Emicizumab prophylaxis in infants with severe haemophilia A without inhibitors: Illustrative real-world cases to support shared decision-making.

Introduction: Emicizumab has been shown to be safe and effective for prevention of bleeds in patients with severe haemophilia A (SHA), both with and without inhibitors. The subcutaneous administration and long half-life make emicizumab an attractive option for prophylaxis in infants with SHA, however data to inform treatment decisions in this younger age group are almost absent.

Aim: The aim of this report is to share real world experience to illustrate how the availability of emicizumab has shifted the prophylaxis paradigm in the management of infants with SHA.

Method: We selected four cases from our own cohort of infants with SHA to outline the rationale for emicizumab prophylaxis in a range of scenarios familiar to paediatric haemophilia treaters.

Results: In Case 1 emicizumab was commenced at 7 days following initial treatment of neonatal ICH with a FVIII infusion. In Case 2 emicizumab was commenced at 5 weeks due to parental anxiety regarding the potential for ICH during infancy. Case 3 commenced emicizumab at 15 months in lieu of standard primary prophylaxis. Case 4 switched to emicizumab prophylaxis at 14 months after a period of primary prophylaxis with FVIII concentrates to alleviate parental anxiety regarding future inhibitor development. No patient had any bleeding events after commencement of emicizumab (median follow up 12 months), and no drug-related adverse effects were observed.

Conclusion: Despite the paucity of data in infants with SHA the potential role of emicizumab prophylaxis should be discussed with families when clinically relevant, with decisions tailored to individual need.