Coagulation factor VIII (Factor VIII) (FVIII or Factor VIII)

Coagulation factor VIII (Factor VIII) is an essential glycoprotein cofactor in the intrinsic blood coagulation pathway, functioning to convert factor X to its activated form (Xa) when bound to factor IXa, calcium, and phospholipids on cell membranes. Synthesized primarily by vascular endothelium and hepatic sinusoidal cells, factor VIII circulates bound to von Willebrand factor, which protects it from degradation and phospholipid-mediated inactivation. Hemophilia A, the most common severe bleeding disorder, results from genetic deficiencies or defects in factor VIII, causing impaired thrombin generation and inadequate fibrin clot formation, leading to uncontrolled bleeding and joint damage. The target is well-established therapeutically, with multiple replacement therapies available including recombinant and plasma-derived factor VIII products, as well as novel bioengineered molecules that enhance stability through covalent VWF linkage. Key therapeutic challenges include the development of inhibitory antibodies in some patients and the rapid clearance of native factor VIII from circulation, necessitating frequent infusions for effective hemostasis control.

Other names

Antihemophilic factor (AHF)Antihemophilic globulinCoagulation factor VIIIFactor VIII:C (activity assay designation)FVIII

Replacement therapy: Recombinant and plasma-derived factor VIII products restore deficient or absent factor VIII activity in hemophilia A patients Cofactor restoration: Administered FVIII binds factor IXa to reconstitute the intrinsic tenase complex Stabilization approaches: Bioengineered molecules covalently link FVIII to VWF domains to improve stability and reduce degradation