- Once-daily Truvada (tenofovir/emtricitabane) was approved by the FDA for the prevention of HIV in 2012. This regimen is known as pre-exposure prophylaxis, or PrEP.
- According to data used by Gilead to obtain the indication, PrEP prevents HIV infection in 92% of at-risk individuals who take it. Now there are new findings confirming this data.
- Although there were no new HIV infections at all in one of the studies (based in San Francisco and tracking 657 men), researchers found that half of the participants in the study had other sexually transmitted infections (STIs), suggesting high-risk behavior.
In a study of 657 at-risk gay and bisexual men, who are part of the Kaiser Permanente healthcare system and used Truvada between 2012 and 2015, there were no new HIV infections.
In a separate study in the U.K., there were some cases of HIV. But according to the researchers, two-thirds of those who were taking PrEP in that study were HIV-infected at the beginning of the study. Overall, however, the use of PrEP reduced the rate of expected infections.
In terms of the high rate of STIs, the researchers suggested that study participants continued to engage in risky sexual behavior, resulting in the infections. The San Francisco study is published in the Clinical Infectious Diseases journal (online September 1) and the U.K. study is published in the Lancet (online September 9).
Truvada has been controversial in certain parts of the HIV/AIDS response community. For instance, the AIDS Healthcare Foundation's president, Michael Weinstein, has argued that use of the medication may discourage safe sex practices. On the flip side, the drug's efficacy seems to speak for itself—although its average annual treatment cost of $23,000 has cause some sticker shock.