Longitudinal Evaluation of Bone Safety in Children and Adolescents With HIV-1 Starting Tenofovir Alafenamide-Containing Antiretroviral Therapy

Abstract

Background Adult participants taking tenofovir alafenamide (TAF) in clinical trials had a better bone safety profile than those taking tenofovir disoproxil fumarate. Herein, we report medium- to long-term effects of TAF-containing regimens on bone health in children and adolescents with human immunodeficiency virus (HIV). Methods This post hoc pooled analysis of data from 2 phase 2/3 clinical studies (NCT01854775 and NCT02285114) evaluated the pharmacokinetics, safety, and efficacy of TAF-based regimens in children and adolescents with HIV-1. Participants were categorized into group 1 (aged 12 to < 18 years, weighing ≥ 35 kg), group 2 (aged 6 to < 12 years, weighing ≥ 25 kg), and group 3 (aged ≥ 2 years, weighing 14 to < 25 kg). Evaluations included virologic suppression, height Z-score, Tanner stage, bone mineral density (BMD) of the spine and total body less head (TBLH; absolute and height-for-age Z-score adjusted [HAZ-adjusted] for both), bone serum markers, bone-related adverse events, and pharmacokinetic assessments. Results Overall, 169 participants were enrolled and treated (78, 61, and 30 in groups 1, 2, and 3, respectively). Median (range) exposure to study drug was 320.3 (8.3-492.3), 290.1 (24.0-393.9), and 168.3 (9.0-193.0) weeks in groups 1, 2, and 3, respectively. Virologic suppression (HIV-1 RNA < 50 copies/mL) rates were high across all groups. Spine and TBLH absolute BMD increased over time in all groups, and spine and TBLH HAZ-adjusted BMD Z-scores increased or remained stable in all groups. There were no significant changes in bone serum markers, and no treatment-related fractures or bone-related adverse events. Conclusions TAF-based regimens demonstrated acceptable medium- to long-term bone safety in children and adolescents with HIV.