Long-term safety and efficacy of rIX-FP prophylaxis with extended dosing intervals up to 21 days in adults/adolescents with hemophilia B.
J Thromb Haemost. 2020 Feb 20;:
Authors: Mancuso ME, Lubetsky A, Pan-Petesch B, Lissitchkov T, Nagao A, Seifert W, Li Y, Santagostino E
BACKGROUND: An international, multicenter extension study evaluated recombinant fusion protein linking recombinant coagulation factor IX (FIX) with recombinant human albumin (rIX-FP) in hemophilia B (FIX ≤2%) patients previously enrolled in a phase III study or who initiated rIX-FP prophylaxis following surgery.
OBJECTIVES: To investigate the long-term safety and efficacy of rIX-FP prophylaxis in adult previously treated patients (PTPs) with hemophilia B.
METHODS: Male PTPs were treated with a 7- (35-50 IU/kg), 10- or 14-day regimen (50-75 IU/kg). Patients ≥18 years who were well-controlled on a 14-day regimen for ≥6 months could switch to a 21-day regimen (100 IU/kg).
RESULTS: A total of 59 patients (aged 13-63 years) participated in the study. Following a single-dose of 100 IU/kg rIX-FP, in patients eligible for the 21-day regimen, the mean terminal half-life was 143.2 hours. Mean steady-state FIX trough activity levels ranged from 22% with the 7-day regimen to 7.6% with the 21-day regimen. Median (Q1, Q3) annualized spontaneous bleeding rates were 0.00 (0.00, 1.67), 0.28 (0.00, 1.10), 0.37 (0.00, 1.68) and 0.00 (0.00, 0.45) for the 7-, 10, 14- and 21-day regimens, respectively. Comparable efficacy was demonstrated for both the 14- and 21-day regimens compared to the 7-day regimen. Overall, 96.5% of bleeding episodes were treated successfully with 1-2 rIX-FP infusions. No patients developed an inhibitor and treatment was well tolerated.
CONCLUSIONS: rIX-FP extended interval prophylaxis provides dosing flexibility and, in selected patients, a 21-day regimen may provide an alternative option to minimize treatment burden and individualize treatment.
PMID: 32078256 [PubMed – as supplied by publisher]