Estimated prophylactic dose required to achieve 3% trough as a function of age and concentrate class in multi-country severe WAPPS-Hemo haemophilia patients.

INTRODUCTION:Web-Accessible Population-Pharmacokinetic Service-Haemophilia (WAPPS-Hemo) data are available to study factor-concentrate usage, defined as the required weekly dose to achieve a 3% trough (WD3T), across standard and extended half-life (SHL/EHL) products. AIM:To provide baseline usage data including (i) differences across plasma-derived (pdSHL) versus recombinant (rSHL) products, (ii) SHL versus EHL, and (iii) effect of age and positive inhibitor history. METHODS:PK profiles (n = 14,416 patients, 0.3-85.2 years) and linear mixed effects models were used to estimate usage versus age, controlling for significant factors, using 95% confidence intervals to perform comparisons across all ages and posthoc tests to assess the differences. RESULTS:Average usage was significantly higher for pdSHL versus rSHL in patients with a positive inhibitor history (PIH; 1.9-2.5 times higher), for SHL versus EHL (4-10 times), and was significantly associated with age. CONCLUSION:Baseline usage patterns from 2017 to early 2023 provide a benchmark for assessing the impact of emerging technologies in haemophilia.