Inclusion Criteria:

- Male or female patients, ≥ 18 years of age, able to understand and give written
informed consent.

- Histologically or cytologically confirmed colorectal adenocarcinoma.

- Stage IV (metastatic) disease.

- Previously treated with at least one prior irinotecan-containing regimen for
colorectal cancer.

- Adequate performance status (ECOG 0 or 1). (Appendix 1)

- Expected survival > 6 months.

- CEA plasma levels > 5 ng/mL.

- Measurable disease by CT or MRI.

- At least 4 weeks beyond treatment (chemotherapy, immunotherapy and/or radiation
therapy) or major surgery and recovered from all acute toxicities.

- At least 2 weeks beyond corticosteroids.

- Adequate hematology without ongoing transfusional support (hemoglobin > 9 g/dL, ANC >
1,500 per mm3, platelets > 100,000 per mm3).

- Adequate renal and hepatic function (creatinine ≤ 1.5 x IULN, bilirubin ≤ IULN, AST
and ALT ≤ 3.0 x IULN or 5 x IULN if know liver metastases).

- Otherwise, all toxicity at study entry ≤ Grade 1 by NCI CTC v4.0.

Exclusion Criteria:

- Women who are pregnant or lactating.

- Women of childbearing potential and fertile men unwilling to use effective
contraception during study until conclusion of 12-week post-treatment evaluation
period.

- Patients with Gilbert's disease or known CNS metastatic disease.

- Patients with CEA plasma levels > 1000 ng/mL are excluded during dose escalation, but
may be included after the MTD is determined.

- Presence of bulky disease (defined as any single mass > 10 cm in its greatest
dimension).

- Patients with active ≥ grade 2 anorexia, nausea or vomiting, and/or signs of
intestinal obstruction.

- Patients with non-melanoma skin cancer or carcinoma in situ of the cervix are
eligible, while patients with other prior malignancies must have had at least a
3-year disease-free interval.

- Patients known to be HIV positive, hepatitis B positive, or hepatitis C positive.

- Known history of unstable angina, MI, or CHF present within 6 months or clinically
significant cardiac arrhythmia (other than stable atrial fibrillation) requiring
anti-arrhythmia therapy.

- Known history of clinically significant active COPD, or other moderate-to-severe
chronic respiratory illness present within 6 months.

- Infection requiring intravenous antibiotic use within 1 week.

- Other concurrent medical or psychiatric conditions that, in the Investigator's
opinion, may be likely to confound study interpretation or prevent completion of
study procedures and follow-up examinations.