Acquired haemophilia A associated with prostate cancer managed with recombinant activated factor VII and emicizumab

Acquired haemophilia A (AHA) is a rare autoimmune bleeding disorder caused by neutralising antibodies against factor VIII. We describe an older man with prostate cancer on active surveillance who presented with spontaneous ecchymoses, progressive anaemia and isolated prolongation of activated partial thromboplastin time. Factor VIII activity was severely reduced, and mixing studies and Bethesda assay confirmed a high-titre factor VIII inhibitor. He achieved initial haemostatic control with recombinant-activated factor VII and was transitioned to emicizumab using an accelerated AHA regimen. No corticosteroids were given inpatient. Emicizumab was used for haemostatic prophylaxis while outpatient once-weekly rituximab was planned for inhibitor eradication. This case highlights early recognition, evaluation for associated malignancy and use of emicizumab as prophylaxis that may allow individualised immunosuppression in selected older patients.