Inclusion Criteria:

- Patients must have metastatic colorectal cancer.

- Patients must have at least one measurable lesion.

- Patients’serum level of CEA must be higher than 5 times of the normal value

- Patients’disease must have failed chemotherapy with 5FU, CPT-11 or oxaliplatin.

- Patients who are unsuitable or refuse chemotherapy will be considered eligible for
this trial.

- Patients’age must be 20 or greater.

- Patients’estimated life expectancy is more than 3 months.

- Patients must have adequate bone marrow function, defined as WBC >= 3500/mm3,
neutrophil >= 1500/mm3, lymphocyte >= 1,000/mm3, and platelet >= 100,000/mm3.

- Patients must have adequate liver and renal function, defined as serum alanine
transaminase (ALT) and aspartate transaminase (AST) =< 5 times normal, bilirubin =<
1.5 times normal range, and creatinine =< 2 times upper normal limit.

- All patients should have documentation of negative result of penicillin test.

- Women or men of reproductive potential may not participate unless they have agreed to
use an effective contraceptive method.

- All patients must be informed of the investigational nature of this study and must
sign and give written informed consent.

Exclusion Criteria:

- Patients who have central nervous system metastasis except for those whose CNS
disease has been treated with radiotherapy and/or surgery and has been stable for at
least two weeks

- Patients who have active acute or chronic infection (at the discretion of the
investigator).

- Pregnant or breast-nursing women

- Patients who have active cardiac disease requiring therapy for failure, angina,
arrythmia, or infarction within the preceding 6 months (exception: any patient whose
cardiac failure is compensated on medications)

- Patients who have asthma

- Patients who have autoimmune disease such as inflammatory bowel disease, lupus
erythematosus, ankylosing spondylitis, scleroderma, and multiple sclerosis

- Patients who have serious concomitant systemic disorders incompatible with the study
(at the discretion of the investigator)

- Patients who have other prior or concurrent malignancy except for in-situ-carcinoma
of cervix or adequately treated basal cell carcinoma of skin.

- Patients who received chemotherapy, steroid or biologic treatment within 4 weeks
prior to enrollment