PRIOR CONCURRENT THERAPY: Biologic therapy: No prior or concurrent immunotherapy Chemotherapy: No prior chemotherapy No prior adjuvant or neoadjuvant chemoradiotherapy, including for advanced pancreatic cancer No other concurrent chemotherapy Endocrine therapy: No prior or concurrent hormonal therapy Radiotherapy: See Chemotherapy No prior radiotherapy, except for palliation to metastatic sites No concurrent radiotherapy Surgery: See Disease Characteristics At least 2 weeks since prior surgery for pancreatic cancer and recovered Prior partial resections of the stomach and duodenum for pancreatic cancer allowed No prior major resection of the small intestine Prior pancreaticduodenectomy for pancreatic cancer allowed Other: No concurrent proton pump inhibitors (e.g., omeprazole) Concurrent antacids or H2 blockers allowed No other concurrent therapy for pancreatic cancer