Factors associated with virological failure in people with HIV treated with bictegravir/emtricitabine/tenofovir alafenamide. Impact of pre-existing mutations and risk of resistance emergence. ANRS-CO3-AquiVIH-NA cohort.

OBJECTIVES: We investigated, in a real-world setting, virological factors associated with virological failure (VF) after bictegravir/emtricitabine/tenofovir alafenamide (B/F/TAF) initiation in people with HIV (PWH) with and without pre-existing drug resistance mutation (PRM) and the emergence of new resistance mutations at virological failure. METHODS: Treatment-experienced PWH from ANRS-CO3-AquiVIH-NA cohort starting B/F/TAF between 2018 and 2021 were stratified depending on their baseline viral load (VL): virologically suppressed (VS; VL <50 copies/mL) and virologically unsuppressed (VU; VL >50 copies/mL). PRM were identified using cumulative genotypic resistance tests (GRT) according to the ANRS algorithm. Factors associated with VF were analysed using a Cox proportional hazards model and survival curves. RESULTS: Among the 636 PWH with available GRT results, 82.7% were VS at B/F/TAF initiation. PRMs to at least one component of B/F/TAF were present for 23.1% of participants (20.9% VS and 33.6% VU), with the M184I/V mutation identified in 89.1% of cases (88.2% in VS and 91.9% in VU). Virological success was higher for those with no PRMs (92.8% no PRM vs 86.4% with PRM). VU PWH had a higher risk of VF [HR 9.53 (5.54-16.40)]. Among the 66 PWH with baseline GRT experiencing VF, new resistance mutations were selected for six (two VU and four VS). After VF, B/F/TAF was maintained for 56/66 (84.8%) participants, of whom 40/56 (71.4%) had a VL <50 copies/mL at their last visit. CONCLUSIONS: Virological suppression was maintained in VS PWH regardless PRMs but to a less extent in VU PWH. Emergence of new resistance mutation occurred rarely in the case of VF.