Recombinant Fusion Protein Linking Coagulation Factor IX With Albumin (rIX-FP) in Chinese Subjects With Hemophilia B Previously Treated With FIX Therapy

Inclusion Criteria: * \- Male Chinese subjects aged ≤ 70 years * \- Subjects with documented severe or moderately severe hemophilia B (FIX activity of ≤ 2%) * \- Subjects have received FIX products for ≥ 150 exposure days (EDs) (subjects aged ≥ 6 years) or ≥ 50 EDs (subjects aged \< 6 years) * \- Subjects have no confirmed prior history of FIX inhibitor formation Exclusion Criteria: * \- Known hypersensitivity (allergic reaction or anaphylaxis) to any FIX product or hamster protein. * \- Known congenital or acquired coagulation disorder other than congenital FIX deficiency. * \- Currently receiving intravenous (IV) immunomodulating agents such as immunoglobulin or chronic systemic corticosteroid treatment. * \- Currently receiving a long-acting recombinant FIX treatment such as coagulation factor IX (recombinant), Fc fusion protein (Alprolix®). * \- Use of traditional or herbal Chinese medicine(s) with an impact on hemophilia, including coagulation, within 28 days before Day 1 and / or refusal to abstain from these during the study until the end of the subject's participation in the study.