DISEASE CHARACTERISTICS:

• Histologically or cytologically confirmed adenocarcinoma of the colon or rectum that is not curable with conventional therapy

  • Recurrent or metastatic disease

• At least 1 unidimensionally measurable lesion

  • At least 20 mm by conventional techniques OR
  • At least 10 mm by spiral CT scan
  • Target lesion must not be in a previously irradiated field unless progression of this lesion has been documented
• No known brain metastases

PATIENT CHARACTERISTICS:

Age:

• 18 and over

Performance status:

• ECOG 0-2 OR
• Karnofsky 60-100%

Life expectancy:

• More than 3 months

Hematopoietic:

• WBC at least 1,500/mm^3
• Absolute granulocyte count at least 1,500/mm^3
• Platelet count at least 100,000/mm^3

Hepatic:

• Bilirubin no greater than 1.25 times upper limit of normal (ULN)
• AST or ALT no greater than 3 times ULN (5 times ULN if liver metastases present)

Renal:

• Creatinine no greater than 1.25 times ULN OR
• Creatinine clearance at least 50 mL/min

Cardiovascular:

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

Gastrointestinal:

• No gastrointestinal tract disease resulting in an inability to take oral medication or a requirement for IV alimentation
• No active peptic ulcer disease
• No unresolved complete or subacute bowel obstruction
• No severe enteropathy that would interfere with absorption of study drug

Ophthalmic:

• No abnormalities of the cornea:

  • Dry eye syndrome or Sjogren's syndrome
  • Congenital abnormality (e.g., Fuch's dystrophy)
  • Abnormal slit-lamp examination using a vital dye (e.g., fluorescein or Bengal-Rose)
  • Abnormal corneal sensitivity test (Schirmer test or similar tear production test)

Other:

• No significant traumatic injury within the past 21 days
• No ongoing or active infection
• No psychiatric illness or social situation that would preclude study
• No other concurrent uncontrolled illness that would preclude study
• No other malignancy within the past 3 years except curatively treated nonmelanoma skin cancer or carcinoma in situ of the cervix
• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective contraception

PRIOR CONCURRENT THERAPY:

Biologic therapy:

• Not specified

Chemotherapy:

• No more than 1 prior chemotherapy regimen for metastatic disease with either fluorouracil (5-FU) and oxaliplatin or 5-FU and a topoisomerase inhibitor (e.g., irinotecan), OR 5-FU (or other single-agent fluoropyrimidine, such as capecitabine) followed by irinotecan for advanced disease
• Prior adjuvant chemotherapy allowed
• At least 4 weeks since prior chemotherapy (6 weeks for nitrosoureas or mitomycin) and recovered

Endocrine therapy:

• Not specified

Radiotherapy:

• See Disease Characteristics
• At least 4 weeks since prior radiotherapy and recovered

Surgery:

• At least 3 weeks since prior major surgery
• No prior surgical procedures affecting absorption

Other:

• No prior epidermal growth factor receptor-targeting therapy
• No other concurrent investigational therapies
• No other concurrent anticancer therapy
• No concurrent combination anti-retroviral therapy for HIV-positive patients

• No concurrent warfarin

  • Low molecular weight heparin allowed