Provided are methods for treating cancer in a patient, comprising administering to a patient in need thereof a therapeutically effective regimen, the regimen comprising administering a gamma-secretase inhibitor, wherein the regimen results in a reduction in the cancer cell population in the patient. In some embodiments of the methods, the therapeutically effective regimen stabilizes, reduces or eliminates the cancer stem cell population.Also provided are compounds of the formula Ior a pharmaceutically acceptable salt thereof, wherein R1, R2, and X are as herein described.
