The inventors successfully produced anti-Epiregulin antibodies showing cross-species reactivity between cynomolgus monkey (non-human animals) and human, anti-Epiregulin antibodies with suppressed chemical degradation, anti-Epiregulin antibodies with lowered isoelectric point, anti-Epiregulin antibodies with increased thermal denaturation midpoint temperature, and anti-Epiregulin antibodies with reduced amount of aggregate by performing appropriate amino acid residue substitutions in the variable-region sequences of the humanized EP27 antibody which inhibits growth of cancer cells by exhibiting cytotoxic activity and neutralizing activity against human Epiregulin-expressing cancer cells.
