Evaluating Panitumumab (ABX-EGF) Plus Best Supportive Care Versus Best Supportive Care in Patients with Metastatic Colorectal Cancer

• Pathologic diagnosis of colorectal adenocarcinoma (diagnostic tissue obtained by tissue biopsy) • Metastatic colorectal carcinoma • Eastern Cooperative Oncology Group (ECOG) performance status of 0, 1 or 2 • Documented evidence of disease progression during, or following treatment, with fluoropyrimidine, irinotecan and oxaliplatin chemotherapy for metastatic colorectal cancer • Radiographic documentation of disease progression during or within 6 months following the most recent chemotherapy regimen • Unidimensionally measurable disease • Tumor expressing epidermal growth factor receptor (EGFr) by immunohistochemistry • At least 2 but not more than 3 prior chemotherapy regimens for colorectal cancer • Adequate hematologic, renal and hepatic function

• Symptomatic brain metastases requiring treatment • History or evidence of interstitial pneumonitis or pulmonary fibrosis • Use of systemic chemotherapy or radiotherapy within 30 days prior to enrollment • Prior epidermal growth factor receptor (EGFr) targeting therapies • Prior anti-tumor therapies including prior experimental agents or approved anti-tumor small molecules and biologics of short (less than a week) serum half life within 30 days before enrollment, or prior experimental or approved proteins within 3 months before enrollment.