Patients: 20 previously treated male hemophilia B patients with FIX activity ≤2% and at least 150 days of exposure to a FIX product before enrollment.
Study design: Open-label dose escalation trial. Patients were administered one of three doses of Rebinyn® (25, 50, or 100 IU/kg) no less than 7 days after receiving the same dose of their prior SHL rFIX (N=7) or pdFIX (N=8). Blood samples for pharmacokinetic analysis were drawn 30 mins for dosing with any product, as well as at 7 intervals after dosing with a patient’s prior product (ending at 48 hours postdose) and 13 intervals after dosing with Rebinyn® (ending at 4 weeks after dosing). Inhibitors were measured using a Nijmegan modified Bethesda assay, and FIX activity was measured using a modified aPTT assay.
Primary endpoint: Safety of Rebinyn® as evaluated by adverse events, antibody formation including inhibitors against FIX and Rebinyn®, physical examination, vital signs, electrocardiogram, injection site reactions, urinalysis, and clinical laboratory asessments.
Secondary endpoint: Pharmacokinetic assessment of Rebinyn® and comparison to other FIX products, based on FIX coagulation activity measurements.