This Monday, May 26, 2006 file picture shows Gilead Sciences Inc.'s Truvada pill in their lab in Foster City, Calif. Two studies announced Wednesday, July 13, 2011 show the pill Truvada helped prevent the spread of the AIDS virus between heterosexual couples in Africa. The drug is already used to treat people with HIV. (AP Photo/Paul Sakuma)

An AIDS drug already shown to help prevent spread of the virus in gay men also works for heterosexual men and women, two studies in Africa found. Experts called it a breakthrough for the continent that has suffered most from AIDS.

"These studies could help us to reach the tipping point in the HIV epidemic," said Michael Sidibe, executive director of the United Nation's AIDS program, in a statement Wednesday as the studyresults were announced.

"This is really a game changer," said Dr. Jared Baeten, the University of Washington researcher who was a leader of one of the studies.

The prevention drug is Truvada, a pill already on pharmacy shelves to treat people with HIV. It's made by Gilead Sciences Inc. of Foster City, Calif. Another Gilead drug, Viread, was also used in one of the two African studies.

Earlier research with Truvada found it prevented spread of HIV to uninfected gay men. But experts were thrilled Wednesday at the first compelling evidence that AIDS medications can prevent infection between men and women. The U.S. Centers for Disease Control and Prevention, which gave advice last fall for use of the preventive drugs among gays, is now developing guidance for heterosexuals in this country.

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