The present invention relates to improved procoagulant antibodies including bispecific antibodies capable of binding to coagulation Factor IX (FIX) or the activated form thereof Factor IXa (FIXa) and optionally Factor X (FX) and the activated form thereof Factor Xa (FXa) and promoting FX activation by FIXa, antibodies binding their epitopes and methods and composition for treating subjects suffering from a coagulopathy such as haemophilia A.本發明係關於改善的促凝血抗體,其包括能夠結合至凝血因子IX(FIX)或其活化型因子IXa(FIXa)及視需要地結合至因子X(FX)及其活化型因子Xa(FXa)及促進透過FIXa的FX活化的雙專一性抗體、結合其等之表位的抗體及用於治療患有凝血病變(諸如血友病A)的對象的方法及組成物。