DISEASE CHARACTERISTICS:

• Histologically confirmed advanced, recurrent, or metastatic colorectal adenocarcinoma

• Resected CNS metastases stable greater than 1 month after completion of radiotherapy for CNS metastases eligible

  • No existing CNS metastases allowed

• Measurable disease

  • At least 1 dimension as at least 20 mm with conventional techniques OR
  • At least 10 mm with spiral CT scan

  • No truly nonmeasurable lesions:

    • Bone lesions
    • Leptomeningeal disease
    • Lymphangitis cutis/pulmonis
    • Abdominal masses not confirmed and followed by imaging techniques
    • Cystic lesions
• Must have progressed on at least 1 prior, but no more than 2 prior, fluorouracil and/or irinotecan containing treatment regimens for metastatic colorectal cancer

• Must have documented HER-2/neu overexpression by immunohistochemistry staining

  • Staining score at least 2+

PATIENT CHARACTERISTICS:

Age:

• 18 and over

Performance status:

• ECOG 0-2

Life expectancy:

• Not specified

Hematopoietic:

• Granulocyte count at least 1,500/mm3
• Platelet count at least 100,000/mm3

Hepatic:

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

Renal:

• Creatinine normal OR
• Creatinine clearance at least 60 mL/min

Cardiovascular:

• No history of cardiac ischemia or congestive heart failure
• LVEF at least 50% by ECG or MUGA

Other:

• Not pregnant or nursing
• Fertile patients must use effective contraception
• No concurrent second malignancy except nonmelanoma skin cancers or carcinoma in situ of the cervix unless completed therapy and considered to be at less than 30% risk of relapse

PRIOR CONCURRENT THERAPY:

Biologic therapy:

• Not specified

Chemotherapy:

• See Disease Characteristics
• No prior platinum containing chemotherapy
• At least 3 weeks since prior chemotherapy and recovered
• No other concurrent chemotherapy

Endocrine therapy:

• Not specified

Radiotherapy:

• At least 3 weeks since prior radiotherapy and recovered

Surgery:

• Not specified