Assessment of risk factors for virological nonsuppression following switch to dolutegravir and lamivudine, or bictegravir, emtricitabine, and tenofovir alafenamide fumarate in a real-world cohort of treatment-experienced adults living with HIV

Conflicting data exists regarding the baseline determinants of virological nonsuppression outcomes in treatment-experienced people living with human immunodeficiency virus (PWH) switching to antiretroviral treatment (ART) with bictegravir/emtricitabine/tenofovir alafenamide fumarate (BIC/FTC/TAF) or dolutegravir/lamivudine (DTG/3TC) in Asia. This retrospective observational study, conducted at a designated HIV-care hospital from October 2019 to January 2023, aimed to address this gap. We assessed the odds of virological nonsuppression (VNS) at weeks 48 using logistic regression. A total of 988 patients were included, 35 patients (3.5%) with VNS at week 48. Pre-existing primary resistance-associated mutations (RAM) to nucleoside reverse transcriptase inhibitor (NRTI) and non-nucleoside reverse transcriptase inhibitor (NNRTI) were identified in 11.0% (51/465) and 14.4% (67/465), respectively. The identified risk factor was a record of virological failure ≥2 times (AOR 5.32, 95% CI 2.04-13.85), while an HIV viral load <50 copies/mL within the past three months before switch (AOR: 0.27, 95% CI 0.11-0.72) was identified as a protective factor. No cases of acquired drug resistance-associated mutations were detected at week 48. Additionally, DTG/3TC was noninferior to BIC/FTC/TAF in achieving or maintaining HIV RNA levels of <50 copies/mL, within a -10% noninferiority margin in the per-protocol analysis (responder proportion: 98.2% vs. 95.0%, respectively; adjusted treatment difference [95% CI], 3.2% [0.7% to 5.3%]). In conclusion, DTG/3TC and BIC/FTC/TAF demonstrated good effectiveness in a real-world cohort, but frequent virological failure before the switch might impact the benefits of these regimens in the short term of follow-up.