Daily Dose of HIV Drug Reduces Risk of HIV Infection

A daily dose of an oral antiretroviral drug, currently approved to treat HIV infection, reduced the risk of acquiring HIV infection by 43.8 percent among men who have sex with men. The findings, a major advance in HIV prevention research, come from a large international clinical trial published online Nov. 23 by the New England Journal of Medicine. The study, titled “Chemoprophylaxis for HIV Prevention in Men,” found even higher rates of effectiveness, up to 72.8 percent, among those participants who adhered most closely to the daily drug regimen.

“We now have strong evidence that pre-exposure prophylaxis with an antiretroviral drug, a strategy widely referred to as PrEP, can reduce the risk of HIV acquisition among men who have sex with men, a segment of the population disproportionately affected by HIV/AIDS,” says Anthony S. Fauci, M.D., director of the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health. “Additional research is needed, but certainly this is an important finding that provides the basis for further investigating, developing and employing this prevention strategy, which has the potential to make a significant impact in the fight against HIV/AIDS.”

“No single HIV prevention strategy is going to be effective for everyone,” adds Dr. Fauci, “and it is important to note that the new findings pertain only to the effectiveness of PrEP among men who have sex with men and cannot at this point be extrapolated to other populations.

Therefore, we must continue to conduct PrEP research among other study populations, such as women and heterosexual men, to provide a comprehensive picture of its potential utility as an HIV prevention tool.”

NIAID sponsored the study, also known as iPrEx, through a grant to the J. David Gladstone Institutes, a non-profit independent research organization affiliated with the University of California at San Francisco. Additional study funding was provided by the Bill & Melinda Gates Foundation. Gilead Sciences, based in Foster City, Calif., donated the study drug.

Led by study chair Robert M. Grant, M.D., of the Gladstone Institute of Virology and Immunology, and study co-chair Javier R. Lama, M.D., of Investigaciones Medicas en Salud, a Peruvian-based research organization, the iPrEx study enrolled a total of 2,499 men who have sex with men and transgendered women who have sex with men. All participants were at least 18 years old and HIV-negative at time of enrollment. The study, which began in June 2007, was conducted at 11 sites in Brazil, Ecuador, Peru, South Africa, Thailand and the United States.

The study participants were randomly assigned to receive either a daily antiretroviral tablet containing combination emtricitabine (FTC 200 milligrams) and tenofovir (TDF 300 milligrams), known by the brand name Truvada, or a placebo pill. Before enrollment, all participants received detailed information about the possible risks and benefits of participating in the trial. Once enrolled, they were evaluated for HIV infection monthly for the duration of their participation in the study. The average enrollment was 1.2 years. In addition, all participants were routinely counseled about safe sex practices and provided condoms and treatment for other sexually transmitted infections.