Hemophilic dog model for evaluating therapeutic effectiveness of plasma protein fractions

Therapeutic effectiveness of factor VIII inhibitor bypassing materials has been evaluated in dogs with hemophilia A. A standardized template gingival biopsy was performed using local anesthesia. Hemophilic dogs bled extensively from the biopsy site, whereas in normal dogs the wound was sealed within 5 + /- 2 min. If untreated, the hemophilic dogs frequently bled for several days. Factor VIII infusion stopped the bleeding promptly. Some experimental preparations of factor VIII inhibitor bypassing materials were shown to be therapeutically effective, whereas others were not. Intravascular thrombi could not be demonstrated histologically. The model should prove useful for evaluating factor VIII inhibitor bypassing materials and also for evaluating their mechanism of action.