APLA Champions Evidence of PrEP's Effectiveness

AIDS Project Los Angeles (APLA) and APLA Health & Wellness this week welcome the results from two major studies showing that pre-exposure prophylaxis (PrEP) is highly effective in preventing new HIV infections among gay, bisexual, and other men who have sex with men (MSM). Findings from the PROUD and IPERGAY studies were presented February 24 at the 2015 Conference on Retroviruses and Opportunistic Infections (CROI) in Seattle.

Both studies found that PrEP reduced the risk of becoming infected with HIV by 86 percent. PrEP is the process of people who are HIV-negative taking a medication every day to reduce the risk of HIV infection. Truvada is currently the only drug approved for PrEP in the United States.

"These results add to the growing body of evidence that PrEP is an extremely effective tool to help prevent the spread of HIV," APLA and APLA Health & Wellness Chief Executive Officer Craig E. Thompson says. "They also highlight the urgent need to accelerate efforts to increase education, awareness, and access to PrEP for those who would benefit from it most."

The PROUD study in the United Kingdom found that, overall, taking PrEP once a day reduced the risk of HIV infection among high risk MSM by 86 percent. Although the researchers did not examine participants' personal level of adherence to the drug, those who took Truvada every day without missing any doses likely had an even higher rate of protection.

The IPERGAY study, conducted with high-risk HIV-negative MSM in France and Canada, examined the effectiveness of a new dosing strategy for PrEP, known as "PrEP on demand." Participants in this study were instructed to take Truvada around the time they planned to have sex.

Specifically, they were instructed to take two doses of the drug between two and 24 hours before sex (or one pill, if the most recent dose was taken between one and six days before), and then, if sex did occur, to take one dose every 24 hours after that first dose, until they had taken two pills since the last time they had sex.

Researchers found that participants using this dosing strategy reduced the risk of HIV infection by 86%. However, because participants in this study were having sex frequently (a median of 10 sex acts per month), on average they took about three to four pills per week.

According to the CDC's statement on the IPERGAY study: "Researchers do not yet know if this regimen will work among MSM who have sex less frequently and would therefore be taking PrEP less often. It is not known whether the regimen will work if taken only a few hours or days before sex, without any buildup of the drug from prior use."

"The maximum protection is still afforded by taking Truvada daily," says Dr. Raphael J. Landovitz, MD, MSc, of the UCLA Center for Clinical AIDS Research & Education. "The IPERGAY study reinforces that there is some forgiveness to daily dosing, but we do not yet have a full understanding of how to time dosing around sex to routinely recommend it -- daily dosing is the safest method that we can recommend at this time."

"These studies provide further evidence of PrEP's potential to dramatically reduce new HIV infections," Thompson adds. "APLA and APLA Health & Wellness encourage everyone at risk for HIV infection to talk with a medical provider about PrEP, as well as other HIV-prevention options."