S0727 Gemcitabine Hydrochloride and Erlotinib Hydrochloride With or Without Monoclonal Antibody Therapy in Treating Patients With Metastatic Pancreatic Cancer That Cannot Be Removed By Surgery

This randomized phase I/II trial is studying the side effects and best dose of monoclonal antibody therapy when given together with gemcitabine hydrochloride and erlotinib hydrochloride and to see how well they work compared with giving gemcitabine hydrochloride and erlotinib hydrochloride alone as first-line therapy in treating patients with metastatic pancreatic cancer that cannot be removed by surgery. Drugs used in chemotherapy, such as gemcitabine hydrochloride, work in different ways to stop the growth of tumor cells, either by killing the cells or by stopping them from dividing. Erlotinib hydrochloride may stop the growth of tumor cells by blocking some of the enzymes needed for cell growth. Monoclonal antibodies can block tumor growth in different ways. Some block the ability of tumor cells to grow and spread. Others find tumor cells and help kill them or carry tumor-killing substances to them. Giving erlotinib hydrochloride and gemcitabine hydrochloride together with monoclonal antibody therapy may kill more tumor cells.