Vaginal Ring Containing Dapivirine Helps Protect Against HIV Infection in Women

Finding an effective HIV prevention intervention for women in sub-Saharan Africa has been challenging. Three trials have failed to demonstrate efficacy of tenofovir-containing tablets or a vaginal gel as preexposure prophylaxis in this population, primarily because of poor adherence (NEJM JW Infect Dis Mar 2015 and N Engl J Med 2015; 372:509; NEJM JW Infect Dis Jul 11 2012; [e-pub] and N Engl J Med 2012; 367:423 and 411). A vaginal ring has been proposed as an alternative approach to providing preexposure prophylaxis among women. To test this idea, researchers conducted a phase 3, randomized, double-blind, placebo-controlled trial at 15 sites in four African countries. The intervention treatment was a vaginal ring containing the non-nucleoside reverse transcriptase inhibitor dapivirine.

A total of 2629 women (median age, 26; 41% married) were enrolled in the study, 1313 in the dapivirine and 1316 in the placebo group. Median follow-up was 1.6 years. A total of 168 HIV infections occurred, 71 in the dapivirine group and 97 in the placebo group, for a 27% reduction in incidence. Antiviral resistance was no different between those who seroconverted and those who did not. When two sites with low retention were excluded, the reduction in HIV-1 incidence increased to 37%. Protection also differed by age: In an exploratory analysis, dapivirine had 56% efficacy among women older than 21 but offered no protection in those younger than 21. This difference could be explained by poor adherence among the younger women.