Bill & Melinda Gates Foundation Funds Durham, N.C., HIV Prevention Study

Investigators at Family Health International, a Durham nonprofit, will use a $6.5 million grant from the Bill & Melinda Gates Foundation to study whether daily doses of tenofovir can prevent HIV transmission in high-risk populations. As opposed to condoms or microbicides that are used -- or not used -- during sex, a pill could provide a constant level of protection, said Ward Cates, the study's primary investigator and president of FHI's Institute for Family Health.

Trials over three years will test the drug in sexually active adults at three test sites in Africa and one in Asia. In addition to testing the safety and efficacy of the protocol, the study will assess patients' adherence to the regimen. The study will test FHI's hypothesis that giving a highly active antiretroviral drug to people before they are exposed to HIV would produce a drug level sufficient to fight off an initial infection, Cates said.

Charles van der Horst, director of University of North Carolina's AIDS clinical trials unit, has reservations about the approach. While women would benefit from a pill protecting them from HIV, the pill will not "prevent them from getting syphilis, gonorrhea, chlamydia or pelvic inflammatory disease, which can still do grave harm to women."

Cates acknowledges that tenofovir taken preventatively would be only one part of a medical arsenal against HIV that includes condoms, preventative drugs, vaccines, microbicides and treatment for STDs -- infections that might increase a patient's likelihood of being infected with HIV. "We need them all," he said.

Tenofovir was chosen because the drug level remains high in cells even though patients take it only once a day, Cates said. The drug has also seemed safe and resistant to virus mutation in prior studies. Tenofovir's maker, Gilead, will provide the study's supply of the drug, which costs $4,000 to $5,000 annually as an HIV treatment. If the study shows tenofovir is effective at preventing HIV transmission, Gilead has told the Gates Foundation that it will make the drug available to the public sector at a low price, much like companies that sell vaccines at cut rates for poor populations, Cates said.

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