Scientists Debate HIV Prevention Products

At the recent 16th Conference on Retroviruses and Opportunistic Infections in Montreal, scientists were told that the PRO 2000 anti-HIV microbicide candidate worked for 30 percent of women who used it in a field trial. While some experts found these results promising, others said there was a one-in-10 possibility they were due to chance.

Lorie Heise of the Global Campaign for Microbicides said perhaps the most encouraging aspect of the study was that 80 percent of the women reported using the product consistently, even knowing they may have received a placebo. This is key because the gel appeared most effective in women who reported the most consistent use. In addition, she said the fact that most women stayed with the study for two years indicates a strong desire to use an effective microbicide if one were developed.

However, Tachi Yamada, director of global health policy for the Bill and Melinda Gates Foundation, was less hopeful. Citing the potential difficulties a woman might encounter in trying to discretely use a microbicide in developing countries, Yamada holds out more hope for a pre-exposure prophylaxis pill.

Other experts worry that any preventive product whose active ingredient is HIV medication, whether delivered in pill or gel form, could help promote the development of drug-resistant virus. "The use of antiretrovirals for prevention could create the spread of resistant variants that compromise treatment programs," said microbiologist John Moore of Weill Cornell Medical College.

However it is delivered, women are anxious for HIV prevention methods they can control, said researcher Sharon Hillier of the University of Pittsburgh School of Medicine. The female microbicide study participants she talked to, Hillier said, "didn?t care if it was a pill or a gel or a diaphragm, they wanted something to help protect them from HIV."

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