Recombinant factor VIIa (rFVIIa): its potential role as a hemostatic agent

Recombinant activated coagulation factor VII (rFVIIa) was developed for the treatment of patients with hemophilia who have developed inhibitors against the factor they are missing. Hemophilia is a serious bleeding disorder and patients with hemophilia develop repeated spontaneous CNS, joint and muscle bleeding. Any trauma, even mild events, may cause life-threatening bleeding, and without treatment, these patients have a life expectancy of about 16 years. Thus, hemophilia can be regarded as a model of severe bleeding, and an agent capable of inducing hemostasis in severe hemophilia independent of the hemophilia proteins (FVIII or FIX) may also be effective in patients without hemophilia who experience serious bleeds. The availability of rFVIIa stimulated research on the role of FVII and tissue factor (TF) in the hemostatic process. As a result, a picture partly different from the one suggested by previous models [1, 2] has emerged. These previous models basically neglected the role of cells and cell membranes. The importance of platelets and platelet membrane phospholipids in hemostasis has been demonstrated, and the new concept of the hemostatic process, focusing on cell surfaces, has been outlined.