Anti-factor IXa and X monoclonal antibody Treatment of congenital FVIII deficiency (hemophilia A)

Hemophilia is an inherited clotting disorder in which spontaneous and prolonged bleeding can appear at any location. Hemophilia A is caused by the inheritance of an abnormal form of factor VIII (FVIII). Emicizumab is a humanized, monoclonal modified antibody designed to replace the function of FVIII by bringing activated factor IX (FIXa) and factor X (FX) into a suitable way to facilitate rapid conversion of FX to activated FX (FXa). In animal primate models of hemophilia A, emicizumab showed hemostatic effects. In severe hemophilia A patients with or without FVIII inhibitors, emicizumab once weekly s.c. is well tolerated and decreased the annualized bleeding rate in all patients. Currently, three phase III studies are ongoing to assess the efficacy, safety and pharmacokinetics of s.c. emicizumab in severe hemophilia A patients. The product has been granted orphan drug designation (Europe, U.S. and Japan). In addition, emicizumab received breakthrough therapy designation by the U.S. Food and Drug Administration (FDA), and priority review status by the Japanese authorities for the treatment of hemophilia A.