2010 Articles

Effectiveness and Safety of Tenofovir Gel, an Antiretroviral Microbicide, for the Prevention of HIV Infection in Women

Abdool Karim, Quarraisha; Abdool Karim, Salim; Frohlich, Janet A.; Grobler, Anneke C.; Baxter, Cheryl; Mansoor, Leila E.; Kharsany, Ayesha B. M.; Sibeko, Sengeziwe; Mlisana, Koleka P.; Omar, Zaheen; Gengiah, Tanuja N.; Maarschalk, Silvia; Arulappan, Natasha; Mlotshwa, Mukelisiwe; Morris, Lynn; Taylor, Douglas

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 (n=445) with placebo gel (n=444) in sexually active, HIV-uninfected 18-40 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 (wy), i.e. person time of study observation, (38/680.6wy) compared to 9.1 per 100 wy (60/660.7wy) in the placebo gel arm (Incidence Rate Ratio (IRR)=0.61; p=0.017).In high adherers (gel adherence >80%), HIV incidence was 54% lower (p=0.025) in the tenofovir gel arm. In intermediate adherers (gel adherence 50-80%) and low adherers (gel adherence < 50%) the HIV incidence 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.