A compound of formula I e.g. (R)-N-(3-((2-(4-(1-aminoethyl)phenylamino )-5-(trifluoromethyl )pyrimidin-4-ylamino)methyl)pyridin-2-yl)-N-methylmethane-sulfonamide or a pharmaceutically acceptable salt thereof wherein A, B, K, R1, R2, R3, R4, R5, R6 are defined in the specification and n is an integer from 1 to 3 and m is an integer from 0 to 3 for the treatment of cancer.