Supplementary Material for: A Jehovah's Witness with acquired hemophilia A who successfully avoided blood transfusions by receiving emicizumab

Introduction: Acquired hemophilia A (AHA) manifests as a significant deficiency in coagulation factor VIII (FVIII) activity caused by the development of autoantibodies against FVIII and results in severe bleeding symptoms that can be life-threatening. Therefore, patients with AHA often require blood transfusions. Emicizumab, a bispecific monoclonal antibody that replaces the function of activated FVIII, has been more widely used to treat AHA. Case Presentation: We report a 70-year-old male Jehovah's Witness with AHA who refused blood transfusions despite experiencing severe bleeding in the left biceps muscle; anemia had progressed by approximately 100x104/μL in just 2 days. Since the use of coagulation factor products had been approved in writing, we administered a single-dose mixture of activated factor VIIa/X (Byclot®) and promptly achieved hemostasis. Subsequently, regular administration of emicizumab was effective in preventing rebleeding and successfully avoiding blood transfusions. Conclusion: For Jehovah's Witnesses with AHA, the administration of emicizumab can be considered a highly valuable treatment.