amfAR, The Foundation for AIDS Research

amfAR Welcomes iPrEx Study Results, Calls for Additional Research and Demonstration Projects

Landmark study shows pre-exposure prophylaxis (PrEP) could be an important new tool for HIV prevention among gay men and other men who have sex with men (MSM) in the U.S. and globally


For Immediate Release

Media Contact:
Cub Barrett, Program Communications Manager
(212) 806-1602

NEW YORK (November 23, 2010)—amfAR, The Foundation for AIDS Research, on Tuesday welcomed the results of a clinical trial that showed a combination of two antiretrovirals (ARVs) could significantly reduce the likelihood of HIV infection among gay men and other men who have sex with men (MSM).

The results, released Tuesday morning on The New England Journal of Medicine’s website, showed an overall 43.8% efficacy rate among study participants. Efficacy appeared to be higher among those participants who took the study drugs consistently.  

“Today marks a major step forward in our quest to combat HIV among MSM and other populations,” said amfAR CEO Kevin Robert Frost. “These results suggest that PrEP could be a very important prevention tool for gay men and MSM when used in combination with other prevention interventions including condoms. The findings underscore the tremendous return on investments in AIDS research, and the need for additional research to learn more about safety issues, whether PrEP could be protective in other populations, and the potential for intermittent use of PrEP.” 

The Pre-Exposure Prophylaxis (PrEP) Initiative, or iPrEx study, was a clinical trial aimed at determining whether two ARVs currently used to treat HIV/AIDS could also help prevent HIV infection among MSM at elevated risk of HIV infection. Two thousand four hundred and ninety-nine participants in six countries were instructed to take either one tablet of Truvada (a combination of tenofovir and emtricitabine) or a placebo, once a day. The trial began in 2007.

“Gay men and other MSM are at the highest risk of HIV infection in the United States, and there are growing rates of HIV among MSM in many other countries,” said Chris Collins, amfAR’s vice president and director of public policy. “Today’s results call for demonstration projects in which we can carefully study how to deliver PrEP in MSM communities in combination with other prevention interventions. Further PrEP clinical research is necessary, but given the severity of the MSM epidemic, we also need to move forward with implementation studies that can assess adherence, safety, and the potential to impact HIV incidence,” Collins said.

Frost and Collins stressed that in this clinical trial Truvada was tested only among high-risk MSM and that further study was necessary to determine efficacy among other groups, such as injection drug users (IDUs), female sex workers, or heterosexual women and men. Success rates were closely correlated with adherence, so in order for this type of intervention to work most effectively, people taking Truvada would need to use the drug regularly. There are potential risks in taking PrEP, including side effects and possible drug resistance. Further safety analyses will be conducted over the coming year.  

“Today’s announcement demonstrates that research is absolutely essential to our domestic and global response to HIV/AIDS,” Frost said. “Even in this difficult economic environment, investments in research continue to be validated. If we’re serious about controlling this epidemic, we need to continue to make those investments.”

About amfAR
amfAR, The Foundation for AIDS Research, is one of the world’s leading nonprofit organizations dedicated to the support of AIDS research, HIV prevention, treatment education, and the advocacy of sound AIDS-related public policy. Since 1985, amfAR has invested more than $307 million in its programs and has awarded grants to more than 2,200 research teams worldwide.