Low-level viraemia and virologic failure among people living with HIV who received maintenance therapy with co-formulated bictegravir, emtricitabine and tenofovir alafenamide versus dolutegravir-based regimens.

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.

Impact of archived M184V/I mutation on the effectiveness of switch to co-formulated elvitegravir, cobicistat, emtricitabine and tenofovir alafenamide among virally suppressed people living with HIV.

OBJECTIVES: Real-world experience regarding the effectiveness of co-formulated elvitegravir, cobicistat, emtricitabine and tenofovir alafenamide (EVG/C/FTC/TAF) as a switch regimen is sparse among people living with HIV (PLWH) harbouring the M184V/I mutation with or without thymidine analogue-associated mutations (TAMs). METHODS: In this retrospective multicentre study, PLWH who were switched to EVG/C/FTC/TAF after having achieved viral suppression (plasma HIV RNA <200 copies/mL) for 6 months or longer were included. Patients with archived M184V/I mutation (case patients) were matched to controls without M184V/I mutation at a 1:4 ratio. Patients with a history of virological failure or resistance to elvitegravir were excluded. The primary endpoint was virological non-success (plasma HIV RNA ≥50 copies/mL) at Week 48 of switch using a modified FDA snapshot analysis. RESULTS: Overall, 100 case patients with the M184V/I mutation were identified, including 6 (6.0%) with K65R and 13 (13.0%) with at least one TAM, and were matched to 400 controls in terms of gender, age (mean = 40.3 versus 39.7 years) and cumulative exposure duration to tenofovir disoproxil fumarate (median = 146 versus 143 weeks). At Week 48, the rate of virological non-success for the case patients and controls was 5.0% (5/100) and 3.3% (13/400), respectively (difference = 1.7%; 95% CI = -2.9%-6.3%), while the rate of virological success was 88.0% and 89.5% for the case patients and controls, respectively. The presence of the K65R mutation or TAMs was not associated with virological non-response. CONCLUSIONS: Among virally suppressed PLWH, EVG/C/FTC/TAF is effective in maintaining viral suppression at Week 48 despite archived M184V/I mutation with or without TAMs.