Background:

Young women aged 15–24 years are disproportionately affected by the HIV epidemic. Two phase III trials of a vaginal ring containing 25-mg dapivirine demonstrated HIV-1 risk reduction in adult women older than 21 years but not in those aged 18–21 years. Lack of protection was correlated with low adherence.

Methods:

In this phase-IIa, randomized, double-blind, placebo-controlled, US, multicenter trial of the dapivirine ring in sexually active females, aged 15–17 years, participants were randomized 3: 1 to a dapivirine or placebo ring to be inserted monthly for 6 months (NCT02028338). Primary safety end points included grade 2 product related adverse events and any grade 3 and higher adverse events. Adherence to ring use was assessed by plasma dapivirine concentrations, residual levels in used rings, and self-report. A plasma dapivirine concentration of> 95 pg/mL was used to define short-term adherence; a residual ring level of< 23.5 mg was used to define long-term adherence. Acceptability was assessed through computer-assisted self-interviews.

Results: