Dapivirine vaginal ring effective in preventing HIV-1

Baeten JM, et al. N Engl J Med. 2016;doi:10.1056/NEJMoa1506110.

December 8, 2016

Women with a monthly vaginal ring containing dapivirine had a reduced risk for HIV-1 infection compared with those with a placebo; in addition, efficacy was increased among women who had higher rates of adherence, according to findings published in The New England Journal of Medicine.

“Antiretroviral medications that are used as prophylaxis can prevent acquisition of HIV-1 infection,” Jared M. Baeten, MD, PhD, of the departments of global health, medicine and epidemiology at the University of Washington, and colleagues wrote. “However, in clinical trials among African women, the incidence of HIV-1 infection was not reduced, probably because of low adherence. Longer-acting methods of drug delivery, such as vaginal rings, may simplify use of antiretroviral medications and provide HIV-1 protection.”

Baeten and colleagues performed a phase 3, randomized, double-blind, placebo-controlled trial to investigate the efficacy and safety of a monthly vaginal ring containing dapivirine — a non-nucleoside HIV-1 reverse-transcriptase inhibitor — compared with a placebo in women aged 18 to 45 years from Malawi, South Africa, Uganda and Zimbabwe.

A total of 2,629 healthy, sexually active, nonpregnant, HIV-1–seronegative women were enrolled in the study and followed from August 2012 and June 2015. Of those, HIV-1 infection occurred in 168 women: 71 in the dapivirine group and 97 in the placebo group.

Compared with the placebo group, the dapivirine group had a 27% lower incidence of HIV-1 infection (95% CI, 1-46; P = 0.046). The incidence was lower by 37% (95% CI, 12-56; P = 0.007) when data from two sites with reduced rates of retention and adherence were excluded.

A post hoc analysis revealed that women older than 21 years of age had higher rates of HIV-1 protection (56%; 95% CI, 31-71; P < 0.001) than women aged 21 years and younger who did not show evidence of protection due to reduced adherence (27%; 95% CI, 133 to 31; P = 0.45). Similar rates of adverse medical events and antiretroviral resistance were observed among women who were infected with HIV-1 in both groups.

“In this multicountry trial, a vaginal ring containing 25 mg of dapivirine that was renewed every month showed evidence of HIV-1 protection, demonstrating the efficacy of a sustained release approach to delivering antiretroviral prophylaxis,” Baeten and colleagues concluded. – by Alaina Tedesco

Disclosure: The authors report funding by the NIH.

 

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