Hemophilia B

This study will examine the safety and efficacy of a Recombinant Coagulation Factor IX Albumin Fusion Protein (rIX-FP) for the control and prevention of bleeding episodes in subjects who have previously received factor replacement therapy for hemophilia B. The study consists of a screening period, a pharmacokinetic (PK) period, followed by approximately a 5 month treatment period. Subjects will receive weekly routine prophylactic therapy and on-demand treatment for bleeding episodes. In addition, subjects who are not on routine factor replacement therapy prior to the study will receive only on-demand treatment for bleeding episodes.