The purpose of this study is to test any good and bad effects of the study drug called PEGPH20. PEGPH20 alone is considered investigational. The Food and Drug Administration (FDA) has not approved the marketing or sale of PEGPH20, but have authorized its use in research studies with humans. PEGPH20 could shrink the cancer but it also can cause side effects. PEGPH20 is an enzyme that breaks down a specific tissue component called hyaluronan produced by some tumors. Pancreatic tumors often have a large amount of hyaluronan. The removal of hyaluronan from tumors may decrease tumor growth.