Factor VIIa

Factor VIIa (FVIIa) is a serine protease playing a pivotal role in blood coagulation. It represents the activated form of Factor VII, synthesised by the liver and matured via vitamin K-dependent γ-carboxylation. FVIIa acts as an initiator in the coagulation cascade, primarily by binding to tissue factor (TF) to form a complex that activates Factor X and Factor IX, thereby initiating the extrinsic pathway. This process is essential for haemostasis and thrombosis. The activity of FVIIa is regulated by multiple factors, including anticoagulants such as tissue factor pathway inhibitor (TFPI) and antithrombin III. FVIIa exerts a finely tuned regulatory role in maintaining haemostatic equilibrium and is implicated in haemorrhagic disorders.