High Adherence to HIV Preventative Vaginal Ring Seen in Study

Trial participants were offered the dapivirine ring for a month at a time for up to 12 consecutive months
Trial participants were offered the dapivirine ring for a month at a time for up to 12 consecutive months

A silicon, vaginal ring infused with the anti-HIV drug dapivirine has been used "at least some of the time" in 89% of women who were given the option in a follow-up trial. The results were announced as part of preliminary findings from the Phase 3b HOPE trial. 

The HOPE trial is a follow-up to the ASPIRE trial, which demonstrated that usage of the dapivirine-containing vaginal ring reduced the risk of HIV infection by 27%. An exploratory analysis of ASPIRE found that the ring reduced the risk of HIV infection by at least 56% in those women who used it "most or all of the time." The HOPE trial aims to further investigate the protection conferred by the ring in relation to patient adherence. 

Over 1,400 women who participated in ASPIRE enrolled in HOPE; study patients were sexually active, HIV-negative women aged 20 to 49 years. They are being offered the dapivirine ring for a month at a time for up to 12 consecutive months. During the first 3 months, the women attend monthly study visits where they may obtain a new ring. They then attend quarterly visits where they may receive 3 rings at a time. 

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Through this, researchers are able to measure patient acceptance, patient satisfaction, and factors affecting adherence and non-adherence. Residual levels of dapivirine in returned rings and blood levels of dapivirine are being assessed to quantify adherence. 

As of October 2017 — the cut off date for interim analysis — 89% of the rings returned had residual dapivirine levels consistent with some use in the prior month. This level of some use in the prior month was ~16% greater than that seen in the ASPIRE trial. Moreover, the rate of study participants developing a new HIV infection was 1.9 per 100 person-years of follow-up. For ASPIRE participants receiving placebo, a mathematical model showed an average HIV incidence of 4.1 new infections per 100 person-years —  approximately twice the rate seen in the new HOPE interim analysis.

"Interim data from the HOPE open-label extension study appear to be sending a positive signal about the desirability of the anti-HIV vaginal ring in a setting more like the real world than previous trials," said Carl W. Dieffenbach, PhD, director of the Division of AIDS at the National Institute of Allergy and Infectious Diseases.

For more information visit NIAID.gov.