Long-term follow-up after a switch to bictegravir, emtricitabine, tenofovir alafenamide (B/F/ TAF) from a boosted protease inhibitor-based regimen

Background: Bictegravir, emtricitabine and tenofovir alafenamide is a guideline‐recommended single‐tablet regimen for people living with HIV‐1 (PLWH). Week (W) 48 primary endpoint results of the phase 3 non‐inferiority study of switching from an atazanavir (ATV) or darunavir (DRV) protease inhibitor (PI)‐based regimen established the safety and efficacy of switching to B/F/TAF. Outcomes from an open‐label extension (OLE) on B/F/TAF are reported here. Method: Virologically suppressed (HIV‐1 RNA < 50 copies/ mL) PLWH on boosted ATV or DRV plus either F/tenofovir disoproxil fumarate or abacavir/lamivudine for ?6 months prior to screening were randomised 1:1 to B/F/TAF or to stay on baseline PI regimen (SBR). After the W48 primary endpoint, all participants received B/F/TAF in the OLE. All participants who received B/F/TAF initially or switched in the OLE are included in analyses. Efficacy was assessed as the proportion with HIV‐1 RNA < 50 c/mL at each study visit (missing = excluded [M = E]) analysis. Safety was assessed by adverse events (AEs) and laboratory results. Results: 577 participants were randomised (290 B/F/TAF, 287 SBR); 272 (93.8%) of participants randomised to B/F/ TAF and 244 (85.0%) randomised to SBR entered the OLE and received B/F/TAF (n = 516): 17% women, 26% Black, median age 48 years (range 20‐79). The median duration of B/F/TAF treatment was 101 weeks. In the OLE HIV‐1 RNA < 50 c/mL was maintained in 97‐100% of participants at all timepoints through 156 weeks. No participant developed resistance to B/F/TAF or discontinued due to lack of efficacy in the OLE. Study drug‐related AEs occurred in 14.2% on B/F/TAF; most of which were grade 1; the most common was headache (2%). Six (1%) participants had an AE leading to premature study drug discontinuation, 4 during the OLE. Estimated GFR, lipids, and weight were relatively stable with minimal changes for most participants through 96 weeks after switching to B/F/TAF. Conclusion: Long‐term follow‐up of PLWH switching to B/F/TAF from a boosted PI regimen demonstrates continued high rates of virologic suppression with no emergent resistance and was generally well tolerated through a maximum of 156 weeks.