Emicizumab prophylaxis beyond clinical trials: a multicenter, prospective real-world study of pediatric hemophilia patients with and without inhibitors

Emicizumab has improved prophylactic management of hemophilia A (HA), offering effective bleed prevention independent of factor VIII (FVIII) inhibitor status. However, prospective real-world pediatric data from low- and middle-income settings remain limited. We conducted a prospective cohort study of 72 children (< 18 years) with HA receiving subcutaneous emicizumab prophylaxis for 12 months. The cohort comprised 70 patients with severe HA and 2 with moderate HA with severe bleeding phenotype. Patients included both inhibitor-positive and inhibitor-negative children. Outcomes included annualized bleeding rate (ABR), joint health assessed by Hemophilia Joint Health Score version 2.1 (HJHS 2.1), and functional capacity measured by the Functional Independence Score in Hemophilia (FISH). The. median ABR decreased from 40 (IQR 36-48) at baseline to 0 (IQR 0-0) after 12 months (P < 0.001), with 79.16% of children experiencing zero treated bleeds. AJBR was 0 in 86.1% of patients, and all target joints resolved by 12 months. The median HJHS improved from 15 (IQR 7-22) to 9 (IQR 3-14) (P < 0.001), and mean FISH score increased from 20.65 ± 4.25 to 26.02 ± 3.57 (P < 0.001), with greatest improvements in squatting, running, and stair climbing. Reductions in ABR, HJHS, and FISH were comparable between inhibitor-positive and inhibitor-negative patients. CONCLUSION: Emicizumab prophylaxis provides profound bleed control and meaningful improvements in joint and functional outcomes in children with HA, regardless of inhibitor status, supporting its use as standard pediatric prophylaxis in routine clinical practice. WHAT IS KNOWN: • Emicizumab effectively reduces bleeding in children with hemophilia A. • Prospective real-world pediatric data in low- and middle-income settings remain limited. WHAT IS NEW: • This study showed near-complete bleed control, full target joint resolution. • Comparable benefits were observed in children with and without inhibitors in a prospective real-world setting.