Effectiveness of dolutegravir/lamivudine versus bictegravir/emtricitabine/tenofovir alafenamide in people with HIV with very high viral load (≥500 000 copies/mL).

OBJECTIVES: To compare the effectiveness of dolutegravir/lamivudine (DTG/3TC) versus bictegravir/emtricitabine/tenofovir alafenamide (BIC/FTC/TAF) at Week 48 in treatment-naive adults with high baseline viral loads (≥500 000 copies/mL) and CD4+ cell count ≥200/mm3 and to assess immune recovery and safety. METHODS: We conducted a single-centre retrospective cohort study including all ART-naive people with HIV-1 (PWH) and HIV-RNA ≥500 000 copies/mL and CD4+ ≥200 cells/mm3 who initiated DTG/3TC or BIC/FTC/TAF during 2019-2024. Effectiveness was assessed as the proportion of participants achieving HIV-1 RNA <50 copies/mL at Week 48 [intention-to-treat, missing = failure (ITT, M = F)]. Immune recovery, metabolic and renal safety were evaluated through changes in CD4+ count, weight, lipid profile and creatinine. Time-to-virologic suppression was analysed using Kaplan-Meier curves and log-rank testing. Safety profile and immune recovery were conducted using Mann-Whitney U test. RESULTS: A total of 40 patients (52.5% on DTG/3TC, 47.5% on BIC/FTC/TAF) were included, with a high prevalence of primary HIV infection (PHI) (76.2% and 84.2%, respectively). No baseline differences were observed between groups. At 48 weeks, virologic suppression rates were 90.5% (19/21) in the DTG/3TC group and 94.7% (18/19) in the BIC/FTC/TAF group (log-rank P = 0.73). Viral decay kinetics were similar between groups. No virologic failures with resistance or treatment discontinuations were observed. Median CD4+ gains were comparable between groups (385 vs 243 cells/mm3; P = 0.30). No significant differences in weight gain, lipid profile, or creatinine levels were observed. CONCLUSIONS: In ART-naive PWH with HIV-RNA ≥500 000 cp/mL and CD4+ ≥200/mm3, including those with PHI, DTG/3TC and BIC/FTC/TAF showed similar effectiveness and comparable safety profiles at Week 48.