Inclusion Criteria:

- Diagnosis of colorectal cancer (either newly diagnosed or recurrent disease) with
evidence of metastatic disease. (Stage IV distant disease)

- Present or past histological documentation of adenocarcinoma of the colon or rectum.
The site of the primary lesion must be or have been confirmed endoscopically,
radiologically, or surgically to be or have been in the large bowel. Patients with a
history of colorectal cancer treated by surgical resection who develop radiological
or clinical evidence of metastatic cancer do not require separate histological or
cytological confirmation of metastatic disease unless:

- An interval of greater than five years has elapsed between the primary surgery and
the development of metastatic disease.

- The primary cancer was a Duke's A or B1.

- Physicians should consider biopsy of lesions to establish the diagnosis of metastatic
colorectal cancer in each case if there is substantial clinical ambiguity regarding
the nature of source of apparent metastases.

Exclusion Criteria:

- Patients who received any prior systemic anticancer therapy for metastatic colorectal
cancer (e.g., chemotherapy, antibody therapy, immunotherapy, gene therapy, vaccine
therapy, cytokine therapy, or other experimental agents).

- Patients cannot have concurrent malignancies at study entry.

- Exceptions: Patients with prior non-colorectal malignancies will be eligible if
they have been disease-free for ³ 3 years or are deemed at low risk for recurrence by
their treating physician (e.g., early stage prostate cancer, melanoma or bladder
cancer). Patients with squamous or basal cell carcinoma of the skin or in situ
cervical cancer that have been effectively treated are eligible, even if these were
diagnosed within 3 years before randomization.