Efficacy and Safety of Recombinant Fusion Protein Linking Coagulation Factor IX with Albumin (rIX-FP) in Previously Treated Patients with Hemophilia B Undergoing Major Orthopedic Surgeries

A fusion protein genetically linking recombinant human coagulation FIX with recombinant human albumin (rIX-FP) has been developed with an improved PK profile, improving hemophilia B treatment by allowing less frequent dosing and FIX consumption for perioperative management. A surgical sub-study was included in 3 Phase III studies, including an on-going Phase IIIb extension study in subjects with hemophilia B, as part of the global PROLONG-9FP clinical program. This report will focus on the use of rIX-FP for perioperative prophylaxis.

Efficacy was evaluated by Investigator assessment (4-point scale), predicted and estimated actual blood loss, and consumption of rIX-FP during the 14-day perioperative period. Safety, including inhibitors to FIX, was assessed. The pre-operative dose of rIX-FP was based on individual incremental recovery, targeting 80-100% FIX activity. FIX activity was monitored at local laboratories to determine repeat doses during the surgical period.

Five major orthopedic surgeries have been assessed to date. Hemostatic response was rated by investigators as excellent or good for all surgeries. A single dose of rIX-FP prior to surgery was sufficient to maintain hemostasis during surgery. Estimated actual blood loss was consistent with predicted blood loss in patients without hemophilia B. The total number of rIX-FP injections ranged from 6-7 over the 14 day post-operative period. The median rIX-FP consumption prior to surgery, Days 1-3, Days 1-7 and Days 8-14 post surgery were 84, 33, 81 and 107 IU/kg, respectively. There were no inhibitors to FIX or antibodies to rIX-FP during the study. The extension study is still ongoing, and additional orthopedic surgeries data may be presented.

These results support the efficacy and safety of rIX-FP for perioperative management in patients with hemophilia B, with prolonged dosing intervals and lower FIX consumption than conventional therapies.