Studies find HIV drug treatments may reduce infection risk among heterosexual couples

NEW YORK — Taking drugs for treating HIV might reduce the risk of infection among heterosexual couples, according to two new studies conducted in Africa.

One study, funded by the Bill & Melinda Gates Foundation and conducted among 4,758 couples in Kenya and Uganda, found that when taken daily, Gilead’s Viread (tenofovir) reduced the rates of infection by at least 62% compared with placebo. Truvada (tenofovir and emtricitabine), another drug made by Gilead, reduced infection risk by 73%.

In the second study, 1,219 sexually active men and women in Botswana were given Truvada, which was found to cut their HIV infection risk by 62.6%.

The studies were designed to evaluate pre-exposure prophylaxis, or PrEP, whereby people take HIV drugs to prevent infection. But PrEP studies have had mixed results. In an earlier PrEP study of 2,000 women in Africa, Truvada did not appear to offer protection.

In a study published in the New England Journal of Medicine in November 2010, researchers evaluated Truvada PrEP in 2,470 gay and bisexual men and 29 transgender women who had sex with men in the United States, South Africa, Thailand, Brazil, Ecuador and Peru; that study found that PrEP reduced the risk of HIV infection by 44%.