It is intended to provide a medicament and a method for treating cancer comprising a compound having MDM2 inhibiting activity and a compound having FLT3 inhibiting activity in combination. The present invention provides a medicament comprising (3'R,4'S,5'R)-N-[(3R,6S)-6-carbamoyltetrahydro-2H-pyran-3-yl]-6"-chloro-4'-(2-chloro-3-fluoropyridin-4-yl)-4,4-dimethyl-2"-oxo-1",2"-dihydrodispiro[cyclohexane-1,2'-pyrrolidine-3',3"-indole]-5'-carboxamide or a pharmaceutically acceptable salt thereof and N-(5-tert-butyl-isoxazol-3-yl)-N'-{4-[7-(2-morpholin-4-yl-ethoxy)imidazo[2,1-b][1,3]benzothiazol-2-yl]phenyl}urea or a pharmaceutically acceptable salt thereof in combination, and a treatment method using these compounds or salts in combination.
