Inclusion Criteria

DISEASE CHARACTERISTICS:

- Histologically confirmed advanced colorectal adenocarcinoma

- Measurable disease, defined as ≥ 1 unidimensionally measurable lesion ≥ 20 mm by
conventional techniques or ≥ 10 mm by spiral CT scan

- Must have received prior irinotecan hydrochloride with a progression-free interval of
< 3 months

- No symptomatic brain metastases

PATIENT CHARACTERISTICS:

- ECOG performance status 0-2

- Life expectancy ≥ 3 months

- ANC ≥ 1,500/mm³

- Platelet count ≥ 100,000/mm³

- Hemoglobin ≥ 9 g/dL

- Total bilirubin ≤ 2 times upper limit of normal (ULN)

- AST and ALT ≤ 3 times ULN (5 times ULN if liver metastases are present)

- Creatinine ≤ 1.5 times ULN

- No significant cardiac abnormalities by ECG

- No known hypersensitivity to the study drugs or any of their components

- No myocardial infarction within the past 12 months

- No uncontrolled congestive heart failure

- No cardiovascular disorder ≥ grade 3 despite treatment

- No other malignancies or invasive carcinomas diagnosed within the past 5 years,
except for adequately treated basal cell carcinoma of the skin or in situ carcinoma
of the cervix

- No significant disease, that in the opinion of the investigator, would preclude study
treatment (e.g., active infections, interstitial lung disease, or peripheral
neuropathy)

- No history of significant neurological or psychiatric disorder (e.g., dementia,
seizures, or bipolar disorder)

- No legal incapacity or limited legal capacity that would preclude study participation

PRIOR CONCURRENT THERAPY:

- See Disease Characteristics

- Recovered from all prior therapy

- More than 30 days since prior participation in another clinical trial

- No concurrent warfarin, phenprocoumon, phenytoin, or sorivudine