Inclusion Criteria:

• Provided signed written informed consent.
• Histologically- or pathologically- confirmed metastatic colorectal carcinoma;
• Documented progression after treatment with at least one standard chemotherapy regimen for metastatic colorectal carcinoma;
• The chemotherapy regimen on which the patient progressed, must have included a fluoropyrimidine;
• Bidimensionally measurable disease;
• Immunohistochemical evidence of an absence of EGFR expression, (ie, EGFR-negative).

Patients who do not have tumor tissue available for EGFR testing will undergo biopsy of accessible tumor. A reference laboratory designated by ImClone will perform the EGFR assay.

• Eastern Cooperative Oncology Group (ECOG) performance status score of 0 to 1 at study entry;
• Adequate recovery from recent surgery, chemotherapy, and radiation therapy. At least 30 days must have elapsed from major surgery, prior chemotherapy, prior treatment with an investigational agent or medical device, or prior radiation therapy;
• Accessible for treatment and follow-up. Patients enrolled in this trial must be treated at the participating center.
• Men and women, 18 years of age and older

Exclusion Criteria:

• Women of child bearing potential (WOCBP) who are unwilling or unable to use an acceptable method to avoid pregnancy for the entire study period and for up to 4 weeks after the study.
• Women who are pregnant or breastfeeding.
• Women with a positive pregnancy test on enrollment or prior to cetuximab administration.
• Sexually active fertile men not using effective birth control.
• Dementia, altered mental status, or any psychiatric condition that would prohibit the understanding or rendering of informed consent;
• A serious uncontrolled medical disorder that would impair the ability of the patient to receive protocol therapy;
• A history of uncontrolled angina, arrhythmias or congestive heart failure;
• Symptomatic or uncontrolled metastases to the central nervous system. Patients receiving a glucocorticoid for CNS metastases will be excluded, but those receiving anticonvulsants will be eligible.
• Any concurrent malignancy other than non-melanoma skin cancer or carcinoma in situ of the cervix. Patients with a previous malignancy but without evidence of disease for greater than or equal to 5 years will be allowed to enter the trial;
• Inadequate hematologic function defined by an absolute neutrophil count (ANC) less than 1,500/mm 3 , a platelet count less than 100,000/mm 3 , or a hemoglobin level less than 9 g/dL.
• Inadequate hepatic function, defined by a total bilirubin level greater than or equal to 1.5 times the upper limit of normal (ULN) and aspartate transaminase (AST) or alanine transaminase (ALT) levels greater than or equal to 5.0 times the ULN.
• Inadequate renal function defined by a serum creatinine level greater than 1.5 times the ULN.
• Prior cetuximab or other therapy, which specifically and directly targets the EGF pathway.
• Prior hypersensitivity reaction to chimerized or murine monoclonal antibody therapy.
• Any chemotherapy not indicated in the study protocol, radiation therapy, hormonal therapy (except for physiological replacement), or any other investigational agent.
• Prisoners or patients who are compulsorily detained (involuntarily incarcerated) for treatment of either a psychiatric or physical (eg, infectious disease) illness.
• Employees of the investigator or study center with direct involvement in this study or other studies under the direction of the investigator or study center, as well as family members of the employees.