysis and give a percent of toxicities.
Were those all the patients in the Phase I,
including those who had rather low therapeutic
doses or only those closer to the MTD or DLT?
DR. WEITMAN: It included all patients
86
including those at the lower dose.
DR. CHESON: So, is that really fair to
include the patients at the really low doses?
DR. WEITMAN: We thought it was. Well,
first of all, we also included patients at a higher
dose, as well. When you look at the numbers of
patients, 13 patients out of the 25 were at the
MTD, at the 52, so the majority, if not more, 51
percent were at that dose, plus there is additional
patients treated above that.
DR. PERRY: What proportion of responses
were seen in that group of people who got 52
milligrams or more?
DR. WEITMAN: The responses were spread
throughout from 30 to 40 to 52 mg/m
2. So, it was
spread I will say fairly equally, but certainly at
the 52 mg dose, that is where the majority of the
patients were treated at.
DR. CHESON: The second point. Looking at
these curves, you said the CR and CRp, which is the
upper curve, has a median of 20.2 weeks. The 50
percent dotted line seems to hit smack right around
87
12 weeks. Am I missing something here? Take that
50 percent line, you draw it across, it hits there.
DR. WEITMAN: Which curve are you looking
at?
DR. CHESON: The upper curve.
DR. WEITMAN: The yellow?
DR. CHESON: The yellow curve. The 50
percent seems to hit at about 12, and not 20.2.
DR. WEITMAN: If I can, I will ask Brett
Wacker to comment on this.
DR. WACKER: The way that the median is
calculated when it goes all the way across, it
takes the average from the first point where it
hits the 50 to the end of it, so that is why the
20.2 is in the middle of that interval.
DR. CHESON: So, we would need longer
follow-up to see what really happens to that.
Okay.
The third, this CRp thing that you have
got there, there have been several published, at
least in adult response criteria in AML, one in
1990 and the other about a decade or so later, in
88
neither of those was CRp included as a response
criterion, and, in fact, it was discouraged in the
most recent International Working Group as being
included because it really hadn't been validated as
being different from CR. In other words, there was
some evidence that CRp's, in fact, don't do as well
as CR's, and the recommendation of that
International Group was that CRp's not be included
with CR's.
Are there data from the pediatric studies
to suggest, to validate CRp as an endpoint? It
snuck in here with the gemtuzimab study, the
pivotal trial there, and it has kind of hung on
ever since, but the most recent response criteria
have clearly suggested that it not be used.
DR. WEITMAN: I think you will see that in
some of the pediatric leukemia studies going
forward, that CRp is becoming more of an endpoint
that they are looking at.
What we felt, at least looking at the
study, number one, was that patients with CRp, most
of these patients, realize came into the study
89
following bone marrow transplant and rarely had any
platelet recovery even coming into the study. So,
it was somewhat hard to know whether lack of
platelet recovery after clofarabine really was any
sign of lack of activity.
When we looked at the patients with
overall survival, there were small differences, but
again small numbers comparing CR with CRp. But I
think it is a valid point that just needs to be
continued to be followed particularly in the
pediatric population.
If I can--
DR. SANTANA: Sorry, go ahead.
DR. WEITMAN: I just wanted to get back to
your question earlier, Victor, about toxicities.
Clearly, those patients that received multiple
cycles, the toxicity that really was dose-limiting
at least as far as giving the subsequent cycles was
bone marrow suppression, and that particularly of
patients that have received 8, 10, 11 cycles of
treatment, that was predominantly what was
requiring a delay in treatment or dose reduction
90
was myelosuppression.
I don't know if that gets to your
question.
DR. SANTANA: Sort of. What I am trying
to assess is those patients that did not get
transplant, that remained on study drug because
they had either a CR or PR. That was particularly
the ALL population, so I believe you had 9
patients, and there were a few patients there that
were in the 100+ day kind of remission status,
which indicates to me that they must have received
a few cycles of therapy.
DR. WEITMAN: Correct.
DR. SANTANA: I was trying to get a sense
of what impact the therapy had on their infection,
hospitalization, liver toxicity, to get at this
issue whether they were truly benefiting or whether
the drug was giving them toxicity that they
otherwise considered difficult to manage.
DR. WEITMAN: Right. I think I will ask,
if I can, Dr. Steinherz, Peter Steinherz, to
comment on that, because he had probably the most
91
experience with these patients that went on
multiple cycles.
DR. STEINHERZ: Patients who received
multiple cycles of clofarabine had a near normal
quality of life. They did fairly frequently after a
cycle of chemotherapy, have a brief fever and
neutropenia admission, but the cycles were done
every 28 days, and other than the two, three day
hospitalizations, the rest of that time was at home
with full quality of life.
DR. SANTANA: Did any of the serious
infections that were reported in the briefing
document occur in those patients?
DR. STEINHERZ: Not once they achieved
remission. The infections that were serious were
really during remission induction.
DR. SANTANA: Dr. Hussain.
DR. HUSSAIN: I have a couple of
questions, please. I don't think I heard in any of
the slides, other than a description of statistics
being traditional, what were the actual efficacy
assumptions that would have been desirable that you
92
put in prospectively in the trial?
The second question is in comparable
settings, I assume transplant and the description
from the experts were that there are multiple drugs
available in the last 10 years, so I assume there
may have been other agents that might have been
tested in previously pretreated or heavily
pretreated patients, that made it to approval.
What were the efficacy or the
characteristics of those agents that led them to be
approved in terms of whatever criteria they were
looking at?
DR. COHEN: In terms of criteria for
approval, in those days, in the 1960s, 1970s, I
don't know for sure, but I would expect it would be
response rate.
DR. HUSSAIN: In the past five years, have
there been no drugs approved in this setting?
DR. COHEN: In pediatric acute leukemia, I
don't think so.
DR. HUSSAIN: Or 10 years?
DR. SANTANA: I don't think there has been
93
any pediatric leukemia drugs approved in more than
a decade.
DR. HUSSAIN: I am sorry, the second
question was dealing with the efficacy endpoint
that were prospectively put in the Phase II trials.
DR. WEITMAN: I will ask Dr. Tannen to
come up and comment on that, please.
DR. TANNEN: Can I have Slide 101, please.
This trial was designed based on using Fleming
2-stage design, and at that time, we have the data
available on the Phase I trial based on 25
patients, and the response rate at that time, they
were observing is 30 percent response rate. The 40
percent response rate was hypothesized for the
clofarabine treatment groups with the control group
of the 20 percent, a 2-fold increase with the
clofarabine.
So, Fleming design basically says that you
look at the data with the 20 patients and observe
the response rate. At that time, the response rate
was observed with ALL, about 20 percent, and the
activity was seen, and the criteria to move to
94
second stage was not met at this time, but based on
the advice from the investigators, as well as the
FDA, it was decided to move to the Stage 2.
Activity was seen at the first stage, and
you have to see what is the clinical significance
of 20 percent response, which was observed in this
trial, and as mentioned by Dr. Weitman, the number
of patients, about 34 percent in AML patients, went
to transplant.
So, the response rate is what we saw here,
the 20 percent, which we believe is clinically very
meaningful, and has to do with the patient
population that is very heavily treated. In the
AML patients, it has to do with the patient
management that is the key issue.
DR. WEITMAN: If I can, I would like to
ask Peter Adamson to step up, as well, and make a
comment about this.
DR. ADAMSON: So, without a reasonable
comparative database to look at, to say, well,
where should the bar be in ALL or AML, I personally
think the assumption of 40-20 was an incorrect
95
assumption, and it missed the mark by a large
measure.
As Steve Sallan had pointed out decades
ago, single-agent activity in newly diagnosed
patients are in the 20 to 40 percent range, and I
think you can count on two fingers the single-agent
activity in ALL above that.
So, setting the bar in this population at
40 percent, my personal view was way off the mark.
Where should it be? I think it is a more difficult
question, but maybe I can share with you very
briefly the Children's Oncology Group challenges in
the same population, so with a concurrent
population, the challenges that we are facing.
We have three, Phase I studies in ALL and
AML going on. For Phase I, as you know, a criteria
for evaluability, they have to make it through a
cycle of therapy, which is 28 days.
We are nearing the point where we are
going to have to abandon that design, because we
have about a 70 to 80 percent inevaluability rate
in Phase I. These patients are so heavily
96
pretreated and are so rapidly progressive, we can't
get Phase I data anymore in leukemia, because we
can't get them through four weeks of therapy.
So, that will set the stage saying the
mere fact that they got through a Phase I, to me,
was an indicator that there is something going on,
because we can't get through Phase I's right now.
Now, in Phase II, where are we putting the
bar? That is a moving target, and maybe I can take
this brief opportunity to come back to Dr. Pazdur's
initial introduction where CR, duration of response
and overall survival are the three criteria.
I certainly agree with those, but it is a
shifting paradigm, because I no longer think we are
going to be able to get duration of response data
in this population, and there are two reasons for
that.
In AML, it is very clear that the current
standard of care is that we whisk these patients to
transplant as soon as feasible, as soon as you have
had cytoreduction, they go to transplant.
So, as much as scientifically, we would
97
all like to see a duration of response that is not
confounded, we are not going to. We are not going
to do it in our trials, and I don't think industry
is going to do it, because the standard of care
won't allow it.
Now, in ALL, duration of response becomes
somewhat of a different challenge. Yes, they are
going to transplant, but I think Dr. Pazdur
correctly pointed out that a reasonably high
fraction of responders didn't have a repeat marrow
assessment.
This is where our scientific desires run
head to head with some ethical concerns, as well as
current standards.
As everyone or many of you know, in
pediatrics, there are additional safeguards
afforded, FDA, DHHS regulations, and for studies
that offer no potential for direct benefit, we
can't mandate those studies in children.
So, as much as we would like to see repeat
marrows done, the reality is once a child is in CR,
it is hard to describe what the benefit to the
98
child is to repeating a marrow later on.
The reality in ALL, for those of us who
take care of it, is it is no secret when a child
recurs. We don't need to look in their marrow. We
look in their marrow to confirm it, but it is not a
secret.
So, it becomes difficult once you have
documented a CR, to go ahead and confirm it later.
We absolutely would like to do that. The reality
on the front lines is that it becomes exceedingly
difficult to.
So, the criteria we have put forward as
far as CR's, duration of response and overall
survival, the CR's, we need to document. AML gets
confounded, ALL, less so, but duration of response
is going to be a pretty difficult standard right
now.
I know I have gone off on a tangent a bit,
but the design as far as 40-20, I think was
misplaced, and I would right now say for ALL, we
are tending to set designs in our studies at 25, so
the Fleming 2 stage at 25 with a 20 percent
99
response rate of interest.
DR. SANTANA: Dr. George, you had a
question and since this is kind of in this area of
discussion. Go ahead.
DR. GEORGE: Well, it is related. I have
a question for the sponsor. In the duration of
response, and, for that matter, the overall
survival curves, it appears that the transplant
issue was handled by simply ignoring it. I mean the
analysis would have been exactly the same if no one
had gotten a transplant, is that correct? This is
the clarification question.
DR. WEITMAN: Well, again, we looked at
those patients that went on to transplant, correct,
and we included that in our duration of remission
and overall survival as part of that.
DR. GEORGE: Well, just to be clear, that
means that if someone did get a transplant, and
then later relapsed, I mean that time to relapse
was taken, whatever it is, just as is.
DR. WEITMAN: Correct.
DR. GEORGE: Another issue that just came
100
up, that I hadn't thought of before, was this issue
of confirming the relapse. I assume all those were
done with some marrow samples, so they were
confirmed.
DR. SANTANA: Let me go back to that
issue, because I got confused, too, reading the
documents. Are we talking about not confirming the
response with follow-up marrow, or not confirming
the relapse with a follow-up marrow?
Can the sponsor clarify that for me? Did
all patients have a confirmatory response for the
tagging of response, and it was that when they
recurred or progressed, a marrow was not repeated
to document that?
DR. WEITMAN: It depends, Victor. Most of
the cases did have repeat marrows done, but
clearly, if there were patients who had no evidence
of relapse, and all of a sudden developed, 20, 30,
40 percent blasts in their peripheral blood, then,
again, a lot of those patients did not have
confirmatory marrows done at that time, but at that
point, that was considered disease progression
101
without necessarily requiring a confirmed repeat
marrow.
DR. SANTANA: So, this issue of not doing
bone marrows was at the time of progression, is
that correct?
DR. WEITMAN: Correct.
DR. BRAWLEY: I didn't understand it that
way either. Can we clarify that?
DR. COHEN: The issue in terms of
confirmed marrows was not confirming the response,
that is, a second marrow was not done within a
month of the first marrow. It had nothing to do
with progression.
DR. BRAWLEY: This is very important. Can
you just slow down just a little bit. You did not
do a marrow to confirm complete response. You sort
of looked at the blood and accepted complete
response on some sort of religious basis, is that
right?
DR. WEITMAN: Otis, no, not exactly.
DR. BRAWLEY: Okay.
DR. WEITMAN: Confirmatory marrows were
102
done in most of these patients. Now, clearly, at
the time that that first marrow that was done that
showed remission, if that patient was in remission
and had a donor, they would go right to transplant.
Many of those patients would still get a
repeat marrow the day or so before transplant, but
again, most of those patients had, first of all,
had a marrow done to confirm response or to show
that they were in remission, and then they would go
either to transplant or would continue on the
study, and those patients that continued on study
without a transplant would get marrows as dictated
by the protocol.
DR. HUSSAIN: Is it possible to put a
slide about that, because I think right now I am
totally confused about what was confirmed, what was
not confirmed.
DR. SANTANA: Do you have a summary of
that?
DR. WEITMAN: Again, what I can just
highlight again is that for patients, I think there
is one slide that has the confirmatory marrows. It
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should be in the briefing document, as well, that I
believe the FDA has supplied to you, as well.
DR. PAZDUR: If you take a look at the
questions for the Committee, it does go through on
Table 2 and Table 4, the differences, and these are
in patients that did not have transplants, because
we look at transplants as really confounding this
whole issue of what a response is.
You could see the data and a single
asterisk means the responses were not confirmed,
double asterisks, responses were confirmed. What
we are talking about here is a discrepancy of
whether these had a confirmatory bone marrow
biopsy.
I guess as the sponsor said, and perhaps
he could give this information because I don't have
it off the top of my head, if you take a look at
all of the patients, how many had a confirmatory, a
bone marrow at, for example, 4 weeks, because that
is what you are after, the CR's.
DR. WEITMAN: Again, just to reconfirm
that all patients had a marrow to document
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remission. Now, as far as confirming remission,
the majority of those patients, and I don't have
the exact numbers, but the majority of those
patients--
DR. PAZDUR: That is the question. What
is the majority?
DR. WEITMAN: Let me get it.
DR. SANTANA: Ruth Hoffman had a comment
or a question?
MS. HOFFMAN: This is for the sponsor, as
well. The overall survival for ALL median was 11.7
weeks at the close of study, and for AML, it was 21
weeks. Because the study for a lot of these
patients was January or February of this year, this
is now 10, 11 months later, do you have the status
of the survivors, how many are still alive?
DR. WEITMAN: If I can show the follow-up
on some of the additional patients.
DR. SANTANA: Go ahead.
DR. WEITMAN: I will ask for the slide
that looks at follow-up patients and survival.
I would like to, if I can, show the
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response follow-up first.
DR. SANTANA: Since you have the survival,
why don't you just do that first.
DR. WEITMAN: Okay. We will start here.
This is just a follow-up for the patients that were
on the study. Again, what was submitted in the NDA,
and again I will comment that the updated data has
not been reviewed by the FDA, and they have not
seen this follow-up data.
Essentially, all it shows is that the
response rates were similar with the additional
follow-up data or additional patients that have
been treated with clofarabine for both ALL and AML.
If I can show the survival slide. In
follow-up, this shows 22 percent of patients alive
with median follow-up of 28 weeks, and I believe
this is as of November, actually, this was the
beginning of November, September 30th of this year
with 18 percent patients alive with median
follow-up of 47 weeks.
DR. SANTANA: Thank you.
Dr. Maldonado, you had a question or a
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comment?
DR. MALDONADO: Just a couple of
questions. This is just for my own clarity on the
biological plausibility of the results we are
seeing here. I hate to take you out of the
clinical, but I want to go back to the basics
seeing that the sponsor had been surprised by the
higher unexpected results.
What is known about the mechanism of
action of clofarabine, and why do you think this is
a different nucleoside analogue?
Pardon my ignorance, but it appears that
that is basically what has been the surprise for
the sponsor, and is that because the cells that
have more permutations to elicit the resistance? I
still don't understand much about the biology and
molecular biology of the drug here.
DR. WEITMAN: I will make two comments. I
will first start by asking Dr. Gandhi to come up
and talk about the preclinical mechanism of action.
DR. GANDHI: Clofarabine is very similar
to other nucleoside analogues with regard to its
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metabolic aspect, that it does require
deoxycytidine kinase to get phosphorylated.
It resembles to some extent to cladribine
and to some extent to fludarabine. With
cladribine, it resembles regarding metabolic
aspect, that is, it is a favored substrate for
phosphorylation.
With regard to clofarabine, it resembles
that once it gets incorporated into DNA, it results
in chain termination, whereas, with cladribine,
there is no chain termination.
Does that answer your question regarding
the comparison with other nucleoside analogues?
DR. MALDONADO: So, you think that the
activity or the efficacy we are seeing in clinic is
because this is a chain terminator versus the other
comparisons?
DR. GANDHI: There are several other
factors. One, especially, in the clinical
pharmacology, which goes a little bit away from the
mechanism of action. When you look at the
clofarabine triphosphate in the leukemia cells
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during therapy, it is very different from
cladribine triphosphate and fludarabine
triphosphate.
All these three nucleoside analogue
triphosphate, they live for a long time in the
indolent leukemia setting in the leukemic
lymphoblasts, but when you compare it for the acute
leukemia setting, fludarabine triphosphate half
life is 7 hours, cladribine triphosphate half life,
which hasn't been tested very well, in fact, we
have the guru right here for all the cladribine
studies, but it was about 7 hours half life, and
for clofarabine triphosphate, the half life is more
than 24 hours.
So, we think there is a benefit with
clofarabine because it remains for a long time in
the acute leukemia blasts.
DR. SANTANA: Dr. Pazdur, you had a
comment?
DR. PAZDUR: I wanted to follow up on
Maha's question about response rate and what is the
appropriate response rate here.
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I want to stress that remember this study
was done as a Phase II trial, and one of the
concepts of a Phase II trial obviously is an
exploratory trial where you would get data and a
response rate which would indicate whether the drug
should be carried on further in drug development.
That was the original intent of when we talk about
what a Phase I study, Phase II, Phase III paradigm
is.
What we are talking about here, though, is
drug approval, and I want to stress that simply a
mere screening for drug activity does not
necessarily constitute the requisite information
that one should have for approval of a drug.
Remember, when we are talking about
approval of a drug under accelerated approval, you
have to be reasonably likely that this response
rate can predict clinical benefit.
Now, you know, we have in the past with
other diseases in adults, for example, lung cancer,
colon cancer, taken a look at single-arm trials in
very refractory diseases, in some of the
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hematological malignancies where we were able to
take a look at duration.
If we can't take a look at duration, maybe
this paradigm of taking a look at very, very
refractory disease patients and trying to approve a
drug on that basis, is not the appropriate paradigm
to have in all clinical scenarios here, and I think
that is an important point.
Somebody could actually do one day a
randomized study for drug approval and surprise the
FDA.
DR. SANTANA: I will not comment on that.
Dr. Martino?
DR. MARTINO: Actually, I want to ask this
question of Dr. Arceci. It is a clinical
understanding that I need.
In these children, when you achieve a
partial remission with this agent or any agent,
what does that mean to you clinically? Is that
meaningful, to what degree is it meaningful, and
what does it mean in terms of their survival?
DR. ARCECI: In terms of the practical
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side of what a partial remission means is that it
usually buys time, and usually, it improves quality
of life during that period of time. It also means
a chance to proceed to a more definitive therapy.
If a patient does not have at least a good
partial remission, it essentially buys that extra
time to finish marrow typing, finish insurance
approval for transplant, then, we don't get to
transplant.
So, a PR has enormous utility in our
business although it, of course, is not going to
result in a cure. Those patients with PR's are
going to relapse clearly and progress, but it gives
us a chance that if we can move that process
forward, we can often cure it, or at least in a
percentage of those patients can cure them.
Is that answering your question?
DR. MARTINO: You gave me a sense of what
I needed to hear. Thank you.
DR. SANTANA: Dr. Poplack.
DR. POPLACK: I just want to go back to
the point that Dr. Pazdur made two comments ago,
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and that related to the ALL patients who were
judged to have responses.
In the data that we received, it is not
possible to determine which patients did or did not
have that confirmatory second marrow, and I think
it is critically important for us to get that
information. So, that is the first point.
The second one is--and that is on Table 2
of the questions that were given to us--the second
question I have for Dr. Weitman is, what would be
the plans--and I assume this is a fair question,
and it seemed like what you stated was a little
vague to me--for a confirmatory study were this,
for example, to be approved?
DR. WEITMAN: With regards to your first
question, my helpful colleagues here pointed out
that 9 of the 15 patients with ALL had a
confirmatory marrow, again a second marrow after
the initial marrow was done, so there was 9 of 15
for ALL.
Two of 9 for AML had a confirmatory
marrow. The remaining patients went on to
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transplant or probably had either progressive
disease at the point, so again, 9 of 15 for ALL,
and 2 of 9 for AML.
DR. POPLACK: I think the information I
would like to get is which of those responses, if
we look at the patients who responded, which ones
did have or didn't have a subsequent marrow.
DR. WEITMAN: If I can then also touch
base on your second question, and that is, again,
our plans are to work with the Children's Oncology
Group towards a randomized study.
As you know, I think doing a randomized
study in this patient population is very difficult,
if not heroic, efforts to undertake, but our plans
would be to move forward with the cooperative
groups and at some point go into a randomized study
where clofarabine is added on to the backbone
therapy of either patients in first relapse or
newly diagnosed patients at the appropriate time,
where this drug was added onto the backbone,
looking for changes in survival or duration of
remission.
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DR. SANTANA: I don't think I heard the
answer to the first question yet, and I think we
need to get an answer because it has come back now
three or four times in the last 10 minutes.
So, of the patients in ALL and AML, who
actually were coded as having a response, how many
of those had a subsequent marrow that confirmed
that response? Can somebody give us that
information?
DR. COHEN: If you look at the FDA review,
Table 11 on page 25 is the AML, and Table 23 on
page 33 is the ALL, and the seventh column down is
patients who had confirmatory marrows.
DR. SANTANA: Can you summarize it
publicly because I think some people don't have the
documents in front of them? I hate to put you in a
position, but--
DR. WAYNE: And also remind us of the page
and the table number, please.
DR. COHEN: This is Table 11, page 25, FDA
briefing document. It lists 9 responding AML
patients and 2 of the 9 had confirmatory marrows,
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and the other 7 did not, of the responders, this is
just responders.
DR. SANTANA: So, 2 of the 9 AML patients
that were coded as having an initial response, had
a confirmatory marrow, is that correct?
DR. COHEN: That is correct.
DR. KURTZBERG: I still don't understand
if that means they had the first marrow that
confirmed their response, and then they did have a
second.
DR. COHEN: This is the second. The
confirmatory marrow is the second one.
DR. SANTANA: It's the follow-up bone
marrow.
DR. COHEN: And for ALL--
DR. PERRY: Excuse me. Just for clarity,
they had a bone marrow that met response criteria,
but only 2 of the 9 had a second bone marrow at
least a month later establishing the came criteria.
DR. SANTANA: That is my interpretation.
DR. COHEN: That is mine, too.
For ALL--
116
DR. SANTANA: That is Table 23 on page 33.
DR. COHEN: Right. There are 15 patients,
confirmatory marrows were 9, 9 of the 15 had
confirmatory marrows.
DR. SANTANA: Thank you.
DR. WEITMAN: Can I ask Dr. Arceci to
comment about Dr. Poplack's question regarding the
COG and plans moving forward?
DR. SANTANA: Yes, I think that is an
important point to clarify.
DR. PAZDUR: While he is coming up to the
table, I would also like to emphasize for Dr.
Poplack that the confirmatory study can be done in
an earlier stage of the disease. We have
repeatedly done this in adult disease where
somebody might get an approval in a very refractive
population of colon cancer patients and then the
confirmatory study is done in the same disease in
an earlier stage.
We have interpreted that as a way of
moving forward drugs and trying to escalate the
speed of drug development basically.
117
DR. ARCECI: I would just comment briefly
on David's point, and that is, a randomized study
of this drug in newly diagnosed patients, or even
in the relapse setting, is very unlikely to happen,
but the cooperative groups right now are, in fact,
moving towards combination trials, and both in AML
and ALL, those studies are moving very rapidly
through the cooperative group mechanism.
We have plans to then try to randomize
those combinations in the setting of newly
diagnosed patients. We are doing that now in
upfront studies with new agents and combining them
to see if we can offer an advantage over standard
therapy.
So, what will probably happen I suspect
with the combinations is that because of the
somewhat noncross-resistant toxicity profile of
clofarabine, in pediatrics, for instance,
anthracyclines are tremendously concerning agent,
and we would eventually love to be able to
introduce combinations that, in fact, don't have
those anthracyclines in cardiac exposures.
118
So, that is the plan right now, at least
in the leukemia trials. I think I will stop there.
DR. MARTINO: Can I ask a question. I
appreciate the word randomization, and we all get
excited over it, but I have yet to hear what
exactly you are thinking to randomize, to what?
DR. ARCECI: Amen. In the Phase III
trial. So, depending upon the results of those
combination studies, what we would very likely do,
for instance, in AML, is to introduce a combination
clofarabine/ara-C, if that combination looks as
promising as we hope.
We would then try to randomize that
against a standard course of intensification or
induction therapy or consolidation therapy, so we
would try to have one arm, for instance. What we
are using now, for instance, is MRC-based therapy
with the modification now--
DR. SANTANA: The adult oncologists maybe
don't recognize the acronym.
DR. ARCECI: I am sorry, the Medical
Research Council. So, we are basing 5 courses of
119
intensive therapy in AML based upon the Medical
Research Council out of Britain. In the U.S., we
are randomizing the addition of gemtuzimab
ozogamicin to that upfront trial.
One group will get several courses of
combination and the other one will get the standard
therapy. In the setting of a combination with
clofarabine and ara-C, it would be particularly
advantageous to try to have a group that would get
that standard therapy versus an introduction or
replacement of an anthracycline, for instance,
containing regimen or another regimen that would be
potentially more toxic, and see if we could get the
same or better outcome. That is the type of
randomization we are currently pondering.
DR. PAZDUR: Could I comment? We are very
concerned about this aspect, and that is why I
spent some time in my introductory comments on the
need for confirmatory studies. I would like to
remind the ODAC Committee that in March of 2003, we
spent an entire I think day and a half or two days
on this issue.
120
Basically, the regulations, although it is
not a requirement, stipulates that there is an
expectation that these trials should be ongoing.
We have not met with the sponsor regarding this
issue. There may be differences on what
cooperative groups need to do versus what our
appropriate studies that would meet a requirement
for a regulatory purpose, i.e., isolating the
effectiveness of the proposed drug.
Here again, we would have to discuss this
in detail with the sponsor. It is quite bothersome
that we are at this point of talking about approval
of the drug, and not having met with the sponsor.
This is something that you will have to
take into consideration regarding this drug. Other
points that I would like to bring up for further
discussion perhaps at the next hour is whether this
confirmatory study needs exclusively to be done in
pediatrics or could be looked at in an adult
indication. Here again, that is something for the
pediatricians to discuss.
I am very concerned about this. The
121
Division is very concerned about the lack of
ongoing studies at this time. Remember, these
studies are to be done with due diligence. One has
to question, if they haven't been done to date or
even initiated to date at due diligence, has the
sponsor demonstrated due diligence if they haven't
been even initiated at this point.
That is a consideration that I think you
need to bring into consideration, whether children
are best served with the approval of this drug at
this time or whether further study needs to be
done.
DR. SANTANA: As a follow-up to that,
because I think you leave us with a sense that we
need to discuss this, but it is, from my own view,
is it a procedural issue that hasn't occurred, you
know, give us some of the reasons why it hasn't
occurred.
DR. PAZDUR: Usually, the sponsor would
come in and discuss these trials with us throughout
the course, and the drug has been in development
for a lengthy period of time here. It is not that
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this drug was developed just within the past year.
One of the things that we stressed at the
previous meeting in March is that there should be a
comprehensive development program for drugs, and
this would include perhaps an exploratory study,
however, we encourage early initiations of
randomized studies, not late, not, well, let's get
the drug approved and then let's talk about
randomized studies.
I would like to emphasize that a lot of
sponsors have been very responsible with this after
our meeting of bringing forth a single-arm study
and discussing a single-arm study, but also making
a commitment and having ongoing accrual to a
randomized Phase III study.
An example of this, for example, is
Velcade, where we approved the drug on a single-arm
study, however, 40 or 50 percent of the patients
were already randomized to a study. This is the
type of drug development program that we are
looking at, a real commitment to drug program.
DR. SANTANA: Yes, go ahead.
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DR. PERRY: I understand exactly I think
what you said except for me there is a difference
between adult and pediatric oncology. In the adult
world, we have lots of patients who aren't going on
cooperative group trials. In the pediatric
community, 90 percent of patients are on
cooperative group trials.
So, it seems to me the sponsor can almost
only work with the cooperative groups, and work at
their pace. They can't very well dictate to the COG
and say do my study and do it now, and do it in
this direction, because I need further approval
from the FDA.
In the adult world, it is an entirely
different playground.
DR. PAZDUR: And specifically, I think
this is why we wanted to discuss this issue here.
DR. SANTANA: I think that is a very
important point. I think there are limitations in
terms of patient resources that pediatric oncology
has, and when we get into Phase II trials that
require a larger number of patients or we get into
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Phase III trials, you know, we have to work with
the existing structure of the cooperative group to
get those studies done.
So, I think your point is very well taken
and the Committee needs to recognize that. I am
not here to defend either side, I am trying to be
impartial, but I think it's a reality of how the
process occurs in pediatric oncology.
DR. PAZDUR: And here again, Victor, this
is why we wanted a public discussion of this.
DR. TEMPLE: I think the crucial point is
that accelerated approval was thought of originally
as something that happens if you get surprised,
that is, you are doing ordinary development,
whatever that requires, but the results are so
impressive in the early studies that you reach the
reasoned judgment that it is better to make it
available before you have the final data and get
those data later.
For obvious reasons, this isn't really to
blame anybody, it has also become, to some degree,
an alternative path to approval where the only
125
thing that people think about at least sometimes is
accelerated approval, and they don't really spend a
lot of time thinking about what the whole program
is going to look like.
We recognize the realities of availability
and things like that. Sometimes people go to other
countries to do the trials where there might be
possibilities that aren't available here.
But I think the main point that Rick wants
to make, and I do, is that it should be playing a
part of a coherent plan, and we would be happy to
talk with them, we would be happy to talk with the
pediatric oncology groups, but it ought to be part
of the thinking process, and we are concerned that
sometimes it doesn't seem to be.
DR. SANTANA: Joanne.
DR. KURTZBERG: I have a question for the
sponsor along these same lines, if accelerated
approval is granted, and if trials were planned as
part of the arrangement, would the sponsor's
support both drug and data collections costs for
those trials even after drug approval?
126
DR. WEITMAN: I would just like to make a
couple comments also. Again, that is, at least
historically, if you look at what the sponsor has
done with Campath in the past, is that we have met
I guess requirement for that drug as far as doing a
post-commitment study. That study is fully accrued
and is completed, and we are in the last phases of
really data collection follow-up on that, so we do
have a track record of meeting that requirement.
As far as going forward, we are fully
willing to support these studies going forward,
certainly with drug, but also financially as needed
to make these studies come to completion.
I think, Joanne, you and I have both been
in the position where drug all of a sudden
disappeared as we have been trying to do these
studies in the pediatric oncology community, and I
think as a sponsor, we fully accept that
responsibility to provide drug, as well as
financial support going further for these studies.
Now, when you go through the cooperative
groups--and I think the point that was made was
127
very appropriate--doing these studies outside the
cooperative group, I think is extremely difficult.
In fact, at this stage, one of the reasons
why it was done early, because a lot of these
patients just weren't eligible for any studies that
were in the cooperative groups going forward. A
lot of these patients now would be, particularly as
we move into less heavily pretreated patient
populations.
So, I think going into that population now
is really where we need to be with this drug. The
support for this agent going forward clearly
depends on I will say a little bit on the
Children's Oncology Group. When I have met with
them and talked to them about just that point, how
to support these studies going forward, there was a
couple of options.
One, they actually asked if we would
provided some support for particularly outside
studies, correlative science studies, and so forth,
but a lot of that support would come through the
CTEP mechanism, and they actually preferred that
128
versus sponsor support, but we are willing to
support it either way depending on what works best
for the cooperative group, as well as to get this
agent moving forward.
DR. SANTANA: Dr. Wayne.
DR. WAYNE: So, though, we are asked to
consider the data presented in the application on
the pediatric trials in regard to the accelerated
approval, it might help to have additional adult
data that might be extrapolated. I was somewhat
pleased and surprised to see on page 112 of your
briefing document, in Table 46, 60 percent, 63
percent CR with cycle 1 in adults on a Phase II
trial with single agent.
Are there data that can be shared further
in that regard? It is the IST study, and no
further mention, or I didn't find any further
mention of that in the briefing document.
DR. WEITMAN: We have had obvious a
continued program, but mostly with the focus on
adult AML. There has been a few ALL patients
treated, but most of it is in the adult population
129
with AML.
The responses again, as I mentioned, in
the combination study, were about 40 percent.
Again, this was pretty much echoed in the
single-agent study, as well, in adult patients with
AML with a fairly high response rate. In fact,
some of the patients, the elderly patients have had
response rates in the 60 percent range with adult
AML previously untreated patients.
That is why the program in adults is
really moving in that direction more than in ALL,
because of the activity we have seen in that
disease subtype.
DR. WAYNE: Do you have more formal data
in regards to that AML trial? Clearly, the very
limited data you have shown us in regard to AML in
pediatrics, and that single-agent agent might be
helpful in regards to extrapolation in AML.
DR. WEITMAN: Well, I don't have a slide
with me today on that, but clearly, again, that has
shown activity. The response rate in the
combination was 40 percent CR and CRp. The adult
130
elderly patients was over 60 percent response rate
with AML. Against, that was in an IST STUDY, that
wasn't a pilot study.
I think across the board, that is where we
have seen the response essentially confirmed right
between 40 and 60 percent with AML.
DR. SANTANA: Dr. Brawley.
DR. BRAWLEY: Steve, I have two questions
really, if you could respond. One of the things
that some of us are concerned about, those of us
who are a little bit more orthodox in our design of
clinical trials, like to set the endpoint and then
not move the endpoint during the trial. Sometimes
we can be accused of tailoring the endpoint to fit
our data.
Can you just respond and assure us that
that hasn't happened here?
DR. WEITMAN: No, absolutely not, Otis,
that hasn't happened here.
DR. BRAWLEY: The next thing, and I don't
want to make any allegations or implications
against anyone, but out of a sense of fairness, can
131
your academic advisors disclose for us their
financial relationships with the company, who own
stock, who has taken honoraria, and that sort of
thing?
DR. SANTANA: Johanna, where is the
Executive Secretary? Can you help us with that?
Do we have--before anybody gets to the podium--do
we have any information from the consultants for
the company in terms of their conflict of interest?
DR. BRAWLEY: Also, is it even appropriate
to ask that question?
DR. SANTANA: It is appropriate publicly
to ask that question, because the consultants
should have cleared that.
There is a question on the table whether
the consultants for the sponsor have cleared issues
of conflict of interest. What is the process?
MS. CLIFFORD: We don't do that.
DR. SANTANA: We don't do that, okay.
DR. PAZDUR: They don't do that.
Obviously, it is up to the individual people that
have presented here if they would like to avail
132
that information.
DR. SANTANA: I personally have no issue
with that. If other members of the Committee feel
differently, this is the time to raise your
concern. I have no issue with the sponsors and
their consultants.
DR. TEMPLE: Just to be clear, I mean our
presumption is that the people who are advocates
for the company have an interest. So, you have
listened to them, and you listen to what they say,
but they are not neutral parties like the advisors
here.
DR. SANTANA: Dr. Mortimer.
DR. MORTIMER: I am just curious. The
cytogenetics, I know you had cytogenetics on one
patient, but what was the impact of cytogenetics
pre- and post?
A second question is after completion of
therapy, did patients receive additional treatment
afterwards, or all these patients stopped with the
study drug?
DR. WEITMAN: Your first question about
133
cytogenetics, I was very interested in that myself
and tried to take a look at it. As you can
imagine, in these patients that have gone through
five, six prior regimens including transplant and
total body irradiation, their cytogenetics ended up
running onto several lines, and trying to really
tease out anything in particular was very difficult
to do.
Certainly, a number of these patients did
have 922, monosomy 7, and some of those patients, I
think there is one of each did respond. But again,
looking at them, trying to make any correlation
between cytogenetics proved extremely difficult in
these multiply relapsed patients.
Your second question?
DR. MORTIMER: Treatment after completion.
DR. WEITMAN: The only patients that
received essentially treatment after study were
those that relapsed and went on to something else,
and that was the same before going to transplant,
as well. The only treatment they received before
transplant was a conditioning regimen before
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transplant.
If I can, I would like to just comment on
Dr. Wayne's question about other results in the
adult population. The Phase II study results,
again, there was 31 patients with AML in that
patient population. Thirteen of those 31 had a CR
and 4 had a CRp, for a total of 55 percent response
rate in that patient population.
There were patients with ALL. That was 12
patients with ALL. Again, these are recurrent
disease patients. Twelve patients had ALL with 1
CR and 1 CRp. Again, because of that difference
with the propensity towards AML's, is where we are
moving with the program in adults.
DR. SANTANA: Dr. Hershfeld, I will give
you the last comment.
DR. HERSHFELD: Well, I will briefly just
comment on the data that Dr. Weitman just stated,
and if I may, I would like to ask a question too.
The Pediatric Subcommittee of this
Committee has been a big proponent of extrapolation
and has previously had discussions about data
135
between adult and pediatric leukemia, and had some
recommendations in that regard, but I should note
that the data that were just cited were not
submitted to the FDA, nor reviewed by the FDA,
therefore, that should be taken into account.
I wanted to ask briefly, if I could, a
risk-benefit question. That is, in risk-benefit,
the risk and the benefit are more or less separated
and then one integrates the two.
I wanted to ask Dr. Weitman if there was a
gain or change in either the risk or the benefit
that was gained with experience with the drug, that
is, patients that sought early on maybe had a
different risk or a different benefit than later
on.
Somewhat related to that, and this relates
to Dr. Brawley's question about the endpoint that
wasn't in the protocol, the transplant goal, the
CR/CRp sum in the ALL patients was 20 percent, and
yet half of those went on to transplant. The
CR/CRp in the AML was 3 percent, and yet 34 percent
of the patients went on to transplant.
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Why the differences or what was the
criteria?
DR. WEITMAN: With regards to your first
question about sort of gaining experience with the
drug, clearly, at least my impression of seeing the
patients going on study, when the study first
opened, we were seeing very heavily pretreated
patients going on study.
As you alluded to, with more experience
with the drug, as people began to see this drug's
activity, they began to put better patients on
study. But we also began to I think get a better
idea of how to manage some of the problems.
Quite frankly, we weren't anticipating the
extent of tumor lysis that we were seeing. These
patients would many times come on with white counts
of 100,000, and within a few days drop their white
count to 0.1, 0.2.
So, again, having considerable tumor lysis
that probably wasn't recognized was going to be a
problem early on, was managed much better as the
study went further, with extra fluids and just
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realizing that this drug has potent activity in
some of these patients.
I believe one of the patients of Dr.
Arceci, that he treated, actually had a uric acid
that went up to like 17 or 18. In my pediatric
experience, I have not seen many patients with a
uric acid of 17 or 18. Again, I think that just
reflects the activity of this drug.
But as time went on, and we began to
realize that, I think we were able to improve that
risk-benefit ratio by again extra fluids,
monitoring, and so forth, just as we learned as we
went forward.
With regards to your other question about
AML and why there was a higher number of those
patients going to transplant, it is a good
question. I am not sure I honestly have an answer
for it. It is what we did see.
Clearly, I think a lot of patients with
AML from the very early point, tried to identify a
donor whenever possible, probably much earlier than
patients with ALL, but again, there was more
138
interest in particularly patients with AML going to
transplant.
There is also more willingness in that
group to take patients in partial remission, where
their ANC may not have fully recovered, to go to
transplant, and that is probably not the same
situation with patients with ALL, where they want
to see a complete remission, solid remission more
likely than not than in patients with AML.
So, I think the threshold particularly for
patients with AML, because those patients do do
reasonably well even if they PR going to transplant
as opposed to patients with ALL.
If I can ask Dr. Arceci and Dr. Sallan
maybe to step up for a second.
DR. SALLAN: I just wanted to step up to
address Dr. Brawley's question. I have no interest
in the company whatsoever other than getting paid
for my time to review the data and to be here.
DR. ARCECI: I, too, think it is an
important question to clarify. My involvement has
been to participate in the study and my interest in
139
drug development, and they paid for my
transportation from Baltimore to Silver Spring.
[Laughter.]
DR. SANTANA: We won't ask how you got
here.
I think we will conclude this part of the
session. We are going to reconvene exactly at
10:45, because we do have a couple of individuals
that have signed up for public hearing.
Thank you.
[Break.]
Open Public Hearing
DR. SANTANA: I have a public paragraph
that I need to read for the record, so let me go
ahead and do that.
Both the Food and Drug Administration,
FDA, and the public believe in a transparent
process for information gathering and
decisionmaking. To ensure such transparency at the
open public hearing session of this Advisory
Committee meeting, the FDA believes that it is
important to understand the context of an
140
individual's presentation.
For this reason, the FDA encourages you,
the open public hearing speaker, at the beginning
of your written or oral statement to advise the
Committee of any financial relationship that you
may have with the sponsor, with its product, and,
if known, its direct competitors.
For example, this financial information
may include the sponsor's payment of your travel,
your lodging, or other expenses in connection with
your attendance at this meeting.
Likewise, the FDA encourages you at the
beginning of your statement to advise this
Committee if you do not have any such financial
relationships. If you choose not to address this
issue of financial relationships at the beginning
of your statement, it will not preclude you from
speaking.
So, I think we have a number of public
speakers. You have a list? Go ahead.
MS. CLIFFORD: We will start with Hal
Wilson.
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DR. WILSON: My name is Dr. Hal Wilson.
The only relationship I have with ILEX is they flew
me here and allowed me to stay in a hotel, which is
nice, because it's a long walk from Phoenix,
Arizona.
The reason why I am here, first, I have a
little background about me. I am a board-certified
family practice physician and I run and own a
practice in Phoenix called Maxel [ph] Medical
Group. I also do a lot of emergency room work with
a group called Emergency Physicians Professional
Association.
I had the opportunity to have dinner last
night with a number of parents of children who
suffered from the diseases that have been discussed
today. I am not such a parent. The reason why I
am here is because I am an uncle, and, Dr. Weitman,
when you had your slides up with the description of
the patient population, I felt like you had a
little picture of my niece on every one of them as
far as being in multiple drugs and failed bone
marrow transplantation, and the whole thing, ended
142
up in M.D. Anderson, and went on clofarabine.
So, that is why I am here. As I was
thinking about what to say today, I thought it
might be a good idea to approach this situation
with a sense of appreciation. I am not here to
crunch numbers or toxicities, risks and benefits.
I just want to say thank you to ILEX and
Dr. Weitman for bringing this drug as far as it has
come along so far. In this particular instance, I
realize it's a case of one that had some benefit.
Dr. Weitman and staff, I appreciate the commitment
you have made to pediatric oncology.
A couple of things that came up in the
discussion today, which I thought was really
interesting, which was fascinating to me, was the
idea that not very many new pediatric drugs have
come down the pipeline for a number of years.
I also heard it said that relapsed
leukemic patients and pediatric oncology patients,
regarding those patients, one of the major
challenges for a pediatric oncologist is the
relapsed patient, and I really appreciate what you
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do as far as dealing with those situations,
because, as everybody knows, by the time the
patient makes it to you, they don't have a lot of
options left.
So, basically, in conclusion, I would just
like to say I remember at the beginning of the
presentation, there was a discussion about
approving a drug based on scientific data versus
providing drug access to patients. In this
particular patient population, I think it is
important to remember that really, they don't have
any other options left.
Thank you.
DR. SANTANA: Thank you for your comments.
MS. CLIFFORD: Colleen McCarthy.
MS. McCARTHY: First, I would like to
disclose that my travel arrangements and my air
fare were paid for by ILEX Oncology.
My name is Colleen McCarthy and I am a
clinical research nurse at Children's Hospital in
Los Angeles, and I work with the Leukemia and
Lymphoma Program.
144
For the past 12 years, I have been a
pediatric oncology nurse working In a variety of
settings, inpatient, outpatient, bone marrow
transplant, nurse education, and now clinical
research, but always my focus has been pediatric
oncology.
I want to tell you a story about one of
our patients that we took care of. In August of
2002, we enrolled our first patient onto the
clofarabine trial. In total, we treated 8 children
on this study. One little boy, I would like to
tell you a quick story about.
We enrolled a 3 1/2-year-old, ALL relapsed
patient, who was diagnosed when he was 1 1/2 years
old. He had had 4 prior regimens before coming
onto this treatment. He had had a bone marrow
transplant included in that.
When he first started his therapy with
clofarabine, he was very irritable, very clingy on
mom. Mom would try and put him down, he wouldn't
walk. Mom was very, very upset that he wouldn't
act normal.
145
We gave him his clofarabine and lo and
behold, a week later, walking, feeling great,
eating, interacting with his siblings, feeling
great. Mom was very, very excited, and most
importantly, he was able to be discharged from the
hospital.
Now, he had been in the hospital for two
months prior to clofarabine, dealing with fevers,
et cetera, from toxicities from prior therapies.
The fact that mom got to go home was so wonderful
for she and her family.
This young child ended up getting 3 more
cycles of therapy, 2 of which were outpatient, so
he was home for about 3 months before he came in
for his last cycle, had a fever, and stayed in for
a few weeks before going home.
The reason I want to bring up this little
boy is because the mom shared with me, when we
started this drug, that she really wanted this drug
to work for as long as it could because she wanted
time with her young son.
The father was not in the house at the
146
time. He is returning to the house about a month
after the child had relapsed. She wanted to make
sure that there would be enough time for this young
boy to be able to be with his dad prior to him
passing away.
He did get 2 months with his father, and
the last thing the mom told me right after the
child did pass away, was the fact that after
getting the clofarabine, after cycle 3, the family
went to Disneyland together, mom, dad, little 1
1/2-year-old sibling, older cousin, and grandma,
and they had a normal day.
For that family to have that one normal
day, she was so thankful. After the fact, when the
child did pass away, she called me and said thank
you for letting my child be part of that study.
So, that is my little story about our 3
1/2-year-old.
As a nurse taking care of patients with
leukemia, when you first meet a family when they
are newly diagnosed, they will ask you what is
next, what should we expect, what treatment, and
147
all these wonderful questions, and those questions,
as a nurse, you are able to answer when the child
is newly diagnosed.
When that same family comes back to you a
few years later with relapsed or refractory and
asks you those same questions, it is very difficult
to answer those questions, because you are not sure
what is next, or what to look forward to, or what
they can expect.
So, I just wanted to point out those quick
little things. Thank you.
DR. SANTANA: We appreciate your comments.
Thank you.
MS. CLIFFORD: The next speakers are Tasha
and Steven Virostek.
MS. VIROSTEK: I am Tasha Virostek and I
do not have a financial relationship with ILEX.
They did, however, pay for dinner last night.
My son Jeffrey lost his battle on
September 25th, 2003, to acute myelogenous
leukemia. I am not here as a scientist, I am not
here as a doctor, but I am here as a mother who has
148
been deeply affected by this terrible disease.
Jeffrey was diagnosed with AML at the age
of 2 1/2. At the time, we knew we were dealing
with a terminal illness, but we had hope that with
the best doctors, the best medicines that were
available, and the best facilities for him, we
would conquer this disease.
Jeffrey received his induction of
chemotherapy beginning in November of 2001. When
he did not receive a remission, a protocol was
abandoned, and a new regimen was sought. What I
found out today is that many of these drugs are 30,
40 years old.
Christmas of 2001, he spent in the
hospital fighting infections, affected by rigors
from medicines given to wipe out fungal infections,
bacterial infections, and viral infections. His
body was too weak to fight infections and also too
weak to combat the side effects of the drugs. It
was depressing and frightening.
Miraculously, he did pull through and he
came home to celebrate his third birthday. His
149
next round of chemotherapy also left him weak and
susceptible to infection.
In March of 2002, we began treatment which
led us to our first bone marrow transplant. This
was our only option, and luckily, we did have a
donor, his sister who was 5 at the time. She was a
perfect match.
This was an extremely difficult process on
Jeffrey because he received even more toxic
chemotherapies which compromised his immune system
and again left him vulnerable to infection. The
chemo made his appetite diminish, prompting the
need for fluids and nutrition via his double lumen
port. Mucositis became prevalent. The intense
pain that accompanied this was unbearable at times
and had to be managed by morphine, which, in turn,
caused him to be lethargic.
This treatment kept Jeffrey from doing
what a 3-year-old should be doing, playing,
learning, laughing, enjoying being a child. As a
parent, it was agonizing to watch your child
struggle with the vary basic functions of life. No
150
one should have to endure so much.
This process also brought many anxieties.
We worried about the short- and long-term effects
of the chemotherapies on his body, liver damage,
damage of the heart and the lungs. We worried
about his future physical and psychological
development, and we worried about the effect on his
spirit. We worried about graft versus host
disease.
Jeffrey's diagnosis with cancer and his
treatments had other consequences on our family.
Being his full-time caregiver, I had to rely on my
extended family to take care of my daughters that
were at home. They were too young to understand
and my absence caused resentment and anxiety
amongst our young children.
Jeffrey's diagnosis brought a lot to our
family, but luckily, when he came home we were able
to have 9 months of remission. During that time,
our lives began to resemble, quote, unquote, a
"normal" life, and in October of 2002, Jeffrey
experienced a Make a Wish trip to Sea World to meet
151
Shamu.
But around his 4th birthday, he relapsed.
We returned to Children's Hospital where we faced
limited choices. We could redo the bone marrow
transplant or we could do nothing. We decided to
fight the cancer. Once again, we spent weeks upon
weeks in the hospital, confined to our small room.
Visits from family and friends were prohibited.
The second bone marrow transplant was
especially difficult on my daughter Megan. With
much trepidation, she received daily shots to
increase the number of stem cells in her peripheral
blood. Placing the catheter in her artery was a
painful experience that she still remembers today.
She then endured a long and difficult extraction
process.
Despite using the best doctors and
treatments available, Jeffrey's cancer returned
just a few weeks after his treatment. Our options
were limited. We had exhausted all known
treatments and he was not eligible for any drug
trials at this time. So, our last-ditch effort was
152
to give Jeffrey additional stem cells combined with
interleukin-2 in the hopes that the good cells
would outnumber the cancer cells.
At this time, our main goal was to
maintain Jeffrey's quality of life. We wanted him
to remain with us at home, so that he could play
with his sisters, he could be a little boy and play
with his friends and visit public places. We
wanted to enjoy each day that we were together and
we were frustrated by the lack of treatment
options.
Jeffrey did experience some pleasures like
a trip to the beach before the cancer took over.
His last weeks with us, however, were filled with
intense pain and suffering. The cancer took his
life.
We know that Jeffrey's story is not an
isolated case. Since the time of his death, our
family has personally known more than half a dozen
individuals who have relapsed and many have since
died.
The professionals in this room have the
153
knowledge, the resources, and the influence to make
a difference in the lives of children with cancer.
I encourage you to conduct your work with the
utmost diligence and expedience to bring new
treatments which will combat leukemia more
effectively, with fewer side effects, that allows a
higher quality of life. So many lives are
depending on you.
DR. SANTANA: Thank you so much for your
comments. I know it is difficult for you to talk
today, but I think it is a very honorable way to
remember your son to share your story with us.
Thank you.
MS. CLIFFORD: The next speaker is Ms.
Nadia Hendry.
MS. MAROUN-HENDRY: Good morning. Thank
you for this opportunity to share my experience
with you.
As I was listening earlier, I want to
clarify that Dr. Steinherz can confirm we have had
many bone marrow follow-ups, and thank you to the
doctors who quickly do that for us parents who are
154
waiting anxiously and chase them down the hall to
get those good and not so good results.
I consider it an honor, not only to speak
on behalf of my son, but hopefully, my remarks will
represent countless children and their families
whose lives, hopes, and future have been derailed
by the horrors of childhood cancer.
Throughout my son Matthew's 4-year ordeal,
struggling with the ravages of leukemia, I came to
see myself as something of an expert on the topic,
but please, make no mistake, I am here only as a
mother, more specifically, I am here as a
heartbroken mother, having lost our beloved son on
March 25th, 2003.
When Matthew was only 3 years old, filled
with wonder and the joy of life, we were informed
that he had cancer, telling you on that day,
September 9th, 1999, our world stopped and lost its
sunlight does not begin to express how profound our
grief was from that day on.
But as so many other parents have known
before me, we had to take our grief and turn it
155
into hope and action. We had to become educated.
Despite having been plummeted into a world of
protocols, side effects, frequent hospitalizations
of over 500 days in the hospital, new
relationships, financial and family turmoil,
somehow with the grace of God, supportive family
and friends, excellent medical care, and faith in
the promise of medical research, we managed never
to lose hope until Matthew drew his last breath.
During his illness, Matthew rose to the
challenge and rigors of numerous protocols and
treatment, including a bone marrow transplant and
subsequent boost. Each course of treatment renewed
our hope that this would be the last.
From the point of diagnosing to his
passing 3 1/2 years later, he only was free of any
drugs or treatment for two months of his life.
Matthew relapsed two months after his first bone
marrow transplant. Prior to his relapsing, he was
diagnosed with Epstein Barr Virus, a possible side
effect that we were aware of to transplant.
After 9 months of treatment at Memorial
156
Sloan-Kettering, preceded by 2 years at Albany
Medical Center, we were devastated with the lack of
options. There was nothing, it was dismal.
Matthew's doctor, Dr. Peter Steinherz,
offered to include him in a clinical trial using
clofarabine. We were given all the necessary
information and eagerly grasped at this one last
opportunity to save Matthew's life.
Remission followed shortly thereafter the
clofarabine was starting, allowing us to go ahead
with the second transplant. This was our last
chance. He stayed in remission and was 100 percent
donor cells, but oddly, we couldn't figure out what
was going on. He was having seizures and numerous
lesions to the brain.
As the seizures became more numerous and
more severe, a decision to treat for a possible
fungal infection was made. After weeks of
treatment with no improvement, it became obvious
that this was not a fungal infection.
By this time, Matthew's speech was
impaired, his thought processes sluggish, he was
157
unable to walk. The severity of his weakened
condition was cause for several hospitalizations
and increased medication.
Matthew's little body was broken and
weary, but never did he lose his spirit. He had a
strong sense of self. Our darling little boy, this
dear old soul told me it was time to face my fears,
and he asked me that I promise there would be no
more hospital.
After years of hope, we had to now turn
our love towards acceptance and making his last
months comfortable and peaceful. We were faced
with what no parent should ever have to deal with,
arranging for the end of our son's life.
It was through his strength of spirit that
we requested an autopsy to determine the cause of
death since he had been on the clinical trial. A
month after Matthew's passing, we learned that he
was clear of leukemia upon time of death, and it
was the Epstein Barr virus that caused his death.
Therefore, we knew the clofarabine has worked.
We had to know, we had to know for
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ourselves, and we had to know for the other
Matthews that this treatment had been effective.
We were happy to know that the clofarabine had been
effective and could only wonder, with very heavy
hearts, what if he had gotten this sooner.
Matthew only had 6 years on this earth. I
will have the rest of my life to wonder what if.
I failed to mention my trip was paid by
ILEX and dinner and my room, and I thank them for
giving us the opportunity to have an extra 8 months
with my beautiful son. Without that, we would not
have had that time. We were living in New York
City for over 9 months. Silly me, I thought the
chance that we would be home in 2 months and
everything would fine, and 9 months later, all
Matthew wanted to do was go home and be with his
dog and his brother and the rest of his family, and
he was able to do that because he took part in
this. It gave us time, and I don't think time can
be measured, and it is priceless.
Thank you.
DR. SANTANA: Thank you for sharing your
159
story with us.
MS. CLIFFORD: The next speaker is Jan
Manlapaz.
MR. MANLAPAZ: Good morning, ladies and
gentlemen. I am Jan Manlapaz. I come here as a
parent. We originally came from the Philippines.
I have a son, who is right now on my left side, who
is an AML patient.
He got multiple relapses, 5 relapses, 1
bone marrow transplant relapse, and I am speaking
on a good tune because this is our bible right now,
got multiple relapse and one bone marrow
transplant, and on July of 2002, the doctors
advised us that he going to live only for around
three months, and with the decision and advice of
Dr. Steinherz, they introduced clofarabine, and
they use it for him. He is now in 22 months in
remission, and we would like to thank you, thank
ILEX for this medicine, and thank all the people
who are in this research.
I want to give the microphone to my son
just for a simple note to say thank you.
160
Thank you for all the doctors for making
me well and thank you, Dr. Steinherz, for giving me
some medicine. Good morning.
[Applause.]
MR. MANLAPAZ: Thank you very much.
DR. SANTANA: I don't think anybody can
beat that comment. So, next.
MS. CLIFFORD: Mr. Dahlman.
MR. DAHLMAN: Thank you. George Dahlman.
I have no interest in ILEX. I didn't go
to dinner last night, and I live in the Washington
area.
My name is George Dahlman. I am the Vice
President of Public Policy for the Leukemia and
Lymphoma Society of the nation's second largest
voluntary cancer organization and the world's
largest dedicated to blood cancers, but probably
more importantly, I am the father of a childhood
cancer survivor, or now, more accurately, an
obnoxious teenager.
In the first capacity, I represent a lot
of patients and family members, and we lobby for
161
government funding, we fund our own research. We
run patient services programs, and we lobby for
better care.
Now, we all know that the leukemia
survival rate has improved dramatically over the
last 30 years. It has gone completely upside-down.
It used to be that survival rates were more like 20
percent, and now they have flipped around, they are
more like 80 percent.
Most of the credit for that dramatic
change is really with the physicians, many of you
pediatric oncologists who have tweaked and changed
the protocols and had the vision and creativity to
really make those differences.
Now, even with that progress, though,
there are no real cures yet as long as there are
kids that still have to go through this, and that
is the cold fact that parents have to face and many
parents have to tragically experience like those
here today.
There is still too many kids who don't
make it, and as a parent who had to look at that
162
prospect, I can tell you there is nothing more
frightening than the thought of losing your own
child. I have known a lot of people like this that
have gone through that.
I would like to say in the memory of those
children and for their parents, and all those
patients yet to come, we still have to keep
tweaking the protocols. That is why I think this
hearing and this drug is such an important
milestone.
That is what clofarabine offers. As we
all know, this is the first one initially labelled
for pediatric leukemia in over a decade, and that
is really a tragedy. It is a deficiency that
should not be allowed to continue.
I am proud to say that my organization and
others that we work with are very actively involved
with trying to develop incentives, public policy
incentives and corporate incentives that will
address that issue.
But now, as we all know, the progress in
this is incremental, and one in which the FDA has
163
traditionally accommodated with even the most
modest improvements in outcome, and professionals,
like yourself, need every weapon in your arsenal to
make those incremental improvements, and
clofarabine offers that kind of incremental
improvement.
Thanks for your attention.
DR. SANTANA: Thank you.
Committee Discussion
We will go ahead and start our questions
and further discussions, but before we do that, as
I heard the previous discussion, I think there were
two central themes that I think would be important
to try to reach some resolution or at least some
further discussion before we go into the questions,
because I think they will be pertinent for
answering those questions in the best way that we
can.
One has to do with this issue of bone
marrow transplantation and how does that impact
both of these studies and the indication that the
sponsor is requesting.
164
To me, what I would like some discussion,
and I am going to ask Joanne Kurtzberg, who is a
bone marrow transplant specialist, to help us with
this issue, is to give us a sense of what is the
practice of bone marrow transplantations with the
pediatric patients that have refractory or
recurrent leukemias, in what settings are
transplants clearly indicated, and what additional
value does treatment prior to transplantation offer
to these patient populations.
I think that will be very pertinent as we
go to trying to establish this issue of clinical
benefit for this drug.
Joanne, can you tackle that one for me?
DR. KURTZBERG: Yes, sir. Well, first of
all, we have to separate the discussion into a
discussion about ALL and AML, because the answer is
really not the same.
In children with ALL, transplant is really
not effective unless they are in remission at the
time of transplant, not partial remission, not
remission with low platelet, real remission, and in
165
all the diseases that we transplant, the success
rates for curative therapy are still the lowest in
children with ALL, because the disease appears to
be more resistant and maybe there is less of a
graft versus leukemia effect.
So, this drug would be helpful or any drug
would be helpful if it could take a child with
resistant disease and put them into a true
remission, but the idea of putting them into a
partial remission, I don't think is operative here,
because results in children in partial remission,
95+ percent of children relapse, if not all.
One thing that was said earlier that I
need to take issue with is that you can certainly
have a child with ALL walk in the door, have normal
to near normal blood count, and be in relapse, and
you cannot tell from the peripheral blood count
necessarily that that child is in remission or
relapse.
As a transplanter, we get many children
referred to us who relapse between the time they
left home and the time they arrive at the
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transplant center, and when you do that marrow,
they have got 20, 25, 30 percent blasts, and you
don't know that from their peripheral counts or
their physical exam or any clinical parameter.
As much as you want to cure every child
that walks in your door, if you take that child to
transplant, you are not going to cure that child.
So, I think rigor in that setting is really
important, and a drug would be valuable in that
setting if it produces a true, durable remission.
In AML, the story is different. Children
with AML, transplanted in relapse, still have
anywhere between a 25 and 40 percent cure rate
depending on the nature of their disease, the
nature of the transplant, the type of donor, and
the type of prep regimen.
So, you could argue in AML that it is not
essential at all to get a child in remission.
Having a drug that cytoreduces may be valuable to
prevent some toxicity, but I am not sure it really
contributes in a heavily pretreated, multiply
relapsed patient to overall outcome.
167
I think it would be an interesting
question to study, but I don't see anything in this
data that helps us know if it really provided an
increased cure post-transplant compared to a child
that was transplanted in frank relapse.
DR. SANTANA: Just to summarize very
straightforward like I like to be, in the setting
of relapsed, refractory ALL, there may be some
added value of getting those patients into
remission prior to transplantation, because those
are the patients that ultimately we think do well
with bone marrow transplant, but in the setting of
a lot of disease in the ALL setting, further
transplantation doesn't really add anything.
Am I correct in that simplistic view?
DR. KURTZBERG: I think so. Patients with
ALL benefit from transplant if they are in a true
remission at the time of transplant.
DR. SANTANA: And then for the AML
patients, it is debatable whether cytoreduction
really improves their ultimate outcome with
subsequent therapy as aggressive as
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transplantation, is that correct?
DR. KURTZBERG: Yes.
DR. SANTANA: Comment about that? Dr.
Hussain.
DR. HUSSAIN: Just to ask the doctor
again, because I think I heard a little bit
different, and that is, it is a complete remission
that is what is important, not any remission, and
the second question is, is that a confirmation of
that remission is crucial because you could be in a
complete remission today and walk out of the door,
and that remission is not maintained, which I think
is central to what we are talking about here.
DR. KURTZBERG: In ALL, yes--
DR. HUSSAIN: That is my question.
DR. KURTZBERG: --remission is important,
and a child who is transplanted not in remission
has an overwhelming probability of relapse, and
generally does not benefit from the transplant,
and, yes, confirmation is important.
DR. HUSSAIN: I am sorry, but we are
talking about a complete remission or any
169
remission?
DR. KURTZBERG: Complete remission.
DR. HUSSAIN: Complete remission.
DR. KURTZBERG: As defined in 1970.
DR. HUSSAIN: So, complete remission and a
confirmed complete remission is crucial.
DR. KURTZBERG: Yes.
DR. RODRIGUEZ: In AML, do I understand
you to say that cytoreduction isn't of any value in
terms of preparing the child for transplant?
DR. KURTZBERG: It can be of value
particularly if the child has a very high tumor
burden, because it can minimize toxicity, but to be
completely honest, there are many ways that you can
do that without achieving a remission. You can use
hydroxyurea and BP-16. You can use ara-C, which
may not put the child in remission, but will have
some lytic effect on the blasts.
So, you know, I don't think this would be
the only option in that setting.
DR. SANTANA: Any other questions on that
point?
170
DR. MARTINO: So, it occurs to me that
perhaps there are two patient populations. There
are patients for whom a transplant is a possibility
in the sense that there is someone who can donate
the marrow, and then there are patients for whom
that appears to be not such a possibility, and the
goals that are striking as being somewhat different
if I had to design a trial, and one of the problems
that I keep struggling with in the data that has
been presented to us is were the studies designed
in a manner that allowed me to answer the questions
that they are suggesting I am able to answer.
I am really struggling with the fact that
to me, there really are two populations, there are
two endpoint potentials here. One is judging is
this good therapy prior to, or concurrent with, or
somehow related to who gets to go to transplant,
and for whom is that a valuable thing to do.
Then, I have patients who really aren't
people going to transplant where I might want to
ask a somewhat different question. Yes, ma'am.
DR. KURTZBERG: I agree with you, but I
171
think the strategy for any new drug for ALL
shouldn't really have transplant as an endpoint.
I mean I think transplant came as an
endpoint because you are dealing with desperate
situations where that is the only possible cure,
and that is kind of what everybody looks to when
they are in that situation, but I think you are
absolutely right, the drug ought to be tested in
first relapse or second relapse patients, and there
are many of those unfortunately, with an endpoint
of response, and it is an additional facet, with
additional therapy planned after that based on the
standard of care. It might be transplant, it might
be more aggressive chemotherapy depending on
duration of first remission and many other things.
But the transplant endpoint really
confuses the whole situation, and I think it just
came to play because of the clinical situation
people are in when their child relapses multiple
times, not because that would be an appropriate
endpoint for proving a drug is good for leukemia.
DR. MARTINO: But what I feel I need to
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judge here is whether the data, as presented,
allows me to answer the question that the study
states it was designed to answer, and I still
remain confused because of this transplant issue,
realizing its clinical value and applicability, but
it doesn't quite allow me to judge what I view as
the question posed in the study.
DR. SANTANA: Dr. Temple.
DR. TEMPLE: If I understood you, you are
saying that at least in ALL, the question is
complete response rate properly documented, and
some people get transplanted, some won't, but you
are saying that is not the most important thing, it
is the complete response rate, which here is in the
neighborhood of 12 percent or something like that,
subject to subsequent debate.
But in AML, that is not as clear from the
sound of what you said. That is not as clear
because getting the count down, which you guys say
could be done in a lot of ways may be of benefit,
so what is the right test there?
DR. KURTZBERG: I think honestly, if I
173
were doing this, transplant wouldn't be in the
discussion, and I would do a standard Phase II
trial where the endpoint was response. I think
that the drug probably does have activity, I am not
questioning that, but I think testing it in first
relapses in upfront window, looking at response at
a month, you know, and squaring that, clearly is a
good thing to do.
DR. TEMPLE: So, in those cases, people
might be willing to wait before they--I mean in the
AML cases here, they were already transplanted
before you got a chance to look at how long the
response lasted, so you never could find out. Do
you think in earlier disease, that sense of urgency
would be less, and you could actually get that
data?
DR. KURTZBERG: Yes, I do, and I also
think you could get better data because the
patients are generally less resistant at that
point.
DR. TEMPLE: Okay.
DR. KURTZBERG: I think the response
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post-transplant is not interpretable. There are so
many kinds of transplants, kinds of prep regimens,
kinds of donors, and covariants that are
confounding, that you can't make a--
DR. TEMPLE: So, specifically, for these,
there are at least a reasonable number of people
with ALL whose response was tracked without a
transplant intervening, so you got some idea of how
long it lasted.
In AML, there were very few who managed to
do that, because the all got transplanted pretty
early if they looked even reasonably good, so you
don't really have duration data, is that correct?
DR. KURTZBERG: Yes, and part of that is
the hidden message that most people don't
transplant children with ALL if they are not in
remission, and these patients weren't in remission,
so not so many of them were transplanted.
DR. TEMPLE: Right. They behave just like
you say they would.
DR. KURTZBERG: But in AML, people do
transplant in relapse.
175
DR. TEMPLE: So, just to be sure I
understand it-- and I am sorry to struggle, I don't
do this for a living--in ALL, in these relatively
advanced and refractory patients, in ALL, you do
get a chance to see, in a small population, what
the complete response rate is, and it is not
confounded by early transplant that messes up
finding out how long it lasts. In AML, it is more
of a problem here because you don't.
Would that be true, is that what you are
saying?
DR. KURTZBERG: The way the data was
presented--
DR. TEMPLE: I am asking you what you are
saying.
DR. KURTZBERG: I think you could, but I
am not sure it happened in this case.
DR. TEMPLE: No, I mean as conducted here.
DR. KURTZBERG: Yes.
DR. SANTANA: Dr. Bukowski, do you have a
question or a comment?
DR. BUKOWSKI: Just a clarification and
176
maybe you can comment on this. Essentially, what
you are saying then is the population in second
relapse and beyond in both diseases is not an
appropriate one to evaluate a new drug in when
using the endpoint of complete response, because of
the confounder of transplant, is that correct?
DR. KURTZBERG: No. I think because in
many situations, you will take a patient in first
relapse to transplant. So, it is not the
transplant--I think transplant is confusing the
whole story. I think that drugs will have a better
chance of being fairly tested in patients in first
relapse because they are less resistant and less
heavily pretreated, and you are more likely to see
activity.
But it could be tested in second, third
relapse, but the endpoint should be response, not
whether they go to transplant and how they survive
after transplant.
DR. BUKOWSKI: So, is it possible, in the
pediatric group, to hold the transplant, to look
for the complete response? I mean it sounds like
177
this wasn't--at least it wasn't possible in this
particular setting.
DR. KURTZBERG: No, I mean complete
response after a first course or maybe two courses
at the most, and, yes, that is possible. First of
all, you wouldn't take the patient with ALL to
transplant without a complete response, and the AML
patient, it is a clinical judgment, but if they to
on a trial like this, they have a month or two to
be assessed.
DR. SANTANA: Dr. Maldonado, did you have
a comment?
DR. MALDONADO: It is not related to
transplant, it is actually a question that I have
been struggling with.
DR. SANTANA: Could you hold onto it then,
because I want to finish this discussion as one of
the points that I wanted to get clarity on.
DR. MALDONADO: Okay.
DR. SANTANA: Did you have a comment on
it, Dr. Poplack, on this issue we are discussing
right now, before we go to the next one?
178
DR. POPLACK: Yes, it's a question. I
think, obviously, one of the scenarios that is
being put forth here is that the value of this
agent is that it can get patients to transplant by
putting them into remission.
So, I would like to ask Joanne perhaps to
educate the group in terms of from her experience,
what percentage of patients who come to transplant
don't get into remission and don't get to
transplant, and what does she see as a potential
for this type of agent in that circumstance.
DR. KURTZBERG: That is a complicated
question because it really varies based on the
practice of the treating oncologist and their bias
for or against transplant and when they refer.
I am a transplanter, so my bias is that
any child who relapses should be referred for
transplant when they achieve their second
remission, but many oncologists don't practice that
way, and they believe a child should go through
multiple relapses before they prove they need to
take the risk that is associated with transplant.
179
So, that confounds the answer to your question.
I think, you know, a child with ALL on
standard therapy who relapses has about a 70
percent chance of achieving a second remission with
standard therapy, and if that child didn't achieve
a remission with standard therapy, and took a new
drug and had a 30 percent chance of achieving a CR,
that would be, to me, a valuable activity in that
drug.
If you take a child who has had 5 relapses
and expose them to any new drug, the chances they
are going to achieve a remission, no matter how
active the drug is, is much, much less. I don't
know how to put a number on it, but that is a
clinical practice issue, not whether the drug is
active issue.
For AML, the chances of achieving a second
remission after relapse, they are about 50, 60
percent with standard therapy, but again it depends
on therapy relapse, off therapy relapse, how close
to recent therapy, so there are a lot of
confounding variables.
180
My point is that I think this has been too
ambitious in taking down the transplant road is
just too complicated, and what you really want to
know, in childhood leukemia, is do you get a
durable response, not that lasts, to me, it doesn't
matter as a transplanter, if it would last two
months, six months, 12 months. It matters to me
the child is really in remission and that you have
the time to get them to transplant, which requires
another two to four weeks.
DR. SANTANA: So, you would define the
clinical benefit for the ALL population as reaching
that goal?
DR. KURTZBERG: Right.
DR. SANTANA: Of getting a remission of
some reasonable duration to allow you then to get
something more definitive.
DR. KURTZBERG: Right.
DR. SANTANA: You would define that as a
clinical benefit.
DR. KURTZBERG: Right.
DR. SANTANA: Ms. Hoffman, and then Dr.
181
Perry.
MS. HOFFMAN: Can you clarify, for the AML
population, I guess the benefit of allo- versus
auto-transplant, and if there is clinical benefit
to taking these AML patients using an
auto-transplant?
DR. KURTZBERG: This is my opinion, but
there is very little benefit to auto-transplant at
all, and if you have a multiply relapsed patient,
there is even less benefit. Not only do you have a
higher risk of relapse, which is 80, 90 percent,
but you also have a much higher risk of secondary
malignancies. Long term, the results in those
patients using auto cells are terrible.
So, I think allo-transplant is where you
need to go in all of these leukemias.
DR. SANTANA: Dr. Perry.
DR. PERRY: I think we have heard from the
patients' description and the parents' descriptions
that these are desperate people, and when any drug,
whether it is this drug or another, produces some
benefit, they see the transplant as the next
182
opportunity for a cure. They are not so naive as
to think that this drug is the miracle drug that is
going to get them disease-free forever.
So, when they see the opportunity for a
transplant, whether the odds are great or small,
they are going to leap upon that, and present
company excluded, most transplanters basically are
hammers, and they see the world as a nail, and if
there is a patient, there is a indication.
DR. KURTZBERG: That is a new one for me.
DR. PERRY: I don't think we can fault the
company for the actions of the patients and the
treating physicians who see a response and then
say, great, now is our chance to leap onto a
transplant, which might be curative. I don't think
the company, in this circumstance, can control
that.
So, I don't think the company designed the
trial to say this drug is a bridge to transplant.
They designed the trial to see does this drug work
and to what degree, and I think to some degree it
works. The question is does it work enough.
183
DR. SANTANA: Dr. Maldonado.
DR. MALDONADO: Now, it is about
transplant. The question is, I mean transplant was
not an endpoint for these trials, and by hearing
the experts, I believe that there may be different
standards for transplant. It doesn't appear to be
a single standard. This is a multiple center
trial, so there may have been a standards that
occurred in the trial.
It is just like hospitalization. I mean
hospitalization is another endpoint that should not
be used as endpoint unless there is criteria for
that, and I haven't seen that criteria outline in
this trial of when a transplant occurs.
More than a transplant, it should be a set
of criteria that the patient meets, and in that
case, it will be complete response. But was that
transplant an endpoint or not?
DR. SANTANA: No, no, that is the
confounding issue, that transplant was never part
of these trials, but what happened in real practice
is, like you have heard comments around the table
184
and from different experts, is that this drug in a
way was used as a bridge for those patients that,
at least in the ALL population that were having a
response and made it onto transplant, and for the
AMLs, everybody decided which patients got
transplant, which ones didn't.
So, it was not a study endpoint and we
should not fault the sponsor for that, because they
didn't have any control over that. That was just
the practice of patients and physicians who
participated in the trial.
DR. MALDONADO: But at the same time, if
that is the reality, why the studies were not
designed with that in mind and set up that as an
endpoint, so measure it in some way?
DR. SANTANA: I can't answer that
obviously, that is a historical issue of why the
studies were not designed that day, but the data we
have is the data that we have.
I want to put this discussion to an end
because we have got to move. I just raised the
issue because to me, if this agent gets approved
185
under the accelerated approval, we have to discuss
the issue of the complete responses and the
durability of those, and then the additional
clinical benefit that those responses provide.
So, I wanted to have the discussion, so
that at least we get some sense from the ALL
population and from the AML population, the
differences in those depending how the discussion
of the questions goes on further.
I am going to stop the discussion here for
that. One more point that I want to discuss before
going to the questions, which is very relevant, and
I am going to ask Dr. Poplack and Dr. Hirschfeld to
comment on, and it is an issue that was raised
earlier by Dr. Pazdur in terms of pediatric drug
development and the timing of studies and how what
we are discussing with this agent today is relevant
to that bigger picture, because I think we are
going to have to address that in the context of any
new drug that is developed for kids that comes to
this Committee.
So, David, can you give me some insight
186
into that issue, and then I will ask Steve to
comment, too?
DR. POPLACK: I think it is pretty obvious
to all that this is the worst situation, the worst
scenario in which to try and do a study of any new
agent. I think that Joanne put it quite well that
one would much prefer to do a study on a new agent
like this at an earlier stage in the clinical
courses of the patients.
That being said, it is not so easy. The
whole concept of therapeutic windows is a whole
theme unto itself in terms of the pros and cons of
that, are the patients really available given the
practice, et cetera.
It is a real conundrum and it requires
superb cooperation frankly, between the group, the
Children's Oncology Group, the sponsors, the FDA,
to make these types of things happen. I think this
isn't the best situation, there is no question
about it.
DR. SANTANA: Steve, would you follow up
on that, please.
187
DR. HERSHFELD: Yes. I will, as I have
for most of my life, agreed with Dr. Poplack in
that it is a multi-dimensional issue and that it
requires coordination and integration of all the
involved parties due to the relative rarity of the
diseases and the lack of resources.
I would just note that when these two,
single-arm studies were developed and they were
designed with response rate as the endpoints, much
as Dr. Kurtzberg had recommended, it was during the
time of transmission of when the Pediatric Oncology
Group and the Children's Cancer Group were merging
into the Children's Oncology Group, and there was
issues of the availability of protocols and
logistical issues about setting up collaborations,
so the sponsor, in essence, wanting to develop a
drug in that time frame, during that historical
period, had relatively few options in terms of what
would be feasible.
DR. SANTANA: Dr. Temple.
DR. TEMPLE: I want to beg the Chair's
indulgence because I thought I understood what Dr.
188
Kurtzberg was saying, but the questions that come
up make me uncertain whether I did. Just one more
time.
My understanding was that you think a
complete response, let's ignore whether these all
were, and whether the rate was high enough for the
moment, is meaningful actually whether or not
people decide to do a transplant--this is in
ALL--whether or not people decide to do a
transplant, so that the transplant situation in
some sense here is not relevant if you once
documented a complete response however you have to
do that, for ALL.
That makes ALL sound simpler to me in this
case, and the only issues would be whether a 10
percent or 12 percent response rate is good enough
and whether the responses were adequately
documented. Those are the usual kinds of questions
we face.
So, is that correct? So, it doesn't
really matter that they didn't specific transplant
or they were confounded by the community behavior
189
or anything in ALL. Is that true?
DR. KURTZBERG: Yes, it's true, and I
would say the same thing for AML, and what I am
saying is that I don't think this duration of
response question for pediatric cancer is important
in this kind of population.
DR. TEMPLE: The AML, I guess I thought
many of the documentation of the response was
truncated by the transplant, so that is perhaps a
separate problem in AML.
DR. KURTZBERG: But there still was an
initial response.
DR. TEMPLE: All right. Fine. Thank you.
Let's go ahead and deal with the
questions.
I am just going to make an introductory
reading of the first paragraphs and then I think we
have the summary page at the end.
DR. MALDONADO: Dr. Santana, I just have a
question for clarity, not related to the questions.
DR. SANTANA: Go ahead.
DR. MALDONADO: I have been hearing how
190
difficult these studies are to define or to be
done. However, when I saw the presentation, I
believe Dr. Arceci or somebody on behalf of the
sponsor.
We are talking about the third most common
cancer in patients and looking at the numbers, the
numbers are not small, so where is the difficulty
other than the COG might not be acting fast enough.
I am just not understanding what the difficulty of
the feasibility of these studies may be. I am
talking about the confirmatory studies.
DR. SANTANA: Part of it is study
availability of when the Phase I or Phase II
studies are really available. I mean you heard an
example earlier today of a comment from COG how
they only have three, Phase I studies open right
now, and that studies close and open constantly,
you know, depending on the number of patients that
are available, so there is a lot more patients out
there than there are studies.
Now, the issue of the studies and how well
designed the studies are and which centers they
191
occur, that is a whole separate discussion. I can
tell you that I think the COG and CTEP and other
major institutions have been advocates to getting
studies open, so that these patients can
participate in, so independent of the law we had
during the cooperative group merger, I think that
is an impetus from the Pediatric Oncology Committee
to do studies and to get these patients on studies.
Ultimately, the decision is made about the
parents, whether they participate or not, so you
may always have 500 patients, but parents make the
final decision whether they want to participate or
not.
DR. MALDONADO: The reason I ask that is
because if the drug becomes available, then, it
will be even more difficult, because then the
sponsor will need to compete with its own drug
being available, so patients will tend not to
enroll in trials, because it is more difficult for
them to comply with the trials than to just get the
drug that is available.
DR. SANTANA: I think a general comment to
192
that, and certainly Dr. Poplack and Dr. Kurtzberg,
as pediatric oncologists can add to that, that has
never been an issue in pediatric oncology. Most
people, even though the drugs are commercial, will
try to design new studies to continue to study
drugs, and patients participate in them.
So, I think the approval of a drug and
making it commercially available in pediatric
oncology has not had the difference in practice
that it may have in adult oncology, because we
still stride to get patients on studies and design
new studies to continue to ask the questions that
are still unresolved.
So, I don't think that ultimately impacts
whether patients participate or not.
So, let's go ahead and get started. So,
this is for NDA 21-673, clofarabine from ILEX
Products, Inc., for the proposed indication of
treatment of pediatric patients 1 to 21 years old
with refractory or relapsed acute leukemia.
The was one, Phase II study conducted in
35 patients with relapsed or refractory AML, at
193
least one relapse or primary refractory. There was
an additional Phase II study conducted in 49
patients with relapsed or refractory ALL, defined
as a combination of at least two relapses or
refractory induction attempts.
Then, in addition, there was a Phase I
study conducted in 25 patients with
relapsed/refractory acute leukemias, a mixture of
ALL's and AML's. Response assessments are
presented in Tables 1, 2, 3, 4, and 5. In both of
these studies, the primary endpoints as defined by
the protocols or the studies, and the ones relevant
to possible approval of the drug, are response rate
and response duration.
In the absence of a reasonable rate of
durable complete responses, which has been
considered clinical benefit in some previous
applications and which did not occur in these
studies, clofarabine can be considered only for
accelerated approval under Subpart H. This would
be based on the conclusion that the responses seen
are reasonably likely to predict a clinical
194
benefit.
Table 1 summarizes the best responses for
ALL, 6 complete responses, 12.2 percent response
rate, and then 4 additional patients with CRp,
complete response without platelet recovery, an
additional 8.2 percent of the patients in that
category.
Table No. 2 briefly summarizes the
response duration for ALL patients that did not go
on to transplant. My interpretation of these
columns is that there were a number of patients who
had the response confirmed with a confirmatory
marrow 3 or 4 weeks later, and those are the ones
in the third column, the 43 and 50 for the CR, and
then there were 3 additional patients who did have
their response subsequently confirmed, and that
response duration was 82, 93+, and 160+ days.
Similar data is presented in Table 3 for
the AML best response in which there were zero
complete responses, for a percentage of zero, and
then there was 1 complete response without total
platelet recovery of 2.9 percent.
195
Similar data in terms of response duration
for AML patients that did not go on to transplant,
which were very few, zero for the CR, zero for the
CRp's, and only 2 PR's that were not transplanted,
had response confirmed by a subsequent marrow.
Table 5 briefly summarizes the response
rates that were seen in the Phase 1 study in which
there was documentation of 2 CR's in ALL out of 17
potential subjects and 1 CRp in the AML subgroup
out of 8 potential subjects.
So, let's go on to the question. I think
you have the introductory paragraph there, so I
won't read it again since it is projected in the
video, and you have it in front of you. I will
give you a minute to read it, and then we will get
started with the questions.
I just want to mention to the Committee
that Dr. Maldonado, as the industry representative,
is a nonvoting member, but everybody else on the
table is voting, and we do appreciate your vote.
The first question is although the
protocol required responses to be confirmed at
196
least three weeks later, this was often not done.
Do you consider an unconfirmed response useful for
considering drug effect?
We will start with you, Dr. Poplack.
DR. POPLACK: It's not confirmed.
DR. SANTANA: Is that a yes or a no?
DR. POPLACK: That's a no.
DR. SANTANA: Anything else you want to
add?
DR. POPLACK: No.
DR. SANTANA: Dr. Kurtzberg.
DR. KURTZBERG: No.
DR. SANTANA: Dr. Wayne.
DR. WAYNE: The people that know me know
there is no such thing as a one-word answer, so I
just have to say I think the data presented, the
testimonials we see today suggest to us that there
is activity, and the question do you consider an
unconfirmed response useful for considering drug
effect, I think the responses we have heard about
and have seen are drug effect.
But it throws a bomb into the china shop
197
of drug approval, but I have to vote yes, I think
that what we have seen or heard suggests drug
effect.
It doesn't meet the standard that has been
set for drug approval in my reading of the
literature, but the question is, as I read it,
unconfirmed response useful for considering drug
effect, I think yes. It doesn't necessarily meet
the bar that we are asked to prove or disprove in
that regard.
DR. SANTANA: Let me clarify that, and
maybe the FDA can help me with that. I interpreted
that as an extension that it is not drug effect,
but drug effect documented as a response.
DR. PAZDUR: As I stated before, we are
not looking at the approval process as a screening
process, so this has to be a meaningful effect
reasonably likely to predict clinical benefit.
DR. SANTANA: Like the response.
DR. TEMPLE: Although that would have to
do with the number of the responses, too, but in
this case, we are just asking about the nature of
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the response.
DR. PAZDUR: It isn't just the screening
process.
DR. WAYNE: So, if you have a truly
refractory patient population, a response rate, in
my view, in fact, supports likely benefit.
DR. KURTZBERG: But that is a question
that is confirmed.
DR. TEMPLE: You are saying even in your
view, even an unconfirmed response, going with the
numbers that are up here, does that for you.
DR. WAYNE: So, this is where we talk
science and data, and split hairs. When I have
distinguished colleagues who are pediatric
oncologists, and loving parents who say that their
children had responses and we see data that they
were responses, that drug is active in a refractory
patient population.
So, that doesn't equate to the sorts of
endpoints you are asking to be met, but I believe,
in a refractory patient population, that those
responses reflect activity of that drug in that
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disease, and therefore, is likely in a more
systematic study to, in fact, translate to clinical
benefit, but I can't prove that.
DR. TEMPLE: Right. I have no brief for
what the answer is, but Dr. Kurtzberg at various
points said there were certain kinds of activity
that really don't tell you anything good is going
to happen, and there are other kinds that do.
DR. WAYNE: But I would just argue that if
you have a drug that kills leukemia cells, that
that is activity. How you apply that activity in a
systematic way to be clinical benefit is a separate
question, but I am just responding literally to
this question. I do believe that unconfirmed
response in shades of gray could, in fact, be
considered drug effect.
DR. TEMPLE: In the end, though, we are
going to be asking whether you think the evidence
of activity that is seen is such that there is
likely to be a clinical benefit. So, in the end,
you have to get to that question.
DR. SANTANA: We will get to that, but we
200
have to wrestle with the question at hand, and I
think you already voted, so we will move forward.
Dr. Rodriguez.
DR. RODRIGUEZ: Yes.
DR. SANTANA: Ms. Hoffman.
MS. HOFFMAN: Yes.
DR. SANTANA: Dr. George.
DR. GEORGE: I have a question before I
can answer this. I am assuming this unconfirmed
response means there was an initial marrow that was
clear, that was a complete response, say, but it
just wasn't confirmed later.
DR. SANTANA: Subsequently. That is the
discussion we had earlier this morning.
DR. POPLACK: The question is quite
ambiguous obviously, and you are talking about--and
I didn't do too well on multiple choice tests,
which is obvious--but there are many ways to look
at this, and I think the real issue is whether one
considers an unconfirmed response useful.
You are talking about an unconfirmed
complete response? What are you really talking
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about?
DR. KURTZBERG: Do you mean the first
marrow showed remission, and you didn't have a
second one three weeks later? I didn't answer it
that way.
DR. SANTANA: I think what they are trying
to ask us is, for all those patients who did have a
bone marrow that assessed a response, but
subsequently, those patients did not have another
marrow, how do you interpret that information with
the lack of an additional subsequent follow-up
marrow? Does that unconfirmed response still tell
you that there was drug effect? That is what they
are asking.
DR. TEMPLE: That is because the protocol
said you were going to confirm them, but we heard
why that was in many cases difficult.
DR. POPLACK: Obviously, if the first
marrow confirms a response, then, that is evidence
of drug activity.
DR. TEMPLE: Confirm here means another
marrow.
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DR. SANTANA: Confirm means here that they
did that third bone marrow, if you want to put it
that way. They did the diagnostic relapse marrow,
they did a marrow after they gave drug to assess a
response, and then my understanding is the protocol
required that there should be another follow-up
marrow. That is the sequence of events, and
obviously, as we heard earlier, there were a number
of patients who had a response with the second
marrow, who did not get that third marrow.
DR. PAZDUR: Here again, by drug effect,
we mean reasonably likely to predict clinical
benefit.
DR. KURTZBERG: Then, I change my vote to
yes.
DR. SANTANA: So, let us start off with
that clarification because I want to make sure
people know what they are voting on.
Let's start with Dr. Poplack.
DR. POPLACK: So, it's a yes given that
change.
DR. SANTANA: Dr. Kurtzberg.
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DR. KURTZBERG: Yes.
DR. SANTANA: Dr. Wayne.
DR. WAYNE: Yes, I didn't change my
answer.
DR. SANTANA: We are starting all over.
We erased everything.
Dr. Rodriguez.
DR. RODRIGUEZ: Same answer as previously,
yes.
DR. SANTANA: Ms. Hoffman.
MS. HOFFMAN: Yes.
DR. SANTANA: Dr. George.
DR. GEORGE: I am glad I brought that up.
Yes, I would say.
DR. SANTANA: MS. Haylock.
MS. HAYLOCK: Yes.
DR. SANTANA: Dr. Hussain.
DR. HUSSAIN: Yes.
DR. SANTANA: Dr. Perry.
DR. PERRY: Yes.
DR. SANTANA: Dr. Mortimer.
DR. MORTIMER: Yes.
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DR. SANTANA: Dr. Santana. Yes.
Dr. Martino.
DR. MARTINO: No.
DR. SANTANA: Dr. Brawley.
DR. BRAWLEY: No.
DR. SANTANA: Dr. Cheson.
DR. CHESON: I would have to say yes,
there is evidence of drug effect.
DR. SANTANA: Dr. Bukowski.
DR. BUKOWSKI: No.
DR. SANTANA: Can you tally the votes for
me? Twelve Yes and 3 No.
Question No. 2. Transplantation,
especially in AML patients, was common in the data
that was presented. Although it is possible that
response to clofarabine encouraged physicians to
consider transplant when they otherwise would not
have, there is no way to know this and there were
no criteria for transplantation in the protocols.
Some patients went to transplantation without a
clofarabine response.
Do the transplantation data contribute to
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the assessment of the effectiveness of clofarabine?
We need to discuss each of the two diseases
separately. So, let's vote on ALL first.
Dr. Poplack.
DR. POPLACK: For the reasons that Dr.
Kurtzberg stated, I would say no.
DR. SANTANA: Dr. Kurtzberg.
DR. KURTZBERG: No.
DR. SANTANA: Dr. Wayne.
DR. WAYNE: No.
DR. SANTANA: Dr. Rodriguez.
DR. RODRIGUEZ: No.
DR. SANTANA: Ms. Hoffman.
MS. HOFFMAN: No.
DR. SANTANA: Dr. George.
DR. GEORGE: No.
DR. SANTANA: Ms. Haylock.
MS. HAYLOCK: No.
DR. SANTANA: Dr. Hussain.
DR. HUSSAIN: Yes.
DR. SANTANA: Dr. Perry.
DR. PERRY: Yes.
206
DR. SANTANA: Dr. Mortimer.
DR. MORTIMER: Yes.
DR. SANTANA: Dr. Santana. Yes.
Dr. Martino.
DR. MARTINO: No.
DR. SANTANA: Dr. Brawley.
DR. BRAWLEY: Yes.
DR. SANTANA: Dr. Cheson.
DR. CHESON: No.
DR. SANTANA: Dr. Bukowski.
DR. BUKOWSKI: No.
DR. SANTANA: Can I get a tally of votes
for ALL.
Ten No, 5 Yes.
So, the same question. Do the
transplantation data contribute to the assessment
of the effectiveness of clofarabine in AML?
Dr. Poplack.
DR. POPLACK: No.
DR. SANTANA: Dr. Kurtzberg.
DR. KURTZBERG: No.
DR. SANTANA: Dr. Wayne.
207
DR. WAYNE: No.
DR. SANTANA: Dr. Rodriguez.
DR. RODRIGUEZ: No.
DR. SANTANA: Ms. Hoffman.
MS. HOFFMAN: No.
DR. SANTANA: Dr. George.
DR. GEORGE: No.
DR. SANTANA: Ms. Haylock.
MS. HAYLOCK: No.
DR. SANTANA: Dr. Hussain.
DR. HUSSAIN: Yes.
DR. SANTANA: Dr. Perry.
DR. PERRY: Yes.
DR. SANTANA: Dr. Mortimer.
DR. MORTIMER: No.
DR. SANTANA: Dr. Santana. No.
DR. MARTINO: No.
DR. BRAWLEY: No.
DR. CHESON: No.
DR. BUKOWSKI: No.
DR. SANTANA: Can I get a tally of the
votes for AML. Thirteen No, 2 Yes.
208
As noted, in the refractory acute
leukemias, the FDA has considered a good complete
response with complete responses of good duration
to represent clinical benefit.
There was clearly no substantial CR rate
in AML, and in ALL, only 2 non-transplanted
patients had a response duration of at least 3
months. The partial response duration in AML is
not assessable in many responders because they had
early transplantation. There is somewhat more
information in ALL, and that refers back to Table
No. 2, if I remember correctly.
So, the third question is does the ODAC
believe that the clofarabine complete response rate
with available response duration data is reasonably
likely to predict a clinical benefit in ALL?
Dr. Poplack.
DR. POPLACK: I guess I would ask, at the
same level? Isn't that the key? At the same level
that was indicated in this trial, is that what you
are getting at?
DR. PAZDUR: This is the drug approval
209
question, reasonably likely to predict a clinical
benefit, what would be used for accelerated
approval.
DR. SANTANA: So, the question is, for
accelerated approval in ALL, this question
addresses the issue that the available response
duration is reasonably likely, the CR rate and the
duration of response in those patients is likely to
provide some assessment or some idea of clinical
benefit.
DR. TEMPLE: The question, of course,
highlights the lack of knowledge about duration in
a number of cases, but, of course, that is because
they got transplanted, and maybe that is not a
problem. So, that is the question.
DR. POPLACK: The issue of duration of
response, I think is actually quite important here,
or lack of follow up, because there are 3 patients
who had very short responses, who relapsed during
that time period, who didn't have follow up, so you
don't know the length of that duration. Those are
the ones of 43, 50, and 82 in 82 days, if I am
210
correct. We didn't have any follow up on those.
DR. SANTANA: No, no, the 82-day did have
a follow up, am I correct, if I interpret the
columns? Yes, they had a confirmed marrow.
So, referring to Table 2, Dr. Poplack, the
last column, as I interpret it, is the 3 patients
with ALL that are CR, who did have a confirmed
marrow, so obviously, one patient had a confirmed
marrow that lasted 82 days, and the other patients
had a confirmed marrow at 93, and that patient we
think is still in remission, and patient 160 had a
confirmed marrow at 160 and is still in remission.
That is how I interpret that table.
DR. POPLACK: So, 43 and 50 that we have
no information on.
DR. SANTANA: Forty-three and 50 were the
short remissions that were not confirmed with a
subsequent marrow.
DR. MARTINO: I need clarification.
DR. SANTANA: Yes.
DR. MARTINO: I need clarification on this
issue. Dr. Pazdur, do I understand that the point
211
to this question is whether the data, as presented,
is sufficient, not that it shows a whiff of
activity, but is sufficient activity to merit
accelerated approval, is that the question you want
answered?
DR. PAZDUR: Yes, it is. That is why I
said this is the approval question. We are asking,
with the data that you have seen in ALL, is the
drug approvable, should the drug be approved under
accelerated approval conditions.
DR. WAYNE: Can we have more discussion at
this juncture about implications of one way or the
other, or do you want us just to vote based on this
question and call it a day?
DR. PAZDUR: What would be your
discussion? We have been discussing this, and, you
know, there is ambiguities in this application
obviously.
DR. WAYNE: So, I think between the
acknowledgment that there is activity, and there is
acknowledgment that more systematic studies are
required, is a big chasm, and the question is, is
212
accelerated approval the best mechanism to, in
fact, prove (a) activity, in (b) systematic
studies, or will accelerated approval complicate
that.
Most importantly, are we, as a committee,
do we have enough knowledge about that key
question, is what next.
DR. TEMPLE: In some ways, that isn't
really the primary question. We do worry about
whether the confirmatory data will get done, but
the point of accelerated approval is that for
diseases with no current treatment, we are prepared
to accept a different kind of evidence of
effectiveness, that is, you don't have survival
data, you don't have mature any kind of data, but
you may have evidence of an activity that convinces
you that there really will be a benefit when you do
the rest of the studies.
That is a very complicated judgment. The
answer is usually not obvious. It has something to
do with how high the rate is. I mean if you only
saw one response, you probably wouldn't find that
213
convincing.
If you found 40 percent, you probably
would, and somewhere in between, we line out, but
it isn't really about whether the best way to get
the data--I mean the best way to get the data is to
plan it all out, have properly done studies, and
look at them early and say, oh, well, fine, I am
ready to approve it now, and then I have got the
data in hand.
Well, we try to get people to do that, and
as Rick says, more and more people are, that is not
our problem here. We don't have that.
DR. PAZDUR: With the available data that
you have here, is what you are seeing here
reasonably likely to predict clinical benefit for
these patients.
DR. TEMPLE: For a group of patients who
don't have any other choice. That is what the
point of it all was.
DR. SANTANA: Yes, Dr. Martino.
DR. MARTINO: I would like to just restate
your words. The way I understand the charge of
214
this committee is that if we vote yes, then, that
basically means that this drug, as of today,
tomorrow, or whenever, becomes available to any
physician who has such a patient. It is common use
in this setting at least, and then beyond this
setting, that we are actually approving.
It isn't that, in fact, perhaps someone
will then show us more data in the future.
DR. PAZDUR: Correct. You have to go on
what is presented here today and make the
scientific decision, a clinical decision on a
risk-benefit situation on the data that you have at
hand on the basis of this single-arm trial.
DR. TEMPLE: And assume that we will, in
one way or another, along with the company,
actually get the rest of the data.
DR. SANTANA: Yes, I was going to add
that.
DR. TEMPLE: We all know that has been a
problem, we are being forceful in insisting on
seeing the protocols prior to approval. We have,
in some cases, urged that there be enrollment in
215
some of the other studies.
We are worried about that, and we didn't
put that question to you. Feel free to comment,
but you should be assuming that we will get the
ultimate data.
DR. SANTANA: I was going to say an
accelerated approval, my understanding, and the
Agency can correct me, is that there is a firm
commitment that the Agency has regulatory oversight
if it doesn't happen that those additional studies
be done and be presented.
DR. PAZDUR: Correct.
DR. TEMPLE: And usually, pretty well
honored, but there have been troubles, I mean I
don't want to hide that from anybody.
DR. SANTANA: Dr. Poplack.
DR. POPLACK: No, you clarified it for me.
DR. SANTANA: So, are we ready to go back
to this question? So, for ALL--I won't repeat the
question--Dr. Poplack, for ALL?
DR. POPLACK: Yes.
DR. KURTZBERG: Yes.
216
DR. WAYNE: Yes.
DR. RODRIGUEZ: Yes.
MS. HOFFMAN: Yes.
DR. GEORGE: No.
MS. HAYLOCK: Yes.
DR. HUSSAIN: No.
DR. PERRY: Yes.
DR. MORTIMER: Yes.
DR. SANTANA: Yes.
DR. MARTINO: No.
DR. BRAWLEY: No.
DR. CHESON: No.
DR. BUKOWSKI: No.
DR. SANTANA: Can I get a tally?
Nine Yes, 6 No.
DR. SANTANA: Question No. 4 is the same
crux of the matter, now with the AML population.
Does the ODAC believe that the 2 clofarabine
complete responses p's, (1 in Phase I and 1 in
Phase II) are reasonably likely to predict a
clinical benefit in AML?
DR. CHESON: Point of clarification.
217
There was not a CR, it was a CRp.
DR. SANTANA: Can you clarify the acronym
that you have put on this question?
DR. PAZDUR: It is CRp, I believe.
DR. CHESON: CRp, it is not a true CR.
DR. PAZDUR: Correct.
DR. SANTANA: Thank you for the
clarification.
Dr. Poplack.
DR. POPLACK: Just again to clarify. Does
this mean that we think that it has activity or
that it doesn't have activity?
DR. PAZDUR: It is not activity. It is a
clinical decision that you have to make based on
available data, that it is reasonably likely that
activity in these patients would represent clinical
benefit in the future.
DR. POPLACK: Clinical benefit meaning
they are going to live longer--
DR. PAZDUR: The survival, the patient
getting some benefit from it.
DR. SANTANA: I think there is two
218
questions. I think since we have a little bit of
time, I will go ahead and let Dr. Wayne, if you
have a clarification, not a long discussion.
DR. WAYNE: So, again, I just want to
point out that this question literally asks about
only the data presented in the pediatric trial.
DR. SANTANA: Correct. We have not seen
any adult data presented systematically by the
sponsor or the FDA, period.
Ms. Hoffman.
MS. HOFFMAN: And this impacts on labeling
in terms of prescribed use for ALL and AML.
DR. PAZDUR: Correct. If the drug is
approved only in ALL, the indication will only be
in ALL.
DR. SANTANA: Okay. Dr. Poplack.
Can you please identify yourself before
you vote, so I don't have to repeat the names.
Thanks, Dr. Poplack.
DR. POPLACK: No.
DR. KURTZBERG: No.
DR. WAYNE: No.
219
DR. RODRIGUEZ: No.
MS. HOFFMAN: Yes.
DR. GEORGE: No.
MS. HAYLOCK: No.
DR. HUSSAIN: No.
DR. PERRY: No.
DR. MORTIMER: No.
DR. SANTANA: No.
DR. MARTINO: No.
DR. BRAWLEY: No.
DR. CHESON: No.
DR. BUKOWSKI: No.
DR. SANTANA: So, there should have been
14 No and 1 Yes.
Does the Agency wish to discuss any
additional information to help you, or give you
further advice?
DR. PAZDUR: Not that I can think of at
this time.
Could we just make an announcement,
because we have to be here, back sharp, at what
time?
220
DR. SANTANA: 12:45.
DR. PAZDUR: 12:45, we will start right at
12:45 whether you are here or not, because many
people have planes.
DR. SANTANA: Thanks, everybody, for your
participation.
[Whereupon, at 12:07 p.m., the proceedings
were recessed, to be resumed at 12:45 p.m.]
221
A F T E R N O O N P R O C E E D I N G S
[12:50 p.m.]
Call to Order
DR. MARTINO: If everyone would take their
seats within the next minute or two, I would like
to get started.
I have a plane to catch at 4:30, I need to
leave here at 4:30, and I mean to do that, so I
remind all of you that have something to say, to
please be clear and succinct. I can be fairly
forceful if need be.
Introductions
MS. CLIFFORD: We are going to start with
Dr. Wilson, if you would like to go ahead and
introduce yourself and your affiliation, please.
DR. WILSON: My name is Wyndam Wilson. I
am in the Experimental Transplantation and
Immunology Branch at the National Cancer Institute.
DR. BISHOP: Michael Bishop, Experimental
Transplantation Branch, National Cancer Institute.
MS. KRIVACIC: Susan Krivacic, Austin,
Texas, Patient Rep, non-Hodgkin's lymphoma
222
survivor.
DR. MALDONADO: Samuel Maldonado from
Johnson & Johnson. I am here as the Industry
Representative to this advisory Committee.
DR. GEORGE: Stephen George, Duke
University.
MS. HAYLOCK: Pamela Haylock, Oncology
Nurse, Consumer Representative.
DR. HUSSAIN: Maha Hussain, Medical
Oncology, University of Michigan.
DR. PERRY: Michael Perry, Medical
Oncology, University of Missouri, Ellis Fischel
Cancer Center.
DR. MORTIMER: Joanne Mortimer, Moores
UCSD Cancer Center.
DR. MARTINO: Silvana Martino, Medical
Oncology, from the John Wayne Cancer Institute.
MS. CLIFFORD: Johanna Clifford, Executive
Secretary to the ODAC.
DR. REAMAN: Gregory Reaman, Pediatric
Oncology, Children's Oncology Group, George
Washington University.
223
DR. BRAWLEY: Otis Brawley, Medical
Oncology/Hematology from Emory University.
DR. CHESON: Bruce Cheson, Head of
Hematology, Georgetown University, Lombardi
Comprehensive Cancer Center.
DR. BUKOWSKI: Ron Bukowski, Cleveland
Clinic, Medical Oncology.
DR. HAZARIKA: Maitreyee Hazarika, Medical
Officer, FDA.
DR. FARRELL: Ann Farrell, Clinical Team
Leader, FDA.
DR. PAZDUR: Richard Pazdur, FDA.
DR. WILLIAMS: Grant Williams, FDA.
DR. MARTINO: Thank you. Ms. Clifford
will now read the Conflict of Interest Statement
for this group.
Conflict of Interest Statement
MS. CLIFFORD: The following announcement
addresses the issue of conflict of interest and is
made a part of the record to preclude even the
appearance of such at this meeting.
Based on the submitted agenda and all
224
financial interests reported by the Committee
participants, it has been determined that all
interests in firms regulated by the Center for Drug
Evaluation and Research present no potential for an
appearance of conflict of interest at this meeting
with the following exceptions:
Dr. Stephen George has been granted a
waiver under 18 USC 208(b)(3) for serving as a
consultant to a competitor on an unrelated matter.
He receives less than $10,000 per year.
Dr. Michael Perry [technical interruption]
for owning stock in a competitor valued between
$5,001 to $25,000. A waiver under 18 USC 208(b)(3)
is not required because the de minimis exception
2640.202(b)(2) applies.
Dr. Ronald Bukowski has been granted a
waiver under 18 USC 208(b)(3) for lecturing for a
competitor on an unrelated matter. He receives
between $5,001 to $10,000.
Dr. Otis Brawley has been granted a waiver
under 18 USC 208(b)(3) for consulting with a
competitor on an unrelated matter. He receives
225
less than $10,001 a year.
A copy of the waiver statements may be
obtained by submitting a written request to the
Agency's Freedom of Information Office, Room 12A-30
of the Parklawn Building.
We would also like to disclose that Dr.
Samuel Maldonado has been invited to participate as
the Non-Voting Industry Representative acting on
behalf of all regulated industry. Dr. Maldonado is
employed by Johnson & Johnson Pharmaceutical
Research and Development.
In the event that the discussions involve
any other products or firms not already on the
agenda for which am FDA participant has a financial
interest, the participants are aware of the need to
exclude themselves from such involvement and their
exclusion will be noted for the record.
With respect to all other participants, we
ask in the interest of fairness that they address
any current or previous financial involvement with
any firm whose products they may wish to comment
upon.
226
Thank you.
DR. MARTINO: Is there anyone on the
Committee that needs to make a statement in terms
of conflict?
[No response.]
DR. MARTINO: Thank you.
Dr. Pazdur will now make some introductory
comments.
Opening Remarks
DR. PAZDUR: Thank you, Dr. Martino.
This afternoon's session focuses on the
marketing application of vincristine sulfate
liposome for the treatment of patients with
aggressive relapsed non-Hodgkin's lymphoma treated
with at least two combination chemotherapy
regimens. The sponsor is seeking accelerated
approval for this agent.
Since there are members of the Committee
who did not attend this morning's session, I would
like to reiterate several comments made earlier
regarding accelerated approval and then comment on
issues specific to this application.
227
The demonstration of clinical benefit is
required to achieve full approval. In oncology,
the demonstration of clinical benefit has usually
been an improvement in overall survival or the
amelioration of disease-related symptoms.
In 1992, the accelerated approval
regulations allowed the use of additional endpoints
for the approval of drugs that are intended to
treat serious and life-threatening diseases. These
drugs may either demonstrate an advantage over
available therapy or provide therapy where none
exists.
The FDA may grant accelerated approval
based on the effect of a surrogate endpoint that is
"reasonably likely" to predict clinical benefit.
A drug is approved under the accelerated
approval rule on the condition that the
manufacturer conduct studies to verify and describe
the clinical benefit. The regulations stated an
expectation that post-marketing studies would
usually be underway prior to accelerated approval,
but this is not a requirement.
228
At a March 2003 ODAC meeting, the ODAC
reinforced the Agency's view that these
confirmatory trials should be ongoing at the time
accelerated approval is granted. Approval with
subsequent commercial availability of the drug may
interfere with the enrollment of a confirmatory
study.
Accelerated approval had been based on
objective response rates with adequate duration in
single-arm trials in patients with refractory
disease. Since an agent must demonstrate an
advantage over available therapy or provide therapy
where none exists, we are asking you to consider if
available therapy exists for the indication under
consideration.
If available therapy exists, a randomized
trial comparing the investigational drug to an
available therapy arm would generally be needed to
demonstrate superiority. Available therapy usually
consists of drugs that are indicated in drug
labeling for the treatment of a specific disease,
however, in oncology, where drugs are frequently
229
used in non-approved indications as single agents
or in combinations, available therapy may
constitute therapy substantiated by "compelling"
literature evidence of efficacy.
There is no regulatory definition of the
word "compelling," hence, we are asking your
opinion regarding this word.
We are not asking you to reach a consensus
on a specific therapy. Available therapy may be a
single drug or it may be a combination regimen.
Available therapy may be several regimens or drugs.
Where there may be a lack of consensus regarding a
single specific treatment, the Agency has even
recommended using several regimens or drugs as a
treatment arm with the stipulation that superiority
is demonstrated by the investigational drug.
The primary endpoint of this single-arm
trial is response rate. The interpretation of
response rate is complex. We have emphasized that
the persuasiveness of the results of a single-arm
trial to support accelerated approval hinges on the
magnitude and the duration of responses observed in
230
trials.
In aggressive lymphomas, we have
emphasized to sponsors the importance of complete
responses with adequate and well-defined durations
as an endpoint for drug approval. In selected
hematological malignancies where partial responses
are observed, we, at the FDA, have been impressed
with substantial response durations, and these have
led to approval.
For example, the recently approved Velcade
for the treatment of refractory multiple myeloma
had a median response duration in excess of one
year. Similarly, the median duration of disease
control for fludarabine in CLL was in excess of one
year.
Since the vast majority of responses noted
in this application are partial responses with
uncertain durations, 13 out of 30 responders did
not even have a single repeat scan or progress
before a repeat scan could be performed, we are
asking your opinion regarding this endpoint.
Remember, this endpoint in this study must be
231
reasonably likely to predict clinical benefit.
In the morning session, we highlighted the
need for confirmatory trials to be ongoing at the
time of drug approval. This is again not a
requirement, however, the ODAC has supported our
viewpoint that accelerated approval trials be part
of a comprehensive drug development plan with early
initiation of confirmatory trials prior to drug
approval.
To date, a confirmatory trial for VSLI has
neither been started, nor agreed upon with the FDA.
In your deliberations, discussion must focus on
this aspect and the impact that any approval would
have on the conduct and the completion of any
confirmatory trial.
I would like to emphasize that accelerated
approval is not simply a screening process for drug
activity. Mere demonstration of a nominal activity
is insufficient for accelerated approval. Response
rate and duration must provide convincing evidence
that the magnitude and duration of responses are
"reasonably likely to predict clinical benefit."
232
This response rate and duration may vary
from disease to disease. The accepted response
rate in refractory metastatic colon cancer may have
little bearing on the response rate accepted for
refractory aggressive lymphomas, hence, we are
asking your clinical judgment in this disease
setting.
There must be confidence in any
recommendation that a drug approved under
accelerated approval represent a benefit over
available therapy or provide therapy where none
exists.
In making a regulatory decision, you must
be able to accurately assess a risk-benefit
relationship. You must be able to have confidence
in the benefit of the drug in relationship to its
toxicity.
As stated in the morning session, your
decision regarding the approval status of a drug
should be based on a clinical risk-benefit
decision, not simply a desire to provide drug
access to patients.
233
Access to a yet to be approved drug can be
accomplished through registration trials or
expanded access programs.
Seeking drug approval exclusively with a
single-arm trial is an inherently risky venture,
hence, we have strongly urged sponsors to consider
the single-arm trials part of a comprehensive drug
development plan that incorporates the early
initiation of randomized trials to define clinical
benefit.
Although single-arm trials are less
expensive, less complex to conduct, involve fewer
patients, and are performed more rapidly than
randomized trials, they frequently do not provide
the information required by physicians and patients
to make rational therapeutic decisions.
If results are robust in a single-arm
trial, then, everyone wins. Most importantly,
patients receive needed therapies earlier. If
results are nominal, resulting in ambiguity,
regarding a risk-benefit decision, randomized
trials will be needed to accurately assess the
234
drug. Unfortunately, this may delay drug approval.
In comparison to single-arm trials,
randomized trials provide the opportunity to
examine additional endpoints, such as survival,
time to progression, and even symptom benefits, and
also provide us an opportunity to more accurately
characterize adverse events.
I hope these opening comments will focus
your deliberations. Thank you.
DR. MARTINO: Thank you, Dr. Pazdur.
At this point, I would like to invite Inex
Pharmaceuticals to introduce themselves and present
their data to the Committee, please.
NDA 21-000, Marqibo (vincristine sulfate
liposomes injection)
Inex Pharmaceuticals Corp.
Sponsor Presentation
Introduction
MS. MANCINI: Good afternoon, Madam
Chairman, members of the Advisory Committee, and
the FDA. My name is Alexandra Mancini, and I am
the Senior Vice President of Clinical and
235
Regulatory Affairs at Inex Pharmaceuticals.
[Slide.
On behalf of Inex and our co-development
partner, Enzon Pharmaceuticals, I would like to
thank you for this opportunity to discuss our NDA
for Marqibo, which is vincristine sulfate liposomes
injection, or what I will call VSLI for short.
The indication we are seeking is for the
treatment of patients with aggressive non-Hodgkin's
lymphoma previously treated with at least two
combination chemotherapy regimens.
[Slide.
We have several consultants with us this
afternoon, two lymphoma experts, a Dr. Fernando
Cabanillas from M.D. Anderson, and Dr. Jane Winter
from Northwestern University.
[Slide.
As well as experts in lymphoma pathology,
Dr. Randy Gascoyne; Radiology, Dr. Scott Gazelle
and Dr. Sandra Chica.
[Slide.
Neurotoxicity, Dr. Shayne Gad;
236
Pharmacokinetics, Dr. Jean-Marie Houle; and
Statistics, Mr. Louis Gura.
[Slide.
We are very pleased to have Dr. Fernando
Cabanillas with us today. Dr. Cabanillas is a
Clinical Professor of Medicine at the M.D. Anderson
Cancer Center, as well as the Medical Director of
Auxilio Mutuo Cancer Center in Puerto Rico.
He was the Chairman of the Lymphoma
Myeloma Department at M.D. Anderson for
approximately 20 years, where he led the
development of many of the most commonly used
chemotherapy regimens for patients with relapsed
lymphoma including MIME, DHAP, and ESHAP. He has
contributed to over 300 original publications in
lymphoma and over 50 book chapters, and he was a
member of the International Workshop that developed
response criteria for lymphoma.
Dr. Cabanillas will now provide a disease
overview aggressive NHL and the unmet medical need.
Overview
DR. CABANILLAS: Thank you, Ms. Mancini.
237
Good afternoon. I would like to give you a brief
overview of non-Hodgkin's lymphoma over the next
few minutes. These lymphomas are broadly
classified into either aggressive or indolent
histologies.
The most common category is the
aggressive, which constitutes approximately 35 to
40 percent of all lymphomas. This group is
relatively homogeneous since it is made up of
essentially diffuse large cell lymphoma and
peripheral T-cell lymphomas.
DLCL, however, can frequently present with
divergent histologies, which means that there are
other areas which contain an indolent cell type.
The treatment, however, is driven by the most
aggressive histology, and the response is measured
in the same way.
At relapse, most patients with aggressive
histologies usually die within a few months.
In contrast, the indolent lymphomas, when
they release, can survive for years.
Finally, the response rate and duration of
238
response of aggressive lymphomas are lower than for
the indolent cell types. Thus, it should not be
surprising that it has been easier to demonstrate
efficacy in indolent lymphomas and consequently,
four agents have recently been approved in the
U.S.A., whereas, there have not been any new agents
approved for aggressive lymphomas in the last 17
years.
[Slide.
First-line treatment of aggressive
lymphoma consists of rituximab plus CHOP. This
combination will cure approximately 50 percent of
patients. Management for patients younger than 65
consists of a standard dose regimen followed by
high-dose chemotherapy and autologous stem cell
transplant if they relapse.
However, only those patients who respond
to standard dose salvage therapy go on to receive
transplant. Patients older than 65 usually are not
considered candidates for transplant. In addition,
there are other reasons for which transplant is not
feasible. Less than 10 percent of such cases can
239
be cured, and their median survival is only six
months.
Finally, with each relapse, the response
rate, as well as the duration, drop considerably.
[Slide.
At the time of third-line therapy, the
situation is even worse. This is not an uncommon
problem and the prevalence in the U.S.A. is 10 to
15,000 cases. There is no established therapy for
patients in second or more relapse.
To make matters worse, their bone marrow
is frequently compromised by prior therapy, thus,
leaving us with few treatment options. These
patients frequently are symptomatic and reduction
in their tumor burden will lead to symptom
improvement.
The results are dismal. Complete
responses are rarely achieved, and survival is very
short, as you will see in the next slide.
[Slide.
This graph depicts the survival of
patients treated at third line or more. This is
240
derived from a study we performed at M.D. Anderson
during the pre-transplant era and the pre-rituximab
era using an ifosfamide/etoposide based regimen
known as MIME.
After one year, 75 percent of the patients
were dead, and at two years, virtually all except 4
percent were dead. This is a highly lethal
disorder. As you will see soon, the patient
population we have treated with VSLI is similar to
the one presented on this slide.
[Slide.
At this point, I would like to discuss the
available literature data on single agents for
relapsed aggressive lymphoma. The FDA briefing
document contains a table with a large number of
papers quoting response rates with single agents
and combination regimens for lymphoma.
As you can see from this table, many of
those response rates are in the range of 40 percent
and as high as 69 percent, which probably strikes
you as unusual for a single agent at third relapse.
At this point, I would like to put this
241
into perspective. Many of these papers were not
adequate for comparison to the VSLI studies for
several reasons. For example, the first five drugs
listed here were tested in less than 10 patients
with the correct histology.
One of the drugs, oxaliplatin, listed as
having a response rate of 24 percent, was tested in
a population which included indolent lymphomas, as
well as aggressive, but the response rate was not
separated for these two histologies.
Finally, the number of prior therapies was
not comparable for the last three agents on the
slide.
[Slide.
This slide is a summary of the previous
slide, and in the first three columns, I have
listed the reasons why the studies are not
comparable to the VSLI studies. There are only 2
of these 11 single agent papers which actually can
be compared to the VSLI studies.
Moving down to combination therapies, you
see that the situation is very similar, and only 5
242
of the 35 papers quoted are comparable.
[Slide.
The two single agent papers that can
actually be compared to VSLI are Rituxan studies by
Rothe and Tobinai. We have added another important
study by Coiffier, which was not included in the
FDA document.
As you can see in the first row of data,
the median number of prior regimens was 2 in all of
these papers, but a substantial percentage of
patients actually were treated at first relapse,
and those are not comparable to the VSLI patients.
As you can conclude from this slide, even
in a population with less relapses than ours, the
response rate is less than 40 percent, and the time
to progression is only 2 to 4 months.
[Slide.
These are the five combination regimen
papers that are adequate for comparison to VSLI.
The top half represents those with a median number
of prior regimens equal to 2, while the bottom have
a median number of 3, which is similar to the VSLI
243
studies.
The response rates range from 39 to 65
percent, but as you can see from the bottom half,
the CR rate is very low at third or more relapse.
The top three regimens are not commonly used
salvage combinations, and neither is ifosfamide,
hydroxyurea, and etoposide shown in the last row
and all of them are certainly more toxic than VSLI,
as you will see later on, that, even though a
popular regimen, is not commonly used to third
relapse because of its serious myelosuppressive
toxicity, which I am sure those of you who have
used it are familiar with.
In summary, the regimens shown here are
not used commonly by the oncology community with
the exception of DHAP, which is used mostly at
second line prior to autologous transplant. It is
highly toxic and thus rarely used in patients at
third or more relapse.
[Slide.
By now, you probably have realized that
there exists several unmet clinical needs in the
244
management of aggressive relapsed lymphomas. Many
patients do not qualify for aggressive combination
regimens or have failed autologous transplantation,
and they need some other alternative.
Some of the characteristics of such
patients are listed here. In the past, patients
with compromised marrow function were treated with
rituximab, which is not myelosuppressive, however,
that is no longer an alternative because by the
time they get to third line treatment, most of
these patients have already been exposed multiple
times to rituximab and are resistant to it.
In summary, there is no compelling
literature evidence for available therapy after
second relapse, and there is a great need for an
agent that can provide clinical and meaningful
benefit without excessive toxicity, because at this
point, we are dealing mostly with palliation, and
we should not induce severe toxicity if we are to
effectively palliate them.
[Slide.
I would like now to introduce Dr. Tom
245
Madden from Inex, who will discuss the pharmacology
of VSLI.
Pharmacology
DR. MADDEN: Thank you, Dr. Cabanillas.
[Slide.
As the name indicates, VSLI is a liposomal
formulation of vincristine sulfate where the drug
is encapsulated within the aqueous interior of
small liposomes. These are composed of
sphingomyelin and cholesterol, and this lipid
composition provides a highly stable bilayer with
relatively low permeability.
[Slide.
The intention with VSLI is to increase
tumor exposure to vincristine, and this is achieved
through two mechanisms, first, by providing higher
drug levels at the tumor sites, and secondly, by
providing a mechanism to provide a sustained
duration of exposure. The following slides will
illustrate these two mechanisms.
[Slide.
Following intravenous administration of
246
VSLI, the liposomes, being particular carriers,
tend to remain within the blood compartment as they
are not able to readily extravasate across the
continuous endothelial lining present in most
normal blood vessels, and this can be illustrated
using a window chamber model, which allows
visualization of florescently labeled VSLI.
The panel on the left-hand side here shows
normal blood vessels, and you can see that the
liposomes are constrained within the vessels with
very little accumulation seen in the interstitial
spaces.
Within tumor including lymphomas, however,
the neovasculature tends to be leaky, exhibiting
pores or discontinuities. The liposomes in VSLI
are of an appropriate size to allow extravasation
through these pores with subsequent accumulation in
the interstitial spaces.
Again, we can illustrate this using the
window chamber model.
As you will see when I start the video,
the blood vessels within the tumor vasculature tend
247
to be smaller, and you will see the architecture is
highly chaotic. You will also see that
extravasation of the liposomes is apparent and
appreciable accumulation occurs in the interstitial
spaces.
The period of time followed in both videos
is the first 60 minutes after VSLI administration.
The VSLI also accumulates preferentially in the
tissues and organs of the mononuclear phagocyte
system, such as the liver, spleen, and lymph nodes.
These are, of course, also sites of lymphoma
involvement.
As you are well aware, vincristine is a
cell-cycle-specific agent inhibiting mitosis.
Studies using lymphoma isolates from patients have
shown that only a small fraction of cells, less
than 5 percent, are actually in the sensitive G2M
phase at any point in time. Therefore, the
duration of vincristine exposure is critically
important in terms of its activity.
[Slide.
This is illustrated on the slide shown
248
here. As you can see, the fraction of tumor cells
surviving is greatly reduced as the exposure time
to vincristine is increased from 1 hour to 24
hours, and I should note that the fraction of
viable or surviving cells shown here is represented
on a log scale.
[Slide.
The rate of vincristine release from VSLI
is therefore a critical factor in terms of its
activity, and has been characterized in several
nonclinical studies. Vincristine release occurs by
passive diffusion across the liposomal bilayer, and
similar behavior is seen in the mouse, rats, and in
the dog.
Shown here for the rat is the rate of
vincristine release in plasma. As you can see,
release is slow and sustained with approximately 50
percent of the drug released by 24 hours and
essentially complete release seen by 72 hours.
[Slide.
These changes in the pharmacokinetics of
vincristine resulting from liposomal encapsulation
249
would be expected to increase antitumor activity.
This was shown in several studies, comparing VSLI
with conventional vincristine against a range of
human and murine tumor models.
The study illustrated here compares
activity in the Namalwa lymphoma model. As you can
see, vincristine is active in this model, but VSLI
shows much increased antitumor activity.
I should note that this increased activity
is seen when VSLI is given at the same dose as
conventional vincristine, as will be discussed
during the clinical presentation. Patients are
administered VSLI at approximately twice the
intensity typically used with conventional
vincristine.
[Slide.
The pharmacokinetics of VSLI have been
characterized in patients, and the slide shown here
illustrates plasma vincristine levels following
administration of VSLI to published data for
conventional vincristine.
As you can see, much higher plasma drug
250
levels are achieved for VSLI, and these are
maintained for a considerable period of time.
Again, you will note that the drug levels shown on
the y axis are represented on a log scale.
At almost all time points, plasma drug
levels are approximately 2 orders of magnitude
higher for VSLI compared to conventional
vincristine.
In summary, VSLI provides increased
exposure to vincristine through higher tumor drug
levels and also an extended duration of exposure.
In nonclinical studies, this results in increased
antitumor activity compared to conventional
vincristine.
I haven't presented any data on the safety
evaluations conducted for VSLI. These show that it
elicits the same toxicities seen with conventional
vincristine, and importantly, no new toxicities
were observed.
I will now pass the podium back to
Alexandra Mancini who will present the clinical
results.
251
Clinical Efficacy and Safety
MS. MANCINI: Thank you, Tom.
[Slide.
There are two trials in the NDA that
provide efficacy data in the indicated population.
We have supportive data from the first study we did
in aggressive NHL, our Phase IIa study.
This was an investigator-sponsored trial
at M.D. Anderson Cancer Center, which was a
broad-based protocol including lymphoma and
leukemia, and there were 92 patients with relapsed
aggressive NHL in that study.
Our primary Phase IIb study was an
international multicenter study that enrolled 119
patients at 42 centers. These are the two largest
trials reported for patients with multiply relapsed
aggressive NHL.
Both were single-arm studies and both used
similar response criteria. They provided
consistent efficacy results in a total of 211
patients, therefore, for brevity, I will focus on
the pivotal study only.
252
[Slide.
A larger safety database was provided that
includes 53 patients.
Our clinical development in aggressive NHL
is ongoing using combination regimens. We have had
several discussions with the FDA, three meetings in
fact, regarding our proposed randomized controlled
trial that would serve as a post-approval
commitment trial.
We received comments from the FDA as part
of our special protocol assessment that we
submitted, and the revised protocol will be
resubmitted shortly. The study will start within a
few months.
[Slide.
Before I present the results of our
studies, I will address several issues raised by
the FDA in their review that relate to the adequacy
of the pivotal trial and its conduct. One must
first be assured that the results are reliable
before embarking on their interpretation.
[Slide.
253
The Agency has raised concerns about the
low number of eligible patients attributed to the
following reasons: numerous protocol amendments
and exemptions, a low histologic eligibility rate,
and incomplete staging in 19 percent of patients.
Additionally, there have been concerns
raised about the Independent Review Panel for
efficacy evaluations, specifically with respect to
the wording of the response criteria, operations of
the core imaging lab, and amendments to the IRP
charter.
I would like to provide further
clarification on these points for your
consideration.
[Slide.
It is true that there were 9 versions of
the protocol, but it is important to note that the
study did not begin enrollment until Version 5. As
shown on this slide, almost all patients were
enrolled under two versions of the protocol,
Versions 8 and 9. Therefore, there were really
only four amendments after the trial started.
254
[Slide.
The initial protocol used for patient
enrollment required that patients had a CR or CRu
to first line chemotherapy, and they also had to
have achieved at least a PR to their last line.
We were unable to enroll patients to this
narrowly defined population. The trial was open
for 6 months, and we had 4 patients enrolled.
Therefore, we amended the protocol. We deleted the
requirement for a complete response at first line
and allowed patients in if they had only at least a
minor response.
We also removed any requirement for a
response to their last therapy, and in doing so, we
now defined a poorer prognosis population.
[Slide.
To further enhance patient enrollment, we
added some additional histologic categories shown
here, but as you can see from the number of
patients, this did not result in significant
additional enrollment.
Once again, this defined a poorer
255
prognosis population, and there were no further
changes to eligibility criteria. Importantly, with
each amendment, the FDA agreed that the trial
population was a suitable population to support an
accelerated approval.
[Slide.
The last amendment changed the schedule to
obtain CTs 4 weeks after the first documentation of
response instead of the original 8 weeks, and we
further clarified the wording that these
confirmatory CT scans should be obtained instead of
must be obtained as we realized the original
wording might be misconstrued as a requirement for
confirmation of response.
This was not the intent, as it is not a
part of the International Workshop criteria. This
protocol amendment was implemented after
approximately half the patients in the trial were
enrolled and before Inex was unblinded to the study
data.
We remained blinded to the data until all
patients were enrolled.
256
[Slide.
We did allow medically justified
exemptions for some patients, but we were always
careful to not allow exemptions that would have
enhanced the apparent VSLI response rate, and we
are prepared to discuss specific exemptions during
the question period.
The net effect of the exemptions was
enrollment of a patient population with a poorer
prognosis.
[Slide.
Correct histologic diagnosis of
non-Hodgkin's lymphoma is problematic in clinical
practice. For this reason, we included a
retrospective central pathology review to confirm
eligibility. Nineteen percent of the patients were
deemed histologically ineligible by the Central
Review, and these were mostly indolent lymphomas.
The FDA excluded an additional 7 patients
described as probably eligible by the Central
Review. Dr. Randy Gascoyne was the lead
pathologist in our Central Review. He is available
257
to discuss these 7 cases during the question period
and why they should be considered eligible.
It is important to clarify that these
histologically ineligible patients were not
protocol violations or due to the amendments.
Enrollment eligibility was determined by the site
pathology assessment.
[Slide.
This slide provides a summary of
histologic eligibility for several large studies in
aggressive NHL. The rate seem in our study, 81
percent, is very consistent with what has been
reported in the literature.
Furthermore, the studies listed here were
all conducted in newly diagnosed patients where one
often has a larger biopsy specimen available for
review.
[Slide.
Now, on this next slide, I believe that
the comments I was prepared to make are perhaps no
longer valid. We have looked ahead at the slides
that the FDA is to present, thank you for giving
258
those to us in advance, and I think that some of
these numbers won't match anymore, so please excuse
that.
But what we were going to comment here was
that in our opinion, some of the categories here
listed as reasons for exclusion are not categories
that we feel should be used for exclusion from an
efficacy analysis.
[Slide.
There was 1 patient who did not have
complete CTs at study entry, and, of course, in an
eligible patients analysis, they should be
excluded.
Having had bone marrow biopsy earlier or
having missing LDH at baseline is not a reason, we
feel, those missed data points should not be a
reason to justify exclusion from an efficacy
analysis.
Negative bone marrow and normal LDH are
required, of course, at the time one declares a
complete response whether or not they were abnormal
at baseline. They are a part of the criteria for a
259
partial response.
The other reason noted here, which was
missing neurologic exams at baseline, I don't
believe that that was a reason, and FDA will
clarify that in their presentation, so I believe
that they have removed that category.
[Slide.
Concerns have been raised that would
suggest that the International Workshop criteria
were not followed. I would like to clarify that
the wording in the protocol did not, in fact,
reduce the strictness of the criteria. As
excellent as the International Workshop criteria
are in providing appropriate guidance for the
response determination in this very complex disease
setting, there are some situations where the
criteria are ambiguous or silent.
The wording clarifications in the protocol
were undertaken to uphold the rigor of these
criteria and to ensure consistent interpretation in
this multicenter environment.
[Slide.
260
Before the study was started, we met with
the FDA to discuss the protocol Version 5, which
contained the clarified wording, and the FDA agreed
with the protocol wording and no changes were ever
made to that.
With respect to the internal operations of
the core imaging lab, the FDA noted correctly that
the manual in the NDA was dated one year after the
reviews of images began. We had a manual in place
before the reviews began, but it was our oversight
that this earlier version was not included in the
NDA, but we have now provided that to the FDA for
their review.
We can summarize, though, that were no
changes to the lab procedures during the entire IRP
process.
[Slide.
With respect to the amendments to the
Independent Review Panel charter, there were no
changes to the conduct of the IRP radiology or
oncology reviews. Most of the amendments were in
place before the reviews began.
261
A few radiology clarifications were
requested by the IRP radiologist, Dr. Scott
Gazelle, for situations not previously anticipated,
and he is available during the question period to
discuss the details.
All images were read in chronologic
sequence and they were locked after review, and no
changes were permitted.
[Slide.
To summarize the conclusions regarding the
study conduct issues, the protocol amendments and
exemptions neither contributed to ineligibility,
nor favored a positive outcome with VSLI. They, in
fact, defined a population with a poorer prognosis.
The histologic eligibility of 81 percent
in this study is comparable to what is reported in
the literature. Only 8 percent of patients were
ineligible for efficacy evaluation due to protocol
violations.
Lastly, the Independent Review Panel
process was well conducted, therefore, we are
confident that we are providing for your
262
consideration today a well-defined and reliable
assessment of objective response in the indicated
population and that our pivotal study meets the
criteria for an adequate and well-controlled trial.
[Slide.
I would like to now turn to the
presentation of the pivotal study results.
[Slide.
As agreed with the FDA, some of the key
eligibility criteria in this trial were as follows.
First of all, this was a population of patients
with aggressive NHL that was either from first
diagnosis de novo or transformed, and it was
required that they had at least received 2 prior
combination regimens, one of which had to contain
an anthracycline.
We required only a minor response to
first-line therapy, which is usually CHOP therapy
containing vincristine.
[Slide.
The additional criteria on this slide
define a population that would not be eligible for
263
many clinical trials in that we did not have a
maximum on the number of prior regimens patients
could have, there was no requirement for response
to prior salvage therapies, no upper limit on age,
ECOG performance up to level 3 was accepted, a
Grade 2 neuropathy was permitted, and as VSLI is
hematologically well tolerated, we were able to
allow enrollment of patients with low granulocyte
or platelet counts, who would not be able to take
standard chemotherapeutic agents.
Some of these criteria, particularly the
first two, allowed a somewhat heterogeneous
population to be enrolled, but this is the
population for whom we are seeking an indication.
[Slide.
VSLI was given as a monotherapy regimen in
this study. It was given as 2 mg/m
2 without any
dose capping, 1 hour infusion every 2 weeks. The
protocol specified 12 cycles maximum with the
intent to go 2 cycles after a complete response.
What is highlighted now in yellow are
points of differentiation from the conventional
264
vincristine dosing schedule. Conventional
vincristine is given at 1.4 mg/m
2 often with dose
capping at a flat dose of 2 mg, and it is usually
repeated every 3 weeks, so by implementing these
changes, we are able to at least double the dose
intensity of vincristine.
[Slide.
The efficacy endpoints in this trial were
the traditional oncology endpoints with objective
response as the primary endpoint. The primary
population for analysis was the intent-to-treat
population as defined in the protocol and the stats
plan.
The secondary population was based on
patients who met the key inclusion criteria and who
were evaluated. That is what we call the
"per-protocol" population, and we identified 77
patients who met those criteria.
[Slide.
The assessments of response were
determined using the International Workshop
Criteria. A key point here was that 6 indicator or
265
target lesions were to be measured carefully
throughout the study, and all other disease was
assessed qualitatively.
According to these criteria, response does
not require subsequent confirmation.
As this was a single-arm study, it was
important to use an Independent Review Panel for
the primary efficacy assessment. The IRP was
blinded to the site's opinion of response, and they
also independently chose 6 indicator lesions.
[Slide.
So, who did we enroll in this study?
[Slide.
In the interest of time, I will discuss
only a few characteristics of the study population.
The extent of prior therapy was a significant
predictor of response in this study. The protocol
required a minimum of 2 prior regimens, and we see
that 19 percent of the patients in the study had
exactly that amount of prior therapy, but the vast
majority of these patients had much more prior
therapy.
266
The mean was 3.8, the median was 3, so
therefore VSLI was being given predominantly as a
fourth- and fifth- line therapy to this population.
[Slide.
Another important perspective that
provides context for the interpretation of our
results is how these patients responded to their
previous therapies. When they were at their
first-line therapy, the overall response rate was
92 percent, 50 percent complete response.
By their second line, the response rate
had dropped down considerably to 41 percent, and we
were now seeing only 20 percent CRs. At their last
therapy, which could have been second line, but was
usually much further along than second line, the
response rate was down to 35 percent with only 13
percent complete response.
I would like to emphasize that
three-quarters of the patients were receiving a
combination regimen as their last line. Therefore,
these data demonstrate that the population in this
trial had disease that had become very difficult to
267
treat.
The median duration of response was 8
months at first-line therapy and had decreased to 5
months with salvage regimens.
[Slide.
Patients were further characterized with
respect to the sensitivity or resistance of their
disease to their last qualifying therapy.
Two-thirds of the patients in this trial had
resistant disease, and half of the patients had
truly refractory disease, meaning that they did not
respond to their last therapy.
Another 17 percent had early relapses
within 3 months. Therefore, only one-third of the
population had sensitive disease with responses
lasting more than 3 months to their last therapy.
[Slide.
Turning now to the efficacy data.
[Slide.
The results are very similar in the
intent-to-treat and per-protocol populations. For
brevity, I will focus on the intent-to-treat
268
population, which was the primary efficacy
analysis. The per-protocol analyses have been
provided for your review in Appendix B of the
briefing document.
The primary efficacy endpoint was the
objective response rate as assessed by the IRP, and
these are the results on this slide. The IRP
determined that 30 patients were responders. That
is 25 percent. We had 8 patients with a CR or CRu,
so these were predominantly partial responses in
this trial.
Additionally, one-quarter of the patients
had stable disease with VSLI therapy.
[Slide.
Now, on this slide, I provided comparison
of 3 different analyses. The first column is the
intent-to-treat data that I just shared with you.
The second column is the per-protocol
population that we defined of 77 patients, and the
response rate is very similar, as is the
distribution being predominantly PRs, but still
maintaining some complete responses in about a
269
quarter of the patients with this disease
stabilization.
In the far right column, I have presented
the FDA eligible analysis, as was shared in their
original posted briefing document. I believe they
will be updating this analysis today, but this
analysis again showed a very similar response rate
at 22 percent with about 4 percent complete
response.
[Slide.
A key focus of today's deliberations is
whether the objective response rate observed in
this study is likely to predict clinical benefit.
We looked at other available data for the
responding patients as we were requested by the FDA
to prepare patient benefit summaries to facilitate
their review.
[Slide.
We determined that there was evidence of
some symptomatic improvement associated with
objective response. There were 8 patients who were
determined to be complete responses or CRu by the
270
IRP. Three of those patients were actually
asymptomatic at study entry, but the remaining 5
patients who were symptomatic either had resolution
of their symptoms or an improvement in their ECOG
performance status.
Of the 22 patients called partial
responses, 15 of them had improvements in symptoms
or ECOG performance status.
I should mention that there was no formal
symptom efficacy endpoint in this trial, so this is
a summary of baselines signs and symptoms or that
resolved after VSLI treatment. Other evidence of
possible clinical benefit was presented in the
briefing document.
[Slide.
Turning now to the secondary efficacy
endpoints, the time-to-event endpoints.
[Slide.
The first one I would like to discuss is
duration of response. This was analyzed using
Kaplan-Meier method, the usual method, and it is
done only, of course, for the 30 responders. The
271
median was not reached in our analysis, but we were
very close at 52 percent probability at the last
event of progression or approximately 3 months.
The FDA analysis appears to have used a
slightly different definition that included
withdrawal due to neurotoxicity as a progression
event, but this analysis provides a similar median
estimate of about 2 1/2 months.
[Slide.
The analysis of time to progression is, of
course, conducted on all 119 patients. The median
here was estimated again to be about 3 months, but,
of course, this was heavily influenced by the
majority of patients in the trial who did not
respond to VSLI treatment, so an additional
analysis was done for the responding patients.
For this subgroup, the estimated median
time to progression was not reached, but once
again, we were approaching the median at 45 percent
probability. So, we were at about 4 months.
[Slide.
The overall survival is shown in this
272
Kaplan-Meier curve. The median was 6.7 months, and
at 2 years, we have 25 percent of the patients
still alive.
[Slide.
The protocol and stats plan prespecified
several subgroup analyses, and there were two
factors that were determined to be statistically
significant predictors of objective response.
[Slide.
With 2 significant predictors of response,
the most informative presentation is for the 4
subgroups, as shown on this slide. The response
rate for patients who had 2 prior regimens was 46
percent, and for the patients who had more than 2
prior regimens, which was a much larger proportion
of the patients on the trial, the response rate was
lower, at 20 percent.
Within each of these 2 big groups, if we
would further subdivide by whether they had
sensitive or resistant disease, we see the impact
of that factor, as well.
So, we have quite a range of response
273
rates here, from the lowest being 15 percent, to
the highest being 64 percent, and what we can
conclude from this analysis is that the overall
response rate of 25 percent, that we saw in our
study, was very much the result of the relative
number of patients in these 4 subgroups that were
enrolled in the study.
Had we had more patients in this subgroup,
the poorest prognosis subgroup of more than 2 prior
regimens with resistant disease, we would have had
a lower response rate closer to the 15 percent.
Had we had more patients with sensitive
disease in the protocol, we would have been in the
30 to 40, 50 percent response rate.
One criticism of this analysis is that
some of the subgroups are very small.
[Slide.
So, on this slide, we are now showing the
Phase IIa supportive study alongside the data that
I just showed you. The denominators here are for
the combined studies, and what is impressive is
that the results for the 2 studies are very
274
consistent for the 4 subgroups. These 2 predictors
of outcomes were consistent in both trials.
Therefore, one can be reassured that the
estimates for these subgroups are reasonable.
[Slide.
This slide summarizes some other subgroup
analyses that are noteworthy as they did not
identify significant predictors of response. The
response rate was not any lower in patients who had
previously undergone autologous stem cell
transplant, nor was the response rate affected by
age. The median age was 60 years.
Twenty-eight patients on this study were
older than 70 years, and this subgroup had a 36
percent response rate, so at least as good as the
total population.
Patients who have relapsed after
transplant and those who are elderly are
particularly in need of an effective therapy that
is minimally myelosuppressive.
[Slide.
Returning now to the question of whether
275
VSLI provides meaningful therapeutic benefit over
existing treatments, we have the rituximab
publications presented earlier by Dr. Cabanillas on
this slide in the first three columns, and now I
have listed the results of our Phase IIb study in
the two right columns.
The furthest right column has the results
for the intent-to-treat population, which had a
median of 3 prior regimens, therefore, to provide a
better comparator I have pulled out the subgroup of
patients who had 2 prior regimens as that is more
comparable to what is in the literature citations.
But it is important to note again that
these 3 publications for rituximab did include a
substantive proportion of patients at first
relapse, which we did not have in our study.
Even with a slightly more favor population
enrolled in these studies, our response rate, which
is shown along this line here, a response rate of
46 percent compares favorably to what was shown
with rituximab.
Duration of response was not reported in
276
the publications, but on time to progression at the
bottom of the table, the VSLI is in the same range.
[Slide.
We can also compare to the rate of
response demonstrated with rituximab for the
patients in our study. There were 20 patients who
had rituximab as a single agent therapy as their
last therapy before coming into the study.
The response rate to rituximab was 25
percent, and there were no complete responses.
With single-agent VSLI then, as their next
therapy, the response rate achieved was 40 percent,
and we did see some complete responses in these
same patients. Therefore, we are seeing a somewhat
higher rate of response.
[Slide.
I would like to turn now to the safety
data presentation.
[Slide.
The mean number of cycles of VSLI
administered was 4.6 with a median of 4, and the
dose intensity was very close to the target of 1,
277
indicating that very few dose reductions occurred
on the study. I should say that was 1 mg/m
2/week.
That was our target at dose intensity.
[Slide.
Fourteen percent of the patients withdrew
due to associated adverse events, which was mostly
neuropathy. It was 13 percent for neuropathy.
There were no treatment-associated deaths.
[Slide.
The dose-limiting toxicity of conventional
vincristine and of VSLI is, of course, neuropathy.
[Slide.
This slide summarizes the number of prior
regimens that the patients had that contained
neurotoxic agents. Eighty-six percent of the
patients had at least 2 prior regimens that
contained a neurotoxic agent. Therefore, it is no
surprise that 85 percent of the patients entered
the study with some level of neurologic deficit.
[Slide.
Now, on this slide, I am showing the worst
grade of neuropathy on study for patients grouped
278
by their grade of neuropathy at study entry. We
did allow up to Grade 2, as I mentioned.
These data are the worst values for any of
the 5 neuropathy symptoms that we tracked, as shown
in the title. The scoring system here is the NCI
CTC scale, which goes from zero, which is normal,
to Grade 4 at the worst end.
For patients who entered this study with
Grade 1 neuropathy, one-quarter of the patients had
no change on study, and about half of them worsened
by one grade to a Grade 2 level, one-quarter went
to a Grade 3 level.
For patients who entered this study at
Grade 2, approximately 40 percent of them did not
have any worsening on the study, but half of the
patients did worsen one grade to Grade 3. As would
be expected, patients who entered the study with
worse neuropathy had a higher chance of developing
Grade 3 neuropathy.
[Slide.
Numbness in the hands was the symptom that
was most adversely affected on this study, and this
279
plot shows the mean change from baseline to Cycle 6
for this parameter.
We observed a gradual cumulative increase
in hand numbness, reaching a peak which was less
than one grade, and again, this is the NCI grading
system that goes to 4.
This peak was reached after 5 cycles, and
the data beyond Cycle 6 don't show any further
increase. We are down to fewer numbers of patients
on the study at that time.
[Slide.
Her analysis was done to estimate the dose
that would result in Grade 3 or 4 neuropathy if all
patients continued to be dosed. The Kaplan-Meier
method was used for estimation, and all five
symptoms were included. Reaching Grade 3 in any
one of these symptoms was called an event in this
analysis.
One-third of the patients on the study
developed a Grade 3 or 4 neuropathy, but as you can
see, they were almost all Grade 3 neuropathies.
There were only 3 patients who went to Grade 4.
280
The estimated median cumulative dose to
achieve this was 21.2 mg/m
2, which is approximately
11 doses of VSLI. This is equivalent to
approximately 15 doses of conventional vincristine.
This is a lot of vincristine for patients who have
received previous neurotoxic agents, and it speaks
to the safety from the liposomal encapsulation.
[Slide.
With the 25 percent response rate, an
important consideration is the risk exposure for
patients who will not respond to VSLI therapy.
This slide summarizes the magnitude of
treatment-emergent worsening in neuropathy from no
change up to 3 grades. This are all zeros here.
This is presented separately from responders versus
non-responders. So these are the grade changes from
baseline to worse value, the treatment-emergent
changes.
As one would expect, the responding
patients who received more drug did achieve bigger
changes in their neuropathy, mostly 1 or 2 grade
changes, however.
281
In the nonresponding patients, 55 percent
of the patients had no change on study, and
one-quarter had a one grade worsening. This group
includes stable disease patients, and which
includes their minor responses, not meeting the
definition of a partial response, and some of our
stable disease patients actually were treated for a
very long time.
So, I have pulled out a smaller group here
in the bottom row, which are the patients who had
rapid progression, and we see that 69 percent of
the patients in that group had no change at all on
study and 19 percent had a one grade worsening.
Because of the gradual development of
neuropathy, we are able to avoid significant
toxicity in patients who will not benefit from this
therapy.
[Slide.
It is also of interest to compare the
timing of the antitumor effect to the timing of the
neuropathy, and when we prepared the patient
summaries, we observed that the antitumor activity
282
was evident very early in those patients who would
be declared responders, usually within the first
two weeks of off the first injection of the drug.
There was evidence of symptomatic
improvement, reduced palpable adenopathy or
decreased LDH long before we were doing CTs. As
shown earlier, the development of neuropathy is
gradual and predictable, therefore, in contrast to
most other drugs, with VSLI, the physician and
patient can make an informed treatment decision
before significant toxicity develops.
[Slide.
With respect to hematologic abnormalities,
at study entry, we see here at study entry,
approximately 80 percent of the patients had some
level of anemia, 40 percent have thrombocytopenia.
One-third of the patients would not have been
eligible for standard chemotherapeutic agents that
were myelosuppressive based on the low neutrophil
or platelet counts as defined here.
[Slide.
This slide now summarizes the treatment
283
emergent grade changes from baseline to worst grade
on study for these three hematologic parameters.
As shown in this column, about half of the patients
for any particular parameter, about half of the
patients had no change on study.
Most of the changes were in the 1 grade
category. Neutrophils was the parameter that had
the most change, and we see 20 percent of the
patients having a 3 or 4 grade change, and
approximately half of those, so 10 percent of the
patients is where it was considered to be treatment
related.
With respect to the worse level of
neutropenia reported on study, 8 percent of
patients had Grade 4 neutropenia and 3 percent had
febrile neutropenia. This occurred in the setting
of only 2 percent prophylactic filgrastim usage,
so this study provides a good estimate of the VSLI
effect on neutrophils.
Grade 4 thrombocytopenia occurred in only
one patient and 6 percent of patients received
platelet transfusions.
284
Based on all of these data, we conclude
that VSLI was hematologically well tolerated in
this study.
Dr. Cabanillas will now describe patients
who achieved net clinical benefit in this study.
Clinical Benefit
[Slide.
DR. CABANILLAS: The FDA has requested
that the company prepare patient benefit summaries
to facilitate the review of clinical benefit.
There were 38 patients considered to be
responders by either the IRP or the investigator,
and summaries were prepared for all of those
patients. In addition, there were 5 patients with
minor responses who had evidence of clinical
benefit.
Therefore, a total of 43 individual
patient benefit-risk assessments were prepared.
[Slide.
Of the 43 patients analyzed for clinical
benefit, there were 41 who actually manifested
evidence of benefit. I will discuss the findings
285
for the first two categories noted in yellow here,
specifically, symptom improvements and patients who
went on to receive stem cell transplants.
Other categories of clinical benefit
included durable responses and better outcomes than
previously achieved. Some of these will be
demonstrated in a few case studies.
[Slide.
This slide summarizes two of the clinical
benefits, improvement in symptoms and improvement
in performance status.
Twenty of the 43 cases had improvement in
either B symptoms or some other symptom related to
lymphoma, 13 patients experienced improvement in
performance status. A total of 26 patients had
improvement in one of these two categories.
Another clinical benefit we consider
important is being able to provide these patients
with the opportunity to receive a stem cell
transplant.
[Slide.
Six patients were able to receive
286
transplants after the VSLI study. Both
responsiveness to VSLI and maintenance of a good
performance status enabled these patients to
receive their transplant. Five of these 6 patients
are actually alive, 1 with disease, and 4 with no
evidence of disease for two to three years.
[Slide.
In the pivotal study, we observed some
very striking outcomes in several patients, and I
wish I could review each one of them, however, in
the interest of time, we will only be able to go
over three of these patients, but we have also some
patients who will be testifying today.
The first case is a 56-year-old lady with
primary mediastinal DLCL and associated symptoms.
Her response to prior therapy had consisted of a
brief PR to CHOP. Upon relapse, she was treated
with ESHAP and RICE without response to either.
She achieved a CRu of 1 year after 20 cycles of
VSLI. Her toxicity consisted of only one episode
of Grade 4 neutropenia.
What is striking about this case is that
287
she was able to obtain a CRu after being refractory
to 3 combination regimens including CHOP. She
benefited also from resolution of B symptoms and
anemia.
[Slide.
This 76-year-old lady with DLCL and IPI of
3 presented with multiple pulmonary metastases and
thrombocytopenia of 72,000. Her prior therapy
included CHOP and subsequently Cytoxan, VP16,
Rituxan.
After 8 courses of VSLI, she obtained a PR
of 8+ months, and her platelets normalized. Her
tolerance to VSLI was excellent with no Grade 3 or
4 toxicities.
The pulmonary metastases improved, but
never disappeared completely. The residual
lesions, however, have not changed for 2 1/2 years,
suggesting that they are scars, rather than
lymphoma.
This patient benefited from a long
chemotherapy-free interval still ongoing at 27+
months, which is a longer remission than she ever
288
experienced with any of her prior therapies.
[Slide.
This third case is a 47-year-old male with
advanced DLCL and a mediastinal mass plus bone
marrow involvement. Front-line therapy with CHOP
failed to induce a response, and second-line
therapy with RICE also failed.
After 8 cycles of VSLI, he achieved a PR
according to the IRP or a CR according to
investigator without serious toxicity. He is alive
with no evidence of disease after 30+ months and
has not required any subsequent therapy.
Therefore, the investigator's assessment
of complete remission was correct.
Most striking about this case is the
achievement of a CR in the context of primary and
secondary refractory to chemotherapy. The B
symptoms and anemia also resolved.
[Slide.
I would like now to turn our attention to
our conclusions about the benefits versus the risks
of VSLI.
289
[Slide.
Our patient population consisted of
patients treated with a median of 3 prior regimens,
which translated into 4th and 5th line therapy for
most of these patients.
One-third of our patients had received a
prior autologous transplant and one-third had low
blood counts, which would have made them ineligible
for a treatment with a myelosuppressive agent.
Half were refractory to the last
qualifying therapy and one-quarter were older than
70 years. Finally, two-thirds had an elevated LDH
at time of entry.
In summary the prognostic factors
associated with this population are extremely
adverse.
[Slide.
In this study, we have 25 percent overall
response rate. In patients treated on second
relapse, however, the response rate was better at
46 percent. We consider this response rate to be
clinically important for this population.
290
In fact, I consider this drug to be the
most active single agent I have used since we
tested a phosphamide back in the 1970s
non-Hodgkin's lymphoma. The objective responses
usually translated into symptomatic improvement.
The median response duration was
approximately 3 months and time to progression was
approximately 4 months. This is in the setting of
an overall median survival in the range of 7
months.
[Slide.
Regarding the risks, we can summarize them
by stating that neuropathy was the dose-limiting
toxicity. Its development is gradual and
cumulative, and only 13 percent withdrew because of
neuropathy.
Compared to other agents, VSLI is well
tolerated with a low incidence of severe
myelotoxicity and hospitalizations. In addition,
nausea and vomiting, as well as alopecia are
infrequent.
[Slide.
291
An important point is that the improvement
in symptoms and the antitumor response occur early
with VSLI. This allows for informed treatment
decisions before serious neuropathy develops.
In essence, there is a favorable
benefit-risk profile for this population, which has
not standard therapy options.
[Slide.
So, why do we need VSLI? It is an
effective and well-tolerated agent for patients on
third relapse or later. It offers a therapeutic
alternative for patients who do not qualify for
aggressive combination regimens or who have
relapsed after transplant, as well as for those
with a compromised marrow function.
VSLI resulted in benefits for 1 out of
every 4 patients with minimal toxicity.
Thank you for your attention during the
presentation. We would be happy to answer your
questions at anytime.
DR. MARTINO: Thank you.
At this point, I would like the FDA to
292
present their evaluation of this data.
FDA Presentation
DR. HAZARIKA: Good afternoon. My name is
Maitreyee Hazarika, medical reviewer.
This NDA submission is for Marqibo, which
is vincristine sulfate liposome injection.
[Slide.
The indication is for the treatment of
patients with aggressive non-Hodgkin's lymphoma
previously treated with at least two prior
combination chemotherapies.
[Slide.
This presentation will go through the
regulatory issues with this application. Study
CA99002 is the major trial submitted. Study
DM97-162 is the supportive study. The FDA analysis
of the efficacy and safety will be discussed
followed by the summary and the issues for ODAC.
[Slide.
The regulatory issues for this application
includes accelerated approval, available therapy,
endpoints, adequate and well-controlled trials, and
293
confirmatory trial requirements.
[Slide.
Accelerated approval is granted by the
Agency if a drug appears to provide a benefit over
available therapy, and the benefit is determined by
the drug's effect on the surrogate endpoint deemed
reasonably likely to predict clinical benefit.
[Slide.
Because accelerated approval requires an
advantage over available therapy, the definition of
this term is critical. Available therapy should be
interpreted as therapy that is reflected in the
approved labeling of regulated products.
[Slide.
There are exceptions where a safe and
effective therapy for a disease exists, but it is
not approved for that particular use by the FDA.
In oncology, treatments that are not
labeled for use but is supported by compelling
literature can be considered available therapy.
The ODAC members will need to use their
expertise on what constitutes available therapy for
294
aggressive non-Hodgkin's lymphoma.
[Slide.
Initially, FDA-approved drugs were based
primarily on clinical data and review of
literature. Most of these drugs listed here are
used as part of a combination in relapsed patients.
[Slide.
Within the past 15 years, FDA has approved
four biologic agents mainly for the treatment of
low grade follicular non-Hodgkin's lymphoma. This
is a different indication from the one being
discussed here today. Approvals were based on
single-arm or randomized, controlled trials. The
first three approvals were based on response rates
and duration. Intron approval was based on a
longer progression-free interval and median
survival.
[Slide.
To determine whether vincristine sulfate
liposome meets the criteria for accelerated
approval, the ODAC and the FDA must consider not
only approved drugs, but also the published
295
literature. There are many known approved
combination therapies used for relapsed aggressive
non-Hodgkin's lymphoma, which also includes
high-dose chemotherapy with stem cell
transplantation.
Some examples are shown here. The
combinations used have overall response rates of 30
to 88 percent with complete responses of 18 to 53
percent.
[Slide.
Many single agents are also used that are
not specifically labeled for non-Hodgkin's lymphoma
indication. Based on published literature, overall
response rates varied from 37 to 69 percent and
complete responses from 13 to 33 percent.
In both the combination and the single
agent reports shown here, these may not be the
exact population. Patients may have received
between 1 to 3 prior therapies and may have mixed
histologies.
Nevertheless, we will be asking the
Committee whether any of these constitute available
296
therapy.
[Slide.
Previous recommendations have been to use
complete response as the endpoint in this disease.
Two important questions should be in the
Committee's mind for this application. Should FDA
consider partial responses to be reasonably likely
to predict for clinical benefit in relapsed,
aggressive non-Hodgkin's lymphoma? If so, would
responses of the magnitude and duration seen in
this study predict for clinical benefit?
[Slide.
There are a few key regulatory points to
consider for the present application. The study
should use a design that permits a valid comparison
with a control to provide a quantitative assessment
of drug effect.
The method of selection of subjects should
provide adequate assurance that they have the
disease being studied.
The methods of assessment of subjects'
response should be well-defined and reliable.
297
[Slide.
Since 1999, the Agency has had around 20
meetings with the sponsor on various issues. In
those meetings, FDA has advised the sponsor that
response duration was of interest. FDA advised the
sponsor for the need for a confirmatory trial, and
FDA has emphasized the endpoint of durable complete
responses.
[Slide.
At the March 2003 ODAC meeting, the
Committee reinforced the Agency's recommendation
that the postmarketing studies be ongoing at the
time of accelerated approval. The FDA expects that
confirmatory studies to demonstrate that treatment
with the drug is associated with clinical benefit
will usually be underway at the time of accelerated
approval, although that is not a specific
requirement.
[Slide.
Study CA99002 is the major trial
submitted. It is a multicenter, open-label,
single-arm Phase II study with a primary endpoint
298
of response rate, which included complete response,
complete response unconfirmed, which is a complete
response with a residue in mass, and partial
responses.
119 patients were enrolled. VSLI was
given at 2 mg/m 2
intravenously over 1 hour every 2
weeks.
[Slide.
Patients had relapsed, aggressive
non-Hodgkin's lymphoma, who had received at least 2
prior combination therapies including 1 prior
anthracycline-based therapy.
[Slide.
Histologies included aggressive de novo
and transformed lymphomas, and included diffuse
large B-cell lymphoma and peripheral T-cell and
anaplastic lymphomas.
[Slide.
According to the Central Pathology Review,
only 75 percent patient histologies were identified
as definite eligible, 30 patients were probable
eligible or ineligible. The majority of the
299
ineligible patients had low grade histology on
biopsy. Two patients had slides missing for
Central Pathology to review.
FDA evaluated only the definitely eligible
patients. Definite eligible have the histology for
the indication proposed for VSLI.
[Slide.
These are the reasons for exclusion from
the FDA efficacy analysis. There were 30 patients
with histology not definitely eligible by Central
Pathology Review. Eight patients did not have
baseline indicator lesions measurable by the
independent radiologist.
A durable disease was defined as at least
1 bidimensionally measurable lesion with clearly
defined margins that were greater than 2
centimeters in the largest dimension by CT scan or
physical examination.
Five patients did not receive 2 or more
prior combination chemotherapy from the time of
diagnosis of transformation. Two patients did not
have a washout period of 4 weeks, and 12 patients
300
did not have complete baseline staging with CT scan
or bone marrow biopsies, or had bone marrow
biopsies done more than 2 months prior to the study
drug administration.
That is a total of 40 percent patients
were considered ineligible for the trial by the
FDA.
The briefing document gives slightly
different numbers, but the results do not change
significantly.
[Slide.
There were other study conduct issues,
such as bone marrow biopsies done between 3 to 8
weeks prior to entry. Missing full set of CT scans
at one or more visits, missing scans for tracking
the disease, and missing baseline neurological
examinations. These patients were included in our
efficacy analysis as we felt that they did not
impact on the response rate.
[Slide.
The FDA analysis used 61 percent of the
enrolled patients who met the critical eligibility
301
criteria. That is, they had relapsed, aggressive
non-Hodgkin's lymphoma, had received 2 or more
prior combination chemotherapies, including 1 prior
anthracycline-based therapy, and had required
baseline scans and bone marrow biopsies.
[Slide.
The response criteria used was based on
the International Workshop to standardize response
or non-Hodgkin's lymphoma. There were 4 categories
based on physical examination - lymph nodes, lymph
node mass, and bone marrow biopsy, complete
response, complete response unconfirmed, which
included a residue mass or indeterminate bone
marrow, partial response, and relapse or
progression.
The normal lymph node size was based on
the abnormal node size at diagnosis. A lymph node
greater than 1 cm was considered compatible with
involvement by non-Hodgkin's lymphoma.
These criteria do not require response
confirmation. Most international cooperative
groups require a confirmatory evaluation for the
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response classification. Although it was agreed to
use these criteria, FDA emphasized that duration of
response must be examined and described.
[Slide.
The sponsor made some modifications to the
International Workshop, such as defining the normal
lymph node size and nodal mass size to be 1.5 cm,
and using indicator lesions that were a minimum
size of 2 cm in at least one dimension.
The FDA analysis of response used the
sponsor modifications.
[Slide.
Prior to any patient enrollment,
amendments included a statement which required
response confirmation by repeat assessment at 4
weeks following the first documentation of
response.
[Slide.
The sponsor's analysis of response rate
included patients with tumor size reduction
documented on at least 1 occasion.
In addition to the same response rate, the
303
FDA analysis was also done on confirmed response
rate where tumor size reduction was confirmed at
least 4 weeks later.
[Slide.
On analyzing response rate documented on 1
occasion, the sponsor found 4 complete responses, 4
complete responses unconfirmed, which to remind you
are complete responses with a residue of mass, and
22 partial responses, for an overall response rate
of 30 patients or 25 percent.
The FDA analysis on the evaluable patients
found 1 complete response, 3 complete response
unconfirmed, and 11 partial responses, for a total
response rate of 21 percent.
[Slide.
The FDA also did an analysis on confirmed
response rates with a greater than or equal to
4-week confirmation, and found zero complete
responses, 2 complete responses unconfirmed, and 9
partial responses,, for a total response rate of 15
percent.
[Slide.
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In the sponsor's analysis, the duration of
response has been estimated using the Kaplan-Meier
procedure. Patients who did not have documented
progression were censored at the time of treatment
cessation, and the sponsor's analysis of duration
of response, 67 percent of the responders were
censored.
Any attempts to interpret a response
duration where two-thirds of the patients are
censored is of questionable value. The sponsor's
median duration of response was reported to be
greater than 85 days. In the FDA analysis of 11
confirmed responders, the median duration was 85
days.
[Slide.
In the sponsor's analysis, out of the 20
censored patients, reasons for treatment cessation
included neuropathy, relapse, underwent bone marrow
transformation, completed study, withdrew consent,
thrombocytopenia, and unknown reason.
Forty-three percent of the responders in
the sponsor's analysis did not have repeat scans or
305
physical examination or progressed before a repeat
scan was done. Thirty percent of patients
discontinued within 30 days of initial response.
[Slide.
Patients completed a median of 4 cycles of
therapy. The dose intensity was 96 percent of
planned. The most common cause of dose delay was
due to neuropathy followed by hematologic toxicity.
Neuropathy was also the most common cause
of dose reductions. Thirteen percent of the dose
reductions were at least 0.24 mg/m2.
[Slide.
The commonest Grade 3 or Grade 4 adverse
events were peripheral neuropathies, both sensory
and motor, which occurred in 60 percent of
patients, followed by myelosuppression in 45
percent of patients. Other adverse events were
fatigue and constipation.
[Slide.
Study DM97-162 was submitted as supportive
evidence. It was a single-center, open-label,
single-arm study in patient with relapsed lymphoma
306
and acute lymphoblastic leukemia.
The primary endpoint was response rate.
132 patients were enrolled, 116 had a diagnosis of
lymphoma, of which 97 patients had aggressive
lymphoma.
[Slide.
There was no independent review of
pathology or radiology. Selected CT scans were
reviewed retrospectively. There was incomplete
documentation of bidimensional measurements.
Case report forms were not used
prospectively. Standardized response criteria for
non-Hodgkin's lymphoma was not used.
Therefore, the use of the study for
support is questionable.
[Slide.
The sponsor reported the response rate in
the aggressive non-Hodgkin's lymphoma population as
29 percent. There was nor duration of response
assessed.
[Slide.
In summary, the submission is multicenter,
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single-arm Phase II study in patients with
relapsed, aggressive non-Hodgkin's lymphoma
submitted for accelerated approval based on the
endpoint of response rate.
In the major study, 72 patients met the
critical eligibility criteria.
[Slide.
The FDA analysis found the response rate
documented on at least 1 occasion to be 20.8
percent with 1.4 percent complete responses. The
confirmed response rate was 15.3 percent with zero
confirmed complete responses.
The FDA analysis contains only patients
who have aggressive relapsed histologies.
[Slide.
The study conduct raises doubt regarding
the method of assessment of response. The duration
was short and not adequately evaluated. The use of
the supportive study is questionable for support.
There is no confirmatory trial underway.
[Slide.
We bring this application to the ODAC
308
Committee for the consideration of several issues.
The first issue is the available therapies for
relapsed, aggressive non-Hodgkin's lymphoma.
Drugs considered under accelerated
approval must demonstrate an advantage over
available therapy. The Committee needs to consider
not only the magnitude of the response rate, but
the data which indicates that this response rate is
comprised primarily of partial responses.
The Agency believes that the duration of
any response rate must be considered in assessing
the potential clinical relevance of any claimed
benefit.
Finally, the Committee should consider if
the sponsor has demonstrated in this single-arm
trial that VSLI represents an improvement over
available therapy, keeping in mind the activity of
multiple drugs and combinations in aggressive
non-Hodgkin's lymphoma.
[Slide.
This is the review team for the
application.
309
Thank you for your attention.
DR. MARTINO: Thank you. At this point,
ladies and gentlemen, we will move on to questions
from the Committee to either the sponsor or the
FDA, and also please know that we have chosen to
not allow you a break after the questions as
several of us need to leave, and I want to give the
group the opportunity to at least have their
questions asked and answered.
Dr. George.
Questions from the Committee
DR. GEORGE: I have a question. Maybe
it's for Dr. Pazdur, but it has to do with
accelerated approval again. The more I learn about
it, the more subtle it seems.
This has to do I think with this
application because of the available therapy issue,
the issue of appear to provide some improvement
over available therapy.
This is not, of course, the same thing as
proving it has any advantage over available
therapy, and it just has to do with accelerated
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approval, because if you were to get full approval
later, you don't have to prove that it is superior
or in any way compared to available therapy.
So, I just want to be sure that that is
correct, and maybe some clarification on what would
be meant by "appear to be superior" or an advantage
over available therapy.
DR. PAZDUR: Let me over the regular
approval is for clinical benefit, and therefore, we
are looking at different endpoints. We would be
looking at a survival benefit. We would be looking
at a very durable CR rate here.
But for accelerated approval, we do want
an improvement over available therapies. Remember,
the whole purpose of accelerated approval, which
came to us from really the AIDS arena, you know,
decades ago, or about 15 years ago, was an effort
by the Agency to get out therapies that were novel,
that were an improvement over available therapy.
So, it isn't appears to be, it should be,
in our interpretation, and provides is the correct
word--thank you, Grant--an improvement over
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available therapy here.
Now, just from a historical perspective,
you know, our first approval or one of our first
approvals, getting back to this available therapy,
was in colon cancer, a disease that I am very
familiar with, and many of you here are, too, for
irinotecan.
There, in 1995, there was no irinotecan,
there was no oxaliplatin, there was no Avastin,
there was no Erbitux, nothing like that existed.
All you had was 5FU and leucovorin, and that was
it.
Now, it was very easy to answer that
question, because nothing existed and there was
complete consensus in the community that any
therapy was going to be better than nothing
basically.
That is why we felt initially very
comfortable going ahead with this. Similarly, in
lung cancer, where you had patients progress on a
platinum-containing combination, on a
Taxotere-containing combination, we feel very
312
comfortable looking at single agent ERISA, and we
approved the drug.
In therapies where there has been, you
know, activity in available therapy, for example
multiple myeloma, when we approved Velcade, for
example, we had durations of responses that were
over a year, so it was very obvious to us that you
didn't need a randomized trial here.
That is a basic, trying to get away from
the nuances of drug regulation, what we are looking
for in a sense is should a randomized study be
done, and that is the clinical issue here, is there
enough evidence that you have from the literature
that you feel that there is compelling evidence
that there is available therapy that would warrant
a randomized study.
The issue also is "compelling" is a very
vague word, it is like beauty, it's like sexy, it's
in the eyes of the beholder. So, it is very
difficult to establish that, and when we looked at
the literature, we found it very confusing, and
that is why we decided we would ask your opinion
313
regarding this, because when you go back, it is
very hard unless you did a actual meta-analysis of
all of these reports to find out exactly what
therapies patients had, et cetera.
So, it is an area of ambiguity in a sense,
what is available therapy.
DR. MARTINO: Dr. Hussain.
DR. HUSSAIN: I had a question regarding
the comments about symptomatic improvement. Were
the data on symptoms collected prospectively and
systematically? I am really curious. I deal with
solid tumors and we would consider a 10 percent
high-grade neuropathy as an unacceptable rate of
neuropathy.
So, I am curious about your comments about
how this drug is so well tolerated, yet, you have a
60 percent Grade 3 or 4 neuropathy, which does not
really speak for a good quality of life in a
setting of this kind of disease.
MS. MANCINI: Yes, I will address your
first question regarding how the symptoms were
collected. Can I clarify, are you asking about the
314
symptoms of neuropathy or the symptoms of disease?
DR. HUSSAIN: I believe the doctor was
asked about quantifying clinical benefit, and we
saw a slide that showed there were improvements in
performance status and symptom improvement, and so
my question is, did you actually go back and look
in the charts and see that the doctor mentioned
something, or there was systematic collection of
the symptoms prospectively.
MS. MANCINI: I can answer that question
then. As I commented, we had no prospective
symptom endpoint in this trial, so therefore, these
are soft data. What we have is what was reported
as baseline signs and symptoms, so as part of
collecting adverse event data. We would watch what
happened to that as the patients were treated, so
you could see as it gets better basically, and as
it is resolved.
So, it is not the same level of evidence
we would normally have for a formal efficacy
symptom endpoint, but the reason we summarized that
data was we were asked to look to see was there any
315
evidence to support that the patients who got
partial responses particularly had other clinical
benefit.
So, it is soft data. It is the level of
data, however, that you would experience in your
clinical practice, the patient complains of tumor
pain, neck pain, et cetera, and then it goes away,
so it is at that level.
DR. PAZDUR: If I could just add to that
because I think I was the person that instigated
this question. We don't put any credibility or
very little credibility in a unblinded single-arm
trial as far as interpreting symptoms.
One of the reasons I just asked this, was
there any kind of supplemental information that
could give some credibility to a response rate,
because a response is, one, you know, even when we
talk about a complete response rate, is it a single
mass going down versus multiple masses, is there
something that might bolster this up, but the level
of proof that we would require to make any labeling
claims about that in any product would not come
316
from a single-arm, unblinded trial.
MS. MANCINI: If i could return to your
second comment, then, I would just like to clarify.
If we could back in the primary presentation,
please, to the slide--excuse me while I flip to it,
to the safety presentation--let's go to Slide 71,
please.
I may have gone quickly over this in the
presentation. There are two factors to consider
when we look at the tolerability of our drug. One
is how did the patients come into the study and
what happened from there.
So, just as a point of perspective, 86
percent of them had had at least 2 prior regimens
containing a neurotoxic agent, so 85 percent came
in with some level of neuropathy.
The next slide, please, 72. This is the
analysis that shows what happened to them by their
worst grade at study entry. So, when you look at
the people who get to Grade 3, they are mostly
coming from patients who started some neuropathy.
So, the incremental toxicity that they
317
have endured is what we are trying to summarize
here. So, for patients who came in with a Grade 2
neuropathy, half of them did worsen to Grade 3.
That is a one-grade change. Had they not come in
with Grade 2, they wouldn't have gone there
probably. So, in patients who came with no
neuropathy, we don't see that high a proportion
going to Grade 3.
I can also share with you the perspective
of if we go to, again in the primary, it is just a
couple of slides further, Slide 75. I think this
is the data that you were referring to--Slide 74, I
am sorry, my eyes are not good.
It is correct to say that a third of the
patients on this study got to Grade 3 or 4
neuropathy, and mostly Grade 3, but as I mentioned
earlier, the withdrawal rate due to neuropathy was
only 13 percent, therefore, Grade 3 neuropathy was
not a reason to stop treating in many patients.
I do have some additional data if you
would like to know what happened to these 37
patients, what the treatment decisions were. Would
318
you be interested in that? Okay.
If we go to Slide 739, please, in the
backups. This is now going to summarize all 37
patients who ended up with a Grade 3 or 4
neuropathy on study.
The first point is that 10 of those
patients had a simultaneous declaration of
progressive disease, therefore, there was no
further treatment decision to be made for those
patients.
So, of the 27 remaining patients, 11
withdrew for neuropathy or withdrew consent, so to
be conservative, we are taking the 7 and the 4, and
saying 11 patients probably withdrew due to
neuropathy, but 16 patients continued with VSLI
therapy. So, just over half of them chose to
continue despite getting to a Grade 3.
The next slide, 740, please. This shows
you for those patients who continued, for the 16
patients, 8 of them had 1 additional dose, and I
have a footnote here to say why did they stop, it
is not because they weren't tolerating it again, it
319
is because 7 of them had progressive disease after
the next cycle.
So, the reason to stop treating in this
study was almost always disease progression. There
are patients who were at Grade 3, but continued,
got 3 or 4 more additional cycles.
So, we conclude that although we did want
to present the total Grade 3/4 neuropathy as being
clinically important, it did not always trigger a
decision to stop treating.
DR. MARTINO: Dr. Wilson.
DR. WILSON: I would like to get some
better idea about how the patients were evaluated.
Of course, PR and CR per se, In the absence of a
meaningful length, is not really worth much. The
overall length of response is somewhere in the
3-month arena.
What did the protocol state in terms of
how often patients had CT scans done? The
documentation says that CTs were required on study
every 4 weeks, but in those patients in whom
therapy was actually stopped, were CT scans also
320
done every 4 weeks, and for those who didn't have
it done every 4 weeks, was this factored in, and
were those patients censored?
MS. MANCINI: Thank you for that question.
That gives me an opportunity to clarify a point in
that in our duration of response analysis, if I
could just have Slide 266, please, just to
demonstrate this point.
The duration of response was calculated in
a classic manner in our study. Start of treatment
is over here on the left, and then the first formal
evaluation of response was after about 6 to 8 weeks
on study.
Then, response was considered to be
continuing until you either had documented
progression or you were lost to follow-up, the
patient was lost to follow-up while still in
response. This happened very seldom.
So, if a patient stopped being treated in
here because of neuropathy, that did not matter.
We continued gathering the CTs. Now, the schedule
for CTs was originally every 8 weeks in the
321
protocol. We then amended it after about half of
the patients had been enrolled to say after the
first evidence of response, please get another set
of CTs 4 weeks later, and then we are back to the
every 8-week schedule.
DR. WILSON: So, I think it is fair to
say that with a median of approximately 3 months,
that many of these patients, if you were only
obtaining scans every 8 weeks, the true median, had
you been doing it on a more frequent basis, might
have even been shorter?
MS. MANCINI: I will ask Dr. Cabanillas to
comment on that in a moment. Many of the
progressions were declared based on the clinical
evidence. We had physical examinations, clinical
visits every 2 weeks on the study.
DR. CABANILLAS: I would like to also show
the Kaplan-Meier curve, Slide No. 270, please,
because it is true that many of these responses
were short, but as you will see from this slide,
those are these patients that relapse early, but
there are a number of patients that actually did
322
enjoy longer disease-free survival.
This is an IRP review. The IRP met at one
point, and they don't keep on meeting to update the
curve, so we don't have obviously a prolonged
duration here, but we do have some patients, and I
mentioned a few of them, and we have some that are
here today that will also show you that they were
actually some of these patients that had very long
remissions.
So, it is true, that if you look at these
patients that they had short remissions, but we
also have to keep in mind the other side of the
coin, which are the ones that did have long
remissions.
The other point that I would like to make
is that, as you know, Wyndam, there has been some
controversy regarding the use of CT scans in
lymphoma, and there is one study in which 39
patients were evaluated with the CT scans to
determine whether they relapse or not. Actually,
those were 39 patients who relapsed, I am sorry,
those were 39 patients who relapsed, and only 2 of
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them were picked up by CTs, by routine CTs.
Most of them were picked up because the
patients developed symptoms or the LDH went up, or
physical examination showed the abnormality, so
even though intuitively, you might think that, yes,
doing more frequency, these might have detected
earlier relapses, I think that in real life, that
is not really what is happening.
DR. PAZDUR: Fernando, could you put that
slide back up, and tell us how many patients were
censored there or still on study?
MS. MANCINI: Yes, that's Slide 270. This
is the IRP analysis, and the circles are the
censored data. In the IRP analysis, there were
two-thirds of the patients as Maitreyee presented.
DR. PAZDUR: Two-thirds were censored.
MS. MANCINI: In this analysis, yes.
DR. PAZDUR: And did the rest progress?
MS. MANCINI: Yes, or continued.
DR. PAZDUR: How many continued?
MS. MANCINI: I am sorry, I am saying it
the wrong way, excuse me. Censored is continuing,
324
the response is continuing at the last time that
they were evaluated. When they are censored, there
is no data for the patient beyond that point, but
they have not been called a failure, they have not
been called a progression.
DR. WILLIAMS: But many of those patients
will never get another evaluation, right?
MS. MANCINI: That's correct.
DR. WILLIAMS: How many patients actually
still are on study and could contribute to ongoing
data versus how many are censored because of
neuropathy, or they went off study, et cetera?
MS. MANCINI: This is an Independent
Review Panel determination. The study is over, so
there is no further data coming, but I can show you
Slide 275, please. Because we have continued to
follow, as part of the survival update, those
patients who were still in response, and the reason
the other curve had this line here was because of
the censoring, we all understand that.
This is now the investigator duration of
response, which again the median was not different,
325
but you do see that there were some patients that
had longer durations.
DR. MARTINO: Dr. Perry.
DR. PERRY: This is for the sponsor. I am
just sort of a country doctor who doesn't do a lot
of lymphomas, but it seems to me that this turbo
vincristine is not going to be fairly compared
against a lot of other agents.
What happens if you go back and look at
vincristine itself, what kinds of responses do we
see in duration of responses if we go back to, say,
how in 1972, I think that is the kind of comparison
I would like to see. I think you are making a bad
comparison for yourself if you are not going back
to the original, because I can't imagine this drug
is going to have, from what you presented, is going
to have much of an impact as a single agent. It is
going to be used in combination to replace
vincristine.
So, if that is the case, does it do
compared to vincristine?
MS. MANCINI: That is very difficult to
326
do. The vincristine is a very old drug and the
literature from that time does not provide us the
data we would need to be comparing durations of
response.
Even the types of disease, as it is
described back in the 1960s, it is impossible to
compare to some of that old work. We have been
able to compare on a safety basis better, but not
very well on the efficacy basis.
We do have perspective, there was work
done in the early days by Dr. Don Jackson with
infusional vincristine, attempting to achieve what
we achieve with the liposome in terms of the
continued exposure, and we certainly can compare
our information to that. I will ask Dr. Cabanillas
to do that. There is no good efficacy comparison,
unfortunately.
DR. CABANILLAS: While you find it, let me
introduce a topic. Dr. Jackson made a study with
infusion of vincristine as a single agent a long
time ago, and he had some interesting findings.
He treated 25 patients with a variety of
327
NHL types. He used a 5-day continuous infusion at
0.25/m 2 after a bolus of 0.5,
and he repeated the
courses every 3 weeks.
The interesting thing is that he had 48
percent neurotoxicity, and the GI toxicity was the
most serious toxicity, which included severe ileus.
Hematological toxicity was minimal. Of course,
during those days, there were not too many agents
that you could offer to the patients, so many of
these patients were actually being treated at first
relapse, so it is not strictly comparable to what
we are showing. We are showing really 4th and 5th
line treatment.
He showed that there was an ability to
deliver high cumulative dose of vincristine with
the low GI toxicity with VSLI. That's his
impression when we showed him our data, and he
thought that the absence of ileus was highly
unusual because that was a very common complication
when he used the high dose infusion of vincristine.
Also, the ability to proceed to transplant
following monotherapy, he found also to be highly
328
unusual.
Now, I think that is a very important
question.
DR. PERRY: Slide 805, response rate.
DR. CABANILLAS: That is the problem. The
response rate, it's a mixture of different
histologies treated at first relapse, so it is
really impossible to compare with ours.
Do you remember exactly what the response
rate was?
MS. MANCINI: It is not literature that we
can compare on efficacy other than we did meet with
him to get his own impressions, and that is what we
are sharing with you here.
I think the best data that we can share,
that is the only data that we can share that is
head to head comparison, is actually preclinical
data. There is no efficacy publications of
singe-agent vincristine. It is always used in
combination.
If you would like we can show you some
preclinical data.
329
DR. MARTINO: Is there someone in the
Committee who actually has the answer to that
question?
DR. WILSON: Actually, they are right that
it was a mixed group, but keep in mind, at least
for the intent-to-treat study here, it was a mixed
group, as well. I believe one-quarter of the
patients were not felt to have a de novo large cell
or a transformed large cell.
If I recall that paper right, the response
rate was around 30 percent, and I also want to say
that one of the things that he did in that paper
was to take patients who he considered to be a
failure using bolus vincristine, and I just want to
reiterate that I think the patient population in
the study was very, very different from what we are
dealing with here, but I do think that it did give
the first hint early on that perhaps changing
exposure schedule may give you a better therapy.
DR. MARTINO: Thank you.
DR. CHESON: We just got the Jackson
abstract up.
330
MS. MANCINI: Thank you.
DR. CHESON: Nodular PL, diffuse
histiocytic, duration of response up to 16.4
months, median 4.4. Complete response and
histiocytic lymphoma and partial in 8 patients, so
9 out of 25 responded, 36 percent. You said 30, I
was over saying 40, so 40 percent response rate
lasting a median of 4.4 months with a variety of
histologies including diffuse large B-cell, diffuse
mixed, diffuse everything.
MS. MANCINI: Did they comment on other
significant predictors of the number of prior
therapies they have had or refractoriness of the
disease?
DR. CHESON: This is just the abstract.
All had received prior vincristine by conventional
bolus. It doesn't say.
MS. MANCINI: That is the difficulty we
have with interpreting the data. In our own
analyses, these were very significant predictors of
outcome, and therefore, it is very hard, as we have
all seen, it is very hard to compare to the
331
literature.
DR. CHESON: But even your best patient
group, it was only around the same response rate.
DR. CABANILLAS: It was 46 percent
response rate on patients treated after second
relapse. These are not first relapse patients.
The minimum acceptable for this study, the VSLI,
was that the patient had to have at least 2
relapses, so these are not really comparable, but
the 46 percent, I think actually compares favorably
with anything in the literature including Rituxan.
I think that it is important to point out
that vincristine is a cell-cycle activation as you
all know, and that is why, even after long exposure
to vincristine, it might actually result in a
higher response rate.
I think that might also explain why
Jackson's results are somewhat better than you
would expect, and also the fact that some patients
were refractory to vincristine, responded to it,
and I think that is what we are seeing also. We
had some patients that were clearly refractory to
332
CHOP, and yet they were able to go on to respond
even, some even with a complete remission.
DR. MARTINO: Thank you.
Dr. Brawley, do you still have a question?
DR. BRAWLEY: Yes. Again, at risk of
being politically incorrect, and without making any
allegations against anyone, would the academic
presenters be willing to disclose any potential
interest they might have in the company including
such things as stock ownership, honoraria, or are
they salaried by the company?
I am also interested in did the company
salary the investigators at the various sites that
put people onto the trial.
DR. CABANILLAS: I think that is actually
a very politically correct question. Let me
explain my interest in the company. When we did
the Phase IIa study at M.D. Anderson, Dr. Ceres
[ph] was the PI on that study, and he realized that
being able to give the drug every 2 weeks at a high
dose constituted a novel way of delivery
vincristine, so in the name, representing M.D.
333
Anderson, he applied for a use patent, which has
been issued to M.D. Anderson, and which we will
also share with M.D. Anderson. I am not a salaried
employee of the company, and, of course, I do
charge consulting fees.
MS. MANCINI: None of the investigators on
our trials are salaried.
DR. CHESON: You don't know about stock
ownership, I suspect.
DR. CABANILLAS: I don't have any stocks,
and I don't have any stock options either.
MS. MANCINI: Inex is a small
pharmaceutical company in Canada. We are not
traded in the U.S. We are on the Canadian stock
exchange, Toronto stock exchange, and people are
free to buy stock if they wish. We do not track
their participation in the Canadian market.
DR. PAZDUR: I would just like to
stipulate that submitted to the IND was the
financial disclosure, which did list Dr. Ceres and
Dr. Cabanillas, I think it was that the patent was
going to be allowed, or something like this, plus
334
the royalties to be paid to M.D. Anderson.
We did go back and check the informed
consent at M.D. Anderson, and it did, in our
estimation, provide adequate explanation and
adequate patient protection to the patients that
were enrolled on the study.
DR. MARTINO: Thank you.
Dr. Reaman.
DR. REAMAN: I just have a question about
the retrospective histopathology review. You cite
the incidence of ineligible patients, about 19 or
20 percent, to be similar to previously reported
studies, some of which were actually done 12, 20
years ago, none of which looked to demonstrate
efficacy of a single agent in a specific disease.
Can you explain why the retrospective
review was performed and why those ineligible
patients were then included?
MS. MANCINI: Yes, I will begin briefly
and then I would like to ask Dr. Gascoyne to
comment on what is the current finding in lymphoma.
Just to begin, why did we include a
335
retrospective review. We understood that getting a
correct histologic diagnosis in clinical practice,
in routine clinical practice, it is difficult to
get right, and Dr. Gascoyne will speak to that more
eloquently than I can.
Therefore, we built into the protocol that
there would be a retrospective review. It was not
the basis for allowing a patient to be enrolled
because we could not get a real-time pathology
assessment. This was an international trial. So,
we use the site pathology to allow patients to be
enrolled, and they were allowed to be treated.
Even if they were subsequently determined to be
histologically ineligible, we did not withhold
treatment for them.
I should also comment that all of the
patients were considered to be histologically
eligible by the treating sites, so what we are
dealing with here is the current situation
lymphoma, and I would like to ask Dr. Gascoyne to
comment further.
DR. GASCOYNE: The first comment I would
336
make is I am slightly biased, because as a
pathologist, and someone who has been doing
lymphoma for 20 years exclusively, I personally
think it all starts and end there with an accurate
diagnosis.
We spent the last 20 years trying to
determine that lymphoma is not one disease, it is
about 35 diseases, and I think to continue to mix
apples and oranges in any kind of trial is a
mistake. So, I quite frankly applaud them for
asking us to be involved in a study where we review
the pathology.
I think the issue of path exclusion speaks
to an issue that is even bigger than this trial,
and it is a problem with what is going on out there
in the community and the acceptance of expertise.
So, I think all of these things need to be
looked at. We excluded cases that we felt were
low-grade lymphoma, and I could sit up here and go
through the reasons why that occurs. I noticed
that the FDA was not willing to accept 7 cases that
we have looked at very seriously, and I will tell
337
you that in current trials, I am currently, and
have been for 5 years, the co-chair of the Eastern
Cooperative Oncology Group from the point of view
of lymphoma although I am a Canadian who lives on
the West Coast, which is a bit of a funny mix.
The kind of criteria we apply to those
ongoing current types of trials are what we applied
here. So, I don't think we were any more or less
rigorous as we applied those criteria. The cases
that we accepted were based on FNAs and needle core
biopsies, follow-up biopsies, but you have to
remember that those were not diagnostic biopsies in
patients with newly diagnosed lymphoma.
We are talking about patients in a
multiply relapse setting. To even get a few cells
at the end of a fine need aspirate is lucky. We
use that information in combination with growth
fraction and other types of ancillary studies in
order to arrive at a diagnosis.
Do I have confidence in those 7 patients
that you decided to exclude, that we left in, the
answer is yes, I would confidently stand here or
338
anywhere else and say that those patients deserved
to be in the trial, and to have been included as
being consistent with the aggressive histology
lymphoma.
DR. WILLIAMS: Can I just ask why you used
the word "probably" then instead of "definitely?"
DR. GASCOYNE: Because in studies like
that, we don't have architecture basically, so you
are talking about cytological detail, and when we
had to combine that, a few of those cases, if you
go back and look on the additional data, we went
back and were able to actually retrieve the
original pathology.
So, they didn't look like discordant even
based on an aspirate, and thus we re-reviewed some
of those diagnoses. I remember one of the cases in
particular we had said it's a needle, it's kind of
crushed, it is hard to interpret, but it was
accompanied by a growth fraction of 80 percent.
When we got the older pathology and there was
primary mediastinal large B cell lymphoma, we were
willing to accept that, in fact, that represented
339
aggressive disease.
That is not what I would call out of line
with current practice. In fact, those kind of
techniques are being used much more frequently here
in the United States than they are in the country
that I come from.
DR. MARTINO: Dr. Cheson.
DR. CHESON: Well, now that I am on, I
have got two questions, one for Randy. So, you
used other than morphology and growth fraction, I
presume. You immunophenotyping and all that stuff,
as well.
DR. GASCOYNE: In the actual diagnoses, we
had information that came from the hospital of
origin, so what we were trying to determine was
their eligibility as aggressive lymphoma, so in
many of the instances, of course, we had phenotype
available, either flow cytometric or paraffin
section immunostains.
But the particular example I was citing,
we actually were aware that there was a growth
fraction, and that was provided in terms of a Ki-67
340
stain. That was labeling at 80 percent. That is
not the labeling presented that one sees in
so-called indolent lymphoma, and I think most
people in practice nowadays would accept that as a
reasonable conclusion based on that material, that
that, in fact, was aggressive lymphoma.
But the ability or the desire here to use
fine needle aspiration and needle core biopsies, as
you know, is a serious matter, but you have to keep
it in the context that we are not dealing with
diagnostic biopsies, where it also is used far too
frequently.
DR. CHESON: My other question is more for
the sponsor, and I guess I can guess what the
answer is. Do you have any information on whether
these patients were treated with other things after
liposomal vincristine and what the responses were
to subsequent therapies, and what these other
therapies were?
MS. MANCINI: No, unfortunately, once they
were off study, we don't have the downstream
therapy. We do know of those 6 cases that went on
341
to stem cell transplant, we do know the outcome for
those patients, and that is what Dr. Cabanillas has
presented.
We collected that data as part of the
survival update, but we do not have all the other
therapies.
DR. MARTINO: Dr. Bishop.
DR. BISHOP: Related to what your last
statement was, the stem cell transplant patients,
and going back to your time to progression slide,
am I correct that there are only 5 patients on that
slide who were greater than 4 months time to
progression?
MS. MANCINI: No, no, there is more than
5.
DR. BISHOP: Those were just the censored.
MS. MANCINI: Those were censored, yes,
there is definitely more. The line was flat at
about 50 percent. We were right at the median
there.
DR. BISHOP: So, you are estimating about
10 patients?
342
MS. MANCINI: Fifteen.
DR. BISHOP: Among those, does that
include the transplant patients?
MS. MANCINI: Transplant patients would
have been censored in that analysis at the time
they went to transplant.
DR. MARTINO: Dr. Wilson.
DR. WILSON: This is a question for both
Randy, as well as the sponsor. It is a little
unusual, in my experience, to do an intent-to-treat
for a Phase II study. A number of cooperative
group studies were shown in which it was shown that
only 80 percent of the patients were eligible based
on histology, and yet when those Phase II studies
are usually published, those 20 percent are
actually not included, so I wasn't quite sure why
that was done like that.
But specifically, Randy, I, too, feel that
we shouldn't be fixing apples and oranges, and I
think that the response to an agent like this, in a
low grade lymphoma, is going to be very different
from a de novo large cell.
343
I guess my question is, number one, do you
really think it is fair to be mixing de novo large
cell with those patients who have histologically
transformed low grade, both, number one, because
the biology of the histologically transformed is
very, very different.
Even though it may look like a high grade
lymphoma, it certainly may not clinically act like
one, and finally, you have some nodes that are low
grade and some that are high grade, so it is very
difficult to know if it's a low grade node
shrinking or the high grade.
DR. GASCOYNE: I can address the last part
of the question. I mean you certainly know
yourself that when you are treating patients and
one site blows up, it wouldn't be uncommon for you
to do a needle aspirate or a needle core at that
site, and make a determination that that previous
lymphoma has, in fact, transformed. We don't
biopsy all the sites and all the patients.
From the old data from the seventies, from
the stage and laparotomy data that came out of
344
Stanford and other centers, we know that there are
discordant histologies. I would agree with you
those biologies are different.
I wasn't involved in the design of that
part of the study. I was simply asked to apply
vigorous criteria to a histologic central path
review and deem which patients were eligible based
on the criteria.
I think we applied that in a uniform way,
the same way I do for ECOG and the same way I do
for British Columbia, and so I don't have any
problem, and I am feeling comfortable about those
data.
DR. WILSON: So when you did score
somebody as a histologically transformed low grade,
they would have been essentially what we now term
as follicular Grade 3B?
DR. GASCOYNE: No. We tried to determine
in any setting in which we had tissue, of course,
we wanted to know architecture, so we wouldn't have
accepted that as transformation, and specifically
that is in the protocol that actually Grade 3B
345
would not have been included.
So, these are patients that we had to have
evidence that they were diffuse large B. It is
quite true that there were some fine needle
aspirates and some needle cores in there, in which
we attempt in some situations to actually do some
additional immunostains in the way of looking at
FTCs, et cetera, to know whether there is any
underlying follicular elements.
So, I am happy that those cases that we
looked at, particularly in regards to looking at if
they are only cytologies, looking a proliferation
rate, that I don't think Grade 3B is associated
with an 80 percent proliferation site, so I think
we can feel relatively comfortable that those were
probably cases of diffuse large B cell lymphoma
that represented transformations.
DR. CABANILLAS: I want to make a comment
regarding your question also, Wyndam, because you
are absolutely right, that the low grade or
indolent lymphomas respond differently to VSLI, but
the way they respond differently is they respond
346
less well because when we did the Phase IIa study
at M.D. Anderson, we found out rapidly that the low
grades were not really responding well, and that is
the reason why the next trial was done exclusively
with aggressive lymphomas.
It makes sense from a scientific
standpoint you would expect that they would respond
lower, because their S phase is lower, so they are
turning over less rapidly and exposing them to a
long duration of concentration of VSLI might not
really make any difference.
DR. WILSON: So, that would be consistent
with the Taxol data, as well, where it is also
hitting the microtubules where the higher grades
seem to do better with it.
MS. MANCINI: I would like to add just to
clarify, you asked a question about the
intent-to-treat analysis and why we presented that,
and if I could go to Slide 429, please. I would
like to also, while we are pulling up that slide,
comment that we did look specifically in response
to a question from FDA at the discordant lymphoma
347
cases where they had a mixed presentation to see if
we could conclude which parts, which types of
histologies were responding, and it was always
clear-cut. The patient either didn't respond and
therefore it was not an issue, or it was such a
dramatic response that all of the disease was
responding consistently.
This slide shows you, on the far right,
was the intent-to-treat analysis that was in the
main presentation. This now shows the per-protocol
population, and the ORR is the 27 percent, which is
very similar to the ITT.
Now, if we talk about those patients who
were histologically ineligible, based on Randy's
review, it was 23 cases, the response rate was
still the same in this trial. People who were
excluded from our per-protocol population for other
reasons had a slightly lower response rate.
Open Public Hearing
DR. MARTINO: Are there other questions?
If not, we will move on to the next part of the
program, which is the open public hearing. Before
348
we do that, I need to read a statement.
Both the Food and Drug Administration and
the public believe in a transparent process for
information gathering and decisionmaking. To
ensure such transparency at the open public hearing
session of this Advisory Committee meeting, the FDA
believes that it is important to understand the
context of an individual's presentation.
For this reason, the FDA encourages you,
the open public hearing speaker, at the beginning
of your written or oral statement to advise the
Committee of any financial relationship that you
may have had with the sponsor, with its product,
and, if known, its direct competitors.
For example, this financial information
may include the sponsor's payment of your travel,
lodging, or other expenses in connection with your
attendance at today's meeting.
Likewise, the FDA encourages you at the
beginning of your statement to advise the Committee
if you do not have any such financial relationship.
If you choose not to address this issue of
349
financial relationship at the beginning of your
statement, it will not preclude you from speaking.
Ms. Clifford will now announce the ladies
and gentlemen who have asked to speak.
MS. CLIFFORD: When I call your name, if
you would please approach the microphone in the
back in the audience, please.
Our first speaker is Helen Smith.
MS. SMITH: Good afternoon. My name is
Helen Smith from Greenbrae, California near San
Francisco.
I would like to thank you for the
opportunity to speak at this meeting. I would also
like to thank Inex Pharmaceuticals for covering my
costs to attend this meeting.
I am a patient of Dr. Jennifer Lucas,
Merin [ph] Oncology where I am being followed for
my non-Hodgkin's lymphoma. I was diagnosed with
non-Hodgkin's lymphoma in 1999. I remember it was
in June when I first noticed I became tired very
easily. I was usually very active.
After my diagnosis in December '99, I
350
participated in a cancer vaccine that was being
conducted by Dr. Levy at Stanford University
Medical Institute. They took one of my lymph nodes
to make the vaccine and then I started a course of
CHOP.
At the end of CHOP, I was given the
vaccine. My cancer did not completely go away.
Later, I had a second round of CHOP. The CHOP did
not make me sick, but I did lose my hair and wore a
wig for a while and felt very tired.
They also gave me medicine to prevent my
blood count from going too low. My CT scans
indicated that I had a lymphoma in my chest and in
October of 2001, I agreed to begin the trial with
VSLI.
I was treated with VSLI during the first
part of 2002. I had 8 cycles of treatment and
during my first treatment I had a fever, but after
that I was fine for the later injections. I did
get some tingling in my fingers and numbness in my
feet, and had difficulty with buttons.
Today, two and a half years later, I am
351
functioning quite well, although I do get tired
easily. I have not had any more cancer treatment.
I have not missed any of my tenpin bowling
sessions, and I use a heavy 14-pound ball, so my
fingers are fine. My only problem is my bowling
average has fallen from 150 to 121.
Thank you.
DR. MARTINO: Thank you.
Next, please.
MS. CLIFFORD: Our next speaker is
Virginia McCormick.
MS. McCORMICK: Good afternoon. My name
is Virginia McCormick and I am from Sparta,
Tennessee, and I think you for the opportunity to
speak at this meeting today. I thank Inex
Pharmaceuticals for covering my costs to attend
this meeting and for all the help that they have
given me.
I am a patient of Dr. Deng [ph] at the
M.D. Anderson Cancer Center in Houston, Texas,
where I am followed for my non-Hodgkin's lymphoma.
Let me begin by telling you that I was
352
diagnosed with non-Hodgkin's lymphoma in 1999. The
first year I took CHOP. The chemo made me weak and
nauseous at time, and, of course, I lost my hair.
This took several months because most of the time
my white cells would get too low and they couldn't
do the chemo, and I would have to go back home and
wait a week and then go back.
When I finally finished the treatment,
this was about six months later, the lymphoma had
returned, and I took other treatment, such as
Rituskin [ph], and this didn't work. During this
time, I had several bone marrow biopsies to see if
it had spread to my bones, and I was thankful that
it had not.
At this point, they wanted to do a bone
marrow stem cell transplant using my own cells, and
my stem cells were harvested and frozen, and I went
into the hospital, and for the first week I took
high-dose chemo and then they gave me my stem cells
back. Again, I was very weak and sick at times.
I was in the hospital for over a month and
within a few months after this, the lymphoma was
353
back again. I asked my doctors if there was
anything else that could be done there. I was told
that it would be too dangerous to do further
treatment because it could do some damage to my
main organs or possibly death.
At this time, my husband and I decided to
go to M.D. Anderson Cancer Center in Houston,
Texas. We just refused to accept the alternative.
At M.D. Anderson, my doctor, Richard Champlin [ph]
told me I could do a bone marrow transplant using a
donor.
So, I asked what my options were, and he
told me that they were having 30 percent survival
rate. So, I told him this was better than what I
had, because I didn't have any.
So, out of 6 of the blood donors, half of
them were a perfect match. So, Dr. Champlin
introduced me to Dr. Deng, who gave me a new
treatment, an anticancer drug called liposomal
vincristine or VSLI. This helped me a great deal
and I was able to receive my bone marrow
transplant.
354
The VSLI was an easy treatment for me to
take. I went into the hospital for one-hour
treatments, which they would watch me for a couple
hours afterwards, and then I could leave the
hospital.
The VSLI made my fingertips numb and the
bottom of my feet were numb, but my hands are okay
now, and my feel are getting better. The VSLI,
with it, I didn't feel weak or sick or anything,
and my hair didn't come out. Since this treatment,
I feel normal again, I feel better than I have in 6
years.
I can go to church, I sing in the choir.
I do my own shopping, and I play with my first
little grandson, who is 3 years old, and which I
might not have been able to do if it had not been
for VSLI.
When I was asked by Dr. Deng if I would be
interested in going to Washington, D.C. to speak at
this meeting, I thought, wow, this is an
opportunity of a lifetime to help so many people,
like it has helped me.
355
So, I am a living example that VSLI does
work and I just praise God that I have been
cancer-free for over two and a half years.
Thank you.
DR. MARTINO: Thank you.
Our next speaker, please.
MS. CLIFFORD: Barbara Cruse.
MS. CRUSE: Hi. My name is Barbara Cruse
and I live in Sugarland, Texas, outside of Houston.
I would like to thank Inex for inviting me
to speak at this meeting, and they have covered our
expenses to be able to come.
My cancer journey began in June of 1997
when I found a lump. I was diagnosed with Stage I
large B cell aggressive lymphoma. I had surgery to
remove the tumor, then 6 rounds of CHOP and 25
treatments of radiation.
On Christmas Eve 1999, my doctor told me
that I had a recurrence of the lymphoma. in
January of 2000, I began treatment at M.D. Anderson
Hospital for the lymphoma preparing for a bone
marrow stem cell transplant using my own stem
356
cells.
I received 3 rounds of chemotherapy
preparing to rid my body of the lymphoma. I was
admitted into the hospital in May for 7 days of
intense chemotherapy to prepare for my transplant.
I spent 5 and a half weeks in the hospital.
Fifteen months later I had a relapse
again. Dr. Fayad, my lymphoma doctor, at M.D.
Anderson was researching an exciting new trial,
which was the VSLI Phase II clinical trial. I was
accepted into the trial and began treatment in
September.
The treatments were done in an infusion
suite at the hospital and lasted 4 hours per
session. I had no side effects during the first 3
treatments. The good news, after 4 treatments, I
was restaged and I had a 96 percent reduction of my
tumor. The bad news, severe neuropathy in my hands
and feet.
In November I had 2 more treatments
preparing me for my second bone marrow stem cell
transplant using my brother's stem cells. I was
357
admitted to the hospital on December 13th and
received 3 days of chemo and then had my
transplant. I did so well with this transplant
that in two and a half weeks, I was released from
the hospital.
As I mentioned earlier, the down side of
the VSLI is the neuropathy. I was not able to
drive for a year and I needed help with daily
activities. I had an EMG to determine how much
nerve damage I had and to see if there was anything
that could be done to help me.
There is no drug that works for
neuropathy. I was told that all the previous
chemotherapy treatments that I had had, had
contributed to my neuropathy.
Finally, in March of this year, I began
going to a doctor and receiving acupuncture of the
neuropathy, which I have seen remarkable
improvement. This summer when I had my checkup
with Dr. DeLema, my bone marrow doctor, we talked
about my treatment options and if I had it to do
over, would I choose the VSLI, and I told him
358
honestly yes, I would choose it even with the
neuropathy.
In my cancer journey, I am one of the
lucky patients who survived with the help of this
very important drug VSLI. Thank you for this
opportunity to share my story.
DR. MARTINO: Thank you.
Are there any final questions from the
panel to either the FDA or the sponsor?
Seeing none, I would like to ask Dr.
Pazdur, do you mind if I give the group a 5-minute
break only, because Dr. Martino needs one? Thank
you. It is 5 minutes, however, ladies and
gentlemen.
[Break.]
Committee Discussion
DR. MARTINO: The final portion of this
meeting is the discussion of the Committee itself,
and that needs to be focused to questions that have
been posed to the Committee from the FDA that
relates to this application.
We have four questions, each of which will
359
require a vote at the end of the discussion that
pertains to the specific question. When we vote, I
will ask each of you to state your name as well as
your vote each time, please.
The first question I will read to you.
Review of the oncology literature suggests
that there are single agents and multiple agent
therapies capable of producing substantial response
rates, including reasonable CR rates, in relapsed,
aggressive non-Hodgkin's lymphoma.
Does the Committee believe that these
therapies constitute available therapy for
relapsed, aggressive non-Hodgkin's lymphoma
previously treated with at least two combination
chemotherapy regimens?
Dr. Cheson, I am going to ask you actually
if you would speak to this issue. Are there prior
therapies, either single-agent or multiple-agent,
that you feel would be an alternative?
DR. CHESON: As you know and as was shown,
there are very few drugs that have been recently
approved for the treatment of lymphoma, but there
360
are a whole bunch of other drugs out there, which
are used regularly in a variety of histologies of
lymphoma, some which have been around for a long
time and others which are relatively new.
I think that there are clearly a variety
of other single agent--it depends on whether you go
along with the company's date or the Agency's
assessment of the data, but there are quite a
number of other drugs out there that can give you
response rates in the range of 30 percent or so
lasting three or so months, be it etoposide, be it
gallium nitrate, be it a variety of other drugs.
There are some new drugs out there. Even
the radioimmunotherapeutics, since there are two, I
won't go and mention any names, there is only one
that has been used for aggressive lymphoma, and
that has been associated with a 43 percent response
rate in patients who have failed a median of two to
three prior regimens.
So, yes, there are a number of other
agents out there with different safety profiles,
some which appear to be, you know, like the
361
radioimmunotherapeutics have more marrow
suppression, don't have neuropathy, so they are
limited, but there are other drugs out there, and
it is quite a list of them that can give you 20 to
30 percent response rates.
DR. MARTINO: Are there other thoughts on
this issue? Are there alternative therapies for
these patients, and might those alternatives
constitute a control against which a randomized
trial might be done?
Dr. Wilson, do you want to speak to that,
please.
DR. WILSON: Well, I guess I would just
reiterate what Bruce said, that is that there
really is a list of agents out there, both in this
range. I think it important to note that the
population of patients has a huge impact.
I think we all know that. I do laud the
group for having broken the patients down, but as
it stands, the response rate of this drug seems
very much in the middle of the pack for many other
agents.
362
In terms of what would you compare this
to, I think there are numbers of agents you could,
and I guess I would like to think about that before
commenting on how to do a comparative study.
DR. MARTINO: Do you feel that, in fact,
if you were asked to choose a comparator, that you
could come up with one? I am not asking you to
tell me your choice, I simply want an answer to
whether you think that you could.
DR. WILSON: Well, if you wanted to come
up with a single agent, I think the answer is yes.
I think that, as Bruce points out, there are agents
with different toxicity profiles. I think one drug
that comes to mind that one could think about would
be etoposide.
The down side to that is that a
hematologic toxicity can be limiting for it, but I
think that if you didn't take tremendously
pretreated patients, that I don't think hematologic
toxicity would be limiting for it, and I think that
that would weigh off against the neurological
toxicity associated with a Vinca alkaloid.
363
DR. MARTINO: Dr. Pazdur, do you want to
comment?
DR. PAZDUR: One does not have to specify
a single drug here, and, in fact, as I stated in my
opening comments, there have been situations where
pharmaceutical sponsors have had varying
combinations or various drugs, and in a randomized
study, you could randomize to a treatment arm,
might have several treatments, kind of a treatment
de jure, as long as there were agreement by the
investigators that that was something that they
would consider a reliable and reputable treatment.
The stipulation is you would have to win
against that treatment arm.
DR. MARTINO: Are there other comments to
this question? If not, we will now turn to the
vote, and we will start with Bukowski on my right,
please. Please state your name and your vote, the
question being: Do we believe that there are
alternatives for this patient population?
DR. BUKOWSKI: So, the name is Bukowski,
and the answer is yes.
364
DR. CHESON: The answer is yes.
DR. BRAWLEY: Yes.
DR. REAMAN: Yes.
DR. MARTINO: Yes.
DR. MORTIMER: Yes.
DR. PERRY: Yes.
DR. HUSSAIN: Yes.
MS. HAYLOCK: Yes.
DR. GEORGE: Yes.
MS. KRIVACIC: Yes with a stipulation that
I don't know if there is potent, if you will, or I
guess show what has been shown here today, so there
is a lot of conflicting data between the FDA's
information and the sponsor's, so I am a bit
conflicted with this question, as well.
DR. BISHOP: Yes, with the stipulation I
can't think of an outstanding agent for patients
with a lack of hematologic reserve.
DR. WILSON: Yes.
DR. MARTINO: Our total is a unanimous
yes, although we have two members who have some
uncertainties.
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The second question is: Previously, the
Agency has stated that the primary relevant
endpoint for aggressive non-Hodgkin's lymphoma were
rate of durable complete response and survival.
Partial responses were not considered predictive of
clinical benefit.
In this setting of relapsed, aggressive
non-Hodgkin's lymphoma, does the Committee agree
that durable CR should generally be the primary
endpoint for approval?
So, the issue again is CR's versus PR's,
or lesser degrees of response.
I would like to hear some comments on this
question, please. Dr. Perry.
DR. PERRY: I think part of the problem
here is the definition of complete response. There
are complete responses and there are complete
responses. It depends on how far you want to go.
Do you do a warm autopsy to biopsy everything
within the abdomen or do you simply say a CT scan
is evidence enough, or a PET scan or a gallium
scan, and what number of biopsies and how many PCRs
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do you do.
Just saying "complete response" in these
days doesn't mean as much as it used to when we had
more primitive techniques and were smarter. We
knew much more than we do now.
So, I think there are partial responses
that are probably now the equivalent of old
complete responses, and I think some of them are
helpful.
DR. WILSON: I do think that PRs are a
relevant endpoint, but I think a PR in the absence
of a duration means little in a disease like this.
So, I know the question is written based on
previous ways in which this data was looked at, but
I think that a PR that lasts for a reasonable
length of time is a reasonable endpoint, but PR
alone, I do not.
DR. MARTINO: I share that feeling
completely. I don't think PR, in and of its own, I
mean a PR can be extremely fleeting and doesn't
always correlate with anything related to the
patient's behavior or the patient's well being. It
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is often an x-ray event and primarily makes the
doctor feel good to be able to talk into a room to
say you have a response, and then not have to do
much more than that.
So, I completely agree that the issue of
durability and/or reduction of symptoms probably
are much more meaningful events.
Dr. Cheson.
DR. CHESON: As we discussed in the
response criteria paper, PRs in the setting of
relapsed and refractory disease are interesting to
identify drugs with some activity to pursue
further, but in and of themselves, I agree with you
that unless they have some durability, they are
rather meaningless, and I guess Dr. Perry has
stepped out, but not only are all CR's not all
CR's, but with the advent of PET technology, for
example, a lot of PR's turn out to be CR's, so we
are getting more sensitive measures of this, but a
true PR in the relapsed, refractory setting
generally bodes ill, and probably wouldn't even be
transplanted by many centers, these with a good
368
conscience.
DR. MARTINO: Dr. Pazdur, did you want to
comment?
DR. PAZDUR: I just wanted to reiterate
something that Bruce said. Here again, we are not
talking about drug screening. We are talking about
drug approval, and these are not necessarily the
same thing or they should not be the same thing
obviously.
So, there has to be a different level that
one is saying that they are going to accept between
something that is of interest to take to another
step in another development, and then saying, well,
this drug is ready for prime time here for general
use with all of the ramifications that that has
associated with it.
DR. MARTINO: For me, this is really a
problem that I have with this entire accelerated
approval process. I have sat on this committee for
about three years now, and it almost occurs to me
that we are looking for what is the least amount of
data to be convincing, and I think that is the
369
wrong approach, but that is what I see that we do,
especially with accelerated approval, is what is
the least amount that you can show me, to which I
will then give you a reward for that.
I actually think that as a medical
community, we have to rethink what our objectives
are and what our purpose are. They should be much
grander than that, and I think you are either
trying to shut me up or you want to say something.
DR. PAZDUR: The only thing I have to say,
Silvana, is go, girl, go.
[Laughter.]
DR. MARTINO: But in all--
DR. PAZDUR: Let me finish my comment,
though. That was just starting there.
When we have a meeting, such as this, we
have a litany of sponsors that come in and pose the
question to us. What is the lowest response rate
that you will take? What is the fewest number of
patients that you will take? And, in fact, we
actually have a euphemism regarding these meetings,
and it is called the "How long can you go?"
370
I think that that really represents a
clarification, and this is one of the reasons why
we have been discussing this and emphasizing the
accelerated approval commitments that these
patients have.
The purpose of accelerated approval was
not accelerated drug company profits. It was
accelerated access to people that had desperate
illnesses, that needed the therapies, and we were
allowing basically a surrogate to be used to get
these therapies out early to these patients that
needed it.
It wasn't a license to do less, less,
less, and less to a point now that we may be
getting companies that are coming in, well, what is
the lowest. It shouldn't be what is the lowest.
It is what is a sufficient amount to give patients
and physicians a real understanding of what their
drug will do.
Granted, we realize that there is a need
to get these drugs out, but we also have to have a
data package that we can understand and will make
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labeling a strong process here. That is why our
commitment really is to get these trials ongoing,
these confirmatory trials, so it is very important
to us.
DR. MARTINO: The fear that I personally
have, as I have treated patients over the past 25
years, is that we, as a medical community, and that
"we" does include the pharmaceutical industry,
really in my observation have aimed for a lower and
lower behavior of drug, and in that process, if we
keep rewarding such behavior, we will see more and
more of it.
There is nothing new in the universe.
That is the way life works. So, we do have to
separate what our responsibilities are and to whom
are these responsibilities.
Dr. Bukowski.
DR. BUKOWSKI: When I think about this, I
think about the issue of unmet need as the main
factor that sort of leads me to think about how and
whether an agent should be considered for approval
in a particular area, and I think that to be
372
somewhat foremost in our minds.
I mean it may not be necessarily the issue
of how low can you go, but is there anything else
available in the area that can be utilized, and I
think that is very, very important, because
clearly, there are many situations where there are
unmet needs, where new agents may well have a very
minimal or modest response rate or modest activity,
but still these may be useful, and I think the
issue is, is getting those agents out to patients
in a very timely basis, with subsequently then
doing the appropriate studies to demonstrate the
clinical benefit associated with the agent.
DR. PAZDUR: Ron, that is specifically why
have the better than available therapy or an
improvement, or a situation where therapies do not
exist, but it has to be a real clinical situation,
it cannot be a contrived situation.
A couple of years ago we had a company
that wanted to develop a drug for leukemic patients
on a respirator, and the reason why patients were
on the respirator was because they received the
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drug on the NDA, which was kind of ridiculous.
So, it has to be a real situation, a
really clinically relevant situation, not a
contrived situation.
DR. MARTINO: Dr. Brawley.
DR. BRAWLEY: Dr. Martino and Dr. Pazdur
are to be praised for their speaking of truth this
afternoon. I just want to add one thing. When we
teach our graduate students the development of
drugs, we teach them things about like how one can
look at data and actually think there is benefit,
but when one probes further, one finds that there
is not a benefit to that drug, there is actually a
net harm to the drug, and this is actually
frequently the reason why we need randomized
clinical trials.
I personally have been burned by clinical
studies that ultimately showed that beta carotene
increased the risk of lung cancer in smokers, and
did not decrease it, and I was one of the people
who said it's just a vitamin, how can it be
harmful. There are numerous examples in the
374
medical literature.
Now, we have heard today from some
patients who told us about some significant
toxicities that they are living with, and now we
have to make a decision is this drug beneficial
given those significant toxicities, and I think we
have not heard about some significant toxicities.
I will finish by saying I am very worried,
while I look at the FDA data versus the company's
data, I am very worried, not that there were
individuals who called responses because they
wanted to make money, I am worried that there are
doctors out there who saw patients who called
responses because they really wanted to see
responses in their patient. They were hoping
against all hope that they could do best for their
patient, but we have to remember there are some
significant discrepancies in data here.
DR. WILSON: We are looking at No. 2, and
we are asking is a PR of a certain length a
reasonable endpoint, but I think we should all
recognize that this is a unique circumstance. This
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drug is known to be active. This is a drug that is
active, and the activity level is well within that
which has been seen before when it has been given
as either a single agent or as a continuous
infusion.
So, I think the bar is perhaps a little
bit even different than is it active. I think the
question is, is it active in a safer way, is it
active in a way that gives it significant additive
value.
DR. MARTINO: Other comments? Yes, Dr.
Hussain.
DR. HUSSAIN: It is just basically what
everybody said. I guess as doctors, you look at
things and you try to be objective, and to me,
objective with a patient benefit means you either
make them live longer or live better, and to look
at a scan, and a scan that goes down from a 6 cm
mass to a 3 cm mass, I would like to ask the
lymphoma doctors, has there been any precedent in
any drug, in lymphoma, in these kinds of settings
where a PR actually translated into a meaningful
376
thing as in patients, when tested prospectively, as
in patients living longer, quality of life
improved, or any direct benefit other than an image
benefit.
DR. CHESON: Well, there is that old
statistical conundrum of the
responder/nonresponder, and the CR's always do
better that the PR's, and the PR's always seem to
do better than the nonresponders. However, as we
all know, there are flaws in that sort of analysis.
Having some response confers some benefit,
but the magnitude of the response, you know, and it
depends what kind of response, was there associated
relieving of an obstruction, was there associated
decrease in symptoms going along with it, but as
you have said before, just shrinking something by
50 percent is not necessarily going to translate
into a meaningful clinical benefit unless there is
some durability of this and there is some
associated clinical benefit along with it.
DR. MARTINO: I think at this point I
would like to call the question to a vote. Again,
377
the important words to this question are does the
committee agree that a durable CR should generally
be the primary endpoint for approval, not PR, CR,
and the word durable.
We will start with Dr. Bukowski on my
right, please.
DR. BUKOWSKI: Yes.
DR. CHESON: Yes.
DR. BRAWLEY: Yes.
DR. REAMAN: Yes.
DR. MARTINO: Yes.
DR. MORTIMER: Yes.
DR. PERRY: Yes.
DR. HUSSAIN: Yes.
MS. HAYLOCK: Yes.
DR. GEORGE: Yes.
MS. KRIVACIC: No.
DR. BISHOP: Yes.
DR. WILSON: Yes.
DR. MARTINO: The total is 12 Yes, 1 No.
The next related question. Would high
rates of PR and long PR duration be reasonably
378
likely to predict clinical benefit, and thus
potentially support an accelerated application? If
so, please describe the PR rate and duration that
would be convincing.
Who would like to speak to that, please?
DR. CHESON: If I can reiterate something
I said before, about PR being a PR, we have a paper
in press in JCO in which we integrated PET scanning
into the International Workshop Criteria, and what
you see is that initially, there is a modest
difference--although this was in upfront patients
with large cell lymphoma--there was a modest
difference between the time to progression or
progression-free survival between the CR's and the
PR's.
Once you throw in PET scanning, the
difference becomes absolutely enormous, so it
depends how you measure these PR's. If you have a
PR that, indeed, is really a CR in disguise, then,
lo and behold, they are going to do quite well, and
so I think you have to look at this in the context
of what are you calling a PR, how are you defining
379
a PR, because that is going to make a big
difference.
DR. MARTINO: I personally would be leery
of answering the question with a number and a
duration, because I think the issue then, for me,
has to do what is the quality of life during that
time.
A PR that achieves improved quality of
life for some length of time is valuable, but it
would have to be accompanied by some true
measurement of quality of life for reduction in
symptoms. In and of its own, it would not impress
me very much.
DR. CHESON: And not just substitution of
one set of symptoms for another.
DR. PAZDUR: Perhaps this question is not
a voting question, but more of a discussion
question.
DR. REAMAN: I think the other discussion
issue is whether or not there are alternatives. I
mean if there are, in fact, other options, should
we really be discussing this in any great detail.
380
DR. BISHOP: The only thing I counter the
Chairperson's comments is that you can apply those
same criteria to a complete response. Yes, we
found that when you want to have a complete
response, and if you don't have quality of life and
everything else, then, should you count a complete
response that way, so I really don't think that is
a fair criteria.
I mean the only things that we have to go
on is improved survival, yes, we would all like
quality of life, but there is other things that as
we heard testify, that people are willing to live
with neuropathy, for one, and yet if that gives
them opportunity to be with family and friends, I
just don't think that is a fair criteria.
So, the duration is difficult to define,
but I don't think that is a fair criteria that you
have to have quality of life to go along with it.
DR. MARTINO: I think your point is
extremely well taken, and for me, what it reminds
me of is that even a CR may not be that meaningful,
which again gets to this issue of what is the point
381
of accelerated approval for me.
DR. PAZDUR: Here again, I think one of
the answers, and maybe when we wrote this question
it perhaps needed a bit of clarification, is there
any PR rate in duration that one would accept.
I think perhaps in this situation, one may
have to take a look at a randomized study if one is
even going to contemplate this, or is it a
situation, in a single-arm trial, that one would
accept a PR rate in a very refractory situation.
DR. WILSON: Without getting into numbers,
I mean I personally think yes, that there are
numbers of PR's, and there is durations that I
think would convince most people that that would be
accompanied by clinical benefit assuming that you
didn't have collection of quality of life issues.
So, I think the answer personally to No. 3
is yes, I think reasonable people can sit down and
hammer out where those numbers should lie. It is
probably beyond the scope of today.
DR. MARTINO: The problem that I see with
this is that when one looks at response rate, and
382
practically all tumors, what you primarily deal
with is PR, and CR rates are few and far between,
and that is a fact of life for all of us that deal
with oncology.
So, invariably, these applications do come
down to not arguing over is the CR rate high
enough, but rather it really comes down to the
issue of PR, whether we accept PR's as valuable or
not, because 90 percent of the time, that is
actually what you are getting pretty much in any
application that I have seen brought to this
committee.
DR. PERRY: Could I move we table the
question?
DR. MARTINO: Rick, are you comfortable
that you have heard enough?
DR. WILLIAMS: It is a basic question for
us, because we will have sponsors come to us, and
let's say there is no available therapy in a
situation, you know, the lymphoma situation, let's
say that is true, they will ask can we do a
single-arm study, and if we get a high enough
383
response rate, might we get accelerated approval.
Now, I don't have a sense. We have always
categorically said CR's are nothing, but we have
primarily been looking at tumors in an earlier
setting, we never really had this question, but now
we are getting the question a lot.
So, I think it is either the possibility,
as you suggest, Wyndam, I think that perhaps, I
mean you never know, a very high PR rate with a
long duration, it is conceivable, or perhaps it is
not, we will say what we have said in the past.
That is, you know, really I am going to
look at CR's, because you certainly can evaluate in
a single-arm study, the PR rate and the PR
duration, so there is no problem evaluating it, and
you may well say that this is way beyond what you
can do with anything out there, but the question is
do we think it is reasonably likely to predict
benefit. That is the essential question we would
have to ask.
DR. PERRY: I think the question differs
upon what tumor you are talking about. For
384
melanoma, we would take just about anything. For
Hodgkin's disease, we want very high standards
indeed. I think that is not a question we can
settle here this afternoon in this committee, at
this particular time, when we are trying to discuss
another drug. That is why I move to table, because,
as I understand it, it is not suitable for
discussion.
DR. PAZDUR: As far as endpoints, we will
be discussing endpoints in other meetings as far as
our ongoing endpoint project, we are going to be
having a hematology symposium on this perhaps this
year, so we will table that.
DR. MARTINO: Dr. Brawley.
DR. BRAWLEY: I would make a plea for PR
with quality of life criteria, and that probably
means that you are going to have to end up looking
at a randomized study, but if I were to see PR's
and better quality of life in a particular drug A
versus the leading drug in the treatment of that
disease, I would vote for it.
DR. MARTINO: Dr. Reaman.
385
DR. REAMAN: I would also like to clarify
from statements that were made earlier, about PR's
being indicative of activity and useful in
screening, we are only talking about PR being an
acceptable endpoint for accelerated approval,
correct, with a guarantee or with a plan for
definitive studies in place.
DR. MARTINO: Dr. Bukowski.
DR. BUKOWSKI: But clearly, there are PR's
that have long duration, and I think we have to
keep that in mind, where we will see refractory
settings where PR's develop that are of long
duration, and that has to be a consideration in our
deliberations.
I think we need to consider all these
alternatives.
DR. PAZDUR: Ron, in my comments
initially, for example, with Velcade, we had a
duration of a year, so we were quite happy with
that. You know, you didn't have to do a randomized
study here. But in the context of the disease that
we are talking about here, with the multiple drugs
386
that are available, to have somebody come in with a
single-arm trial with just PR, unless it was some
eye-popping results, I would discourage people, and
I think the tone of this whole conversation has
been a randomized study, so you have available
therapy even if you have to develop the drug in a
combination regimen before you first take it out
into a randomized setting might need to be done.
DR. BUKOWSKI: I agree with that, Rick,
and I purposely said durable as the modifier here,
and I think that has to be a part of it if you are
looking at a single-arm study. Clearly, the
randomized trial is the best way to do this.
DR. MARTINO: I think maybe we can sort of
summarize by saying that the Committee doesn't have
a strong feeling that response rate alone, without
some other bit of meaningful information, that that
alone is not probably adequate for an accelerated
approval.
Dr. George.
DR. GEORGE: A couple of comments. One is
I think it has been implied or even stated, and
387
something I agree with, you can't prove clinical
benefit from studies like this, these single arms,
so that you have to do something else.
The point I would like to make is you can
design such studies, so you could come up with
numbers here if you make certain assumptions, such
as, for example, as you do in ordinary studies, you
hypothesize certain differences you want to pick
up.
You could do the same thing here if you
said the only possible benefit is going to be in
those that have responses of some kind, and then
you can take it from there and say, well, if that
is true, then, what kind of response rates would
you have to have to even have a chance of finding a
clinical benefit in studies of a certain size.
In other words, a complete response or a
partial response, has to be at least a certain
level or you will never pick it up with a
reasonable size study.
There are ways to get at these numbers,
and if will depend on the disease, of course, but
388
it is not just sitting around the table saying,
well, what kind of duration of response or
percentage of responders could lead us to a
favorable conclusion. You could actually put
numbers on it.
DR. PAZDUR: No. 4 is the approval
question.
DR. MARTINO: So, we will move on to that
last one.
It reads: Do the partial responses at the
rate seen and for the duration reported for this
agent predict clinical benefit in relapsed,
aggressive non-Hodgkin's lymphoma?
Do you want to expound at all on what
clinical benefit means? I am reminding you of
earlier today when we had an issue of what is the
meaning of this, what is the exercise at hand here.
DR. PAZDUR: I think since we are talking
about accelerated approval, this question should be
reasonably likely to predict clinical benefit.
Here again, this is a predictor of clinical
benefit. Clinical benefit has been something that
389
is tangible to the patient, an improvement in
survival, as Maha said, an improvement in
disease-related symptoms, something tangible to the
patient.
So, what we are asking is does the partial
response rate and the duration, with all the
problems that we have discussed with this, is this
reasonably likely to predict clinical benefit.
DR. BRAWLEY: You are not asking is the
drug active? You are asking a different question.
DR. PAZDUR: Correct. This is an approval
question. We assume that the drug has some
response rates here. There is no argument with
anybody on that. This is an approval question.
Is it reasonably likely, with the data
that you saw, does this predict clinical benefit,
i.e., an improvement in survival, disease-related
symptoms, et cetera, something tangible to the
patient?
DR. BISHOP: Does that response include
comparison to currently available treatments?
DR. PAZDUR: We have already answered that
390
in a sense.
DR. BISHOP: No, I look at this question
different than that. This is asking does this have
benefit. You said this is in regard to approval,
and your opening minutes comments for accelerated
approval strictly assigned a demonstration of
clinical benefit, and you listed the four things -
survival, amelioration of symptoms, advantage over
available treatments.
DR. PAZDUR: That was advantage over
available treatments is what you need to show for--
DR. BISHOP: So, that is a definition of
clinical benefit in this question.
DR. PAZDUR: It is a requisite for
accelerated approval.
DR. WILLIAMS: You have already basically,
by answering No. 1 the way you did, probably ruled
out any possibility of approval if we went along
with that advice, but you would also have to answer
No. 4.
DR. MARTINO: Can I just make it very
simple? I think what the question is about is with
391
what we have heard today, and the discussions that
we have undergone today, do you believe that there
is enough substantial data to give approval to this
drug, so that it is available for someone to use
tomorrow.
DR. PAZDUR: Accelerated approval.
DR. MARTINO: It is that issue. Do you
think the data is good enough that you now want the
world to have it tomorrow, or do you think the data
is not of such magnitude. It is an issue of
magnitude, not is there a whiff of response. That
is the question.
Again, we cannot confuse the issue of is
there any activity, is there any value. It is not
the minimum requirement here. We cannot be aiming
for what is the lowest. That cannot be our goal
here. If it is, I am done with this group as of
this moment if that is our goal.
Dr. Bukowski, you are up first.
DR. BUKOWSKI: No.
DR. CHESON: No.
DR. BRAWLEY: No.
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DR. REAMAN: No.
DR. MARTINO: No.
DR. MORTIMER: No.
DR. PERRY: No.
DR. HUSSAIN: No.
MS. HAYLOCK: No.
DR. GEORGE: No.
MS. KRIVACIC: No.
DR. BISHOP: No.
DR. WILSON: No.
DR. MARTINO: The vote is unanimous to
Question No. 4. It is No.
DR. PAZDUR: Thank you for your time and
interest.
[Whereupon, at 4:03 p.m., the meeting was
concluded.]
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