F3 and hemophilia: Endogenous tissue factor pathway inhibitor (TFPI) is primarilysynthesized by endothelial cells.54 Itplays a role in inactivating the tissue factor/FVIIa complex.28,54 Therefore, targeting TFPI can enhance the tissue factor (extrinsic)pathway of coagulation, which might benefit patients with hemophilia.Concizumab (mAb 2021) is the first monoclonal antibody developed againstTFPI (Figure 2).