Conatumumab/Panitumumab Combination Metastatic Colorectal Cancer Study

Inclusion Criteria

• Histologically or cytologically confirmed metastatic adenocarcinoma of the colon or rectum
• Radiographically documented disease progression per modified Response Evaluation Criteria in Solid Tumors (RECIST) during or following treatment with fluoropyrimidine, irinotecan, and/or oxaliplatin chemotherapy for Metastatic Colorectal Cancer. Progressive disease must be documented during or ≤ 6 months after the last dose of the most recent chemotherapy regimen prior to enrollment.
• At least 1 uni-dimensionally measurable lesion measuring ≥ 20 mm in one dimension per modified RECIST. Lesion must not be chosen from a previously irradiated field, unless there has been documented disease progression in that field after irradiation and prior to enrollment. All sites of disease must be evaluated.
• Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1
• Available archived paraffin-embedded tumor tissue from the primary tumor or metastasis for submission to the central laboratory
• Man or woman ≥ 18 years of age at the time of enrollment
• Hematologic function within the following limits:
• Absolute neutrophil count (ANC) > 1.0 x 10^9 cells/L
• Platelets ≥ 100 x 10^9/L
• Renal function within the following limits:
• Creatinine < 2.0 mg/dL
• Hepatic function within the following limits:
• Aspartate aminotransferase (AST) ≤ 2.5 x upper limit of normal (ULN) (≤ 5 x ULN if liver metastases)
• Alanine aminotransferase (ALT) ≤ 2.5 x ULN (≤ 5 x ULN if liver metastases)
• Bilirubin ≤ 2 x ULN
• Metabolic function within the following limits:
• Amylase ≤ 2 x ULN
• Lipase ≤ 2 x ULN
• Magnesium ≥ lower limit of normal
• Negative pregnancy test ≤ 72 hours before enrollment (for woman of childbearing potential only)
• Must have received 1, 2, or 3 prior chemotherapy regimens for Metastatic Colorectal Cancer
• Competent to comprehend, sign, and date the independent ethics committee/institutional review board (IEC/IRB) approved written informed consent

Exclusion Criteria

• History of other primary cancer, unless:
• Curatively resected non-melanomatous skin cancer
• Curatively treated cervical carcinoma in situ
• Other primary solid tumor curatively treated with no known active disease present and no treatment administered for ≥ 5 years before enrollment
• Prior treatment with anti-epidermal growth factor receptor (EGFr) inhibitors (eg, cetuximab, erlotinib, gefitinib), unless treatment was received in the adjuvant setting ≥ 6 months before enrollment
• Use of systemic chemotherapy and radiotherapy ≤ 30 days before enrollment
• Use of prior anti-tumor therapies with a short serum half-life (less than 1 week) including prior experimental agents or approved anti-tumor small molecules ≤ 30 days before enrollment
• Use of anti-tumor therapies with a longer serum half-life (eg, bevacizumab) including prior experimental or approved protein/antibodies ≤ 42 days before enrollment
• Any investigational agent or therapy ≤ 30 days before enrollment
• Known allergy or hypersensitivity to any component of panitumumab and/or AMG 655
• History of or known presence of central nervous system (CNS) metastases
• History of interstitial lung disease (eg, pneumonitis, pulmonary fibrosis) or evidence of interstitial lung disease on baseline chest computerized tomography (CT) scan
• Clinically significant cardiovascular disease (including myocardial infarction, unstable angina, symptomatic congestive heart failure, serious uncontrolled cardiac arrhythmia) ≤ 1 year before enrollment
• Active inflammatory bowel disease or other active bowel disease causing chronic diarrhea (defined as ≥ Common Terminology Criteria for Adverse Events [CTCAE] grade 2 [CTCAE version 3.0])
• Known positive test for human immunodeficiency virus (HIV) infection, hepatitis C virus, acute or chronic hepatitis B infection
• Any co-morbid disease or condition that could increase the risk of toxicity (eg, significant ascites, significant pleural effusion)
• An