High adherence to on-demand PrEP and no increase in sexual risk behaviours

Uptake of PrEP and condom and sexual risk behavior among MSM during the ANRS IPERGAY trial.

Sagaon-Teyssier L, Suzan-Monti M, Demoulin B, Capitant C, Lorente N, Preau M, Mora M, Rojas Castro D, Chidiac C, Chas J, Meyer L, Molina JM, Spire B, Group AIS. AIDS Care. 2016 Feb 17:1-8. [Epub ahead of print]

The double-blind phase of the randomized ANRS IPERGAY trial, evaluating sexual activity-based oral HIV pre-exposure prophylaxis (PrEP), was conducted among high-risk men who have sex with men (MSM). Results showed an 86% (95% CI: 40-98) relative reduction in HIV incidence among participants with tenofovir disoproxil fumarate-emtricitabine vs. placebo. The present pooled analysis aimed to analyze (i) participants' adherence to the prescribed treatment and/or condom use during sexual intercourse and (ii) sexual behavior during the double-blind phase of the study. Four hundred MSM were enrolled in the trial. Every 2 months they completed online questionnaires collecting sexual behavior and PrEP adherence data regarding their most recent sexual intercourse. A total of 2232 questionnaires (M0-M24) were analyzed. Changes over time were evaluated using a mixed model accounting for multiple measures. Irrespective of sexual partner and practice type, on average, 42.6% (min: 32.1-max: 45.8%) reported PrEP use only during their most recent episode of sexual intercourse; 29% (22.9-35.6%) reported both PrEP and condom use; 11.7% (7.2-18.9%) reported condom-use only, and 16.7% (10.8-29.6%) reported no PrEP or condom use with no significant change during the study. Scheduled (i.e., correct) PrEP use was reported on average by 59.0% (47.2-68.5%) of those reporting PrEP use during their most recent sexual intercourse. Overall, 70.3% (65.3-79.4%) and 69.3% (58.3-75.4%) of participants reported, respectively, condomless anal and condomless receptive anal intercourse during their most recent sexual encounter without significant change during follow-up. Overall, on average 83.3% (min: 70.4-max: 89.2%) of participants protected themselves by PrEP intake or condom use or both during the trial, and no increase in at-risk sexual practices was observed. None of these indicators showed significant trend during the follow-up, although we found a tendency toward decrease (p = .19) of the median number of sexual partners strengthening the absence of behavioral disinhibition. On-demand PrEP within a comprehensive HIV prevention package could improve prevention in MSM.

Abstract access [1]

Editor’s notes: HIV pre-exposure prophylaxis (PrEP) is an effective method of HIV prevention, and it is now recognised as a key element of combination prevention strategies in key populations. The IPERGAY trial evaluated the intermittent use of oral PrEP, timed around sexual activity, in gay men and other men who have sex with men. The investigators hypothesised that taking PrEP ‘on demand’, i.e. at the time of sexual activity rather than daily, would improve adherence and therefore its effectiveness. The reduction in HIV incidence in the trial is one of the highest reported at 86%.

This analysis of trial participants in the double-blind phase of the trial demonstrated that PrEP and/or condom use at the most recent sexual intercourse was reported at 80% of visits, and there was no evidence of a change over time. Adherence remained quite high over the 24 months of follow-up, with 60% reporting correct use of PrEP at each visit, although numbers were small owing to early stopping of the placebo arm. As with other studies of PrEP, there was no evidence of an increase in reported sexual risk behaviours over time. In addition, there was some suggestion of a trend towards a decreased number of partners. However, as trial participants were offered a comprehensive care package (including regular adherence and risk reduction counselling), it is difficult to separate the effects of the intensive support from the effects of the PrEP regimen itself.

The successful integration of PrEP into HIV combination prevention programmes will require an understanding of factors that facilitate its uptake and who is most likely to benefit from its use, as well as ensuring regular HIV testing and adequate support services are available.

Europe [4], Northern America [5]
Canada [6], France [7]
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