Recombinant nematode anticoagulant protein c2 and other inhibitors targeting blood coagulation factor VIIa/tissue factor

Lee AYY, Vlasuk GP (McMaster University, Hamilton, ON, Canada; and Corvas International, Inc., San Diego, CA, USA). Recombinant nematode anticoagulant protein c2 and other inhibitors targeting blood coagulation factor VIIa/tissue factor (Minisymposium). J Intern Med 2003; 254: 313–321. Originally isolated from a haematophagous hookworm, recombinant nematode anticoagulant protein c2 (rNAPc2) is an 85‐amino acid protein with potent anticoagulant properties. Unlike conventional anticoagulants that attenuate blood coagulation via inhibition of thrombin or activated factor X (FXa) at the downstream portion of the cascade, rNAPc2 is a potent inhibitor of the activated factor VII/tissue factor complex (FVIIa/TF), the key physiological initiator of blood coagulation. Its mechanism of action requires prerequisite binding to circulating FXa or zymogen factor X (FX) to form a binary complex prior to its interaction and inhibition of membrane‐bound FVIIa/TF. The binding of rNAPc2 to FX results in an elimination half‐life of longer than 50 h following either subcutaneous or intravenous administration. Recombinant NAPc2, like other inhibitors of FVIIa/TF including tissue factor pathway inhibitor (TFPI) and active site‐blocked FVIIa (ASIS, FFR‐rFVIIa or FVIIai), may have a promising role in the prevention and treatment of venous and arterial thrombosis, as well as potential efficacy in the management of disseminated intravascular coagulopathies because of their potent and selective inhibition of FVIIa/TF.