A Switch to Doravirine/Islatravir (DOR/ISL) in Participants With Human Immunodeficiency Virus Type 1 (HIV-1) Who Are Virologically Suppressed on Antiretroviral Therapy (ART) (MK-8591A-051)

The primary objectives of this study are to evaluate the safety and tolerability of a switch to Doravirine/Islatravir (DOR/ISL) compared with continued baseline antiretroviral therapy (ART), through Week 48; and to evaluate the antiretroviral activity of a switch to DOR/ISL compared with continued baseline ART at Week 48. The primary hypothesis is that DOR/ISL is non-inferior to continued baseline ART, as assessed by the percentage of participants with HIV-1 ribonucleic acid (RNA) ≥50 copies/mL at Week 48, with a margin of 4 percentage points used to define non-inferiority.

Inclusion Criteria: * Is Human Immunodeficiency Virus-1 (HIV-1) positive with plasma HIV-1 Ribonucleic Acid (RNA) \<50 copies/mL at screening * Has been receiving continuous, stable oral 2-drug or 3-drug combination (± PK booster) antiretroviral therapy ART with documented viral suppression (HIV-1 RNA \<50 copies/mL) for ≥3 consecutive months prior to providing documented informed consent and has no history of prior virologic treatment failure on any past or current regimen * Female is not a participant of childbearing potential (POCBP); or if a POCBP uses an acceptable contraceptive method or abstains from penile-vaginal intercourse as their preferred and usual lifestyle; has a negative highly sensitive pregnancy test; and whose medical history, menstrual history, and recent sexual activity has been reviewed by the investigator Exclusion Criteria: * Has HIV-2 infection * Has hypersensitivity or other contraindication to any of the components of the study interventions as determined by the investigator * Has a diagnosis of an active acquired immunodeficiency syndrome (AIDS)-defining opportunistic infection within 30 days prior to screening * Has active hepatitis B virus (HBV) infection * Has chronic hepatitis C virus (HCV) infection consistent with cirrhosis * Has a ≤5 years prior history of malignancy * Is taking or is anticipated to require systemic immunosuppressive therapy, immune modulators, or strong and moderate cytochrome P450 3A (CYP3A) inducers * Has taken long-acting HIV therapy at any time * Is currently participating in or has participated in a clinical study and received (or is receiving) an investigational compound or device from 45 days prior to Day 1 through the study treatment period * Has a documented or known virologic resistance to Doravine (DOR)