A Dose-Ranging Study to Compare Doravirine (MK-1439) Plus TRUVADA® Versus Efavirenz Plus TRUVADA® in Human Immunodeficiency Virus (HIV)-1 Infected Participants (MK-1439-007)

Part I - Dose-Ranging. Part I will evaluate the (1) safety and tolerability and (2) efficacy (antiretroviral activity) of 4 doses of doravirine compared with efavirenz, when each is given in combination with TRUVADA® for at least 24 weeks in approximately 200 participants. A single dose of doravirine will be selected for further study after all participants complete the Week 24 visit in Part I. Participants receiving any dose of doravirine in Part I will be switched to the selected doravirine dose and continue in the study for up to 96 weeks, but will not be randomized to Part II. Part II - Selected Dose. Part II will be initiated after the doravirine dose has been selected as indicated above for Part 1. Approximately 120 additional participants will be randomized in 1:1 ratio to the selected dose of doravirine or efavirenz, each in combination with TRUVADA® for 96 weeks of blinded treatment. Part II will evaluate the safety of the selected dose compared with efavirenz, particularly with regard to central nervous system (CNS) adverse events.