FDA approve Truvada to reduce the risk of sexual transmission
1 August 2012. Related: HIV prevention and transmission.
Simon Collins, HIV i-Base
On 16 July 2012, the US Food and Drug Administration approved Truvada (tenofovir/FTC) to reduce the risk of HIV infection in uninfected individuals who are at high risk of HIV infection and who may engage in sexual activity with HIV-infected partners. 
The indication specifies “Truvada is to be used for pre-exposure prophylaxis (PrEP) in combination with safer sex practices to prevent sexually-acquired HIV infection in adults at high risk. Truvada is the first drug approved for this indication”.
Truvada for PrEP is meant to be used as part of a comprehensive HIV prevention plan that includes risk reduction counseling consistent and correct condom use, regular HIV testing, and screening for and treatment of other sexually-transmitted infections. Truvada is not a substitute for safer sex practices
The PrEP indication means Truvada is approved for use as part of a comprehensive HIV prevention strategy that includes other prevention methods, such as safe sex practices, risk reduction counseling, and regular HIV testing.
As a part of this action, FDA is strengthening Truvada’s Boxed Warning to alert health care professionals and uninfected individuals that Truvada for PrEP must only be used by individuals who are confirmed to be HIV-negative prior to prescribing the drug and at least every three months during use to reduce the risk of development of resistant HIV-1 variants. The drug is contraindicated for PrEP in individuals with unknown or positive HIV status.
Approval was based on two large, randomised, double-blind, placebo-controlled clinical trials. The iPrEx trial in 2,499 HIV-negative men or transgender women who have sex with men and with evidence of high risk behavior for HIV infection and the Partners PrEP trial in 4,758 heterosexual couples where one partner was HIV-infected and the other was not (serodiscordant couples). Result from both studies have been widely reported (including in HTB).
As a condition of approval, Gilead is required to collect viral isolates from individuals who acquire HIV while taking Truvada and evaluate these isolates for the presence of resistance. Additionally, the company is required to collect data on pregnancy outcomes for women who become pregnant while taking Truvada for PrEP and to conduct a trial to evaluate levels of drug adherence and their relationship to adverse events, risk of seroconversion, and resistance development in seroconverters.
Within two weeks of this FDA decision, the NEJM pubished three further PrEP studies. All are available as free access. [2, 3, 4]
Although these have previously been presented at conferences over the last year (and reported in HTB), the full studies are important due to the varying level of protection.
The TDF2 and Partners PrEP studies, reported an efficacy rate of 62% to 75% but the FEM-PrEP study was discontinued early because of a lack no evidence for protection was observed.
Reduced adherence may contribute to the FEM-PrEP results, but these results have not yet been explained.
The journal also included an editorial reviewing the future of PrEP. 
- FDA press release. Truvada approved to reduce the risk of sexually transmitted HIV in people who are not infected with the virus. (16 July 2012).
- Thigpen MC et al. Antiretroviral preexposure prophylaxis for heterosexual HIV transmission in Botswana. N Engl J Med 2012; 367:423-434. (2 August 2012).
- Baeten JM et al. Antiretroviral prophylaxis for HIV prevention in heterosexual men and women. N Engl J Med 2012; 367:399-410. (2 August 2012).
- Van Damme L et al. for the FEM-PrEP Study Group. Preexposure Prophylaxis for HIV Infection among African Women. N Engl J Med 2012; 367:411-422. (2 August 2012).
- Cohen M and Baden LR. Preexposure Prophylaxis for HIV — Where Do We Go from Here? Editorial. N Engl J Med 2012; 367:459-461. (2 August 2012).