The present invention relates to the use of a compound of formula (I) wherein R 1 , and R 3 are as defined in the description and R 2 is a phenyl group which is substituted with 2 or 3 C 1 -G 6 alkoxy groups, or a physiologically acceptable salt thereof, or a solvate of the compound of formula (I) or of the salt thereof, for treatment of colorectal or gastric adenocarcinoma.