Oxaliplatin, Gemcitabine, Erlotinib, and Radiation Therapy in Treating Patients With Unresectable and/or Metastatic Pancreatic Cancer or Biliary Tract Cancer

OBJECTIVES: * Determine the maximum tolerated dose (MTD) of oxaliplatin and gemcitabine hydrochloride when combined with radiotherapy in patients with unresectable and/or metastatic pancreatic or biliary tract adenocarcinoma. (Part 1) * Determine the MTD of erlotinib hydrochloride and gemcitabine hydrochloride when combined with oxaliplatin at the MTD and radiotherapy in these patients. (Part 2) OUTLINE: This is a multicenter, nonrandomized, parallel group, uncontrolled, open-label, dose-escalation study of gemcitabine hydrochloride, oxaliplatin, and erlotinib hydrochloride. * Part 1: Patients receive gemcitabine hydrochloride IV over 30-60 minutes and oxaliplatin IV on day 1. Patients also undergo external beam radiotherapy (EBRT) once daily on days 1-5. Treatment repeats every 7 days for up to 6 courses. Cohorts of 3-6 patients receive escalating doses of gemcitabine hydrochloride and oxaliplatin until the maximum tolerated dose (MTD) is determined. The MTD is defined as the dose preceding that at which 2 of 3 or 2 of 6 patients experience dose-limiting toxicity (DLT). Up to 10 patients are treated at the MTD. * Part 2: Patients receive gemcitabine hydrochloride, oxaliplatin\*, and EBRT as in part 1. Patients also receive oral erlotinib hydrochloride once daily on days 1-5. Treatment repeats every 7 days for up to 6 courses. Cohorts of 3-6 patients receive escalating doses of gemcitabine hydrochloride and erlotinib hydrochloride until the MTD is determined. The MTD is defined as the dose preceding that at which 2 of 3 or 2 of 6 patients experience DLT. Up to 10 patients are treated at the MTD. NOTE: \*Patients receive oxaliplatin at the MTD determined in part 1. After completion of study treatment, patients are followed every 3 months.