Syntonix was formed to discover and develop novel therapeutic proteins for the treatment of chronic diseases such as hemophilia, anemia, multiple sclerosis and autoimmune disorders.

Biogen IDEC, which acquired Syntonix in 2007, is developing Syntonix’s lead product, recombinant factor IX Fc fusion protein (rFIXFc) for the treatment of hemophilia B. The Syntonix product 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.