A dosing regimen comprising administering 4,4,4-trifluoro-N-[(1S)-2-[[(7S)-5-(2-hydroxyethyl)-6-oxo-7H-pyrido[2,3-d][3]benzazepin-7-yl]amino]-1-methyl-2-oxo-ethyl]butanamide or a pharmaceutically acceptable salt or hydrate thereof for treating a solid tumor cancer at a specified loading dose for a defined period of doses followed by a maintenance dose and optionally administering a corticosteroid during administration of the loading dose is provided.
