CROI 2015 Program and Abstracts

Abstract Listing

Poster Abstracts

Conclusions: All measures revealed high adherence. The distribution of adherence varied among types of self-report queries; the widest was seen with rating, suggesting greater potential utility for identifying individuals with adherence challenges. Correlation with MEMS and UPC was significant, but modest, likely reflecting differences in measurement techniques (e.g., daily variation vs monthly summaries). All measures significantly discriminated between detectable and undetectable tenofovir levels; however, MEMS performed best and is less resource intensive than UPC. 977 Self-Reported Recent PrEP Use Has Strong Relation to Drug Detection in iPrEx OLE Rivet Amico 1 ;Vanessa McMahan 2 ; Megha Mehrotra 2 ; Peter L. Anderson 2 ; Juan Guanira 2 ;ValdileaVeloso 2 ; Robert M. Grant 2 the iPrEx study team 1 University of Michigan, Ann Arbor, MI, US; 2 Gladstone Institute, San Fransicso, CA, US Background: Gross inaccuracies in participant-reported adherence has dampened or eliminated confidence in self-report as a method to characterize PrEP use. Sophisticated measurement strategies available in clinical trials, however, are unlikely candidates for adoption in clinical practice, contributing to concerns about PrEP roll-out. Self-report of self-selected open-label PrEP use has not been characterized to date and may differ from observations in efficacy trials. We examined the performance of self-report in this specific context using self-reported recent PrEP use among iPrEx open label extension (OLE) participants contrasted to drug detection. Methods: All iPrEx OLE participants choosing to receive PrEP at the 11 geographically-diverse research sites were informed that a blood specimen collected at some point during their first 12 weeks of receiving PrEP would be evaluated for drug levels and results would be shared with them. Recall of dates of last 3-doses taken was collected via interview at all on-drug visits. Drug levels were determined using blood plasma by liquid chromatography tandomMS having a lower limit of quantification of 10 ng/ml, reflecting dosing in the past 3 days. Self-report (at least one dose in the past 3-days vs no dosing) was compared to drug detection (detected versus not detected) using binary logistic regression. Results: 1172 participants had drug levels matched to self-report. The vast majority reported having had at least one dose in the past three days (84%) and of these 83% had detectable drug (PPV). Among the 16% reporting not having dosed, 82% had no drug detected (NPV). Sensitivity of self-report was 96%; specificity was 48%. Self-report was highly associated with drug level, OR 21.57 [14.42-32.26], which retained significance when controlling for site or whether the report was of taking or not taking PrEP. Age interacted with self-report and drug detection; among those reporting recent dosing, age positively associated with having drug detected. Conclusions: In this study where participants had the choice of receiving open label PrEP, reports of recent PrEP use had high association and moderate concordance with drug detection. Participants misclassified as “adherent’ via self-report tended to be younger, suggesting the need to develop alternative assessment strategies for younger PrEP users. 1 Dept of Medicine and Institute of Infectious Disease and Molecular Medicine, Cape Town, South Africa; 2 HIV Prevention Trials Network, Seattle, WA, US; 3 The Desmond Tutu HIV Centre, Cape Town, South Africa; 4 University of Michigan, Ann Arbor, MI, US; 5 Johns Hopkins University, Baltimore, MD, US; 6 University of Colorado, Aurora, CO, US; 7 FHI360, Durham, NC, US; 8 PSP/DAIDS/NIAID/NIH, Bethesda, MD, US; 9 Center for Mental Health Research on AIDS, Bethesda, MD, US; 10 University of California, San Francisco, CA, US Background: HIV pre-exposure chemoprophylaxis (PrEP) is becoming a standard of prevention care in many countries; however concerns about costs and side effects can limit uptake. The HPTN 067 ADAPT trial, a Phase II, randomized, open-label clinical trial of oral emtricitabine/tenofovir disoproxil fumarate (FTC/TDF) PrEP, included a cohort of South African women in Cape Town. The study investigated whether a nondaily versus daily regimen of FTC/TDF, resulted in equivalent prophylactic coverage of sex events, less tablets required and fewer side effects. Methods: After 6 weeks of directly observed dosing (DOT), participants were randomly assigned to one of three unblinded PrEP dosing regimens for 24 weeks of self-administered dosing: daily (D), twice weekly with a post-intercourse boost (T), or before and after intercourse (E). Pills were dispensed from a Wisepill device that recorded each opening. Participants were contacted weekly to reviewWisepill data and sex events. Plasma and PBMC were collected and analyzed for tenofovir (TFV) and FTC and their active metabolites at 10 and 30 weeks. Coverage was defined as >1 pill taken in the 4 days before and >1 pill taken in the 24 hours after sexual intercourse. Adherence was defined as the percentage of recommended pills taken for each regimen. In contrast to data from PrEP efficacy trials, results suggest that use of self-report in practice may be a valuable tool. 978LB HPTN 067/ADAPT Cape Town: A Comparison of Daily and Nondaily PrEP Dosing in AfricanWomen Linda-Gail Bekker 1 ; james Hughes 2 ; Rivet Amico 4 ; Surita Roux 3 ; Craig Hendrix 5 ; Peter L. Anderson 6 ; Bonnie Dye 7 ;Vanessa Elharrar 8 ; Michael J. Stirratt 9 ; Robert Grant 10

Poster Abstracts

579

CROI 2015