Open label, nonrandomized, dose escalation trial of MVT-5873/MVT-1075 to evaluate safety, dosimetry, determine the MTD and recommended phase 2 dose, and define the pharmacokinetics of MVT-1075. The population consists of subjects with CA19-9 positive malignancies (i.e., predominately pancreatic adenocarcinoma) who may benefit from a CA19-9-based radioimmunotherapy.