Animal Cell Transplantation: FDA Meeting July 13 and 14


Advances in organ and cell transplantation, and in basic
immunology, have now raised the possibility of transplantation of
organs or cells from animals to humans. For example, it is known
that immune cells in baboons are resistant to HIV infection. If
these cells could survive transplantation to humans, and could
work properly in humans, they might conceivably provide
immunological resistance to HIV, like human cells do -- except
that the baboon cells could not be destroyed by the virus. If it
works -- still a big if -- such a procedure might allow the
reconstitution of an immune system in persons with late-stage
AIDS.

The reverse -- transplantation of human immune cells to a
baboon -- has already been done. So far the cells have survived,
and tests indicate that proliferation responses are functional,
according to treatment activists who have followed this work
closely.

The first test of baboon to human cell transplantation was
scheduled to have been tried already; the principal investigators
are transplantation specialists at the School of Medicine of the
University of Pittsburgh, and AIDS specialists at the University
of California San Francisco Medical Center. Under the Federal
regulations which were in effect until recently, such a test only
needed to be approved by a local IRB (institutional review
board). It did not need additional approval by the FDA -- just
like a surgeon does not need FDA approval to try a new,
experimental operation. But shortly before the first baboon to
human transplant was to be done, the FDA expanded its authority
into this new area, and told the researchers that they would have
to get FDA approval first.

The researchers complied, postponing the trial and applying
for FDA approval. However, animal to human transplantation
involves major issues which must be considered -- including the
theoretical risk of transmitting an animal disease to humans,
conceivably even causing an epidemic. But this risk must be seen
in perspective. Animal to human transplants have been attempted
several times in the last 25 years, with some long-term
engraftment; so far no dangerous animal diseases have been
transmitted. And tens of thousands of people die every year
because of lack of human organs to transplant.

Some experts believe that there should be more animal trials
first, before attempts to transplant animal tissues into humans.
But others fear that such trials will take years to finance,
organize, and conduct, and cannot be definitive anyway. Sorting
out all these heavy policy issues might take a long time,
seriously delaying an early proof-of-concept trial.

The requirement for advance FDA approval could well mean, in
practice, that the very difficult general policy issues for the
whole field of "xenogeneic" (animal to human) organ and cell
transplantation will have to be considered first -- before even
the earliest proof-of-concept human trials can go forward. A
bureaucracy usually prefers to delay making decisions in a
completely new area, until it has a policy in place. If that
happens in this case, it could disastrously delay the research.
The alternative is to allow the small, early research to begin,
even while the overall policy is being worked out.

These matters will be considered at a critical FDA meeting
on July 13 and 14, at the Holiday Inn in Bethesda, Maryland.
This meeting is open to the public.

David Hook, of the Xenogeneic Committee of ACT UP/Golden
Gate in San Francisco, told AIDS TREATMENT NEWS that people
should call the FDA's Office of AIDS and Special Health Issues,
301/443-0104, to tell the FDA that the baboon transplantation
trial should go forward without delay.

For more information, including on how you can be involved,
leave a message for David Hook on the voicemail of ACT UP/Golden
Gate, 415/252-9200.

Comment

Until now most of the AIDS community has known little about
this issue, which has been brewing quietly behind the scenes for
about two years. Those involved preferred not to seek publicity
until recently, when the research was threatened with long
delays.

But now the activists and researchers who want to move this
research forward do need public support. This situation presents
a challenge to the AIDS community. We must get up to speed
quickly in this complex and difficult area; otherwise, decisions
seriously harmful to people with AIDS are likely not only to be
made, but also to become institutionalized.

[Note: This preliminary article is based on interviews with
treatment activists, and on published information. Due to time
constraints, we did not interview the researchers.]