Study of Recombinant Factor IX Product, IB1001, in Previously Treated Subjects With Hemophilia B

Primary Objectives: * to evaluate safety of IB1001 within the first 50 exposure days, * to determine IB1001 pharmacokinetics (PK), and * to assess efficacy of IB1001 prophylaxis with respect to breakthrough bleeding and with respect to control of hemorrhaging in subjects with severe hemophilia B within the first 50 exposure days Secondary Objectives: * to evaluate long-term safety of IB1001; and * to evaluate long term efficacy of IB1001. Exploratory Objectives: * to evaluate markers of thrombogenicity during the first 24 hours post-infusion \[thrombogenicity markers will include at a minimum D-dimer test; however should there be a clinical reason (e.g., three consecutive elevations in D-dimer levels, a possible clinical thrombogenic episode), sufficient samples will be collected to also evaluate levels of fragment 1+2 (F1+2) and thrombin-antithrombin III complex (TAT)\] * to evaluate IB1001 immunogenicity response (development of inhibitory and non-inhibitory factor IX binding antibodies and antibodies to host cell proteins)