A new study has demonstrated that individuals at high risk for HIV infection who took a daily tablet containing an HIV medication - either the antiretroviral medication tenofovir or tenofovir in combination with emtricitabine - are less likely to become infected with HIV than those who received a placebo pill.
These findings are clear evidence that this new HIV prevention strategy, called pre-exposure prophylaxis (or PrEP), substantially reduces HIV infection risk.
The study, led by the University of Washington’s International Clinical Research Center, involves 4,758 HIV serodiscordant couples, in which one partner has HIV and the other does not, from nine research sites in Kenya and Uganda.
“This study is the largest study to date looking at the effectiveness of PrEP,” said Dr. Connie Celum, Professor of Global Health and Medicine at the University of Washington and principal investigator of the study, known as the Partners PrEP Study. “This study demonstrates that antiretrovirals are a highly potent and fundamental cornerstone for HIV prevention and should become an integral part of global efforts for HIV prevention.”
Study results up to the end of May 31 were reviewed this month (July) by the Partners PrEP Study Data and Safety Monitoring Board (DSMB), an independent group of experts that monitors the study’s conduct and safety, as well as the ongoing effect PrEP may have on preventing HIV infections.
Due to the strong HIV prevention effect seen, the DSMB recommended that the Partners PrEP Study results be made public and the placebo arm of the trial discontinued.
A total of 78 HIV infections occurred in the study, among which 18 were taking tenofovir (TDF), 13 were taking tenofovir combined with emtricitabine (FTC/TDF), and 47 were taking the placebo. This means those who received TDF had an average of 62 per cent fewer HIV infections and those who received FTC/TDF had 73 per cent fewer HIV infections than those who received placebo.
“This is an extremely exciting finding for the field of HIV prevention,” said Dr. Jared Baeten, co-chair of the study and an Associate Professor of Global Health and Medicine at the University of Washington. “Now, more than ever, the priority for HIV prevention research must be on how to deliver successful prevention strategies.”
TDF and FTC/TDF were statistically similar in their levels of protection against HIV and reduced HIV risk in both women and men. PrEP was found to be safe, that is, the rate of serious medical events was similar for those assigned to TDF, FTC/TDF, and placebo.
Ten percent of women who became pregnant during the study were discontinued from the study medication. Pregnancy rates were similar across the three arms and there was no evidence that TDF or FTC/TDF was associated with pregnancy complications.
The study was designed to find out whether TDF or FTC/TDF would reduce the risk of acquiring HIV for persons who had an HIV infected sexual partner.
Of the 4,758 couples enrolled in the study, one-third of the HIV uninfected partners were randomly allocated to receive TDF, a third of FTC/TDF, and a third of matching placebo.
The study was funded by the Bill and Melinda Gates Foundation.
For more information log on to www.uwicrc.org
