SAFETY AND EFFICACY OF MONOCLONAL ANTIBODY-PURIFIED FACTOR-IX CONCENTRATE FOR MANAGEMENT OF BLEEDING AND SURGICAL PROPHYLAXIS IN PREVIOUSLYTREATED CHILDREN WITH HEMOPHILIA-B

Purpose: This study provides information about the safety and efficacy of repeated infusions of a monoclonal antibody-purified factor IX con centrate, Mononine(R) [Coagulation Factor IX (Human) Monoclonal Antibo dy Purified], in children with hemophilia B. Patients and Methods: The study included 18 previously treated patients with hemophilia B 3 mon ths to 20 years old who received a monoclonal antibody-purified factor IX concentrate (MAb Factor IX) either for surgical coverage or for sp ontaneous or trauma-induced bleeding as part of a larger study in all ages. Eleven children received MAb Factor IX concentrate for surgical procedures, including synovectomy (four), multiple dental extractions (three), hernia repair (two), maxillofacial reconstruction (one), and catheter placement (one). Five were treated to control spontaneous ble eding, one patient for two separate episodes of trauma, and one patien t for both spontaneous and trauma-induced bleeding. Results: From phar macokinetic data in 10 patients, the average maximum post-infusion fac tor IX level was 62.4% (range = 45-149%) and the average recovery was 1.13 U/dl rise per U/kg of factor IX infused (range = 0.41-2.53 U/dl). The average dose of factor IX before surgery was 49.0 U/kg (range = 3 4.0-100.8 U/kg). The overall average dose of factor IX concentrate adm inistered for surgery or treatment of bleeding was 52.7 U/kg (range = 19.0-113.0 U/kg). The average number of doses for all patients was 11. 4 (range = 2-30). The average recovery obtained with repeated dosing f or surgical coverage or treatment of severe hemorrhage was 1.25 U/kg r ise per U/kg infused (range = 0.64-2.45). The average total dose admin istered during treatment was 26,791 U (range = 2,050-104,120 U), Hemos tasis in all patients was excellent, and no patients experienced a thr omboembolic complication. Two patients experienced clinical adverse ev ents considered probably related to treatment (venospasm and burning a t the injection site), which resolved spontaneously. Conclusions: Thes e results demonstrate that repeated doses of monoclonal antibody-purif ied factor IX are safe and effective for the management of spontaneous or trauma-induced bleeding and for surgical coverage in pediatric pat ients with hemophilia B.