Since it has been confirmed that the antitumor agents of the invention containing as the active agent (3R)-N-(1-(1-tert-butylcarbonylmethyl)-2,3-dihydro-2-oxo-5-(2-pyridyl)-1H-1,4-benzodiazepin-3-yl)-N'-(3-(methylamino)phenyl)urea favorably inhibit the proliferation of cancer in various cancer-bearing mice and have a low toxicity, they are particularly useful in treating pancreatic cancer, intestinal cancer and gastric cancer. In case of using the medicaments of the invention particularly in polypharmaceutical chemotherapy, administration dose of an antitumor agent having strong side effects can be lowered, so that realization of a polypharmaceutical chemotherapy achieving a favorable antitumor effect and reduced side effects can be expected.
Since it has been confirmed that the antitumor agents of the invention containing as the active agent (3R)-N-(1-(1-tert-butylcarbonylmethyl)-2,3-dihydro-2-oxo-5-(2-pyridyl)-1H-1,4-benzodiazepin-3-yl)-N′-(3-(methylamino)phenyl)urea favorably inhibit the proliferation of cancer in various cancer-bearing mice and have a low toxicity, they are particularly useful in treating pancreatic cancer, intestinal cancer and gastric cancer. In case of using the medicaments of the invention particularly in polypharmaceutical chemotherapy, administration dose of an antitumor agent having strong side effects can be lowered, so that realization of a polypharmaceutical chemotherapy achieving a favorable antitumor effect and reduced side effects can be expected.