Safety and Pharmacokinetics of Intravaginal Rings Containing Vicriviroc (MK-4176) and/or MK-2048

The development of safe and effective HIV prevention strategies is an important global health priority. IVRs have previously been approved as a delivery method for various medications, and this study will evaluate IVRs containing HIV antiretroviral medications. The purpose of this study is to assess the safety and pharmacokinetics of a combination IVR called MK-2048A that contains vicriviroc (MK-4176) and MK-2048, compared to IVRs containing vicriviroc alone and MK-2048 alone. This study will enroll healthy, HIV-uninfected women, 18 to 45 years old. Participants will be randomly assigned to receive an IVR containing either vicriviroc, MK-2048, MK-2048A (which contains vicriviroc and MK-2048), or placebo. Participants will receive their assigned IVR at the enrollment visit, and the IVR will be removed on Day 28. Participants will attend study visits at screening, enrollment (Day 0), and Days 1, 2, 3, 7, 14, 21, 28, 29, 30, 31, and 35. Study visits may include behavioral assessments, adherence counseling and assessments, medical history reviews, physical examinations, urine collection, blood collection, pelvic specimen collection, and rectal specimen collection (optional).