Researchers presented the cases of 2 patients with severe hemophilia A who experienced breakthrough bleeding despite being on emicizumab prophylaxis in a study published in the International Journal of Hematology.

The first patient was diagnosed with severe hemophilia A after experiencing an intracranial bleeding episode 6 days after birth. Despite surgical intervention, he presented with the same problem 2 months later. His physicians initiated immune tolerance therapy with a human recombinant factor VIII (rFVIII) product and started him on emicizumab prophylaxis. 

At 6 years of age, he suffered from a head contusion. Computed tomography (CT) of the brain revealed intracranial hemorrhage, which prompted his physicians to immediately administer a bolus infusion of rFVIII. 

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Further investigations revealed no signs of anemia or thrombocytopenia, and brain CT indicated that the bleeding did not increase in size. His physicians decided on a conservative course of action, prescribing him continuous infusions of rFVIII. After 9 days, his symptoms gradually improved and a follow-up CT indicated hematoma absorption. He was switched to a bolus infusion of rFVIII for 4 days and was subsequently discharged on day 14. 

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The second patient had a similar history to the first individual: He too was diagnosed with severe hemophilia A after experiencing an intracranial hemorrhage a few days after birth. A craniotomy was performed under hemostatic management with rFVIII. 

At 1.5 years of age, the patient was started on emicizumab prophylaxis, which successfully prevented any breakthrough bleeding episodes for a number of years. However, at age 6, he fell off his bicycle and injured the left side of his abdomen. Four days later, severe abdominal pain and left knee restriction resulted in his being hospitalized. 

Laboratory investigations revealed a shortened activated partial thromboplastin time (<23.0s) but no signs of anemia or thrombocytopenia. An abdominal CT revealed significant left retroperitoneal and iliopsoas muscle hemorrhages. He was thus prescribed concomitant treatment with bolus infusions of rFVIII.

His condition improved and a contrast-enhanced CT scan on day 2 of admission revealed no hematoma enlargement. His physicians thus decided on a conservative treatment strategy: bolus infusions of rFVIII for 8 days followed by single infusions (50 IU/kg/day) for 12 days. His condition continued to improve and his rFVII was switched to being administered every other day. On day 28, the patient was discharged. 

These case studies highlight the importance of exploring the extent of trauma-induced hemorrhage even if patients are on emicizumab prophylaxis. 


Yamada Y, Nakajima Y, Ohara A, et al. Two pediatric cases of severe hemophilia A in which emicizumab prophylaxis failed to prevent traumatic extra-articular hemorrhageInt J Hematol. 2022;1-6. doi:10.1007/s12185-022-03490-x