Factor eight inhibitor bypass activity (FEIBA) in the management of bleeds in hemophilia patients with high-titer inhibitors.
The development of high-titer inhibitors to FVIII and less often to other coagulation factors are the most serious complication of hemophilia therapy and makes treatment of bleeds very challenging. At present, bypassing agents, such as factor eight inhibitor bypass activity (FEIBA) and activated recombinant factor VII (rFVIIa) are the only coagulation factor concentrates available for the treatment of bleeds in inhibitor patients. Both products are effective and safe, and their efficacy has been found to be comparable (approximately 80%) in a recent prospective study. A significant number of patients report a better effect of one or the other of the products, and in a minority of the patients none of the products are particularly effective. The hemostatic efficacy of bypassing agents is not considered equal to that of coagulation factor replacement in patients without inhibitors by most physicians. An improvement in hemostatic efficacy may be achieved by optimizing the dosing of by passing agents. However, the lack of standardized and validated laboratory assays reflecting the hemostatic efficacy of the bypassing agents is an obstacle to this achievement.
Tjønnfjord
Geir E
GE
Medical Department, Division of Hematology, Rikshospitalet-Radiumhospitalet Medical Center, Oslo, Norway. geir.tjonnfjord@rikshospitalet.no
Holme
Pål Andre
PA
D001779:Blood Coagulation Factors / Q000627:therapeutic use*; D005169:Factor VIII / Q000037:antagonists & inhibitors*; D015942:Factor VIIa / Q000627:therapeutic use*; D006467:Hemophilia A / Q000150:complications*; D006470:Hemorrhage / Q000188:drug therapy* / Q000209:etiology; D006801:Humans; D011994:Recombinant Proteins / Q000627:therapeutic use; D016896:Treatment Outcome
D001779:Blood Coagulation Factors; D011994:Recombinant Proteins; D005169:Factor VIII; C103587:recombinant FVIIa; C065655:anti-inhibitor coagulant complex; D015942:Factor VIIa