Pivotal Study (Pharmacokinetics, Efficacy, Safety) of BAX 326 (rFIX) in Hemophilia B Patients

Main Inclusion Criteria: * Participant is 12 to 65 years old at the time of screening * Participant and/or legal representative has/have provided signed informed consent * Participant has severe (factor IX (FIX) level \< 1%) or moderately severe (FIX level 1-2%) hemophilia B (based on the one stage activated partial thromboplastin time (aPTT) assay), as tested at screening at the central laboratory * Participant is previously treated with plasma-derived or recombinant FIX concentrate(s) for a minimum of 150 exposure days (EDs) (based on the participant's medical records); if a verifiable, documented history is unavailable, the participant can be enrolled if s/he has 100-150 EDs to any FIX product that are not fully documented and has participated in Study 050901 for at least 50 EDs to Immunine prior to enrollment (not valid for US and Japan). * Participant has no evidence of a history of FIX inhibitors * If the participant is to receive prophylactic treatment, the participant is willing to receive prophylactic treatment over a period of 6 months. * If the participant is to receive on-demand treatment, the participant has ≥12 documented bleeding episodes requiring treatment within 12 months prior to enrollment and is willing to receive on-demand treatment for the duration of this study. Main Exclusion Criteria: * The participant has a history of FIX inhibitors with a titer ≥0.6 Bethesda Units (BU) (as determined by the Nijmegen modification of the Bethesda assay or the assa…