Comprehensive Assessment of the Transition to Efanesoctocog Alfa Prophylaxis in a Paediatric Haemophilia A Cohort

BACKGROUND: Efanesoctocog alfa is a novel recombinant factor VIII (FVIII) with an ultra-extended half-life and stable pharmacokinetics, approved for prophylaxis in children with haemophilia A (HA). OBJECTIVE: To describe the experience of transitioning paediatric patients with HA to efanesoctocog alfa using a comprehensive assessment. METHODS: Prospective observational study in a paediatric haemophilia unit. Patients <18 years without inhibitors were transitioned from prior prophylaxis to efanesoctocog alfa. Treatment regimen, adherence, annual bleeding rate (ABR), pharmacokinetics, joint health, sports, quality-of-life, treatment burden, treatment satisfaction/preference were compared at baseline and during follow-up between efanesoctocog alfa and previous treatment. RESULTS: Eighteen patients (mean age 9.42 years) were included. After 365 ± 84.08 days, adherence improved and no inhibitors were detected. A significant increase in half-life was observed (from 13.57 ± 3.6 to 57.13 ± 6.1 h) which led to a lower ABR score in the series (0.39-0.05) and an improvement of joint health after 6 months (n = 15 patients), due to a relevant synovitis reduction (20% reduction in elbows; 13.3% in ankles) despite patients were moderately-highly physically active. Quality-of-life perception improved after 3 months (EQ-VAS increased: 90.72 ± 10.31 to 95.25 ± 5.3; p = 0.03) as well as treatment burden (HEMO-TEM global score in 12-18 year-old patients: 16.08 ± 11.43 to 11.72 ± 14.8). Patients/caregivers expressed a strong preference for efanesoctocog alfa. CONCLUSION: Transitioning to efanesoctocog alfa was safe and effective in this paediatric cohort. Despite limited follow-up, data suggest this therapy offers meaningful clinical and psychosocial benefits.