Inclusion Criteria:

- Pathologic diagnosis of colorectal adenocarcinoma (diagnostic tissue obtained by
tissue biopsy)

- Metastatic colorectal carcinoma

- Eastern Cooperative Oncology Group 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 is required

- Bidimensionally measurable disease

- Tumor expressing low to negative levels of EGFr by immunohistochemistry

- At least 2 but no more than 3 prior chemotherapy regimens for metastatic colorectal
cancer

- Adequate hematologic, renal and hepatic function

Exclusion Criteria:

- Symptomatic brain metastases requiring treatment

- Patient with a history of interstitial pneumonitis or pulmonary fibrosis or evidence
of interstitial pneumonitis or pulmonary fibrosis

- Use of systemic chemotherapy or radiotherapy within 30 days before enrollment

- Prior anti-EGFr antibody therapy with the exception of the small molecule EGFr
tyrosine kinase inhibitors, which are permitted

- Prior anti-tumor therapies including prior experimental agents or approved anti-tumor
small molecules and biologics of short (less than 1 week) serum half-life within 30
days before enrollment, or prior experimental or approved proteins within 6 weeks
before enrollment