Long-term analysis of B/F/TAF in treatment-naïve adults living with HIV through four years of follow-up


BACKGROUND: Bictegravir/emtricitabine/tenofovir alafenamide (B/F/TAF) is a guideline-recommended single-tablet regimen for people with HIV-1 (PWH). Week (W) 48 primary and W96 and W144 secondary endpoint results of the blinded phase from two studies established non-inferiority of B/F/TAF to dolutegravir/abacavir/lamivudine (DTG/ABC/3TC) and DTG+F/TAF in treatment-naïve PWH. We present pooled outcomes from an open-label extension (OLE) in participants initially randomized to B/F/TAF through W192.
METHODS: We conducted two randomized, double-blind, phase 3 studies in treatment-naïve adult PWH: Study 1489 B/F/TAF vs DTG/ABC/3TC and Study 1490 B/F/TAF vs DTG+F/TAF. Unblinding occurred after all participants completed W144, after which all were offered B/F/TAF in OLE. Participants who were originally randomized to B/F/TAF and entered OLE were pooled into an all-B/F/TAF group. An analysis at W192 assessed efficacy as the proportion with HIV-1 RNA <50 c/mL using missing=excluded (M=E) and missing=failure analyses; safety was assessed by adverse events (AEs) and laboratory results.
RESULTS: Of 634 participants originally randomized to B/F/TAF, 506 (80%) opted for OLE (89% men, 33% Black, median age 32 years [range 18-71]). An on-treatment analysis at W192 revealed 99.2% of B/F/TAF participants maintained HIV-1 RNA <50 c/mL (M=E) and had a median increase in CD4 count of +289 cells/ml from baseline. No participant on B/F/TAF failed with resistance. Among the B/F/TAF group through W192, 79% (471/594) of treatment-emergent AEs were Grade 1 or 2, most commonly diarrhea, nasopharyngitis, headache, upper respiratory tract infection and syphilis. AEs led to drug discontinuation in 1% (n=7) of participants. Median (Q1, Q3) weight change from baseline to W192 was 4.9kg (1.3, 9.9), with 3kg (0.3, 5.8) gain occurring in the first year of treatment.

CONCLUSIONS: Through 4 years of follow-up, B/F/TAF resulted in high rates of virologic suppression with no treatment-emergent resistance, and a low frequency of AEs and few drug discontinuations.