Recombinant factor VIIa: a universal hemostatic agent?

Recombinant factor VIIa (rVIIa) has proved effective for the treatment and prevention of hemorrhage in patients with inherited hemophilia A and B who develop inhibitors to factor VIII or IX, and patients with acquired hemophilia A. More recently, there is evidence that rVIIa may also be effective in the control of abnormal bleeding in a variety of other conditions, such as inherited factor VII deficiency, thrombocytopenia, Glanzmann's thrombasthenia, and liver disease. In some of the reports, rVIIa appeared to be effective in controlling massive hemorrhage in which there was no response to conventional measures. It is now considered by some to be potentially the first universal hemostatic agent. However, further prospective, controlled, and adequately powered clinical studies are clearly required. It will be of particular interest to determine the efficacy of rVIIa in conditions such as severe thrombocytopenia, severe von Willebrand disease, severe defects in platelet activation, and severe deficiencies of factors V, X, II, and fibrinogen in which effectiveness would seem to be unlikely based on our current understanding of mechanisms of action of rVIIa.