A Phase II Study of Gemcitabine and Erlotinib As Adjuvant Therapy In Patients With Resected Pancreatic Cancer

Inclusion Criteria: * Patients with potentially resectable pancreatic cancer (including ampullary cancer), prior to or after surgery will be accrued to this study. * Patients who sign consent prior to surgery must have appropriate diagnostic imaging and be evaluated by one of the surgical co-investigators as having resectable disease, and probable pancreatic adenocarcinoma. * Patients, who sign consent after surgery, must have adenocarcinoma of the pancreas with negative surgical margins. * Adjuvant therapy should start within 10 weeks of surgery * Age 18 years or older * ECOG performance status of 0 - 1 (see Appendix A) * Ability to take oral medications without difficulty * Adequate bone marrow function as evidenced by an absolute neutrophil content (ANC) \> 1500/mL and platelet count \> 100,000/mL * Adequate renal function as evidenced by serum creatinine within institutional limits or creatinine clearance \> 50 ml/minute if above upper institutional limits (ULN) * Adequate hepatic function as evidenced by ALT and total bilirubin within 2 times ULN. * Provision of written informed consent. * Men and women of childbearing potential must be willing to practice acceptable methods of birth control to prevent pregnancy. Exclusion Criteria: * Positive margins on post operative surgical specimen or evidence of metastatic disease (positive retroperitoneal margin is allowed) * Biliary tree cancers are not allowed (Note: Ampullary cancer allowed). * Known severe hypersensitivity to erlotinib or any of the excipients of these products * Any prior treatment with radiation therapy or chemotherapy or vaccines for pancreatic cancer. * Other coexisting malignancies or malignancies diagnosed within the last 3 years, with the exception of basal cell carcinoma or squamous cell carcinoma of the skin or cervical cancer in situ. * Concomitant use of phenytoin, carbamazepine, barbiturates, rifampicin, phenobarbital, or St. John's Wort. Other agents which inhibit CYP3A4 may be used with caution (Appendix B) * Treatment with a non-approved or investigational drug prior to treatment. * Incomplete healing from previous oncologic or other major surgery. * Pregnancy or breast feeding (women of childbearing potential). * As judged by the investigator, any evidence of severe or uncontrolled systemic disease (e.g., unstable or uncompensated respiratory, cardiac, hepatic, or renal disease). * Evidence of any other significant clinical disorder or laboratory finding that makes it undesirable for the subject to participate in the trial.