According to a Pharmalive report, a supplemental New Drug Application (sNDA) has been submitted to the U.S. Food and Drug Administration (FDA) for the approval of once-daily Truvada™ (emtricitabine/tenofovir disoproxil fumarate) for pre-exposure prophylaxis (PrEP) to reduce the risk of HIV-1 infection among uninfected adults.

The sNDA is based on the results of two large Phase III placebo-controlled trials of Truvada as PrEP. The first trial randomised 2,499 high-risk HIV-negative adult men who have sex with men in the US and countries in Africa, Asia and South America, to Truvada or matching placebo once daily. The overall results showed that Truvada reduced the risk of acquiring HIV by 44% (95% CI, 15 to 63; P=0.005). Results from this trial were published in The New England Journal of Medicine in November 2010, (see NELM abstract at the link below).

The second study was conducted among 4,758 heterosexual couples in Kenya and Uganda in which one partner was infected with HIV and the other was not. Initial results reported an overall 73% risk reduction compared to placebo (no further study details available).

Additional supportive data come from a Phase III randomised, double-blind, placebo-controlled trial conducted in Botswana among 1,200 HIV-negative heterosexual men and women which found that participants taking once-daily oral Truvada for PrEP had 63% fewer HIV infections compared with those receiving placebo (no further study details available).

A separate Phase III study of Truvada for PrEP ( FEM-PrEP) was stopped in April 2011 based on a recommendation that the trial would not be able to establish the efficacy of Truvada among HIV-negative women in sub-Saharan Africa. Further analysis of this data is currently underway.

According to Centres for Disease Control and Prevention (CDC) guidance, effectiveness of Truvada for PrEP is highly dependent on medication adherence; the importance of confirming that patients who take Truvada are at substantial ongoing risk for HIV infection; the need to provide counselling on the importance of adhering closely to the prescribed regimen and using other HIV prevention methods; and the importance of regularly testing for HIV infection.

In the UK, Truvada is currently licensed for the treatment of HIV-1 infected adults aged 18 years and over.