DISEASE CHARACTERISTICS:

• Histologically confirmed stage IV colorectal cancer
• Arg, KIT (CD117), or PDGF-R expression (1+ in 20% of cells) in the tumor or microvasculature

• At least one unidimensionally measurable lesion

  • At least 10 mm by spiral CT scan
• No known brain metastases

PATIENT CHARACTERISTICS:

Age:

• Any age

Performance status:

• ECOG 0-2 OR
• Karnofsky 60-100%

Life expectancy:

• At least 12 weeks

Hematopoietic:

• Granulocyte count at least 1,500/mm^3
• Platelet count at least 100,000/mm^3

Hepatic:

• Bilirubin no greater than 2.0 mg/dL
• AST/ALT less than 2.5 times upper limit of normal

Renal:

• Creatinine no greater than 2.0 mg/mL

Cardiovascular:

• No symptomatic congestive heart failure
• No unstable angina pectoris
• No cardiac arrhythmia

Other:

• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective barrier contraception during and for 3 months after study participation
• No other malignancy within the past 3 years except non-melanoma skin cancer or carcinoma in situ of the cervix
• No concurrent uncontrolled illness
• No ongoing or active infection
• No psychiatric illness or social situation that would preclude study compliance

PRIOR CONCURRENT THERAPY:

Biologic therapy:

• Not specified

Chemotherapy:

• More than 4 weeks since prior chemotherapy (6 weeks for nitrosoureas or mitomycin) and recovered

Endocrine therapy:

• Not specified

Radiotherapy:

• More than 4 weeks since prior radiotherapy and recovered

Surgery:

• More than 3 weeks since prior surgery (excluding diagnostic biopsy)

Other:

• No other concurrent investigational agents
• No concurrent therapeutic doses of anticoagulants (e.g., warfarin)
• No concurrent grapefruit
• No concurrent combination antiretroviral therapy for HIV-positive patients