Dapivirine Vaginal Ring Efficacious in Preventing HIV-1 Infection

HealthDay News — Use of a vaginal ring containing dapivirine is efficacious for prevention of HIV-1 infection, according to a study published in the the New England Journal of Medicine.

Annalene Nel, MB, ChB, PhD, from the International Partnership for Microbicides in Silver Spring, Maryland, and colleagues conducted a phase 3 trial involving 1959 healthy, sexually active women, aged 18 to 45 years, from South Africa and Uganda. Participants were randomized in a 2:1 ratio to receive vaginal rings containing 25mg dapivirine, which they inserted themselves every four weeks for up to 24 months, or placebo.

During follow-up, the researchers found that there were 4.1 seroconversions per 100 person-years in the dapivirine group, compared with 6.1 seroconversions per 100 person-years in the placebo group. The incidence of HIV-1 infection was significantly lower in the dapivirine vs the placebo group (hazard ratio, 0.69; P =.04). Among women aged older than 21 years and those aged 21 years or younger there were no significant differences in the efficacy of the dapivirine ring (P =.43 for treatment-by-age interaction). There were more serious adverse events in the dapivirine group than in the placebo group (2.9% vs 0.9%, respectively).

“Among women in sub-Saharan Africa, the dapivirine ring was not associated with any safety concerns and was associated with a rate of acquisition of HIV-1 infection that was lower than the rate with placebo,” the authors write.

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Nel A, van Niekerk N, Kapiga S, et al; for the Ring Study Team. Safety and efficacy of a dapivirine vaginal ring for HIV prevention in women. N Engl J Med. 2016;375:2133-2143. doi: 10.1056/NEJMoa1602046