The present invention relates to antibodies, which are directed to the human IGF-1 receptor (IGF-1R) and are to be administered for the treatment of cancer. The antibodies of the present invention have been altered to comprise antibodies with one or more selected germlne framework amino acid residues which replace one or more corresponding somatically mutated residues in the variable region of the unaltered antibody. The modification results in the framework region mutations converted to germline. The modification results in a reduced propensity for the antibody to elicit an immune response (reduced immunogenicity) following administration to a human subject.