Abstract Body

B/F/TAF, approved for adults living with HIV-1, is a single-tablet regimen (STR) containing the novel integrase strand transfer inhibitor (INSTI) bictegravir (B) 50 mg, emtricitabine (FTC) 200 mg, and tenofovir alafenamide (TAF) 25 mg. B/F/TAF has a high barrier to resistance and no food restriction. Short-term safety and pharmacokinetics (PK) of B/F/TAF in children and adolescents, reported previously, support the use of the full adult strength tablet in this population. The 48-week (W) safety and efficacy data for 6- to <18-year-olds receiving B/F/TAF are reported.

Virologically suppressed adolescents (12 to <18 yrs) weighing ≥35 kg (Cohort 1) and children (6 to <12 yrs) weighing ≥25 kg (Cohort 2) with HIV-1 RNA <50 c/mL for ≥6 months before screening and CD4 ≥200 cells/μL received B/F/TAF once daily, in a prospective, 48-week, single-arm, open-label trial. Adverse events (AEs), laboratory results, and HIV-1 RNA <50 c/mL were assessed.

Fifty adolescents and fifty children (total n=100) were enrolled. At baseline for Cohort 1, median age was 15 yrs (range 12-17 yrs), weight 44.7 kg (range 35-123 kg), 64% female, 65% Black, median CD4 count 751 cells/μL, 90% vertically infected. For Cohort 2, median age was 10 yrs (range 6-11 yrs), median weight 29 kg (range 25-69 kg), 54% female, 72% Black, median CD4 count 930 cells/μL, and 96% vertically infected. All 100 participants (100%, 100/100) had HIV-1 RNA <50 c/mL at W24 and 98% (74/75) at W48 by US FDA Snapshot Algorithm; no participant had treatment-emergent resistance. CD4 count remained stable to W48. With a 50-week (range 20-93 wks) median duration of exposure to study drug, the only study drug-related AE reported with greater than single participant incidence was abdominal discomfort (2%, 2 participants; grade 1). One participant discontinued after W16 due to an AE (grade 2 insomnia and anxiety). All participants reported B/F/TAF size and shape as acceptable and taste as palatable; median percent adherence (pill counts) to study drug was high at 99% (range 80-100%).

This 48-week efficacy, safety, acceptability, and palatability data, combined with the previously reported PK data, support the use of the first, unboosted, INSTI-based STR of B/F/TAF 50/200/25 mg for the treatment of adolescents and children (6 to <18 years of age and weighing ≥25 kg) living with HIV-1 and prompts further pediatric studies of appropriate formulations of B/F/TAF for children weighing <25 kg.