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

Abstract

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.

Keywords: MSM; On-demand HIV pre-exposure prophylaxis; adherence; sexual behavior.

Figure 1.

Condom and/or PrEP use reported during the last sexual intercourse (ANRS IPERGAY trial, n = 320 participants with at least one analyzable questionnaire between M2 and M24, corresponding to 1212 sexual intercourse analyzed). Low exposure: anal sex with condoms or oral sex; high exposure: condomless anal sex. *Total: corresponds to the number of sexual intercourses analyzed among the 320 participants between M2 and M24. **Trends were tested for each category: low exposure with PrEP (p = .49); low exposure without PrEP (p = .38); high exposure with PrEP (p = .18); high exposure without PrEP (p = .86).

Figure 2.

Use of PrEP, reported during the last anal sexual intercourse (ANRS IPERGAY trial, n = 259 participants with at least one analyzable questionnaire between M2 and M24; all of them reported at least on recent episode of anal sexual intercourse protected by PrEP use, corresponding to 731 anal sexual intercourses analyzed). PrEP correct use: according to protocol or taking at least 1 pill within 24 h before and 1 pill within 24 h after sex; PrEP suboptimal use: taking at least 1 pill 48 h before or 48 h after sex. *Total: corresponds to the number of anal sexual intercourses protected by using PrEP analyzed among the 259 participants between M2 and M24. **Trends were tested for each category: suboptimal use (p = .50); correct use (p = .50).

Figure 3.

Evolution of median number of sexual intercourse (A), sexual partners (B), condomless last insertive or receptive anal intercourse (C), and condomless last RAI (D) over time (ANRS IPERGAY trial, n = 400 participants).