Study To Compare On-Demand Treatment To A Prophylaxis Regimen Of BeneFIX In Subjects With Moderately Severe to Severe Hemophilia B

A Multicenter, Open-label Study To Compare On-demand Treatment To A Prophylaxis Regimen Of Nonacog-alfa (Benefix) In Subjects With Moderately Severe To Severe Hemophilia B (Fix:c</=2%)

The purpose of this study will be to determine if a once-weekly prophylaxis regimen of BeneFIX in subjects with moderately severe to severe Hemophilia B is safe and effective.

Inclusion Criteria:

• Documented history of moderately-severe to severe hemophilia B (FIX activity </=2%).
• Male subjects, aged 12 years to 65 years.
• Subjects with at least 100 exposure days (EDs) to factor IX products.
• Subjects with a minimum of 12 bleeding episodes, 6 of which must be joint bleeds, in the 12-month period before the Screening visit.

Exclusion Criteria:

• Subjects who have received FIX as a primary or secondary prophylaxis regimen within the last 12 months prior to the Screening visit.
• Subjects who have had major surgery or an orthopedic surgical procedure within the past 3 months prior to Screening visit.
• Subjects for which major surgery or orthopedic surgery is planned within the duration of study participation.
• Subjects with a past history of, or current FIX inhibitor, defined as >ULN (upper limit of normal) of the reporting laboratory.
• Subjects with a known hypersensitivity to any FIX product or hamster protein.