Failure of factor VIII inhibitor bypassing activity (Feiba) to secure haemostasis in haemophilic patients with antibodies.

Factor IX concentrates have been widely advocated in the treatment of haemophilic patients with factor VIII inhibitors. Five such patients were given the 'activated' factor IX concentrate--factor VIII inhibitor bypassing activity (Feiba)--for 14 separate bleeding episodes. In six of the episodes, including two with external blood loss, bleeding progressed in spite of treatment. In none of the other eight episodes was there a prompt response, and it was not possible to ascribe a definite therapeutic effect.