Eftrenonacog Alfa

**Semantic type:** Pharmacologic Substance

**Definition:** A recombinant fusion protein composed of the Fc region of human immunoglobulin (Ig) G1 covalently linked to a recombinant form of human blood coagulation factor IX (FIX) that has structural and functional properties similar to endogenous Factor IX, that can be used to treat hemophilia B (congenital factor IX deficiency; Christmas disease) and other bleeding episodes. Upon administration, eftrenonacog alfa, by providing and replacing missing factor IX needed for effective hemostasis, may normalize the activated partial thromboplastin time (aPTT), increase blood clotting, and reduce and control bleeding episodes. The Fc region of human IgG1 binds to the neonatal Fc receptor (FcRn). As FcRn is part of a naturally occurring pathway that delays lysosomal degradation of immunoglobulins by cycling them back into circulation, the Fc domain is able to prolong the plasma half-life of eftrenonacog alfa.

**Synonyms:** - Alprolix - BIIB-029 - Coagulation Factor IX Recombinant Immunoglubulin G1 Fusion Protein - EFTRENONACOG ALFA - Factor IX Recombinant Fc Fusion Protein - Factor IX recombinant Fc fusion protein - rFIXFc