Coagulation factor VIII (B-domain deleted, platelet-expressed) (BDDFVIII)

Coagulation factor VIII (FVIII) is a vital blood-clotting protein that functions as a non-enzymatic cofactor for activated factor IX (FIXa) in the intrinsic pathway of the coagulation cascade (Shi et al., 2006). The platelet-expressed B-domain deleted FVIII (BDDFVIII) variant is a bioengineered form of the protein where the large, non-essential B-domain is removed to facilitate gene delivery, and expression is restricted to megakaryocytes using specific promoters like ITGA2B (Yarovoi et al., 2003). This targeting allows FVIII to be synthesized in megakaryocytes and stored within the alpha-granules of circulating platelets. Upon platelet activation at the site of vascular injury, the stored BDDFVIII is released locally, providing a concentrated procoagulant response. This localized delivery is designed to provide effective hemostasis while shielding the FVIII protein from circulating neutralizing antibodies, making it a promising therapeutic strategy for Hemophilia A patients with inhibitors (Montgomery & Shi, 2012). By facilitating the formation of the tenase complex and the subsequent activation of factor X, this variant restores the essential thrombin generation required for stable clot formation.

Other names

Platelet-targeted Factor VIIIpFVIII2bF8B-domain deleted Factor VIIIF8-BDDFactor 8

Acts as a critical cofactor for activated factor IX (FIXa) to form the tenase complex, which proteolytically activates factor X to factor Xa on phospholipid surfaces, thereby amplifying thrombin generation at the site of injury.