 Patients receive oral gefitinib daily beginning on day 1, irinotecan IV over 90 minutes on days 1 and 15, and leucovorin calcium IV over 2 hours and fluorouracil IV over 3-5 seconds followed by a 22-hour infusion on days 1, 2, 15, and 16. Courses repeat every 28 days in the absence of disease progression or unacceptable toxicity. 