AIDS TREATMENT NEWS #226, July 7, 1995
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
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
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.
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
[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.]