Biogen Idec Inc. announced the company recently submitted a Biologics License Application (BLA) to the U.S. Food and Drug Administration (FDA) for the marketing approval of recombinant factor IX Fc fusion protein (rFIXFc) for the treatment of hemophilia B. rFIXFc is the first product candidate in a new class of long-lasting clotting factor therapies that are being developed with the goals of reducing the burden of treatment for this condition and enhancing protection from bleeding. The regulatory submission was based on results from B-LONG, the registrational phase 3 clinical study in hemophilia B to date. rFIXFc is a clotting factor developed using Biogen Idec's novel and proprietary monomeric Fc fusion technology, which makes use of a naturally occurring pathway that delays the destruction of factor and cycles it back into the bloodstream, resulting in a longer circulating half-life.

With this technology, rFIXFc is designed to provide long-lasting protection from bleeding and reduce the treatment burden associated with hemophilia B, which currently can require more than 100 injections annually for prophylaxis with commercially-available factor IX products. Fc fusion technology is used in seven FDA-approved products for the long-term treatment of chronic diseases including rheumatoid arthritis, psoriasis and platelet disorders. Hemophilia B is a rare, inherited disorder in which the ability of a person's blood to clot is impaired.

Hemophilia B occurs in about one in 25,000 male births annually and is caused by having substantially reduced or no factor IX activity, which is needed for normal blood clotting. People with hemophilia B therefore need injections of factor IX to restore the coagulation process and prevent frequent bleeds that could otherwise lead to pain, irreversible joint damage and life-threatening hemorrhages. The Medical and Scientific Advisory Council of the National Hemophilia Foundation recommends prophylaxis as the optimal therapy for people with severe hemophilia B. Currently, prophylaxis in hemophilia B typically requires injections up to three times per week to maintain a sufficient circulating level of clotting factor.