Antiretroviral Drugs Could Prevent Vaginal Transmission Of HIV

Antiretroviraldrugs might be effective at preventing the vaginal transmission of HIV,according to a study published in the Jan. 14 issue of PLoS Medicine,the Austin American-Statesman reports. For the study, VictorGarcia-Martinez, professor of internal medicine at the University of Texas-Southwestern, and colleagues engineered micewith human stem cell transplants so the mice's bodies would mimic how a humanimmune system would react to HIV (Roser, Austin American-Statesman,1/15).

Researchers then gave the mice daily doses of the antiretroviral drugsemtricitabine and tenofovir disoproxil fumarate for seven consecutive days,starting 48 hours before intravaginal exposure to HIV, the ANI/New Kerala reports. The study showed thatnearly 90% of the mice that did not receive antiretrovirals contracted thevirus, but none of the mice that received antiretroviral treatment testedHIV-positive, ANI/New Kerala reports.

"Our observations support the potential for [antiretroviral drugs] tofunction as an effective pre-exposure prophylaxis against further spread ofAIDS," Garcia-Martinez said. However, he added that the humanized mousemodel "clearly recapitulates very important aspects of humans, but at theend of the day, these are mice. It will take additional work to translateobservations to humans" (ANI/New Kerala, 1/15).

Human clinical trials under way in Africa, Thailandand the U.S.are testing Garcia-Martinez's concept and could "propel the researchahead," the American-Statesman reports. Garcia-Martinez saidhe expects trial results in three years. He added that Africawould stand to benefit the most if the research proves effective but that PrEPcampaigns would require major funding. Antiretrovirals cost about $3,500 ormore annually and can cause side effects, David Wright, principal investigatorof AIDS research at Central Texas Clinical Research, said, adding that developing countriesdo not have "enough money to buy" the drugs even for those who areliving with the disease. Wright also raised the concern that people takingantiretrovirals as a method of PrEP might forgo using condoms.

Garcia-Martinez said his team did not analyze either issue. "We provedthat transmission via the vaginal tract can be prevented. We can't control whatfree people are going to do," he said (Austin American-Statesman,1/15). He added, "Our motivation is to look for interventions that can beimplemented rapidly and have the potential to make a big difference. We don'twant something in 10 years. We want female-controlled prevention measuresnow" (HealthDay/Yahoo News!, 1/15). Rowena Johnston, vice presidentfor research at the American Foundation for AIDSResearch, said,"The principle of this paper is a very important one. We need differentways of attack" (Austin American-Statesman, 1/15).

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