Truvada is is a drug already used to treat HIV, but recently, it has been shown to reduce the risk of HIV infection. Now the FDA is approving Truvada for preventive use against HIV. This is a huge deal, considering 50,000 people in the U.S. are diagnosed with HIV every year.


Manufactured by San Francisco-area biotech firm Gilead Sciences, Truvada was approved after two clinical trials which studied 2500 HIV-negative men who engaged in risky sexual behavior. Through the trial, doctors found that the drug drastically reduced incidence of infection as long as subjects used the drug regularly. From the FDA announcement:

The iPrEx trial evaluated Truvada in 2,499 HIV-negative men or transgender women who have sex with men and with evidence of high risk behavior for HIV infection, such as inconsistent or no condom use during sex with a partner of positive or unknown HIV status, a high number of sex partners, and exchange of sex for commodities. Results showed Truvada was effective in reducing the risk of HIV infection by 42 percent compared with placebo in this population. Efficacy was strongly correlated with drug adherence in this trial.


That's right, HIV infection was reduced by nearly half. Amazing.

Obviously, it's still too early to know exactly how effective the drug will be in the broader population. There are important factors—like remembering to take the pill—which are hard to control for. Also, this wouldn't be the first clinical trial to yield inaccurate results. Still, when the stakes are so high, it's hard not to get a little bit excited about every inch of ground scientists gain. [FDA via Technology Review]

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