Background
Bictegravir/Emtricitabine/Tenofovir alafenamide (B/F/TAF) is a simple highly potent antiretroviral (ART) regimen with a high genetic barrier to resistance. However, real-world evidence in the presence of drug resistance mutations (DRMs) remains limited. We investigated virological factors associated to virological failure (VF) after switching to B/F/TAF in individuals with pre-existing DRMs.
Methods
We performed a retrospective study in participants from the French regional prospective cohort ANRS-CO3-AquiVIH-NA. We included individuals treated with B/F/TAF between 2018/01/01 and 2021/12/31. Two groups were identified at B/F/TAF initiation: virologically suppressed (VS; Viral load (VL)<50cp/ml) and virologically unsuppressed (VU; VL>50 cp/mL). DRMs prior to B/F/TAF initiation were identified using cumulative genotypic resistance tests (GRT) according to the current ANRS algorithm. Factors associated with VF, defined as either two consecutive VL>50 cp/mL or a single VL>1000 cp/mL over 60 months of follow-up, were analyzed using a Cox proportional hazards model and survival curves.
Results
Among the 636 participants with available GRT results, 82.7% were VS at B/F/TAF initiation. In the VU group, median [min; max] VL was 222 cp/ml [51-2,574,903 cp/mL] at baseline. DRMs to at least one component of B/F/TAF were present for 23.1% of participants (20.9% in VS and 33.6% in VU), with the M184I/V mutation identified in 89.1% of cases (88.1% in VS and 91.9% in VU). The occurrence of VF differed between VS and VU groups with an increased risk of VF (HR 9.9 ; CI 95% 5.7-16.9) in VU, and between participants with pre-existing DRMs (20/147; 13.6%) and those without (35/489; 7.2%). In VS participants, VF rates were: 4.5% (5/110) and 4.1% (17/416) among those with and without pre-existing DRMs, respectively. In VU participants, VF rates were 40.5% (15/37) and 24.7% (18/73) among those with and without pre-existing DRMs, respectively.
Conclusions
This study highlights the good effectiveness of B/F/TAF in real-world settings. Indeed, B/F/TAF maintained virological suppression in VS participants regardless of pre-existing DRMs. In VU participants, the risk of VF was significantly higher compared to VS participants. These findings suggest that close medical monitoring of VU individuals should always be applied, even in those initiating B/F/TAF.