Clinical, humanistic, and economic burden of severe haemophilia B in adults receiving factor IX prophylaxis: findings from the CHESS II real-world burden of illness study in Europe

Background Real-world studies of the burden of severe haemophilia B in the context of recent therapeutic advances such as extended half-life (EHL) factor IX (FIX) products are limited. We analysed data from the recent CHESS II study to better understand the clinical, humanistic, and economic burden of severe haemophilia B in Europe. Data from male adults with severe haemophilia B receiving prophylaxis were analysed from the retrospective cross-sectional CHESS II study conducted in Germany, France, Italy, Spain and the United Kingdom. Inhibitors were exclusionary. Patients and physicians completed questionnaires on bleeding, joint status, quality of life, and haemophilia-related direct and indirect costs (2019-2020). All outcomes were summarised using descriptive statistics. Results A total of 75 CHESS II patients were eligible and included; 40 patients (53%) provided self-reported outcomes. Mean age was 36.2 years. Approximately half the patients were receiving EHL versus standard half-life (SHL) prophylaxis (44% vs 56%). Most patients reported mild or moderate chronic pain (76%) and had >= 2 bleeding events per year (70%), with a mean annualised bleed rate of 2.4. Mean annual total haemophilia-related direct medical cost per patient was euro235,723, driven by FIX costs (euro232,328 overall, n = 40; euro186,528 for SHL, euro290,620 for EHL). Mean annual indirect costs (euro8,973) were driven by early retirement or work stoppage due to haemophilia. Mean quality of life (EQ-5D) score was 0.67. Conclusions These data document a substantial, persistent real-world burden of severe haemophilia B in Europe. Unmet needs persist for these patients, their caregivers, and society.