Incentives conditioned on tenofovir levels to support PrEP adherence among young South African women: a randomized trial

INTRODUCTION: HIV incidence remains high among African adolescent girls and young women (AGYW), who would benefit from pre‐exposure prophylaxis (PrEP). Strategies to increase PrEP adherence and persistence need to be evaluated in African AGY, including incentives conditional on high adherence. METHODS: The 3Ps for Prevention Study was a 12‐month prospective cohort of 200 women ages 16 to 25 initiating PrEP in South Africa from 2017 to 2018. Participants received retrospective feedback about drug levels at Months 1, 2 and 3; half was randomized to receive a 200 Rand shopping voucher ($13 US) at Months 2, 3 and 4, conditioned on high intracellular tenofovir diphosphate (TFV‐DP) levels in dried blood spots (≥500 fmol/punch at Month 1, ≥700 fmol/punch at Months 2 and 3). The primary analysis was intention‐to‐treat, comparing the proportion with high PrEP adherence (≥700 fmol/punch) at Month 3 by randomized group, based on 100% efficacy among men who have sex with men. RESULTS: Median age of the 200 women was 19 years (interquartile range [IQR] 17, 21); 86% had a primary sexual partner. At Month 3, the mean TFV‐DP level was 822 fmol/punch (SD 522) in the incentive group and 689 fmol/punch (SD 546) in the control group (p = 0.11). Forty‐five (56%) of 85 women in the incentive group and 35 (41%) of 85 women in the control group had TFV‐DP levels ≥700 fmol/punch (RR 1.35; 95% CI 0.98, 1.86; p = 0.067), which declined to 8% and 5% in the incentive and control groups at Month 12 (no significant difference by arm). 44% refilled PrEP without gaps, 14% had a gap of ≥3 weeks in coverage subsequently restarted PrEP and 54% accepted at the final dispensing visit at Month 9. No new HIV infections were observed after PrEP initiation. CONCLUSIONS: Among South African AGYW initiating PrEP, drug levels indicated high PrEP adherence in almost half of women at Month 3, with a non‐statistically significant higher proportion with high adherence among those in the incentive group. Over half persisted with the 12‐month PrEP programme although high adherence declined after Month 3. Strategies to support PrEP adherence and persistence and longer‐acting PrEP formulations are needed.