Researchers have launched an early human trial of an HIV-preventing vaginal ring that requires replacement every three months instead of every month, as is the case with the ring currently up for regulatory approval. The nonprofit International Partnership for Microbicides (IPM) announced the launch of the trial, which is being conducted in San Francisco and Birmingham, Alabama, in collaboration with the National Institutes of Health (NIH)–funded Microbicides Trials Network (MTN).

The Phase I, randomized, three-arm MTN/IPM 047 study will assess the safety and pharmacokinetics (how the active drug is processed in the body) of long-acting vaginal rings containing three different amounts of the antiretroviral dapivirine. The study will also examine how acceptable the rings are for use among the female participants and how well the women adhere to the instructions for its use.

About 48 HIV-negative women 18 to 45 years old who are not pregnant will be randomized to receive a vaginal ring designed for three months of use that contains 100 milligrams of dapivirine; a three-month ring containing 200 mg of dapivirine; or a one-month ring containing 25 mg of dapivirine.

Those in both of three-month ring groups will not know the dose included in their rings. They will be instructed to use a single ring continuously for 13 weeks. Those in the one-month comparison group will know they are receiving the 25 mg ring, which they will be instructed to replace at weeks four and eight of the study.

All participants will receive HIV testing and counseling on reducing their risk of the virus and other sexually transmitted infections. They will also receive condoms and other health services.

The results of the trial are expected in late 2018.

To read a POZ feature article on the future of new HIV prevention products known as microbicides, including vaginal ring products, click here.

To read a press release about the study, click here.