Studies show HIV medications used as preventive measure can fight infections
Wednesday, July 13, 2011 at 8:14 pm
HIV researchers on Wednesday announced that two new studies on the use of anti-retroviral medications as a preventative measure in those not infected with the virus that causes AIDS have proven effective in heterosexuals.
The Centers for Disease Control and Prevention made its announcement Wednesday morning following the unexpected release of study data on a Washington University study of the medications use in Africa.
The use of anti-retrovirals taken before any exposure to HIV is called Pre-Exposure Prophylaxis, or PrEP. Those exposed to HIV can use the medications to prevent infection, but only if the medication is provided within 72 hours of exposure. That procedure is dubbed Non-Occupational Post Exposure Prophylaxis, or n-PEP.
The Washington study found the use of tenofovir (TDF) and tenofovir combined with emtricitabine (FTC/TDF) proved effective at preventing transmission compared with the effects of a placebo.
Through May 31, 2011, a total of 78 HIV infections occurred in the study: 18 among those assigned TDF, 13 among those assigned to FTC/TDF, and 47 among those assigned placebo. Thus, those who received TDF had an average of 62% fewer HIV infections (95% CI 34 to 78%, p=0.0003) and those who received FTC/TDF had 73% fewer HIV infections (95% CI 49 to 85%,p<0.0001) than those who received placebo.
The FTC/TDF pill is sold under the brand name Truvada.
“This is an extremely exciting finding for the field of HIV prevention. Now, more than ever, the priority for HIV prevention research must be on how to deliver successful prevention strategies, like PrEP, to populations in greatest need,” said Dr. Jared Baeten, co chair of the study and a UW associate professor of global health and medicine. “We are incredibly grateful to the investigators, site teams, participants, and communities for their dedication to this research and to HIV prevention. The level of investment and motivation from each of these groups was tremendous.”
In the CDC study, conducted with the assistance of the Botswana Ministry of Health, researchers found that once daily Truvada had an average of 63 percent success in preventing heterosexual men and women from being infected with HIV.
“These are exciting results for global HIV prevention. We now have findings from two studies showing that PrEP can work for heterosexuals, the population hardest hit by HIV worldwide,” said Kevin Fenton, M.D., director of CDC’s National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention. “Taken together, these studies provide strong evidence of the power of this prevention strategy.”
An earlier study — called iPrEx — of men who have sex with men found that daily Truvada had an overall efficacy rate of 44 percent in preventing infections in that group. Those who actually took the pill daily as prescribed were found to have significantly higher efficacy rates. That study led the Centers for Disease Control and Prevention in Atlanta to issue interim guidance on prescribed Truvada as a preventative measure in February.
The Washington University study and the CDC/Botswana study are the first to show PrEP works in heterosexuals and the CDC is now beginning the process of developing guidance for PrEP in heterosexuals.
But the studies may only add to a continuing crisis and questioning about the cost of HIV medications. Right now, Truvada costs about $12,000 a year. While those medication costs are covered by Michigan’s AIDS Drug Assistance Program (ADAP) for people who are living with HIV, there is no program to fund PrEP of n-PEP.