Adherence to the dapivirine vaginal ring and oral PrEP among adolescent girls and young women in Africa: interim results from the REACH study


BACKGROUND: Adolescent girls and young women (AGYW) account for most new HIV infections in sub-Saharan Africa. WHO has endorsed oral PrEP and dapivirine vaginal ring (ring) for women at substantial risk of HIV infection. However, adherence to both products was lower among younger women in randomized placebo-controlled trials. We assessed interim safety, adherence and acceptability of both products among AGYW between February 2019 and April 2021.
METHODS: MTN-034 (REACH) enrolled 16'21-year-old HIV-uninfected, non-pregnant AGYW from South Africa, Zimbabwe, and Uganda. In the first two study phases, AGYW were randomized to either monthly dapivirine ring or daily oral tenofovir disoproxil fumarate/emtricitabine (TDF/FTC) for six months, then switched to the second product for six months. Safety is assessed by '¥ grade 2 adverse events (AEs); adherence by residual drug levels in returned rings and plasma dried blood spots (DBS) for oral PrEP. In this analysis, dapivirine levels indicating release of '¥0.1071mg/day (0.9mg/28d) were defined as moderate and '¥0.1426mg/day (3.0mg/28d) as high adherence. DBS concentration of '¥700fmol tenofovir diphosphate/punch was defined as moderate adherence(associated with 100% efficacy among men who have sex with men) and '¥1200fmol/punch as high. Acceptability was measured by self-report.
RESULTS: 247 AGYW were enrolled with an average age of 18. Twenty six months into the study, retention to study visits is 94.4%. Approximately 35% of participants had at least 1 sexually transmitted infection at baseline (chlamydia: 28.7% [71/247]; gonorrhea 8.5% [21/247]). Most participants had at least moderate adherence to ring (77.8% [1064/1368]) and oral PrEP (58.6% [768/1310]). High adherence was observed in 50.2% of ring and 22.4% of oral PrEP users (687/1368 and 294/1310 of timepoints). AEs of '¥ grade 2 were experienced by 78% (187/241) of ring users and 77% (188/245) of oral PrEP users. Acceptability varied, with 88.5% (193/218) liking ring and 63.9% (140/219) liking oral PrEP. One HIV acquisition and 4 incident pregnancies were reported.
CONCLUSIONS: Adherence to oral PrEP and dapivirine ring was higher than previously observed among African AGYW, and both were well-tolerated and highly acceptable. Dapivirine ring is a viable, promising new HIV prevention method, and adherence to both products can be achieved with support strategies.