Disclosed are pharmaceutical formulations comprising a compound of formula (I): in which R1, R2, R3, and R4 are as described herein, or a pharmaceutically acceptable salt thereof. Also provided are methods for treating pancreatic adenocarcinoma comprising administration of a compound of formula (I), or a pharmaceutically acceptable salt thereof, and methods of detecting the change in expression levels of one or both of FoxA1 and FoxO6 in a pancreatic adenocarcinoma tumor sample from a mammal, wherein the mammal has been administered a compound of formula (I), or a pharmaceutically acceptable salt thereof.