Gene Therapies for Congenital Hemophilia A or B

Most commonly, hemophilia is a recessive X-linked congenital bleeding disorder that predominantly affects males caused by deficiency of coagulation factor VIII (hemophilia A) or factor IX (hemophilia B). Deficiency or absence of clotting factor results in impaired hemostasis, prolonged bleeding, and rebleeding. Etranacogene dezaparvovec-drlb, fidanacogene elaparvovec-dzkt, and valoctocogene roxaparvovec-rvox are gene therapies designed to deliver a copy of the gene for the clotting factor using adeno-associated virus vector. Etranacogene dezaparvovec-drlb is designed to deliver a copy of the gene encoding the Padua variant of human coagulation factor IX (hFIX Padua) while fidanacogene elaparvovec-dzkt is designed to deliver a copy of human coagulation factor IX transgene modified to a high-specific factor IX activity variant known as FIX-R338L. Valoctocogene roxaparvovec-rvox is designed to deliver a functional copy of transgene encoding the B-domain deleted SQ form of human coagulation factor VIII.