TOPICS > Science

Taking Risks to Fight AIDS

February 9, 1996 at 12:00 AM EDT


ELIZABETH FARNSWORTH: Dr. Jonathan Allan is an AIDS researcher at the Southwest Foundation for Biomedical Research in San Antonio, and Dr. Paul Volberding is the director of the AIDS program at San Francisco General Hospital, where the transplant was performed. Welcome to both of you. Dr. Paul Volberding, how is Mr. Getty now, how–what are the results of the experiment as of now?

DR. PAUL VOLBERDING, AIDS Researcher: (San Francisco) Well, I saw Jeff this morning, and he’s looking great. He looks better than he looked in the video. So despite what he’s been through, he’s done very well. His immune system is, if anything, somewhat stronger than it was when he started the procedure. He’s feeling healthy. He’s very active, and he’s a real courageous person.

ELIZABETH FARNSWORTH: Did the baboon cells have anything to do with that?

DR. VOLBERDING: I don’t think so at this point. Evidence that we have is that there are no detectable baboon cells in his blood, which doesn’t mean that there aren’t a few there, or that they might not appear later, but at this point, I think that Jeff is not benefiting from the baboon cells. He may be benefiting from the procedure and from the medications that he’s been receiving as a result of that.

ELIZABETH FARNSWORTH: Explain that. What might have helped him that was done?

DR. VOLBERDING: Well, Jeff went through a preparation that was actually we thought the riskiest part of this whole transplant where he got radiation therapy to his immune system and also chemotherapy to try to clear out some space in his bone marrow for the new cells to grow. That process and then the anti-viral therapy that he’s getting, he’s getting very potent drugs against HIV, to try to help again create more space in his bone marrow, we think are probably the explanation, but it really opens up a lot of new questions in areas of research actually that we, we hope to explore.

ELIZABETH FARNSWORTH: So you’ve learned something but it’s not what you expected to learn, is it?

DR. VOLBERDING: Well, not surprisingly, in this kind of innovative research, we really agree with, with Jeff, that we have to be bold. We have to take safety into consideration, of course, but we have to be bold and in the process of doing this kind of very innovative research, we can open up unexpected avenues for further work.

ELIZABETH FARNSWORTH: Dr. Allan, would you consider the experiment a failure at this point?

DR. JONATHAN ALLAN, AIDS Researcher: (San Antonio) Well, I was pretty disappointed that it seems that the baboon cells didn’t ingraft in the recipient, and so I was, I was very disappointed. At the same time, my concerns about infectious disease risks remained the same.

ELIZABETH FARNSWORTH: Yes. You’ve had many doubts about this experiment. Would you describe some of them.

DR. ALLAN: Well, there’s essentially three areas that you have to consider. The first is, is the infectious disease risk, and in looking at that, you have to weigh that versus the benefit from this procedure.

ELIZABETH FARNSWORTH: Okay. Briefly explain that.

DR. ALLAN: Well, the thing is that baboons are not clean animals. They harbor several viruses that we’ve–we know they carry that we can’t eliminate, and they may carry several viruses that have yet to be discovered, and the problem with that is that it’s a virtual guarantee that these viruses, some of which may be transmitted to the recipients, so we can’t prevent those kinds of infections, and the real problem ends up being is that many of those infections have long clinical latency periods which means that it may be several months to several years before one knows whether the recipients are even infected.

ELIZABETH FARNSWORTH: Okay. I’ll come back to that in a minute. Tell us your other objections to this experiment.

DR. ALLAN: Well, what follows with that is also the science, because really, we’re really asking too much from the baboon cells because from what we know, at least at this point, in a state of the art in terms of immunology that we shouldn’t expect this to work because the baboon cells are unlikely to be able to function immunologically in a human host. So we may be able to get the baboon cells to ingraft, we may even get them to grow, but it’s highly unlikely that they should be able to function immunologically in a human.

ELIZABETH FARNSWORTH: Dr. Volberding, what about those objections?

DR. VOLBERDING: Well, the two areas that Jonathan is talking about are ones that we’ve obviously considered in the two years that this process has been under consideration. This protocol was more reviewed than any research I’ve done in the last 15 years with HIV.

ELIZABETH FARNSWORTH: Reviewed by the FDA and various committees.

DR. VOLBERDING: Exactly. Reviewed by national and local committees, and one of the major areas of concern was, of course, the public health, the possibility that we would be introducing a virus from the baboon into Jeff, and that that might pose a broader public health risk. The problem we have is that Jonathan’s concerns are appropriate but there’s really no answering them. If we’re ever going to do this work, we think that this was the appropriate time to do it, under these conditions of really maximum safety we felt, and we’ve been monitoring Jeff and plan to keep monitoring him closely. Now, in terms of the immune function, we agree that it’s unlikely in a sense that this will be a dramatic benefit. On the other hand, again, almost the only way we can, we can learn how these cells might work in a human environment is to actually do the, do the procedure. And there have been some leads in other animals that this might actually result in functional immune cells because the baboon cells are, we think, not possible to be infected with AIDS, this is the obvious background for this kind of work.

ELIZABETH FARNSWORTH: Does this experiment make invalid your assumptions about what a baboon’s stem cells might do, or do you just try again?

DR. VOLBERDING: Well, we’re going to consider that carefully. We agree with, with the concerns that Jonathan and others have expressed that this must go very cautiously, that there are risks. We accept that. We certainly don’t want to see large scale trials of this sort conducted. We think it should be done under extremely careful conditions. We’re going to follow Jeff longer to see if there’s any evidence of infection from the baboon. So far, we haven’t seen any, and also to see whether we can find any evidence of ingraftment. The more we feel that the safety is, is under control, the more likely we would be to do a few more patients to see if, if, in fact, by changing some of the conditions we might be able to make this work better.

ELIZABETH FARNSWORTH: Dr. Allan, some–there is some evidence humans have developed fatal inflammation of the brain, for example, from bites from Rhesus monkeys. Given this problem and your concern and I gather other people in your field’s concern, why was there not more of an outcry when this happened, when this experiment was conducted in December?

DR. ALLAN: Well, the situation is that the, this procedure was only approved for one individual and knowing that the actual risk to the population is very small because really in order for a new infectious disease to establish itself it has to be transmitted from patient to contacts, and only doing one minimizes that, but at the same time, one must also realize that you’re opening the door for more procedures. With that risk, with that door opening comes an increased risk. The more people that get baboon tissue, whether they’re hearts or baboon bone marrow, increases the risk of transmitting viruses to the general population, and to my mind it’s a needless risk because there are other procedures that are currently being developed, new drug therapies that really have a lot of promise. This particular procedure, while it’s very innovative, has in many respects very little chance for success, so we may be jeopardizing the public health in a needless fashion. I would hope that we could try and learn as much as we can from this one procedure without moving too quickly, which could actually promote infectious diseases.

ELIZABETH FARNSWORTH: Well, Dr. Allan, Dr. Volberding, thanks for being with us.