Study to Evaluate Safety, Pharmacokinetics, and Antiviral Activity of Lenacapavir Administered Subcutaneously in Human Immunodeficiency Virus (HIV) -1 Infected Adults

A Phase 1b Randomized, Double-Blinded, Placebo Controlled, Multi-Cohort Study of the Safety, Pharmacokinetics, and Antiviral Activity of GS-6207 Administered Subcutaneously in HIV-1 Infected Subjects

The primary objectives of this study are:

Part A: To evaluate the short-term antiviral activity of lenacapavir (formerly GS-6207) with respect to the maximum reduction of plasma HIV-1 RNA (log10 copies/mL) from Day 1 through Day 10 compared to placebo in HIV-1 infected adults who are antiretroviral treatment naive or are experienced but capsid inhibitor (CAI) naive.

Part B: To evaluate the short-term antiviral activity of tenofovir alafenamide (TAF) with respect to the maximum reduction of plasma HIV-1 RNA (log10 copies/mL) from Day 1 through Day 10 in HIV-1 infected adult subjects who are antiretroviral treatment naïve or are experienced but without resistance to TAF.

Key Inclusion Criteria:

• Plasma HIV-1 RNA ≥ 5,000 copies/mL but ≤ 400,000 copies/mL and CD4+ cell count > 200 cells/mm^3
• Treatment naive or experienced but CAI (for Part A only) and integrase strand transfer inhibitor (INSTI) naïve, and have not received any antiretroviral therapy (ART) within 12 weeks of screening
• Screening genotype report must show sensitivity to B/F/TAF to allow its initiation on Day 10
• Screening genotype report must show sensitivity to at least one agent in either non-nucleoside reverse transcriptase inhibitor (NNRTI) or protease inhibitor (PI) class to allow its use as part of standard of care oral antiretroviral treatment in the future
• Have adequate renal function (estimated glomerular filtration rate ≥ 70 mL/min)
• No clinically significant abnormalities in electrocardiography (ECG) at Screening
• Willing to initiate B/F/TAF on Day 10 after completion of all assessments

Key Exclusion Criteria:

• Pregnant or lactating females

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