Subjects with metastatic PDA who have received FOLFIRINOX or a gemcitabine-containing regimen and have achieved stable disease or better will be enrolled onto this study. Subjects should have had at least 6 months of chemotherapy and decline continuation of chemotherapy and should have stable disease or better on 2 scans taken at least 6 weeks apart. If applicable, subjects should also have a stable or declining CA19-9.