Gefitinib in Treating Patients With Recurrent Metastatic Colorectal Cancer

DISEASE CHARACTERISTICS: Histologically or cytologically proven adenocarcinoma of the colon or rectum Measurable disease Evidence of new or progressive metastatic disease within 6 months of last treatment Must have received prior systemic treatment with fluorouracil (and/or its analogs, with or without leucovorin calcium or levamisole) and irinotecan in the adjuvant or metastatic setting Metastatic tumor site accessible for biopsy No known brain metastases PATIENT CHARACTERISTICS: Age: 18 and over Performance status: ECOG 0-2 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 or ALT no greater than 2.5 times ULN (5 times ULN if tumor involvement of the liver) Renal: Creatinine no greater than 1.5 times ULN OR Creatinine clearance at least 60 mL/min Cardiovascular: No New York Heart Association class III or IV heart disease 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 contraception No ongoing active or uncontrolled infections Other prior malignancies allowed provided prior therapy is discontinued and no evidence of disease No other uncontrolled illness or psychiatric illness/social situations that would preclude study Must be able to take and retain oral medications PRIOR CONCURRENT THERAPY: Biologic therapy: No prior signal transduction inhibitors (e.g., vascular endothelial growth factor-, vascular endothelial growth factor receptor-, and epidermal growth factor receptor-targeted agents) for colorectal cancer Chemotherapy: See Disease Characteristics At least 4 weeks since prior chemotherapy and recovered No other prior cytotoxic chemotherapy (e.g., oxaliplatin) for colorectal cancer Endocrine therapy: Not specified Radiotherapy: At least 4 weeks since prior radiotherapy and recovered Surgery: Not specified Other: No other prior systemic therapy for colorectal cancer No other prior investigational or approved agents for colorectal cancer No other concurrent investigational agents No concurrent antiretroviral therapy for HIV-positive patients