Two-Drug Regimens Dolutegravir/Lamivudine and Dolutegravir/Rilpivirine Are Effective with Few Discontinuations in US Real-World Settings: Results from the TANDEM Study.

INTRODUCTION: Dolutegravir/lamivudine (DTG/3TC) and dolutegravir/rilpivirine (DTG/RPV) are fixed-dose, complete, single-tablet, two-drug regimens (2DRs) indicated for HIV-1. DTG/3TC is approved for antiretroviral therapy (ART)-naive people with HIV-1 and virologically suppressed individuals to replace current ART; DTG/RPV is indicated for virologically suppressed individuals as a switch option. Virologic efficacy and effectiveness of these DTG-based 2DRs have been demonstrated in phase 3 clinical trials and real-world cohorts, primarily from Europe. This study characterized real-world use of DTG-based 2DRs for HIV-1 treatment in the USA.

METHODS: TANDEM was a retrospective medical chart review across 24 US sites. Individuals aged ≥ 18 years who initiated DTG/3TC or DTG/RPV before September 30, 2020, with ≥ 6 months of follow-up were included. One cohort included ART-naive people who initiated DTG/3TC (n = 126), and two other cohorts included virologically suppressed (HIV-1 RNA < 50 copies/mL) people on stable ART regimens for ≥ 3 months before switch to either DTG/3TC (n = 192) or DTG/RPV (n = 151). Clinical characteristics, treatment history, and outcomes are described.

RESULTS: Virologically suppressed individuals were older than those who were ART-naive, and the ART-naive cohort had higher proportions of individuals assigned male at birth and of Hispanic ethnicity. The most common healthcare provider-reported reason for choosing a DTG-based 2DR was avoidance of long-term toxicities (25-33% across cohorts), followed by simplification/streamlining of treatment. Among ART-naive people on DTG/3TC, 94% achieved virologic suppression after initiation, and 83% maintained suppression at last follow-up; discontinuation rate was < 1%. Among cohorts who switched to DTG-based 2DRs, 96% maintained virologic suppression on DTG/3TC and 93% on DTG/RPV; 2% on DTG/3TC and 3% on DTG/RPV discontinued.

CONCLUSION: Motivation for selecting DTG-based 2DRs was primarily driven by a desire to avoid or manage toxicities and simplify treatment. Results demonstrate that DTG/3TC and DTG/RPV are effective in real-world settings, with few discontinuations, reflecting data from clinical trials.