Dapivirine vaginal ring shows no safety concerns when used in third trimester

SEATTLE — The dapivirine vaginal ring, a microbicidal therapy designed to prevent sexual transmission of HIV, demonstrated no safety concerns when used during the third trimester of pregnancy, according to data from the DELIVER study.

“For years, we’ve suffered from a lack of high-quality data about whether a drug is safe or not to use in pregnancy,” Katherine Bunge, MPH, MD, assistant professor of obstetrics, gynecology and reproductive sciences at the University of Pittsburgh School of Medicine, said during a press briefing at the Conference on Retroviruses and Opportunistic Infections 2023. “We know that pregnant people need HIV prevention products, and so the Microbicide Trials Network set out to conduct a safety study of daily oral pre-exposure prophylaxis in the monthly dapivirine ring.”

This ongoing phase 3b study, the DELIVER study, included two cohorts of pregnant women. The first cohort enrolled 150 women who were 36 weeks or more along in their pregnancy with randomization to the dapivirine vaginal ring (n = 101) or the oral pre-exposure prophylaxis emtricitabine/tenofovir disoproxil fumarate (Truvada, Gilead; n = 49). The second cohort enrolled 157 women who were 30 to 35 weeks gestation with randomization to the dapivirine vaginal ring (n = 106) or emtricitabine/tenofovir disoproxil fumarate (n = 51).

Most participants in all cohorts delivered full-term live births with 2% of births premature in the first cohort and 6% premature in the second cohort vs 13% expected prematurity rate, although participants were already late in pregnancy when enrolled, researchers noted. One stillbirth occurred in each study cohort, which were both deemed unrelated to the intervention, compared with an expected stillbirth rate of 4%, according to researchers.

The most common complications observed among all study participants were gestational hypertension, eclampsia and preeclampsia, but with rates lower than or similar to the local background rates of 10.5%: 3% of women using the dapivirine vaginal ring in the first cohort and 8% in the second cohort experienced hypertensive disorders of pregnancy as did 8% of women using emtricitabine/tenofovir disoproxil fumarate in the first cohort and 10% in the second cohort.

The DELIVER study also included a third cohort of 251 women who were 12 to 29 weeks gestation. According to the researchers, follow-up of the third cohort is expected to be completed by mid-2023, with the results anticipated during late 2024 or early 2025.

“I would just like to emphasize that studying the safety of an investigational product is hard in pregnancy, but it can be done,” Bunge said. “We are doing it, and it should be done because pregnant people deserve better.”

Reference:

• No safety concerns seen with use of dapivirine vaginal ring during third trimester of pregnancy, according to interim results of DELIVER study. www.mtnstopshiv.org/news/no-safety-concerns-seen-use-dapivirine-vaginal-ring-during-third-trimester-pregnancy-according. Published Feb. 20, 2023. Accessed Feb. 20, 2023.