Comparison of treatment effect of chemotherapy with panitumumab to chemotherapy alone

- Man or woman at least 18 years old - Diagnosis of metastatic colorectal cancer (mCRC) - One and only one chemotherapy regimen for mCRC consisting of first-line 5-FU -based chemotherapy - Radiologically documented disease progression per modified Response Evaluation Criteria in Solid Tumors (RECIST) criteria during treatment or within 6 months of last dose of first-line chemotherapy - At least 1 uni-dimensionally measurable lesion of at least 20 mm per modified RECIST - Eastern Cooperative Oncology Group (ECOG) status of 0, 1, or 2 - Paraffin-embedded tumor tissue from the primary tumor or metastasis available for central analyses - Adequate hematologic, renal, and hepatic functions - Negative pregnancy test within 72 hours of enrollment - Other protocol-specified criteria may apply

- History of or known presence of central nervous system (CNS) metastases - History of another primary cancer within 5 years of randomization - Prior irinotecan therapy - Prior anti-epidermal growth factor receptor (EGFr) antibody therapy or treatment with small molecule EGFr inhibitors - Any investigational agent or therapy within 30 days before randomization - Known allergy or hypersensitivity to irinotecan, 5-FU or leucovorin - History of interstitial lung disease or evidence of interstitial lung disease on baseline chest computed tomography (CT) scan - Active inflammatory bowel disease or other bowel disease causing chronic diarrhea - Known positive tests for human immunodefiency virus (HIV), hepatitis C viris (HCV), acute or chronic active hepatitis B virus (HBV) - Major surgery within 28 days of randomization or minor surgical procedure within 14 days of randomization - Pregnant or breast-feeding - Man or woman of child-bearing potential not consenting to use adequate contraceptive methods or abstinence during the course of the study and for 6 months after last study drug administration (women) or 1 month after last study drug administration (men) - Other protocol-specified criteria may apply