Inclusion Criteria: - Metastatic colorectal adenocarcinoma; - Subjects must have become refractory to treatment or unable to continue treatment due to toxicity or other reasons during or after treatment with fluoropyrimidine, irinotecan and oxaliplatin for metastatic colorectal cancer including those who relapsed during or within 6 months from the completion of adjuvant therapy using the above agents; - Tumor expressing EGFr levels by immunohistochemistry (membrane staining must be positive in 1% of evaluated tumor cells). Exclusion Criteria: - Subjects who have prior experimental or approved antibodies (eg, bevacizumab) within 3 months before enrollment; - Subjects who have prior EGFr targeting agents; - Chemotherapy other than fluoropyrimidine (including oral agents such as UFT, TS-1), irinotecan, and oxaliplatin (or raltitrexed) for colorectal carcinoma in accordance with specified regimens (leucovorin and levamisole are not considered as chemotherapy