Efficacy and Safety of Switching to the 2-Drug Regimen Dolutegravir/Lamivudine Versus Continuing a 3- or 4-Drug Regimen for Maintaining Virologic Suppression in Adults Living With Human Immunodeficiency Virus 1 (HIV-1): Week 48 Results From the Phase 3, Noninferiority SALSA Randomized Trial
Josep M. Llibre, Carlos Brites, Chien‐Yu Cheng, Olayemi Osiyemi, Carlos Galera, Laurent Hocqueloux, Franco Maggiolo, Olaf Degen, Stephen Taylor, Elizabeth A. Blair, Choy Man, Brian Wynne, J Oyee, Mark Underwood, Lloyd Curtis, Gilda Bontempo, Jean van Wyk
Abstract
BACKGROUND: In TANGO, switching to dolutegravir/lamivudine (DTG/3TC) demonstrated long-term noninferior efficacy vs continuing tenofovir alafenamide-based regimens in treatment-experienced adults with HIV-1. The phase 3 SALSA study evaluated efficacy and safety of switching to DTG/3TC compared with continuing various 3-/4-drug current antiretroviral regimens (CARs). METHODS: Adults with HIV-1 RNA <50 copies/mL and no previous virologic failure were randomized (1:1, stratified by baseline third agent class) to switch to once-daily fixed-dose combination DTG/3TC or continue CAR (primary endpoint: proportion of participants with HIV-1 RNA ≥50 copies/mL at week 48; Snapshot, intention-to-treat-exposed population, 5% noninferiority margin). RESULTS: Overall, 493 adults (39% women; 39% aged ≥50 years; 19% African American/African heritage; 14% Asian) were randomized to switch to DTG/3TC (n = 246) or continue CAR (n = 247). At week 48, 1 (0.4%) participant in the DTG/3TC group and 3 (1.2%) in the CAR group had HIV-1 RNA ≥50 copies/mL (Snapshot), demonstrating noninferiority (adjusted difference, -0.8%; 95% CI, -2.4%, .8%). Zero participants met confirmed virologic withdrawal criteria; therefore, no resistance testing was performed. Drug-related adverse events were more frequent with DTG/3TC (20%) than CAR (6%) through week 48 but comparable post-week 24 (5% vs 2%, respectively). Proximal tubular renal function and bone turnover biomarkers improved with DTG/3TC. Both groups had generally minimal changes in lipids and inflammatory biomarkers. CONCLUSIONS: Switching to DTG/3TC was noninferior to continuing CAR for maintaining virologic suppression at week 48 with no observed resistance, supporting the efficacy, good safety, and high barrier to resistance of DTG/3TC. CLINICAL TRIALS REGISTRATION: www.clinicaltrials.gov, NCT04021290.