An in vitro analysis and clinical experiences with FEIBA as an agent for bypassing therapy to hemophilic patients with inhibitors are performed and obtained the following results;
1. The time course of generation of Xa and IIa in plasma of hemophilia with or without inhibitors are measured by the use of chromogenic synthetic substrats, S-2222 and S-2238, after the addition of Ancrod in order to defibrinate the plasma. Although the generation of amydolytic activities in the cases with hemophilia decreases remarkably in comparision with normal plasma, the amydolytic activities can be normalized by the addition of FEIBA into the hemophilic plasma with inhibitor.
2. When the hemophilic patients with inhibitors are treated by the drip infusion of FEIBA, the clotting time of PTT are apparently shorten in parallel with the increase of Xa and IIa generations.
3. When antiserum of factor IX or factor VII is added into the mixture of FEIBA and phospholipids suspended in calcium solution, the inhibitory effect of anti-factor VII serum is more stronger than that of antifactor IX serum on the IIa generation and the former shows marked inhibitory action indicating dosedependent reaction. Therefore, it is suggested that factor VII in FEIBA might play an important role in the bypassing therapy.
