Doravirine/Islatravir (DOR/ISL) in Heavily Treatment-Experienced (HTE) Participants for Human Immunodeficiency Virus Type 1 (HIV-1) Infection (MK-8591A-019)

This is a 2-part, phase 3 clinical study evaluating the antiretroviral activity and safety/tolerability of islatravir (ISL), doravirine (DOR), and a fixed dose combination (FDC) of DOR/ISL (also known as MK-8591A) in heavily treatment-experienced (HTE) participants with human immunodeficiency virus type 1 (HIV-1) infection. It is hypothesized that the percentage of participants receiving DOR/ISL to achieve ≥0.5 log10 decrease in HIV-1 ribonucleic acid (RNA) from study baseline (Day 1) to Day 8 is superior to placebo, each given in combination with failing antiretroviral therapy (ART).