DISEASE CHARACTERISTICS:

• Histologically or cytologically confirmed breast cancer

  • Clinical evidence of metastatic disease
• Candidate for first- or second-line chemotherapy for metastatic disease
• Must have received prior anthracycline or taxane therapy (may have had both in the neoadjuvant, adjuvant, or metastatic setting)

• At least 1 measurable lesion at least 20 mm by CT scan or MRI OR at least 10 mm by spiral CT scan

  • The following are not considered measurable disease:

    • Small lesions less than 20 mm by CT scan or MRI
    • Bone lesions
    • Ascites
    • Pleural/pericardial effusion
    • Inflammatory breast disease
    • Lymphangitis cutis/pulmonis
    • Abdominal masses not confirmed and followed by imaging techniques
    • Cystic lesions
• No active CNS metastases (treated CNS metastases stable for more than 8 weeks are allowed)

• Hormone receptor status:

  • Not specified

PATIENT CHARACTERISTICS:

Age

• 18 and over

Sex

• Male or female

Menopausal status

• Not specified

Performance status

• ECOG 0-2

Life expectancy

• At least 3 months

Hematopoietic

• Absolute neutrophil count at least 1,500/mm^3
• Platelet count at least 100,000/mm^3
• Hemoglobin at least 8.5 g/dL

Hepatic

• Bilirubin no greater than 1.5 times upper limit of normal (ULN)
• AST no greater than 3 times ULN
• Alkaline phosphatase no greater than 3 times ULN

Renal

• Creatinine no greater than 1.5 times ULN

Cardiovascular

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

Gastrointestinal

• No inability to take oral or nasogastric medication
• No requirement for IV alimentation
• No active peptic ulcer disease

Ophthalmic

• No abnormalities of the cornea based on history (e.g., dry eye syndrome or Sjögren's syndrome)
• No congenital abnormality (e.g., Fuch's dystrophy)
• No abnormal slit-lamp examination using a vital dye (e.g., fluorescein or Bengal-Rose)
• No abnormal corneal sensitivity test (Schirmer test or similar tear production test)

Other

• Not pregnant or nursing
• Negative pregnancy test

• Fertile patients must use effective contraception

  • Sub-dermal implants and condoms are not considered acceptable forms of contraception
• No other invasive non-breast malignancy within the past 5 years except adequately treated basal cell or squamous cell skin cancer
• No ongoing or active infection
• No psychiatric illness or social situation that would preclude study compliance
• No other concurrent uncontrolled illness

PRIOR CONCURRENT THERAPY:

Biologic therapy

• At least 2 weeks since prior immunotherapy
• No prior cetuximab

Chemotherapy

• At least 2 weeks since prior chemotherapy and recovered
• No more than 1 prior chemotherapy regimen for metastatic disease
• No more than 2 prior chemotherapy regimens total, including adjuvant therapy

Endocrine therapy

• Prior hormonal therapy allowed in metastatic and/or adjuvant setting

Radiotherapy

• At least 2 weeks since prior radiotherapy
• No prior radiotherapy to more than 25% of bone marrow
• No prior strontium chloride Sr 89

Surgery

• More than 4 weeks since prior major surgery
• No prior surgical procedures affecting absorption

Other

• No prior epidermal growth factor receptor-targeting therapies (e.g., gefitinib or EKB-569)
• No concurrent combination antiretroviral therapy for HIV-positive patients
• No other concurrent antitumor therapy