CROI 2019 Abstract eBook

Abstract eBook

Poster Abstracts

taking ≥4 tablets/week, those who took ≤2 or 2−3 tablets had an IRR (95% CI) of 24.56 (7.48−80.63) or 11.44 (2.96−44.23), respectively. Individuals over 40 years old were more likely to be taking ≥4 tablets/week, the established protective dosage of FTC/TDF PrEP, as compared to those aged 30−39 years [OR (95% CI)=1.53 (1.18−2.00)]. Younger participants were less likely to remain adherent at ≥4 tablets/week [OR (95% CI)=0.73 (0.57−0.92)] for individuals age 25−29 and 0.30 (0.23−0.38) for those under 25 years. Conclusion: In this multi-national pooled analysis of FTC/TDF PrEP use in a diverse geographical population of MSM, individuals taking ≥4 tablets/week were protected from HIV infection at a low incidence rate of 0.14/100 person- years. Age over 40 years was significantly associated with increased adherence. 987 PREDICTORS OF LONG-TERM HIV PrEP ADHERENCE AFTER TRIAL PARTICIPATION IN MSM Martin Hoenigl 1 , David J. Moore 1 , Peter L. Anderson 2 , Katya Calvo 3 , Michael Dube 4 , Eric Ellorin 1 , Jill Blumenthal 1 , Sheldon Morris 5 , for the California Collaborative Treatment Group (CCTG) 601 Team 1 University of California San Diego, San Diego, CA, USA, 2 University of Colorado Anschutz Medical Campus, Aurora, CO, USA, 3 Harbor–UCLA Medical Center, Torrance, CA, USA, 4 University of Southern California, Los Angeles, CA, USA, 5 University of California San Diego, La Jolla, CA, USA Background: The efficacy of tenofovir disoproxil fumarate (TDF) / emtricitabine (FTC) for HIV pre-exposure prophylaxis (PrEP) in men who have sex with men (MSM) has been well documented in randomized controlled trials. Following trial completion, participants are challenged with establishing care, acquiring PrEP, and remaining adherent. This study aimed to identify predictors of PrEP adherence during a 12-month post trial period. Methods: This study followed an existing PrEP demonstration project, the TAPIR randomized controlled multi-center trial of text messaging versus standard care for adherence to daily TDF/FTC PrEP in MSM, conducted in Southern California between 2014-2016 (NCT01761643). At the last TAPIR trial visit, study provided PrEP was discontinued and participants were provided with information about where to obtain PrEP in the community. During week 48 of the TAPIR trial and during prospective observational post-trial visits at months 6 and 12, adherence was estimated by dried blood spot (DBS) intracellular tenofovir diphosphate (TFV-DP) levels. Adequate adherence was defined as TFV-DP concentration of >719 fmol/punch reflecting four or more tablets per week. Binary logistic regression analysis was performed to assess predictors of completing post-trial visits and PrEP adherence among those who completed ≥ 1 visit. Results: Of 395 TAPIR participants who were provided with free PrEP during TAPIR for a median of 585 days (range 3-757 days), 113 (29%) completed one or more post-trial visits. Multivariate predictors of completing post-trial visits included adequate adherence at the week 48 TAPIR visit, total days of TAPIR participation, and less problematic substance use (Table). Among 113 participants who completed ≥ 1 post-trial visit, 67 (59%) had adequate adherence at their last post-trial visit. Adequate adherence at the week 48 TAPIR trial visit was the only significant predictor of adequate adherence post trial (Table). Participants with adequate adherence at the week 48 TAPIR visit had also significantly higher DBS TFV-DP levels at last post-trial follow up (median 993 fmol/punch, IQR 0-1397 vs. median 636 fmol/punch, IQR 0-758; p=0.03). Conclusion: PrEP users followed for up to 3 years had high rates of adequate adherence suggesting that PrEP can be used effectively by individuals for years. Longer term adequate adherence was best predicted by having adequate adherence at week 48 of the PrEP trial. Additional measures are needed for those that have persistent low PrEP adherence.

Poster Abstracts

988 PrEP STIGMA PREDICTS PrEP UPTAKE AND ADHERENCE: RESULTS FROM THE RADAR COHORT STUDY Brian Mustanski , Michael E. Newcomb, Daniel T. Ryan Northwestern University, Chicago, IL, USA Background: Increasing the uptake of pre-exposure prophylaxis (PrEP) to prevent HIV acquisition among at-risk populations, such as young men who have sex with men (YMSM), is of vital importance to slowing the HIV epidemic. Stigma and negative injunctive norms, such as the so called “Truvada Whore” phenomenon, hamper this effort. In our prior research we developed a measure of PrEP Stigma and Positive Attitudes (PSPA) and demonstrated that these injunctive norm beliefs differ by race/ethnicity and cluster geographically among YMSM in Chicago. Methods: PSPA were measured in 622 participants in the RADAR longitudinal cohort study of YMSM and transgender women living in Chicago (YMSMT). Analyses were conducted on data from 105 YMSMT with PSPA measured at two time points 6 months apart (to assess measure stability), and 622 participants who reported on PSPA at one time point and reported on PrEP use and adherence 6 months later. Results: There were no significant changes in either dimension of PSPA over 6 months. Participants with higher PrEP stigma were significantly less likely to report currently taking PrEP at the next visit 6 months later (OR=0.49, 95% CI: 0.29, 0.82) while controlling for age, race and gender identity. Of those participants taking PrEP at the next visit (n=24), participants who reported missing at least one dose in the past week had significantly higher PrEP stigma scores (t=-2.39, P < .05) compared to participants who did not miss a dose in the past week. Participants with higher positive attitudes towards PrEP were significantly more likely to have reported currently taking PrEP at the next visit (OR=5.07, 95% CI: 2.42, 10.61) while controlling for age, race and gender identity. Conclusion: These results provide important information about PrEP attitudes and how PrEP stigma is related to PrEP uptake and adherence. In concert with previously published cross-sectional research on PrEP stigma, these prospective findings demonstrate the importance of addressing PrEP stigma in order to improve uptake and adherence among populations in greatest need of HIV prevention interventions. 989 LONGITUDINAL PREDICTORS OF PrEP DISCONTINUATION AMONG YMSM AND TRANSGENDER WOMEN Michael E. Newcomb , Ethan Morgan, Brian Feinstein, Brian Mustanski

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