This is a single-arm trial in which previously untreated, wild-type k-ras metastatic colorectal cancer patients will receive therapy with the combination of panitumumab with capecitabine and oxaliplatin. During the treatment period of 6 cycles, subjects with evidence of complete response, partial response or stable disease will continue to receive the combination of chemotherapy with panitumumab until disease progression, unacceptable toxicity or withdrawal of consent. Those patients with disease stabilization who are not appropriate for chemotherapy may continue with panitumumab alone. Patients with disease progression will be discontinued from chemotherapy and panitumumab and will be followed every 3 months after the last drug administration until death. Tumor response will be assessed according to the RECIST criteria (investigator's read of scans), every 6 weeks through week 18 and every 3 months thereafter, until disease progression. Disease progression will also be evaluated radiographically at the time of clinical suspicion of progression.