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

Inclusion Criteria: 1. Age of at least 12 years 2. Body Mass Index of ≤ 29, with a minimum body weight of 40 kg 3. Written Institutional Review Board (IRB)/ Ethics Committee (EC)-approved informed consent form (ICF) 4. Willingness to make the required study visits, and follow instructions while enrolled in the study (up to 12 months) 5. Severe (factor IX activity ≤2 U/dL) hemophilia B patients with a minimum of 3 bleeding episodes over the preceding 6 months or 6 bleeding episodes over the preceding 12 months or in the event the subject is on prophylaxis, a minimum of 3 bleeding episodes over the preceding 6 months or 6 bleeding episodes over the preceding 12 months prior to being placed on prophylaxis 6. Subjects must be on prophylaxis or switch to a prophylaxis regimen for the duration of the PK and Treatment/Continuation Phase of the study 7. Previously treated patients with a minimum of 150 exposure days to a factor IX preparation 8. Willingness to adhere to the 5-day washout of any factor IX replacement therapy prior to PK evaluations 9. Immunocompetent (CD4 count \>400/mm3) and not receiving immune modulating or chemotherapeutic agents 10. Platelet count at least 150,000/mm3 11. Liver function: alanine transaminase (ALT) and aspartate transaminase (AST) ≤2 times the upper limit of the normal range 12. Total bilirubin ≤1.5 times the upper limit of the normal range 13. Renal function: serum creatinine ≤1.25 times the upper limit of the normal range 14. Hemoglobin ≥7 g/dL at the time of the blood draw Exclusion Criteria: 1. History of factor IX inhibitor ≥0.6 BU (Bethesda units) 2. Existence of another coagulation disorder 3. Evidence of thrombotic disease, fibrinolysis or disseminated intravascular coagulation (DIC) 4. Use of an investigational drug within 30 days prior to study entry 5. Previous use of IB1001 6. Use of medications that could impact hemostasis, such as aspirin 7. Hypersensitivity to the active substance or to any of the excipients in the investigational products 8. Known allergic reaction to hamster proteins 9. History of poor compliance, a serious medical or social condition, or any other circumstance that, in the opinion of the investigator, would interfere with participation or compliance with the study protocol 10. History of adverse reaction to either plasma-derived factor IX or recombinant factor IX that interfered with the subject's ability to treat bleeding episodes with a factor IX product