Antitumor Effect Potentiator, Antitumor Preparation, and Method for Treating Cancer

An antitumor effect fortifier comprising as an active ingredient an effective amount of platinum (II) cis-oxalato(1R,2R-diaminocyclohexane) so as to enhance the antitumor activity of antitumor agent containing a therapeutically effective amount of tegafur, an amount, effective for the enhancement of antitumor effect, of gimeracil and an amount, effective for the suppression of side effects, of oteracil potassium; and a relevant antitumor agent. Further, there is provided a method of therapy for cancer, characterized in that an amount, effective for the enhancement of antitumor effect, of platinum (II) cis-oxalato(1R,2R-diaminocyclohexane) is concomitantly administered to a mammal. Still further, there is provided an antitumor agent consisting of a pharmaceutical preparation form composed of at least two separate preparations containing efficacious ingredients consisting of tegafur, gimeracil, oteracil potassium and platinum (II) cis-oxalato(1R,2R-diaminocyclohexane) each alone or in an arbitrary combination, or a pharmaceutical preparation form constituted of a single preparation containing all the efficacious ingredients. Still further, there is provided a relevant kit.