Alternative treatment options for pediatric hemophilia B patients with high-responding inhibitors: A thrombin generation-guided study.

Little is known about the challenging treatment of pediatric patients with hemophilia B and inhibitors due to disease rarity. We describe three patients diagnosed in childhood and followed up to 9 years. All three had allergic reactions to Factor IX, but two were later safely treated for bleeding episodes with activated prothrombin complex concentrates (APCC = FEIBA). The third was given only recombinant activated Factor VIIa. Based on ex vivo thrombin generation analysis, a new alternative treatment of combined bypassing agents was administered for bleeding episodes and several minor surgical procedures with no treatment-associated adverse events or thrombosis.