A LOT of hype, a little hope and the usual clashes between activists and scientists featured at the 14th International AIDS Conference in Barcelona last week.
Vaccines have made some progress, but don鈥檛 believe everything you hear. The report that VaxGen鈥檚 AIDSVAX is in late-stage clinical trials in Thailand and elsewhere triggered speculation that a vaccine could be available by 2005. But many scientists think AIDSVAX鈥檚 chances of working are virtually nil. And there鈥檚 only slightly less pessimism about a large trial due to start later this year that will test AIDSVAX in combination with another potential vaccine.
AIDSVAX consists of HIV鈥檚 gp120 surface protein. This does generate antibodies 鈥� but not, it鈥檚 thought, ones that disable the virus, which is why people are so pessimistic. 鈥淚 don鈥檛 think that approach is going to work very well, and I don鈥檛 think any serious scientist thinks it will,鈥� HIV co-discoverer Robert Gallo told the conference.
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But at least the International AIDS Vaccine Initiative (IAVI), set up in 1996, seems to be making real progress in bringing order to a previously uncoordinated research field. The first efforts to make a vaccine centred on generating antibodies. When scientists realised that the antibodies many potential vaccines were triggering weren鈥檛 effective, they changed tack and tried to produce vaccines that stimulate cell-based immunity. Now many think a successful vaccine will need to trigger both cellular immunity and effective antibodies that neutralise the virus.
In response to the gaping holes in our knowledge, the IAVI launched the Neutralizing Antibody Consortium last week to accelerate research in this area. The IAVI also aims to pick the three most promising new vaccines and get them into trials to test their efficacy within three years. IAVI president Seth Berkley reminded delegates, however, that the search for a vaccine would be 鈥渁 marathon, not a sprint鈥�, and warned against 鈥済iddy optimism鈥�.
On the treatment front, the new 鈥渆ntry inhibitor鈥� class of anti-HIV drugs generated some excitement, with much made of the positive results in phase III trials for the leader, Roche鈥檚 T-20, also called enfuvirtide. New treatments are desperately needed, as resistance to existing drugs is one of the biggest problems for HIV patients.
But again, you have to look past the hype. All current anti-HIV drugs work by blocking virus replication inside cells. The entry inhibitors stop HIV getting into cells in the first place. However, enfuvirtide has to be given by twice-daily injections, which is a real drawback 鈥� if patients fail to follow this difficult treatment regime, the virus is more likely to become drug-resistant. But more entry inhibitors are on the way, some of which could come in pill form.
No AIDS conference would be complete without banners attacking the big drugs companies, and noisy protests about the developing world鈥檚 worsening plight, the lack of foreign aid and discrimination against HIV patients, among other things. Activists hijacked a speech by US Health Secretary Tommy Thompson, climbing on stage and calling him a murderer.
But the campaigners who chose to present conference papers instead of chanting slogans probably made more of an impression. A report compiled by aid agencies, for instance, estimated that the number of children orphaned by AIDS in the developing world will almost double to 25 million by the end of the decade.
One glimmer of hope for poor countries battling HIV was the attention given to vaginal microbicides, over-the-counter creams that block transmission of sexually transmitted diseases. Delegates presented research on the 55 anti-HIV microbicides in development, including 11 in human trials. Work on vaginal microbicides has been overshadowed by the more glamorous vaccine field. Yet this approach is already used successfully against other infections, and could be invaluable for women whose partners refuse to wear condoms.
Alan Stone, chairman of the International Working Group on Microbicides, told 快猫短视频 that the growing realisation that a vaccine is many years off has led to renewed interest in this area. 鈥淚t鈥檚 gradually dawning on people that for some women a cheap microbicide would be a lifeline.鈥�
