Two case reports of acquired haemophilia A as complications of alemtuzumab treatment for multiple sclerosis

Objective To describe the case histories of two patients who developed acquired haemophilia A following treatment with alemtuzumab for multiple sclerosis. Results Two patients, a 48-year-old woman and a 31-year-old woman, developed acquired haemophilia A 21 months after their second doses of alemtuzumab. Both presented with spontaneous bruising, and the second case reported menorrhagia. One patient required treatment to control bleeding. Both patients responded to treatment with prednisolone and cyclophosphamide to eliminate the inhibitor. Conclusions Acquired haemophilia A is a rare complication following treatment with alemtuzumab. Activated partial thromboplastin time and prothrombin time should be performed in cases of abnormal bleeding in which the platelet count is normal, to facilitate timely diagnosis and prevention of major bleeding complications.