Using commercially available plasma from patients with coagulation factor XI disorders, the present inventors have found that multispecific antigen binding molecules that substitute for FVIII function have a plasma procoagulant effect. In an example, the plasma procoagulant effects of a bispecific antibody that substitutes for FVIII function were studied using FXI deficient plasma or FXI neutralized plasma, with each of the APTT, CWA and TGA plasma coagulation evaluation methods. As a result, the present inventors discovered that, for FXI deficient plasma, in all of the plasma coagulation evaluation methods mentioned above, the bispecific antibody that substitutes for FVIII function exhibits a plasma procoagulant effect. Furthermore, in acquired FXI neutralized plasma as well, the bispecific antibody that substitutes for FVIII function was found to exhibit a plasma procoagulant effect. Therefore, it has been shown that, not only can multispecific antigen binding molecules that substitute for FVIII function be used for the prophylaxis and/or treatment of bleeding in hemophilia A, acquired hemophilia A and von Willebrands disease, which are caused by FVIII dysfunction, but the procoagulant properties of multispecific antigen binding molecules that substitute for FVIII function allow them to be used for the prophylaxis and/or treatment of bleeding in coagulation factor XI disorders.Selon la présente invention, en utilisant du plasma disponible dans le commerce provenant de patients atteints de pathologies liées au facteur de coagulation XI, les présents inventeurs ont découvert que des molécules de liaison à lantigène multispécifiques qui se substituent fonctionnellement au FVIII avaient un effet procoagulant sur le plasma. Dans une expérience, les effets procoagulants sur le plasma dun anticorps bispécifique qui se substitue fonctionnellement au FVIII ont été étudiés sur du plasma déficient en FXI ou du plasma où FXI avait été neutralisé, à laide des méthodes dévaluat
