The aim of the study is to determine if Iressa added to chemotherapy with Irinotecan, 5Fluorouracil and Leucovorin can prolong the period of time without any disease worsening (Time to Progression) in patients with metastatic colorectal cancer.

Inclusion Criteria:

• Histologically confirmed metastatic colorectal cancer
• Presence of measurable metastases
• No previous treatment for metastatic cancer

Exclusion Criteria:

• No presence of Central Nervous System metastases
• No other co-existing malignancies or malignancies diagnosed within the last 5 years with the exception of basal cell carcinoma or cervical cancer in situ
• Any evidence of severe or uncontrolled systemic disease (e.g. unstable or uncompensated respiratory, cardiac, hepatic or renal disease)