Sexual Risk and Study Drug Detection in MSM Participants in a Phase II Study of Maraviroc (MVC) +/- Tenofovir DF (TDF) or FTC versus TDF/FTC for PrEP

Presented at HIVR4P 2018 – (P05.06) Sexual Risk and Study Drug Detection in MSM Participants in a Phase II Study of Maraviroc (MVC) +/- Tenofovir DF (TDF) or FTC versus TDF/FTC for PrEP

Kenneth Mayer, Krista Yuhas, K. Rivet Amico, Timothy Wilkin, Raphael Landovitz, Paul Richardson, Mark Marzinke, Craig Hendrix, Susan Eshleman, Leslie Cottle, Adriana Andrade, Karen Klingman, Wairimu Chege, Alex Rinehart, James Rooney, Phillip Andrew, Ying Chen, Marybeth McCauley, Roy Gulick, HPTN 069/ACTG 5305 Study Group

Background: PrEP effectiveness depends on medication adherence while engaging in HIV risk behavior. We evaluated antiretroviral (ARV) plasma concentrations in relation to reported sexual risk behavior in a study of MVC +/- TDF or FTC versus TDF/FTC for PrEP in at-risk MSM and cis- or transgender women (HPTN 069/ACTG 5305).

Methods: The current analysis included data from 226 participants (pts) who were male at birth for whom computer-assisted self-interview behavioral data and plasma ARV drug assays were available at 24 and/or 48 week visits. Poisson generalized estimating equations (GEE) regression were used to test for associations between sexual risk, sociodemographic and behavioral variables, and study drug detection. Covariates associated with the outcome at p< 0.10 in bivariate analyses were included in a multivariable model

Results: The median (IQR) age was 30 (25, 37) years old; 98% identified as MSM. Almost half (48.2%) had completed college; 27.4% were Black and 21.7% Latino. At weeks 24 and 48, equal proportions of pts reported condomless anal sex (CAS) in the prior month with 0, 1 or >1 partners. The prevalence of CAS was similar at 24 and 48 weeks. Study ARV’s were detected in the plasma of 69% of those who reported no CAS at week 24 or 48, compared to 92% who reported CAS with 1 partner and 92% of those who reported CAS with >1 partner during the same time period. GEE models found that CAS was associated with detectable ARV drug concentrations (p value < 0.001). Individuals with greater education were more likely to have detectable plasma ARV drugs (p value = 0.005), while age, race or ethnicity were not associated with ARV drug detection.

Conclusions: In a study in which all participants received at least one ARV for PrEP, pts who reported condomless anal sex and/or advanced education had higher rates of ARV drug detection. Findings suggest that CAS, education and PrEP adherence are related; thus, engaging PrEP users in understanding their HIV risks may facilitate prevention effective PrEP use.