Safety, Efficacy, and Pharmacokinetics Study of Tarceva to Treat Advanced Colorectal Cancer

Subjects must fulfill all of the following criteria to be eligible for study entry: * Signed informed consent * At least 18 years of age * Histologically confirmed metastatic colorectal adenocarcinoma of the colon or rectum Resected or biopsied primary tumors or metastatic site will serve as the basis for histologic confirmation. * Measurable disease (defined as at least one dimension \>2 cm \[\>1 cm on spiral CT scans\]) * ECOG performance status of 0 or 1 * Life expectancy \>3 months * Use of an effective means of contraception in men and in women of childbearing potential * Ability to comply with study and follow-up procedures