On-Demand Pre-Exposure Prophylaxis Drastically Reduces HIV Risk

The final phase of a double-blind study confirmed that on-demand pre-exposure prophylaxis (PrEP) is highly effective in reducing the risk of HIV in seronegative men who have sex with men (MSM), and who report high-risk behavior.

ANRS IPERGAY is a French-Canadian study conducted with the HIV-AIDS community organization AIDES, with the first phase of the study started in 2012. Participants were randomized to receive either an oral antiretroviral combining TDF and FTS (Truvada) at the time of sexual relations or a placebo.

The results of this study showed that Truvada reduced the risk of HIV infection by 86%. When the findings became available in November 2014, ANRS IPERGAY entered into its second and last phase.

The primary goal of the last phase was to confirm the benefits of on-demand PrEP and long-term safety. Additionally, the study also examined its impact on sexual behavior.

In the study, all participants were given Truvada. The results of the follow-up between November 2014 and June 2016 conducted in 362 volunteers, 333 of whom participated in the randomized phase plus 29 new recruits, were more impressive than the findings of the first phase.

In the open-label phase, 1 person who interrupted PrEP was infected by HIV. The incidence was found to be only 0.19 infections per 100 person-years of follow-up. In the Truvada arm, the incidence during the double-blind phase was 0.91%.

“The results of the ‘open-label’ phase of the trial confirm the very good efficacy and safety of on-demand PrEP in reducing the risk of HIV infection in high-risk MSM,” said researcher Jean-Michel Molina. “These results should promote broader use of PrEP in at-risk populations in countries where justified by the epidemic situation.”

The findings were presented at the international AIDS 2016 conference in South Africa.

“The question today is no longer to know whether PrEP is effective and should be used, but rather how to make it available rapidly to the people most at risk,” said Jean-François Delfraissy, director of ANRS.

In regards to condom use, a study of sexual behavior during the open-label phase of the trial showed a slight drop in the use of condoms. Researchers found that this was particularly seen among individuals identified as being keen users of condoms in the double-blind phase.

However, in the vast majority of cases, the use of PrEP ended up compensating for the decline.

“The decrease in condom use in the ‘open-label’ trial is not worrying at present,” said researcher Bruno Spire. “The trial participants were sure of being protected by PrEP, which they knew is effective. A small minority of participants, however, use neither PrEP nor condoms. We must try to understand what is holding them back. Henceforth it seems important to speak of diversified prevention, which includes freedom of choice, rather than combined prevention, because it is somewhat illusory to imagine that most people will be able to use several methods of prevention at the same time.”