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Press Release

Two Major Studies Prove HIV Pre-Exposure Prophylaxis (PrEP) Works in Heterosexual Women and Men; Build on iPrEx Data Showing PrEP Reduces HIV Infections in Men Who Have Sex With Men

July 13, 2011

The following statement was released by iPrEx Protocol Chair Robert Grant, MD, MPH of the Gladstone Institutes and the University of California at San Francisco.

"Today's news from the Partners PrEP and CDC Botswana (TDF2) studies detailing the safety and effectiveness of PrEP in heterosexual women and men is a major step forward in HIV prevention research with global implications for helping to end the AIDS epidemic.

PrEP involves uninfected people taking antiretroviral medications, which are usually used to treat HIV, to reduce their chances of HIV infection. With 2.6 million people worldwide newly infected by HIV each year, the compelling evidence presented by the iPrEx, Partners PrEP and TDF 2 studies -- that PrEP greatly reduces the risk of HIV infection both in heterosexual men and women and among men who have sex with men -- makes it increasingly clear that PrEP can play an important role in helping to slow the global epidemic in multiple populations at risk.

Partners PrEP and TDF2 are the are the third and fourth studies in 12 months to demonstrate that oral or topical PrEP reduces HIV infections significantly. In November 2010, results from the Global iPrEx study ( showed robust and highly statistically significant evidence that daily PrEP using the emtricitabine/ tenofovir combination tablet known commercially as Truvada reduced HIV infection risk among men who have sex with men (MSM) by an average of 44% overall, and by 90% among those who used PrEP consistently enough to have detectable drug in the body. An update on the iPrEx study to be presented at the 6th IAS Conference on HIV Pathogenesis, Treatment and Prevention in Rome next week demonstrates that the prevention impact of PrEP is consistent over time and across study subgroups.

In July, 2010 the CAPRISA 004 study showed that a topical form of PrEP using tenofovir gel, also known as a microbicide, safely reduced HIV infections in heterosexual women. Follow-up research is underway to determine why one other study, FEM-PrEP, was not able to demonstrate PrEP's effectiveness. The scientific evidence for PrEP is clearly mounting, however, as four out of five large-scale clinicaltrials of PrEP have shown a strong HIV prevention benefit.

On all fronts there are new, highly effective approaches for prevention, including oral PrEP for MSM and heterosexual men and women, clean needles for injecting drug users, male circumcision for heterosexual men, vaginal gels for heterosexual women, early treatment for discordant couples and suppressive therapy for pregnant women. These new opportunities demonstrate that we can win the war on HIV, if we act now. PrEP presents a unique HIV prevention advantage because it can help stop the cycle of infections from people who are newly infected with HIV but unaware of their status. Making PrEP available is also an important strategy to draw people in to HIV testing and help HIV-negative people remain negative.

Recently, iPrEx launched a 72-week open-label extension of the study, called iPrEx OLE ( at eleven sites in six countries. iPrEx OLE will provide Truvada PrEP to any HIV-uninfected participants from the original iPrEx study. No placebo will be used in iPrEx OLE. Approximately 2,000 MSM are expected to participate in the open-label extension, which will gather important additional information on longer-term PrEP safety, efficacy and adherence. Additional studies of oral and topical PrEP now underway include the VOICE trial in Africa and a CDC study of PrEP in injecting drug users in Thailand.

The iPrEx study congratulates the 1200 women and men who participated in TDF2 and the more than 4700 couples who participated in the Partners PrEP study, as well as the study organizers and implementers, for their outstanding contribution to our understanding of PrEP and for taking us another important step forward toward a world in which the HIV epidemic can end."

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