Antiretroviral Drugs Could Prevent HIV Transmission

Antiretroviraldrugs might be effective at preventing the transmission of HIV, according to astudy published online in the February issue of PLoS Medicine, theSan Jose Mercury News reports (Johnson, San JoseMercury News, 2/4). For the study, Jose Gerardo Garcia-Lerma of CDC andcolleagues exposed five groups of macaques to SIV, the simian form of HIV, oncea week for 14 weeks.

Researchers then gave four groups various dosages and combinations of Emtriva,or emtracitibine, and Viread, also known as tenofovir. The remaining group didnot receive antiretrovirals (Joshi, ANI/Topnews, 2/5). One group received a dailyinjection of emtracitibine, which reduced the risk of HIV transmission by3.8-fold compared with the control group. A second group received daily oral dosesof both emtracitibine and tenofovir, which reduced the risk of transmission by7.8-fold compared with the control group. A third group of macaques receiveddaily injections of emtracitibine and higher doses of tenofovir before beingexposed to SIV, and the fourth group received the same combination before andafter exposure to the virus. Walid Heneine, a CDC researcher and co-author ofthe study, said the combination of emtracitibine and higher doses of tenofovirprovided 100% protection against SIV.

"The findings from this intermittent study suggests that ultimately it ispossible to provide a promising new avenue for future research, where it opensup the floor for a lot of more research for intermittent dosing," Heneinesaid (Berman, VOA News, 2/5). Heneine cautioned that theformulation the monkeys received contained more tenofovir compared with theversion administered to humans. He added that it is too early to know if thecombination could prevent HIV transmission among humans. According to the MercuryNews, other studies to test if the combination could prevent HIV inhumans are under way in the U.S.and several other countries (San Jose Mercury News, 2/4).

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