Efficacy and Safety of Switching to Dolutegravir/Lamivudine Versus Continuing a Tenofovir Alafenamide-Based 3- or 4-Drug Regimen for Maintenance of Virologic Suppression in Adults Living With Human Immunodeficiency Virus Type 1: Results Through Week 144 From the Phase 3, Noninferiority TANGO Randomized Trial

Background: Switching to dolutegravir/lamivudine (DTG/3TC) was noninferior to continuing tenofovir alafenamide (TAF)-based regimens for maintaining virologic suppression at week 48 of the TANGO study. Here we present week 144 outcomes (efficacy, safety, weight, and biomarkers).

Methods: TANGO is a randomized (1:1, stratified by baseline third agent class), open-label, noninferiority phase 3 study. Virologically suppressed (>6 months) adults with human immunodeficiency virus type 1 (HIV-1) switched to once-daily DTG/3TC or continued TAF-based regimens.

Results: A total of 741 participants received study treatment (DTG/3TC, n = 369; TAF-based regimen, n = 372). At week 144, the proportion of participants with an HIV-1 RNA level ≥50 copies/mL (primary end point, Snapshot; intention-to-treat-exposed population) after switching to DTG/3TC was 0.3% (1 of 369) versus 1.3% (5 of 372) for those continuing TAF-based regimens, demonstrating noninferiority (adjusted treatment difference, -1.1 [95% confidence interval, -2.4 to .2), with DTG/3TC favored in the per-protocol analysis (adjusted treatment difference, -1.1 [-2.3 to -.0]; P = .04). Few participants met confirmed virologic withdrawal criteria (none in the DTG/3TC and 3 in the TAF-based regimen group), with no resistance observed. Drug-related adverse events were more frequent with DTG/3TC (15%; leading to discontinuation in 4%) than TAF-based regimens (5%; leading to discontinuation in 1%) through week 144, but rates were comparable after week 48 (4%; leading to discontinuation in 1% in both groups). Changes from baseline in lipid values generally favored DTG/3TC; no clinical impact on renal function and comparable changes in inflammatory and bone biomarkers across groups were observed.

Conclusions: Switching to DTG/3TC demonstrated noninferior and durable efficacy compared with continuing TAF-based regimens in treatment-experienced adults with HIV-1, with good safety and tolerability, and no resistance through 144 weeks.