Jim Pickett, on behalf of IFARA, spoke with an international panel of HIV experts about pre-exposure prophylaxis (PrEP). Simon Collins explained that the PROUD study in the U.K. had shown 86% protection against HIV and no increase in risky sexual behaviors when tenofovir/emtricitabine (Truvada) was taken daily. Jean-Michel Molina discussed the IPERGAY study conducted in France and Montreal, where tenofovir/emtricitabine was taken on demand in a regimen of four daily pills, started before and finished after intercourse. The median number of sexual encounters was one per week, so that most study participants took tenofovir/emtricitabine four times a week. Prior once-daily PrEP trials had shown that dosage to be effective in preventing HIV. The current study results may therefore not be applicable to fewer encounters -- and hence fewer tenofovir doses.
While the first two studies were conducted among gay men and transgender women, Jared Baeton reported on a pilot study in Kenya where PrEP in serodiscordant heterosexual couples reduced HIV risk by 96%. The HIV-negative partner takes tenofovir until the HIV-positive partner starts treatment and becomes virally suppressed, and for six months thereafter. PrEP thus becomes "a bridge to antiretroviral therapy," Baeton said. He believes that PrEP's "effectiveness in real-world settings can be even higher than the efficacy in randomized trials."
Myron Cohen saw injectable agents for HIV prevention as good reassurance for serodiscordant couples, and helpful for HIV-negative people who do not want to be seen taking HIV medications. The three drugs being studied for this purpose require two shots every three months. Uptake so far has been very good, but study participants are highly motivated despite the discomfort associated with the injections.
Mitchell Warren hoped that these new formulations would not replace any existing prevention drugs, but simply offer more options. He urged that the HIV community must "begin to act on the evidence" and use PrEP more widely outside clinical trials to see a public health impact. A robust pipeline for other agents is also necessary, since PrEP will not work for everyone, Warren said.
Watch the video to learn more:
About the panelists:
Mitchell Warren, executive director of AVAC, New York City.
Jean-Michel Molina, head of the Department of Infectious Diseases, Saint Louis Hospital, Paris, France.
Myron Cohen, M.D., UNC School of Medicine, Chapel Hill, N.C.
Jared Baeton, Department of Global Health, University of Washington, Seattle.