An object of the present invention is to provide a novel treatment method with fewer side effects for elderly cancer patients and terminal cancer patients. A pharmaceutical composition for treating or putting an elderly or a terminal cancer patient into remission, comprising, as an active ingredient, (2S)-2-[(2S,3R)-3-amino-2-hydroxy-4-phenylbutanoylamino]-4-methylpentanoic acid or a pharmacologically acceptable salt thereof.