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

Inclusion Criteria:

- Documented history of moderately-severe to severe hemophilia B (FIX activity
- 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.