Eftrenonacog alfa 2,000unit powder and solvent for solution for injection vials

The coagulation protein factor IX (FIX) is a vitamin K-dependent coagulation factor and one of the critical serine proteases involved in the coagulation cascade. Upon activation by factor XIa in the intrinsic coagulation pathway and by the factor VII/tissue factor complex in the extrinsic pathway, factor IX, in combination with factor VIII, activates factor X. Activated factor X mediates the conversion of prothrombin to thrombin which sequentially leads to thrombin converting fibrinogen into fibrin. A blood clot is then formed [FDA Label]. With a mutation in the gene encoding the coagulation protein factor IX (FIX), patients with hemophilia B have factor IX deficiency and are at high risk for recurrent bleeding episodes.

Eftrenonacog alfa is composed of a single molecule of recombinant FIX (rFIX) covalently fused to the dimeric Fc domain of immunoglobulin (Ig) G1 (rFIXFc). It serves as a replacement therapy to increase the plasma levels of factor IX thereby enabling a temporary correction of the factor deficiency and correction of the bleeding tendencies [FDA Label]. The Fc region of human immunoglobulin G1 binds with the neonatal Fc receptor which is expressed throughout life as part of a naturally occurring pathway that protects immunoglobulins from lysosomal degradation by cycling these proteins back into circulation, resulting in their long plasma half-life. The binding of eftrenonacog alfa to the neonatal Fc receptor delays degradation and recycles the fusion protein back into circulation for increased plasma half life and prolonged therapeutic action [FDA Label, A31557].