Recombinant FIXFc: a novel therapy for the royal disease?

INTRODUCTION: Hemophilia B, the deficiency or complete absence of coagulation factor IX (FIX), affects an estimated 80,000 people throughout the world. Some of these individuals are managed with prophylaxis, which involves the intravenous infusion of FIX concentrate two to three times weekly to prevent bleeding. Because FIX prophylaxis remains underutilized, patients with hemophilia B are at risk for bleeding that may be severe and potentially life- or limb-threatening, and they may experience arthropathy resulting from recurrent hemarthroses. AREAS COVERED: This review focuses on recent advances in therapeutic protein fusion technology as they apply to FIX deficiency. The National Library of Medicine Medline database was searched for articles containing the term 'Fc fusion proteins'. EXPERT OPINION: Genetically engineered recombinant FIX fused to the Fc portion of immunoglobulin significantly extends FIX half-life, thereby decreasing the frequency of prophylactic infusions. This in turn may increase the adoption of, and adherence to, prophylaxis, leading to better outcomes for hemophilia B patients.