ZD 1839 in Treating Patients With Locally Advanced or Metastatic Colorectal Cancer

DISEASE CHARACTERISTICS: Histologically or cytologically confirmed colorectal adenocarcinoma Metastatic or locally advanced disease Not amenable to curative therapy Documentation of disease progression within the past 6 months Previously treated with fluoropyrimidine- and irinotecan-based chemotherapy (including capecitabine) administered either concurrently (no more than 2 regimens) or sequentially (no more than 3 regimens) for advanced disease At least 1 unidimensionally measurable lesion At least 20 mm by conventional techniques OR at least 10 mm by spiral CT scan No known brain metastases PATIENT CHARACTERISTICS: Age: 18 and over Performance status: ECOG 0-2 OR Karnofsky 60-100% Life expectancy: More than 12 weeks Hematopoietic: Absolute neutrophil count at least 1,500/mm^3 Platelet count at least 100,000/mm^3 Hepatic: Bilirubin no greater than 1.5 times upper limit of normal (ULN) AST/ALT no greater than 3 times ULN (5 times ULN if liver metastasis present) Renal: Creatinine no greater than 1.5 times ULN OR Creatinine clearance at least 60 mL/min Cardiovascular: No symptomatic congestive heart failure No unstable angina pectoris No cardiac arrhythmia Ophthalmic: No significant ophthalmic conditions, including: Severe dry-eye syndrome Keratoconjunctivitis sicca Sjogren's syndrome Severe-exposure keratopathy Disorders that may increase the risk for epithelium-related complications (e.g., bullous keratopathy, aniridia, severe chemical burns, or neutrophilic keratitis) Other: Able to take oral gefitinib No other uncontrolled concurrent illness No ongoing or active infection No psychiatric illness or social situation that would preclude study participation No prior gastrointestinal disorders (e.g., malabsorption syndrome) No prior allergic reactions attributed to compounds of similar chemical or biological composition to gefitinib No other prior malignancy except carcinoma in situ of the cervix, nonmelanoma skin cancer, or other cancer from which the patient has been free of evident disease for more than 5 years and/or has less than a 20-30% estimated likelihood of recurrence Not pregnant or nursing Negative pregnancy test Fertile patients must use effective contraception PRIOR CONCURRENT THERAPY: Biologic therapy: Not specified Chemotherapy: See Disease Characteristics At least 30 days since prior chemotherapy and recovered Endocrine therapy: Not specified Radiotherapy: Not specified Surgery: No prior gastric resection Other: No other prior therapy for advanced disease No concurrent combination antiretroviral therapy for HIV-positive patients No other concurrent investigational or commercial agents or therapies for the malignancy