The present invention relates to the combination of the HDM2-p53 interaction inhibitor drug (S)-5-(5-Chloro-1-methyl-2-oxo-1,2-dihydro-pyridin-3-yl)-6-(4-chloro-phenyl)-2-(2,4-dimethoxy-pyrimidin-5-yl)-1-isopropyl-5,6-dihydro-1H-pyrrolo[3,4-d]imidazol-4-one [HDM201] and the BCL2 inhibitor 4-(4-{[2-(4-chlorophenyl)-4,4-dimethylcyclohex-1-en-1-yl]methyl}piperazin-1-yl)-N-[(3-nitro-4-{[(oxan-4yl)methyl]amino}phenyl)sulfonyl]-2-[(1H-pyrrolo[2,3-b]pyridin-5-yl)oxy]benzamide [venetoclax]. The present invention further relates to the use of said combination in the treament of cancer, in particular hematological tumors. The present invention further relates to dose and dosing regimen related to this combination cancer treatment.