A 3-(indolyl)- or 3-(azaindolyl)-4-phenylmaleimide derivative of formula wherein R 1 is H, C 1 -C 6 -alkyl, phenyl-C 1 -C 4 -alkyl or phenyl, R 2 is a group having the formula wherein R 4, R 5 and R 6 are C 1 -C 6 -alkoxy, and R 3 is indolyl or azaindolyl which may carry one, two or three substituents independently selected from C 1 -C 6 -alkyl, C 1 -C 6 -alkoxy, phenyl, OH, halogen, NH 2, C 1 -C 6 -alkylamino, di-C 1 -C 6 -alkylamino, C 1 -C 6 -alkyl-R 10, heteroaryl with 5 or 6 ring atoms containing 1 or 2 heteroatoms which are independently selected from O, N, and S, or heterocyclyl with 5 or 6 ring atoms containing 1 or 2 heteroatoms which are independently selected from O, N, and S, wherein R 10 is selected from: a) amino, b) C 1 -C 6 -alkylamino, c) di-C 1 -C 6 -alkylamino, d) hydroxy, e) C 1 -C 6 -alkoxy, f) saturated heterocyclyl with 5 or 6 ring atoms containing a nitrogen heteroatom and optionally 1 or 2 additional heteroatoms which are independently selected from O, N and S, wherein the heterocyclyl is attached to the C 1 -C 6 -alkyl group via the nitrogen atom and may carry one, two, three or four C 1 -C 6 -alkyl substituents; g) phenoxy, h) benzyloxy, i) R 11 CONR 12 -, j) NR 12 R 12 CO-, k) C 1 -C 6 -alkyl-NHCONH-, l) C 1 -C 6 -alkyl-NHCOO-, m) C 1 -C 6 -alkyl-OCONH-, n) R 12 -OSO 2 O-, o) R 11 SO 2 O-, p) R 12 -OSO 2 -, q) R 11 SO 2 -, r) (R 12 O) 2 P O-, s) (R 12 O) 2 P -, and t) (R 12 O)R 11 P O-, R 11 is C 1 -C 6 -alkyl and R 12 is H or C 1 -C 6 -alkyl; a physiologically acceptable salt thereof, or a solvate of the compound of formula or of the salt thereof for use in the treatment of colorectal or gastric adenocarcinoma. R 1 is H, C 1 -C 6 -alkyl, phenyl-C 1 -C 4 -alkyl or phenyl, R 2 is a group having the formula wherein R 4, R 5 and R 6 are C 1 -C 6 -alkoxy, and R 3 is indolyl or azaindolyl which may carry one, two or three substituents independently selected from C 1 -C 6 -alkyl, C 1 -C 6 -alkoxy, phenyl, OH, halogen, NH 2, C 1 -C 6 -alkylamino, di-C 1 -C 6 -alkylamino, C 1 -C 6 -alkyl-R 10, heteroaryl with 5 or 6 ring atoms containing 1 or 2 heteroatoms which are independently selected from O, N, and S, or heterocyclyl with 5 or 6 ring atoms containing 1 or 2 heteroatoms which are independently selected from O, N, and S, wherein R 10 is selected from: a) amino, b) C 1 -C 6 -alkylamino, c) di-C 1 -C 6 -alkylamino, d) hydroxy, e) C 1 -C 6 -alkoxy, f) saturated heterocyclyl with 5 or 6 ring atoms containing a nitrogen heteroatom and optionally 1 or 2 additional heteroatoms which are independently selected from O, N and S, wherein the heterocyclyl is attached to the C 1 -C 6 -alkyl group via the nitrogen atom and may carry one, two, three or four C 1 -C 6 -alkyl substituents; g) phenoxy, h) benzyloxy, i) R 11 CONR 12 -, j) NR 12 R 12 CO-, k) C 1 -C 6 -alkyl-NHCONH-, l) C 1 -C 6 -alkyl-NHCOO-, m) C 1 -C 6 -alkyl-OCONH-, n) R 12 -OSO 2 O-, o) R 11 SO 2 O-, p) R 12 -OSO 2 -, q) R 11 SO 2 -, r) (R 12 O) 2 P O-, s) (R 12 O) 2 P -, and t) (R 12 O)R 11 P O-, a) amino, b) C 1 -C 6 -alkylamino, c) di-C 1 -C 6 -alkylamino, d) hydroxy, e) C 1 -C 6 -alkoxy, f) saturated heterocyclyl with 5 or 6 ring atoms containing a nitrogen heteroatom and optionally 1 or 2 additional heteroatoms which are independently selected from O, N and S, wherein the heterocyclyl is attached to the C 1 -C 6 -alkyl group via the nitrogen atom and may carry one, two, three or four C 1 -C 6 -alkyl substituents; g) phenoxy, h) benzyloxy, i) R 11 CONR 12 -, j) NR 12 R 12 CO-, k) C 1 -C 6 -alkyl-NHCONH-, l) C 1 -C 6 -alkyl-NHCOO-, m) C 1 -C 6 -alkyl-OCONH-, n) R 12 -OSO 2 O-, o) R 11 SO 2 O-, p) R 12 -OSO 2 -, q) R 11 SO 2 -, r) (R 12 O) 2 P O-, s) (R 12 O) 2 P -, and t) (R 12 O)R 11 P O-, R 11 is C 1 -C 6 -alkyl and R 12 is H or C 1 -C 6 -alkyl; a physiologically acceptable salt thereof, or a solvate of the compound of formula or of the salt thereof for use in the treatment of colorectal or gastric adenocarcinoma.