FOSTER CITY, Calif. (KGO) -- A drug developed in the Bay Area is showing that it works in preventing HIV from spreading, according to a new study.
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Research with the Kirby Institute found that no new cases of HIV developed in a study of more than 350 gay male couples having unprotected sex.
Those couples include one partner who has tested positive for HIV and another who is negative.
The HIV-negative partners used the drug called Pre-Exposure Prophylaxis or PREP.
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It's also called Truvada.
Foster City-based Gilead is the manufacturer.
To learn more about PREP click here.