A Switch to Doravirine/Islatravir (DOR/ISL) in Participants With Human Immunodeficiency Virus Type 1 (HIV-1) Who Are Virologically Suppressed on Bictegravir/Emtricitabine/Tenofovir Alafenamide (BIC/FTC/TAF) (MK-8591A-052)

The primary objectives of this study are to evaluate the antiretroviral activity of a switch to Doravirine/Islatravir (DOR/ISL) compared with continued Bictegravir/Emtricitabine/Tenofovir Alafenamide (BIC/FTC/TAF) at Week 48; and to evaluate the safety and tolerability of a switch to DOR/ISL compared with continued BIC/FTC/TAF, through Week 48. The primary hypotheses are that (1) DOR/ISL is non-inferior to continued BIC/FTC/TAF, 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; and (2) DOR/ISL is superior to BIC/FTC/TAF, as assessed by the percentage of participants with HIV-1 RNA ≥50 copies/mL at Week 48.

The key inclusion and exclusion criteria include but are not limited to the following: Inclusion Criteria: * Is HIV-1 positive with plasma HIV-1 RNA \<50 copies/mL * Has been receiving BIC/FTC/TAF therapy 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 participant of childbearing potential, not pregnant or breastfeeding, and is willing to use an acceptable contraceptive method or abstain from heterosexual intercourse for study duration Exclusion Criteria: * Has HIV-2 infection * 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 with laboratory values consistent with cirrhosis * Has a history of malignancy ≤5 years prior to providing documented informed consent except for adequately treated basal cell or squamous cell skin cancer, in situ cervical cancer, or cutaneous Kaposi's sarcoma * Is taking or is anticipated to require systemic immunosuppressive therapy, immune modulators, or strong and moderate cytochrome P450 3A (CYP3A) inducers * Has a documented or known virologic resistance to DOR * Has taken long-acting HIV therapy at any time (e.g., cabotegravir, lenacapavir) * 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 except those currently enrolled in the comparator arm of an ongoing DOR/ISL study