Studies show success, highlight challenges of PrEP strategy

The results of three clinical trials published on Wednesday in the New England Journal of Medicine show that the antiretroviral drug Truvada, a combination of tenofovir and emtracitabine, can be "highly effective at preventing infection in HIV-free individuals -- as long as those individuals take the drug every day as prescribed," CNN's "The Chart" reports (7/11). The strategy of using antiretrovirals to prevent HIV among healthy people at risk of contracting the virus is known as pre-exposure prophylaxis, or PrEP, USA Today notes. "Two studies from Africa in heterosexual patients found that the drugs reduced the rate of HIV infection by 62 percent to 75 percent, a success rate that's comparable to results from studies of gay men," the newspaper writes, adding, "A third study in African women at high risk of infection, however, was ended early after researchers saw the drugs had no effect on HIV rates, largely because fewer than 40 percent of study participants took their pills as instructed" (Szabo, 7/11).

"'Why the results differ across the various studies reported to date is unclear,' said an accompanying editorial by Myron Cohen from the University of North Carolina and Lindsey Baden of Brigham and Women's Hospital in Boston," Agence France-Presse reports. "Learning more through future study is important because PrEP is increasingly being seen as a part of an integrated HIV prevention approach, they wrote," according to the news agency. An FDA advisory panel in May recommended Truvada be approved for PrEP, and a final decision is expected by September, AFP notes (Sheridan, 7/11).