To provide a novel anticancer drug which is useful for treating prostatic cancer associated with an androgen receptor mutation. As the results of intensive studies on mutated androgen-associated diseases for which the conventional anti-androgen drugs are inefficacious, the present inventors found that a compound, said compound being the active ingredient of a medicinal composition according to the present invention, exhibits an effect of inhibiting the transcriptional activation in a human mutated androgen receptor (AR) and has an excellent antitumor effect on a mouse carrying human prostatic cancer cells, thereby completing the present invention. The compound that is the active ingredient of the medicinal composition according to the present invention is useful for treating diseases such as prostatic cancer in which a series of androgen receptors participate.本發明之課題為提供一種新抗癌藥，其對於治療伴隨雄激素受體突變所發生的前列腺癌而言為有效的。關於課題之解決手段，本發明申請人針對以往抗雄激素藥為無效的突變雄激素相關疾病潛心研究的結果，發現本發明之醫藥組成物的有效成分之化合物在人體突變雄激素受體(AR)表現出轉錄活化的抑制作用，此外還發現在人體前列腺癌細胞荷瘤小鼠之中具有優異的抗腫瘤作用，因而完成了本發明。故本發明之醫藥組成物的有效成分之化合物，對於以前列腺癌為首的雄激素受體一連串相關疾病而言為有效的。
