The present invention provides ISVD polypeptide derivatives capable of binding to
blood coagulation factor IX (a) and
factor X (a), which are potent and provide sufficiently long half-lives, thereby allowing effective subcutaneous and
oral administration. Thus, the ISVD polypeptide derivatives disclosed herein are suitable for treating hemophilia A, hemophilia A with inhibitors, and acquired hemophilia A by various routes of administration, including subcutaneous and
oral administration.