Treatment success of rescue regimens after dual therapy failure in people living with HIV in a real-life setting

Abstract

Few data on the management of two-drug regimen (2DR) failure in people living with human immunodeficiency virus (PLWH) are available. Retrospective study on treatment-experienced PLWH on a 2DR, who underwent virological failure [(VF) two consecutive viral loads (VLs) ≥50 copies/mL, a single VL ≥1000 copies/mL, or an antiretroviral therapy (ART) switch after a single VL ≥50 copies/mL with previous blips] or discontinuation for toxicity (baseline). We included integrase strand transfer inhibitor (INSTI)-based [one INSTI plus one nucleoside reverse transcriptase inhibitor (NRTI) (n=78) or one non-NRTI (n=20)] or boosted protease inhibitor (PI/b)-based [one PI/b plus one NRTI (n=116) or one INSTI (n=12)] 2DRs. Probabilities of treatment success (TS), VF, and discontinuation for any other cause of rescue regimens were estimated by Kaplan-Meier curves. A stepwise Cox model was performed to assess predictors of TS. Overall, 226 PLWH were evaluated: at baseline, 144 individuals discontinued 2DR for toxicity and 82 had VF [median viremia 81 (63-212) copies/mL]; 171 switched therapy (49.7% to a triple-regimen, 40.9% to a different 2DR), while 55 (exclusively among those with VF) maintained their failing regimens. The probabilities of 12- and 24-month TS were 75.6% and 64.7%, respectively. Higher TS probabilities were observed in individuals who switched ART at 2DR failure (p=0.003) and in PLWH who discontinued 2DR for toxicity (p=0.008). A therapy switch was the only predictor of TS (p=0.002). Overall probability of success of rescue regimens introduced after 2DR failure is good; an immediate ART switch is associated with higher efficacy, so this approach should be encouraged.