Effectiveness and Acceptability of urine tenofovir drug-level feedback on HIV pre- exposure prophylaxis adherence in young South African women

Abstract

Background Oral pre-exposure prophylaxis (PrEP) adherence in young African women has been suboptimal, necessitating interventions to improve PrEP adherence. We conducted a pilot randomised controlled trial to evaluate the effectiveness of drug-level feedback (DLFB) counselling based on a point-of-care (POC) urine tenofovir assay on PrEP adherence in young South African women. Methods Nested within the INSIGHT observational cohort in Johannesburg, South Africa, we randomised cisgender women aged 16-30 years one month after initiating PrEP to either DLFB based on a POC urine test or standard of care (SOC). The primary outcome of tenofovir diphosphate (TFV-DP) ≥700 fmol/punch in dried blood spots (DBS), indicating high adherence, was assessed two months later and analysed by intent-to-treat. Acceptability of DLFB counselling was assessed by self-administered questionnaire. Baseline characteristics associated with TFV-DP ≥700 fmol/punch at the outcome visit were assessed in multivariate analysis using modified Poisson regression. Results From Nov 2022 to Jan 2023, 103 participants (53 POCT; 50 SOC) were enrolled; 15% (15/103) with previous PrEP experience and a median age of 24 (IQR: 21-27) years. At randomisation 83% (44/53) had a positive POC urine test. Overall, median follow-up time to outcome visit was 51 days (interquartile range [IQR] 48-56), and 96% (99/103) completed follow up. At the outcome visit, 17% (17/103) had TFV-DP>700 fmol/punch detected; 19% (10/53) in the DLFB group compared to 14% (7/50) in the SOC group (relative risk [RR] 1.35, 95% confidence interval [CI] 0.56-3.27) in the intent-to-treat analysis. Participants found DLFB based on the POC urine test highly acceptable. Participants liked receiving POC test results on the same day as PrEP refill (90%, 44/49) and reported that DLFB counselling would motivate more frequent PrEP use (92%, 45/49). No baseline characteristics were significantly associated with high adherence in multivariate analysis. Conclusion: In this pilot randomised evaluation, real-time adherence counselling based on a POC urine TFV test is a promising intervention that was highly acceptable to young women and associated with a trend towards higher adherence compared to SOC, but this was not statistically significant. v These findings should be confirmed in larger randomised studies with robust estimates of effectiveness, longer follow-up, and cost-effectiveness evaluations to inform program implementation on oral PrEP adherence support.