Safety and Pharmacokinetic Study of a Recombinant Coagulation Factor IX Albumin Fusion Protein in Subjects With Hemophilia B

Inclusion Criteria: * Male, 12 - 65 years, with body weight ≥ 30 kg and ≤ 120 kg * Documented severe Hemophilia B (FIX activity of ≤ 2%) or tested by the central laboratory at screening * Subjects who have received FIX products for \> 150 exposure days (EDs) (estimated) * No confirmed prior history of FIX inhibitor (history of positive FIX inhibitor defined as two consecutive positive tests - a confirmatory test on a second, separately drawn sample shortly after the previous positive test) and confirmed no detectable FIX inhibitors (negative FIX inhibitor defined as \< 0.6 Bethesda Units \[BU\] by the central laboratory at screening * Subjects can be treated on-demand or under prophylactic therapy * Signed Informed Consent/Assent Exclusion Criteria: * Known hypersensitivity (allergic reaction or anaphylaxis) to any FIX product or hamster protein * Any known congenital or acquired coagulation disorder other than congenital FIX deficiency * Platelet count \< 100,000/µL * Immunocompromised (CD4 count \< 200/mm3), (HIV positive subjects may participate in the study and protease inhibitors and antiviral therapy are permitted, at the discretion of the Investigator) * Currently receiving IV immunomodulating agents such as immunoglobulin or chronic systemic corticosteroid treatment * Serum aspartate aminotransferase (AST) or serum alanine aminotransferase (ALT) concentration \> 5 times (x) the upper limit of normal (ULN) * Serum creatinine \> 2 x ULN * Evidence of thrombosis, including deep vein thrombosis, stroke, pulmonary embolism, myocardial infarction and arterial embolus within 3 months prior to enrollment * Use of an Investigational Medicinal Product (IMP) within 30 days prior to the first rIX-FP administration * Experienced life-threatening bleeding episode or had major surgery or an orthopedic surgical procedure during the 3 months prior to study entry * Subject currently on a dose and/or regimen of FIX that would preclude participation in the study due to possible increased risk of bleeding because of the requirement to withhold treatment during the PK sampling period * Suspected inability (e.g., language problem or mental condition) or unwillingness to comply with study procedures or history of noncompliance