Multicenter Trial of ESK981 in Patients With Select Solid Tumors

This protocol will enroll patients with pancreatic adenocarcinoma and adenosquamous carcinoma (Cohort 1), gastrointestinal/pancreatic neuroendocrine neoplasms with Ki-67 \> 20% (Cohort 2) and neuroendocrine prostate carcinoma (Cohort 3)). Each cohort will have its own interim analysis after enrollment of 10 patients. Subjects will be given a one-month (28 day) supply of study drug (ESK981). Subjects will be instructed to take 4 capsules, with or without food, once per day for 5 consecutive calendar days, then take a drug holiday for 2 consecutive days before repeating the 5 days on-2 days off cycle in sets of 4 weeks or 28 calendar days. Subjects will be asked to keep a pill diary noting the date they take their study drug.