The Bay Area Reporter - October 29, 1999
Jeff Getty ACT UP/Golden Gate Writers Pool

Some of the "big gun" researchers included Time magazine coverboy Dr. David Ho, HIV co-discoverer Dr. Jay Levy, Dr. Judy Lieberman, Dr. Fred Valentine, Dr. Gene Shearer, and University of California San Francisco (UCSF) AIDS researchers Dr. Michael MaCune and Dr. Steven Deeks. Also present were ACT UP/Golden Gate's Matt Sharp and Jeff Gustavson, along with Project Inform's Martin Delaney, Brenda Lein, and other staff.

According to Lein, one of the event's organizers, the think tank was an overall success. Lein said that she was very excited about one area of research that experienced a breakthrough at the seminar. In the past, most scientists and drug companies have had a great deal of trouble developing immune-based therapies for AIDS because the federal Food and Drug Administration (FDA) had not agreed to accept most current methods of immune measurement. Since any new drug must meet FDA approval, the only way to measure immune drug responses have been through clinical observation of patients that involve expensive long-term trials. But an FDA official attending the think tank said that he would go back to the FDA and hold meetings to decide which immune measurement assays could be utilized by drug developers and accepted by the FDA for validation.

One proposed assay would be the use of currently available flow cytometry devices that count human T-cells. Lein indicated that these machines could count immune system cell populations that have been stimulated or altered by treatment with new immune therapies. For example, if a therapy is shown to create appropriate cell population expansion needed for fighting HIV with specific antigen presentation or natural killer cells, then the FDA might grant approval of such a therapy based on cytometry assay results and when combined with promising clinical data. Many of these types of assays are already used in organ transplantation to better allow and predict organ engraftment.

"There have been major technological advances in these assays in the last few months. Moving forward into the field of measuring immune response is an important step towards getting new drugs developed to help the immune system," said Lein.

Another popular subject discussed at the gathering was possible defects in cell antigen presentation. "There is a significant lack of research in this area," said Lein. She noted that there are two new potential products being looked at: CD40-ligand and Flt3-ligand. These are naturally occurring molecules or immune system components that enhance antigen presentation. "Antigen presentation is when the cells of the immune show other cells the infectious critters in the body that need to be eliminated. If the immune system can't see HIV, it might not respond adequately to get rid of it," she said. Both of these ligand are owned by Immunex from Seattle and are currently under development.

Another therapy that showed a great deal of interest was Interleukin7. "Though it is not yet manufactured for human use, animal tests have shown this to be a promising immune enhancing product for the future," said Lein. Scientists at UCSF have done the basic work on this cytokine and, according to Lein, it could eventually be useful in late-stage AIDS patients.

A recent hot-button topic that has been actively discussed in the AIDS population as well as the think tank is structured therapy interruption (STI). Most AIDS patients call this a "drug holiday." The group heard presentations of the latest data from these trials. It was discussed in the context of people who are on a three- or four-drug antiviral therapy. The theory proposed is that a treatment interruption could lead to less HIV resistance. So far, the results have not been very promising. The jury is still out on this approach, but Lein said the group thought there may be a role for this approach in the future.

ACT UP/Golden Gate's Sharp, who also works at the Asian Pacific Islander Wellness Center attended as a community observer. He said that the think tank was very important because not all researchers seemed to be aware of each other's research. While sitting at the same table as the well-known Ho, Sharp learned that Ho had no knowledge of thymic transplant research in AIDS. When Ho was told that Sharp had a thymic transplant, Ho indicated that he had never even heard of the procedure "It is so vital to get everyone in the same room and come up with new extreme cutting edge ideas. This happens without the usual chastisement among scientists," Sharp said.

Sharp thinks that the need for immune based therapies has reached a critical point. "Now that we are able to bring viral levels down, we should have more options to boost the immune system," he said.

Interleukin2 (IL2) received some discussion, and IL2 studies in late-stage patients were presented. The findings show that in patients with low HIV viral loads, IL2 can increase CD4 counts. It worked in people who did not benefit from older drugs or mono therapy. Should PWAs rush to use IL2?

"People with low CD4s are eligible for current studies," Lein said. As for treating late-stage AIDS patients with standard IL2 therapies, Lein was cautious. "Should a person with less than 50 T-cells learn about IL2, and its side effects? There are settings where it might be appropriate to try. But if someone has an active infection, IL2 could worsen that condition," she said.

There was also some discussion about low-dose daily IL2 therapy. (Data about a recent low-dose study was reported at a September San Francisco AIDS conference and has been causing a buzz among AIDS patients.) Lein indicated that there will be more data on low-dose IL2 reported in about three months.

Other concepts that were discussed for further research were: allo immunization (a type or human white blood cell immunization), immune suppression with drugs like cyclosporin, and possible thymus transplantation.

One approach that had been promoted and applied from previous think tanks was CD8 or CD4 cell expansion. Results from completed studies indicated that this approach did not work in late-stage AIDS patients.
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