Effectiveness and Safety of Tenofovir Gel an Antiretroviral Microbicide

The CAPRISA 004 trial assessed effectiveness and safety of a 1% vaginal gel formulation of tenofovir, a nucleotide reverse transcriptase inhibitor, for the prevention of HIV acquisition in women. A double-blind, randomized controlled trial was conducted comparing tenofovir gel with placebo gel in sexually active, HIVuninfected18 to 40 year-old women in urban and rural KwaZulu-Natal, South Africa HIV serostatus, safety,sexual behavior and gel and condom use were assessed at monthly follow-up visits for 30 months. HIV incidence in the tenofovir gel arm was 5.6 per 100 women-years, i.e.person time of study observation, (38/680.6 women-years)compared to 9.1 per 100 women-years (60/660.7 women years) in the placebo gel arm incidence was 54% lower in the tenofovir gelarm. In intermediate adherers (gel adherence 50 to 80%)and low adherers (gel adherence < 50%) the HIVincidence reduction was 38% and 28% respectively.

Tenofovir gel reduced HIV acquisition by an estimated 39% overall, and by 54% in women with high gel adherence. No increase in the overall adverse event rates was observed. There were no changes in viral load and no tenofovir resistance in HIV seroconvertors. Tenofovir gel could potentially fill an important HIV prevention gap, especially for women unable to successfully negotiate mutual monogamy or condom use. 

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