Breakthroughs in HIV Prevention Research 2010

2010 has been a year of good news for the field of HIV prevention research. By testing the use of HIV treatment medications for prevention, CAPRISA 004 and iPrEx uncovered potential new uses for existing drugs. Yet despite the excitement surrounding these results, development of new IV prevention tools – particularly those that are woman-controlled – must continue in earnest. According to UNAIDS, more than half of all people living with HIV today are women and girls. And of the estimated 15 million people living with HIV in low- and middle-income countries who need treatment, 5.2 million have access. We must persevere in tirelessly exploring every possibility for putting new HIV prevention products into the hands of women and men who need them.

When the exciting results of the CAPRISA 004 microbicide trial were announced at the XVIII International AIDS Conference in Vienna last July, the world took notice. A topically applied gel containing the antiretroviral agent tenofovir was found to reduce a woman’s risk of acquiring HIV during sex by 39 percent. Women who used the gel in at least four out of five sex acts had a 54 percent reduction in HIV infections. And the gel reduced a woman’s risk of acquiring genital herpes infections by 51 percent.

CAPRISA 004 marked the first time that a topical agent showed a significant decrease in the rate of HIV acquisition among HIV-negative women. This was welcome news to the field of HIV prevention research, where topical agents had a history of disappointing results in clinical trials. Since then, the U.S. Food and Drug Administration has granted fast-track approval status to 1 percent tenofovir gel and confirmed that the current National Institutes of Health-funded VOICE trial can serve as a confirmatory study for the gel.

Meanwhile, the HIV prevention field has continued its winning record. In late November, the New England Journal of Medicine announced the results of the iPrEx trial, which found that a once-daily dose of oral Truvada reduced the risk of HIV infection by 44 percent in a group of 2,499 men who have sex with men. The iPrEx study is the first to demonstrate that an antiretroviral pill can reduce HIV infection rates in humans.

Four other trials are currently investigating the safety and effectiveness of antiretroviral drugs for HIV prevention:

• The FEM-PrEP trial is testing daily oral Truvada for HIV prevention among 3,900 women in sub-Saharan Africa. Results are expected in 2013. FEM-PrEP is led by FHI and is funded by the Bill & Melinda Gates Foundation and USAID.

• The VOICE (MTN 003) trial is evaluating the effectiveness of different prevention strategies: daily oral Truvada, daily oral tenofovir, and daily topical tenofovir among 5,000 sexually active women. Results are expected in 2013. The trial is being conducted by the Microbicide Trials Network; the University of Pittsburgh leads the network.

• The Partners PrEP trial is testing oral tenofovir and Truvada with 3,900 HIV serodiscordant couples. The trial is funded by the Bill & Melinda Gates Foundation and led by the University of Washington. Results are expected in late 2012.

• A CDC trial is evaluating oral tenofovir in 2,400 injecting drug users in Bangkok, Thailand. Results are expected in 2012.

In addition, next year the International Partnership for Microbicides will initiate two trials to test another form of topical PrEP, a vaginal ring containing a new antiretroviral, dapivirine.