A Study of Islatravir (MK-8591) in Anti-Retroviral Therapy-Naive, Human Immunodeficiency Virus-1 Infected Participants (MK-8591-003)

Inclusion criteria

• Non-pregnant, non-breast feeding, postmenopausal or surgically sterile female
• Female with reproductive potential agrees to use (or have male partner use) two acceptable methods of birth control
• Male agrees to use acceptable method of contraception during study and for 90 days after last dose of trial drug
• Has stable baseline health, other than HIV infection
• Has no significantly abnormal electrocardiogram
• Is HIV-1 positive
• Have a screening plasma HIV-1 RNA ≥ 10,000 copies/mL within 30 days prior to the treatment phase of this study. For inclusion in Panel Islatravir Extended Observation, participants must also have a screening plasma HIV-1 RNA ≤ 25,000 copies/mL within 30 days prior to the treatment phase.
• Is ART naive
• Has not received any investigational agent or marketed ART within 30 days of trial drug administration
• Is diagnosed with HIV-1 infection >= 3 months prior to screening
• Is willing to receive no other ART during treatment phase of study
• Has no evidence of mutations conferring resistance to nucleoside reverse transcriptase inhibitors (NRTIs)

Exclusion criteria

• Is mentally or legally institutionalized/incapacitated, or has significant emotional problems, or has a history of clinically significant psychiatric disorder of the last 5 years
• Has a history of clinically significant endocrine, gastrointestinal, cardiovascular, hematological, hepatic, immunological (outside of HIV-1 infection), renal, respiratory, genitourinary, major neurological abnormalities or diseases
• Has a history of cancer (malignancy)
• Has a history of significant multiple and/or severe allergies, or had an anaphylactic reaction to drugs or food
• Is positive for hepatitis B surface antigen
• Has a history of chronic Hepatitis C
• Had major surgery or lost 500 mL of blood with 4 weeks prior to screening visit
• Has participated in another investigational trial within 4 weeks prior to dosing visit
• Will use any medications, prescribed drugs, or herbal remedies 4 weeks prior to dosing of trial drug, up to the post-trial visit
• Consumes excessive amounts of alcohol, caffeinated beverages, or tobacco products
• Uses illicit drugs or has a history of drug abuse within the prior 2 years