Tenofovir Microbicidal Gel Significantly Cuts HIV Infection Rate

Tenofovir Microbicidal Gel Significantly Cuts HIV Infection Rate

by David Evans

After decades of research, a microbicidal gel—in this case made from the antiretroviral drug tenofovir—has finally proved effective in preventing transmission of HIV in women, cutting the overall infection rate by 39 percent. These data were reported Tuesday, July 20, at the XVIII International AIDS Conference in Vienna and were met with a prolonged standing ovation from delegates in attendance.

The results were also published online  July 19 in the journal Science.

AIDS researchers have been seeking a biomedical HIV prevention tool since the virus was first isolated 27 years ago. During the past 15 years, given the poor progress being made on a vaccine, much attention has been focused on developing microbicidal gels. Unfortunately, 11 studies of six different products have so far failed to find an effective microbicide, and at least one study found that the microbicide being tested actually placed women at greater risk of contracting HIV.

Experts and community advocates have placed much hope, however, in a new group of microbicides that are being developed using existing and experimental drugs initially designed to treat HIV. The first of these to be explored is the drug tenofovir, which in its oral form is sold as Viread (also found in Truvada and Atripla).

Previous studies have reported that a 1 percent tenofovir gel was highly effective at reducing viral transmission in monkeys, either when used daily or intermittently. Small studies in humans found the gel generally safe and well tolerated. The first large study to explore the effectiveness of the gel in humans was the Centre for the AIDS Program of Research in South Africa (CAPRISA) 004 study, the results of which were reported today