Efficacy and Safety of Switching to Dolutegravir/Lamivudine Fixed-Dose Two-Drug Regimen Versus Continuing a Tenofovir Alafenamide-Based Three- or Four-Drug Regimen for Maintenance of Virologic Suppression in Adults With HIV-1: Phase 3, Randomized, Non-inferiority TANGO Study.

BACKGROUND: The 2-drug regimen (2DR) dolutegravir (DTG) + lamivudine (3TC) is indicated for treatment-naive adults with HIV-1. We present efficacy and safety of switching to DTG/3TC in virologically suppressed individuals. METHODS: TANGO is an open-label, multicenter, phase III study that randomized adults (1:1, stratified by baseline third agent class) with HIV-1 RNA /=50 copies/mL at Week 48 (FDA Snapshot algorithm) in the intention-to-treat-exposed population (4% non-inferiority margin). RESULTS: 743 adults were enrolled and 741 received >/=1 dose of study drug (DTG/3TC, N=369; TAF-based regimen, N=372). At Week 48, proportion of participants with HIV-1 RNA >/=50 copies/mL treated with DTG/3TC was 0.3% (1/369) vs 0.5% (2/372) with a TAF-based regimen (adjusted treatment difference [95% CI], -0.3 [-1.2, 0.7]), meeting non-inferiority criteria. No participants receiving DTG/3TC and 1 receiving a TAF-based regimen met confirmed virologic withdrawal criteria, with no emergent resistance at time of failure. Drug-related grade >/=2 adverse events and adverse events leading to study withdrawal were reported in 17 (4.6%) and 13 (3.5%) participants with DTG/3TC and 3 (0.8%) and 2 (0.5%) with a TAF-based regimen, respectively. CONCLUSIONS: The 2DR DTG/3TC was non-inferior in maintaining virologic suppression vs a TAF-based regimen at Week 48, with no virologic failure or emergent resistance reported in the DTG/3TC group, supporting its use as a simplification strategy for virologically suppressed people living with HIV-1.