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Successful immune tolerance induction using efanesoctocog alfa in severe hemophilia A: a case series
Aqsa Ashraf1, Rebekah Kuhlman2, Osman Khan3
1Hematology-Oncology Section, Department of Internal Medicine, College of Medicine, University of Oklahoma Health Campus, Oklahoma City, Oklahoma, USA.
The development of neutralizing factor VIII (FVIII) inhibitors remains a major therapeutic challenge in severe hemophilia A. We report 2 patients with complex inhibitor histories who achieved rapid, sustained inhibitor eradication with efanesoctocog alfa. Immune tolerance induction was initiated at 100 U/kg 3 times weekly, with subsequent dose reduction after inhibitor clearance. Inhibitor titers declined to undetectable levels (<0.5 Bethesda Units) within 6 weeks in one case and 3 months in the other, with FVIII recovery exceeding 90%. Transition to once-weekly individualized prophylaxis maintained functional FVIII activity and therapeutic FVIII trough levels (4%-6%), allowing discontinuation of emicizumab. Sustained bleed-free outcomes were achieved with individualized prophylactic dosing without inhibitor recurrence. These cases support efanesoctocog alfa-based immune tolerance induction as a promising strategy for rescue and retreatment in patients with complex inhibitor histories.
The development of neutralizing factor VIII (FVIII) inhibitors remains a major therapeutic challenge in severe hemophilia A. We report 2 patients with complex inhibitor histories who achieved rapid, sustained inhibitor eradication with efanesoctocog alfa. Immune tolerance induction was initiated at 100 U/kg 3 times weekly, with subsequent dose reduction after inhibitor clearance. Inhibitor titers declined to undetectable levels (<0.5 Bethesda Units) within 6 weeks in one case and 3 months in the other, with FVIII recovery exceeding 90%. Transition to once-weekly individualized prophylaxis maintained functional FVIII activity and therapeutic FVIII trough levels (4%-6%), allowing discontinuation of emicizumab. Sustained bleed-free outcomes were achieved with individualized prophylactic dosing without inhibitor recurrence. These cases support efanesoctocog alfa-based immune tolerance induction as a promising strategy for rescue and retreatment in patients with complex inhibitor histories.
