Objective: An extended half-life
factor IX (FIX) fusion
protein linking recombinant FIX with recombinant
human albumin (rIX-FP), indicated for the treatment of
hemophilia B, was approved by the European Medicines Agency in May 2016. We aimed to compare clinical outcomes and drug utilization in patients who switched from prior FIX
therapies to rIX-FP.Methods: Anonymized patient chart data were collected from German institutions treating patients with
hemophilia B. Patients were included if they had been treated with rIX-FP for ≥8 weeks at the time of data collection.
Bleeding rates and FIX consumption were compared between rIX-FP and patients' prior FIX products.Results: Data were obtained for 81 male patients treated with rIX-FP, including 59 who received prophylaxis with both their prior drug and rIX-FP (prophylaxis-to-prophylaxis group). Mean factor consumption in this group was 44.2 IU/kg/wk for rIX-FP compared with 82.3 IU/kg/wk for all prior FIX products. In addition, intra-patient analysis of factor consumption showed lower consumption of rIX-FP compared with prior FIX in 56 of 59 patients. Among the patients for whom bleed data were available (n = 42), annualized
bleeding rate decreased from a mean (standard deviation) of 2.6 ± 2.9 on prior product to 0.3 ± 0.6 on rIX-FP. The proportion of patients with zero bleeds increased from 24% with prior
therapy to 81% with rIX-FP.Conclusion: rIX-FP was associated with substantial reductions in
bleeding rates and consumption of FIX compared with standard half-life products that require more frequent administration.