A pre-exposure prophylaxis (PrEP) regimen of tenofovir/emtricitabine taken before and after sex reduced the risk of HIV among men who have sex with men (MSM) by an average of 86%, according to results presented by a French national HIV research agency. The study was presented by the ANRS agency at the Conference on Retroviruses and Opportunistic Infections (CROI).

The IPERGAY trial was a randomized, placebo-controlled study that enrolled 400 participants beginning in February 2012. Due to high efficacy results, the study was stopped by an independent data safety review board in October 2014. Study participants were instructed to take the pills three days around the time of sex:

  • Two pills between 2-24 hrs before sex (or 1 pill if last doe was taken 1-6 days ago)
  • Two additional single-pill doses 24 and 48 hours after last pre-sex dose
  • One pill daily if additional sex events took place before the regimen was completed

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These results show evidence that an event-driven regimen was effective for high-risk MSM who have frequent sex (median 10 sex acts/month and eight partners every two months). Researchers also presented results from the PROUD study, which found that daily oral PrEP with tenofovir/emtricitabine lowered risk among MSM by 86%.

The Centers for Disease Control and Prevention (CDC) reports that researchers are not sure if an event-driven regimen will work among MSM who have sex less frequently or among those at high-risk for HIV infection; study data suggested participants were taking PrEP about 3-4 days a week. Further, there was no data on the efficacy for heterosexual men and women, injection drug users, or on regimen adherence outside a trial environment.

The CDC still recommends only daily use of PrEP as approved by the Food and Drug Administration (FDA), and to follow current CDC guidelines for those at substantial risk for HIV infection.

For more information visit CDC.gov.