Exploring PrEP to prevent MSM HIV infections

Gay Men Don't Engage in Riskier Sex When Taking AIDS Pills, CDC Study Says

By Simeon Bennett

Gay and bisexual men didn’t have riskier sex or suffer serious side effects while using Gilead Sciences Inc.’s Viread in a study of whether taking pills to prevent HIV infection would loosen inhibitions or harm health.

Gay and bisexual men who took a daily pill -- either Viread or a placebo -- were no more likely to take greater sexual risks on the assumption they were protected than those who didn’t take one, researchers from the U.S. Centers for Disease Control and Prevention said at the International AIDS Conference in Vienna today. The study also compared the rate of side effects between those who received Viread and those who got a placebo, and found no significant difference.

The study supports efforts to test whether drugs approved to treat AIDS patients can also be used to prevent infections in the first place. That theory, called pre-exposure prophylaxis, or PrEP, was partially validated this week when a vaginal gel containing Viread was shown to reduce infections by 39 percent among women in South Africa.

“It is encouraging to hear there were no serious safety concerns and that the men in the study did not appear to increase risk-taking behaviors while taking a pill,” said Mitchell Warren, executive director of the New York-based AIDS Vaccine Advocacy Coalition, in an e-mailed statement. “Much more safety, adherence and risk data will be needed before PrEP can be implemented if it is proven effective.”

400 Men

The study involved 400 HIV-negative gay and bisexual men in San Francisco, Atlanta and Boston. About half received either Viread or placebo immediately, and the other half started nine months later.

There were seven HIV infections overall, and none in the group that took Viread. The trial wasn’t designed to test whether the drug prevented infections and no conclusions about its effectiveness can be drawn from the study, the researchers said. The distribution of infections could be due to chance, said Lisa Grohskopf, a CDC researcher who presented the results.

“PrEP is one of the most-promising new prevention approaches being explored, and if effective, could help address an urgent need for additional solutions to help slow the HIV epidemic in the U.S. and around the world,” the CDC said in a statement.

[Posted by Paul Causey, MSM-Asia mailing list, 2010-07-24]