The agency approved Gilead Sciences' pill Truvada as a preventive measure for people who are at high risk of acquiring HIV through sexual activity, such as those who have HIV-infected partners.
Public health advocates say the approval could help slow the spread of HIV, which has held steady at about 50,000 new infections per year for the last 15 years. An estimated 1.2 million Americans have HIV, which develops into AIDS unless treated with antiviral drugs. With an estimated 240,000 HIV carriers unaware of their status, doctors and patients say new methods are needed to fight the spread of the virus.
Gilead Sciences Inc. has marketed Truvada since 2004 as a treatment for people who are already infected with the virus.
But starting in 2010, studies showed that the drug could actually prevent people from contracting HIV when used as a precautionary measure. A three-year study found that daily doses cut the risk of infection in healthy gay and bisexual men by 42 percent, when accompanied by condoms and counseling.
Last year another study found that Truvada reduced infection by 75 percent in heterosexual couples in which one partner was infected with HIV and the other was not.
Because Truvada is on the market to manage HIV, some doctors already prescribe it as a preventive measure. FDA approval will allow Gilead Sciences to formally market the drug for that use, which could dramatically increase prescribing.
Truvada's groundbreaking preventive ability has exposed disagreements about managing the disease among those in the HIV community. Groups including the AIDS Healthcare Foundation asked the FDA to reject the new indication, saying it could give patients a false sense of security and reduce the use of condoms, the most reliable preventive measure against HIV.
But FDA scientists said Monday said there was no indication from clinical trials that Truvada users were more likely to engage in risky sexual behavior.
"What we found was that condom use increased over time and sexually transmitted infections either remained at baseline levels or decreased," said Dr. Debra Birnkrant, FDA's director of antiviral products. "So in essence, we don't have any strong evidence that condoms were not used or there was a decrease in condom use."