Efficacy Analysis of Cetuximab Plus Irinotecan in Patients With Wild-type KRAS Without Regard to Epidermal Growth Factor Receptor (EGFR) Expressions

Inclusion Criteria: * Colorectal adenocarcinoma, Wild KRAS, 18-75 yr * Estimated life expectancy of more than 3 months * ECOG performance status of 0 to 1 at study entry * Adequate bone marrow function * Adequate liver function * Documented progression during or within 3 months of irinotecan-containing regimens as a first-line chemotherapy * Immunohistochemical evidence of a presence or absence of EGFR expression by PharmDx Kit * Informed Consent Exclusion Criteria: * Central nervous system (CNS) metastases or prior radiation for CNS metastases. * Intestinal obstruction or impending intestinal obstruction due to peritoneal carcinomatosis * Surgery (excluding biopsy for diagnosis) during 4 weeks prior to inclusion in the study. * Evidence of gastrointestinal bleeding * Exposure to Cetuximab * Prior administration of monoclonal antibodies, EGFR signal transduction inhibitors or EGFR-targeted treatment * KRAS mutant Status * Patients with serious toxicity to previous irinotecan-based chemotherapy * Other serious illness or medical conditions