Oral ISL QM as PrEP in Cisgender Women at High Risk for HIV-1 Infection (MK-8591-022)

Inclusion Criteria: * Confirmed HIV-uninfected based on negative HIV-1/HIV-2 test results before randomization. * Sexually active (vaginal and/or anal sex) with a male sexual partner in the 30 days prior to screening. * High risk for HIV-1 infection. * Not pregnant or breastfeeding, and one of the following conditions applies: Not a woman of childbearing potential (WOCBP) or is a WOCBP and is using an acceptable contraceptive method during the intervention period and for at least 42 days after the last dose. * A WOCBP must have a negative pregnancy test within 24 hours prior to the first dose of study intervention. Exclusion Criteria: * Hypersensitivity or other contraindication to any of the components of the study interventions as determined by the investigator. * Findings of chronic hepatitis B virus (HBV) infection or past HBV. * Current or chronic history of liver disease. * History of malignancy within 5 years of screening except for adequately-treated basal cell or squamous cell skin cancer, or in situ cervical cancer. * Past or current use of cabotegravir, lenacapavir, or any other long-acting HIV prevention product. * Currently participating in or has participated in an interventional clinical study with an investigational compound or device, within 30 days prior to Day 1. * Expecting to conceive or donate eggs at any time during the study.