Concizumab: First Approval.

Concizumab (Alhemo™), a subcutaneously administered humanised monoclonal IgG4 antibody against tissue factor pathway inhibitor (TFPI), binds to the Kunitz-2 domain of TFPI and prevents TFPI from binding to activated Factor X. Concizumab is being developed by Novo Nordisk for the treatment of hemophilia A and B with and without inhibitors. In March 2023, concizumab was approved in Canada for the treatment of adolescent and adult patients (12 years of age or older) with hemophilia B who have FIX inhibitors and require routine prophylaxis to prevent or reduce the frequency of bleeding episodes. This article summarizes the milestones in the development of concizumab leading to this first approval for the treatment of hemophilia B.