Emicizumab utilization, safety, and outcomes in people with severe hemophilia and no inhibitors: 3-year follow-up. A report from the UK Haemophilia Centre Doctors’ Organisation

Background: Emicizumab prophylaxis is restricted to severe hemophilia A in the UK. Treatment choice and safety remain a matter of debate. Objectives: This study was conducted to investigate factors influencing treatment choice, continued use, safety, and clinical outcomes associated with emicizumab in a national cohort of persons with severe hemophilia A without current inhibitors. Methods: A 3-year study was conducted in 618 persons with severe hemophilia A who switched to emicizumab and 413 who continued factor (F)VIII prophylaxis. Outcome measures included annualized bleed rates (ABRs), the Hemophilia Joint Health Score, and health-related quality of life. Conclusions: Emicizumab selection was influenced by ABR and inhibitor history but not age. Emicizumab was generally well tolerated, with only 2.3% discontinuing the drug. A significant within-person improvement in all bleeding outcomes was observed with emicizumab.