Various bispecific antibodies that specifically bind to both blood coagulation factor IX/activated blood coagulation factor IX and blood coagulation factor X and functionally substitute for the cofactor function of blood coagulation factor VIII, that is, the function to promote activation of blood coagulation factor X by activated blood coagulation factor IX, were produced. From these antibodies, multispecific antigen-binding molecules having a high activity of functionally substituting for blood coagulation factor VIII were successfully discovered. 血液凝固第IX因子/活性化血液凝固第IX因子及び血液凝固第X因子の双方に特異的に結合し、血液凝固第VIII因子の補因子機能、すなわち活性化血液凝固第IX因子による血液凝固第X因子活性化を促進する機能を代替する機能を有する種々の二重特異性抗体を作製した。これらの抗体の中から、血液凝固第VIII因子の機能を代替する活性の高い多重特異性抗原結合分子を見出すことに成功した。【選択図】なし
