Incidence of low-level viraemia (LLV) was similar between bictegravir- and dolutegravir-based ART.

Among PLWH receiving second-generation INSTIs, LLV was not associated with subsequent virologic failure (VF).

In patients who developed VF, there were no emergent resistance-associated mutations.

Real-world experience with low-level viraemia (LLV) and its impact remain less reported among people living with HIV (PLWH) who receive antiretroviral therapy (ART) containing second-generation integrase strand transferase inhibitors, including dolutegravir and bictegravir. This retrospective cohort study included virally suppressed PLWH who achieved plasma HIV-RNA viral load (PVL) <50 copies/mL for ≥6 months and were switched to either dolutegravir- or bictegravir-based ART. Incidence rates of developing LLV events (PVL, 50–200 copies/mL) and virologic failure (VF) (PVL ≥1000 copies/mL) were compared between the dolutegravir and bictegravir cohorts. A total of 623 and 862 PLWH switched to dolutegravir-based and bictegravir-based ART, respectively, were included. The incidence rate of developing LLV was 6.2 per 100 person-years of follow-up (PYFU) in the bictegravir cohort and 3.8 per 100 PYFU in the dolutegravir cohort [incidence rate ratio (IRR) = 1.63, 95% confidence interval (CI), 0.90–2.95; P = 0.08], while rates of VF were 0.69 per 100 PYFU and 0.95 per 100 PYFU, respectively, in the bictegravir and dolutegravir cohorts (IRR = 0.72, 95% CI 0.12–3.39; P = 0.34). Presence of LLV events was not associated with subsequent VF in multivariate analysis. Secondary analysis also demonstrated that resistance-associated mutations (RAMs) to nucleoside reverse transcriptase inhibitors (NRTIs) before switch were not associated with adverse virologic outcomes in either cohort. In conclusion, among virally suppressed PLWH, the incidences of developing LLV or VF were similar after switch to dolutegravir- or bictegravir-based ART. Pre-existing RAMs to NRTIs or LLV events were not associated with subsequent VF.

Viral rebound

Viral blip

Integrase strand transfer inhibitor

Nucleoside reverse transcriptase inhibitor

Resistance-associated mutation

Genetic barrier

© 2022 The Author(s). Published by Elsevier Ltd.