Study to Evaluate the Efficacy of GS-9131 Functional Monotherapy in Human Immunodeficiency Virus (HIV)-1-Infected Adults Failing a Nucleos(t)Ide Reverse Transcriptase Inhibitor-Containing Regimen With Nucleos(t)Ide Reverse Transcriptase Inhibitor Resistant Virus

A Phase 2 Study to Evaluate the Efficacy of GS-9131 Functional Monotherapy in HIV-1-Infected Adults Failing a Nucleos(t)Ide Reverse Transcriptase Inhibitor-Containing Regimen With Nucleos(t)Ide Reverse Transcriptase Inhibitor Resistant Virus

The primary objective of this study is to evaluate the short-term antiviral potency of GS-9131 functional monotherapy compared to placebo-to-match (PTM) GS-9131, each administered once daily with the existing failing antiretroviral (ARV) regimen as demonstrated by the proportion of participants achieving human immunodeficiency virus ribonucleic acid (HIV-1 RNA) > 0.5 log10 decreases from baseline after up to 14 days of therapy in HIV-1 positive, ARV treatment experienced adult participants with nucleos(t)ide resistant virus.

This is a two-part study. Part 1 consists of three cohorts: 2 Sentinel Cohorts and 1 Randomized Cohort. Eligible participants from Part 1 will proceed to Part 2 followed by an optional open-label extension.

Key Inclusion Criteria:

• Plasma HIV-1 RNA ≥ 500 copies/mL at screening Visit
• Currently taking a failing ARV regimen that contains 2 NRTIs and a NNRTI
• No prior or current ARV regimens containing integrase inhibitor (INSTI) or protease inhibitor (PI)
• Screening genotype must show at least the protocol defined resistance mutation profile

Key Exclusion Criteria:

• Active, serious infections (other than HIV-1 infection) requiring parenteral antibiotic or antifungal therapy within 30 days prior to Day 1
• Participation in any other clinical trial, including observational studies, without prior approval from the sponsor is prohibited while participating in this trial
• Use of an investigational drug other than the study drug
• Individuals with chronic hepatitis B virus (HBV) infection are not permitted to participate
• Active tuberculosis infection

NOTE: Other protocol defined Inclusion/ Exclusion criteria may apply.