Virological efficacy of switch to DTG plus 3TC in a retrospective observational cohort of suppressed HIV-1 patients with or without past M184V: the LAMRES study

Objectives: The aim of this study was to assess the efficacy of dolutegravir plus lamivudine (DTG + 3TC) in a large set of virologically suppressed HIV-1 infected individuals with or without past M184V mutation.Methods: This observational study included individuals who switched to DTG + 3TC with >= 1 genotype before switch. Survival analysis was used to evaluate the role of past M184V on virological rebound (VR) or blips after DTG + 3TC switch.Results: A total of 712 individuals followed in several clinical centres in France, Italy and Spain were anal-ysed. Past M184V was present in 60 (8.4%) individuals. By 3 years after switch, the overall probability of VR and blips was 6.7% and 6.9%, respectively, without any statistical significance according to the pres-ence/absence of past M184V. A significantly higher probability of VR was found in individuals harbouring M184V before DTG + 3TC with a duration of virological suppression (Ts) <=.3.5 years compared to others (M184V + Ts <=.3.5 years: 22.7%; M184M + Ts <=.3.5 years: 9.0%; M184V + Ts > 3.5 years: 7.8%; M184M + Ts > 3.5 years: 4.9%; P = 0.007). This finding was not confirmed in multivariable models adjusting for be-havioural and demographic variables. Genotypic resistance test after VR under DTG + 3TC was available for 8/39 individuals; one poorly adherent individual developed M184V. No resistance to INIs was found. Conclusion: In this retrospective observational study, the probability of VR and blips in patients switching to DTG + 3TC was very low after 3 years of treatment regardless M184V. The effect of a short duration of previous virological suppression in individuals with M184V remains troubling and needs ad hoc clinical trials to be confirmed.(c) 2022 The Authors. Published by Elsevier Ltd on behalf of International Society for Antimicrobial Chemotherapy. This is an open access article under the CC BY-NC-ND license ( http://creativecommons.org/licenses/by-nc-nd/4.0/