Nonacog Alfa Prophylaxis And Treatment Of Bleeding Episodes In Previously Treated Patients With Hemophilia B

Inclusion Criteria: 1. Male subjects ≥12 years to ≤65 years with a diagnosis of congenital moderately-severe to severe hemophilia B (FIX activity ≤2%). 2. Documented history of at least 50 exposure days (EDs) to FIX-containing products. 3. Evidence of a personally signed and dated informed consent document indicating that the subject (or a legally acceptable representative, parent(s)/legal guardian) has been informed of all pertinent aspects of the study. For minors under the age of legal consent in India, assent of the participating child needs to be documented for the age range 12 to 18 in addition to the parental informed consent. Exclusion Criteria: 1. Prior history of inhibitor to FIX or positive inhibitor testing (≥0.6 BU/mL) during Screening. Clinical signs or symptoms of decreased response to FIX. 2. Known hypersensitivity to the active substance or any of the excipients. 3. Known allergic reaction to hamster proteins. 4. Presence of any bleeding disorder in addition to hemophilia B. 5. Participation in other studies involving investigational drug(s) (Phases 1-4) within 30 days before the current study begins and/or during study participation. 6. Planned surgery within 6 months from the start of the study. 7. Unsuitable to participate in study for any other reason as assessed by the investigator; including any disorder, except for conditions associated with hemophilia B, which in the investigator's opinion might jeopardize subject's safety or compliance with the protocol. 8. Subjects (or a legally acceptable representative) is not able to understand study documents and study procedure. 9. Immunocompromised subjects due to human immunodeficiency virus (HIV) infection (defined as viral load above or equal to 100,000 copies/mL; and for HIV+ subjects: cluster of differentiation 4 positive (CD4+) lymphocyte count below or equal to 200/μL). HIV status and CD4+ lymphocyte count results may be obtained at screening or from available medical records; results must be not older than 6 months prior to screening. 10. Subjects who are investigational site staff members directly involved in the conduct of the study and their family members, site staff members otherwise supervised by the Investigator, subjects who have been previously enrolled into the study, or subjects who are Pfizer employees directly involved in the conduct of the study. 11. Planned use of any non-study medication for treatment of hemophilia (eg, other factor replacement agents, bypassing agents, or non-factor treatments \[such as anti-tissue factor pathway inhibitors\]).