Additional Study Information: The purpose of this study is to test whether GVAX pancreas vaccine and CRS-207 together are safe and work better than chemotherapy to treat individuals with advanced pancreatic cancer who have received at least one prior chemotherapy treatment for metastatic cancer. This study will also look at whether CRS-207 alone is safe and works better than chemotherapy to treat pancreatic cancer patients who have received at least one prior chemotherapy treatment. The main goal of the study is to test how well the vaccines work in individuals who have received at least 2 prior chemotherapy treatments of which one must have included gemcitabine. However, a small number of individuals who have received just one prior chemotherapy treatment of any type will also be included. Other goals of the study are to learn more about how the immune system responds and how the patient's tumor might respond to the treatments given in the study.