Use of Bypassing Agents and Risk of Thromboembolic Events in Patients with Haemophilia and Inhibitors.

Up to 30% of haemophilia A patients and up to 3% of haemophilia B patients develop neutralizing antibodies (inhibitors) to factor VIII or factor IX, rendering replacement therapies ineffective and making the management of bleeding episodes particularly challenging.1–3While patients with low titre inhibitors may benefit from higher doses of factors VIII or IX, patients with higher antibody levels may require therapies that bypass the need for factor VIII and factor IX.4 Currently available options of bypassing agents are the “activated” prothrombin complex concentrate (aPCC) factor