A compound useful as a cathepsin S inhibitor is provided. The present inventors have a cathepsin S inhibitory action, and prevent and / or prevent autoimmune diseases including allergic lupus erythematosus (SLE) and lupus nephritis, allergy, or transplant rejection of organs, bone marrow, or tissues. Alternatively, compounds that can be active ingredients of therapeutic pharmaceutical compositions were investigated, and it was confirmed that the phenyldifluoromethyl-substituted proline amide compounds of the present invention have cathepsin S inhibitory activity, thereby completing the present invention. The phenyldifluoromethyl-substituted proline amide compound of the present invention has a cathepsin S inhibitory action, and is used as an agent for preventing and / or treating autoimmune diseases including SLE and nephritis, allergies, or transplant rejection of organs, bone marrow or tissues. Can be used. [Selection figure] None【課題】カテプシンＳ阻害剤として有用な化合物を提供する。【解決手段】本発明者らは、カテプシンＳ阻害作用を有し、全身性エリテマトーデス（ＳＬＥ）やループス腎炎を含む自己免疫疾患、アレルギー、又は、臓器、骨髄若しくは組織の移植片拒絶の予防及び／又は治療用医薬組成物の有効成分となりうる化合物について検討し、本発明のフェニルジフルオロメチル置換プロリンアミド化合物がカテプシンＳ阻害作用を有することを確認し、本発明を完成した。本発明のフェニルジフルオロメチル置換プロリンアミド化合物は、カテプシンＳ阻害作用を有し、ＳＬＥや腎炎を含む自己免疫疾患、アレルギー、又は、臓器、骨髄若しくは組織の移植片拒絶の予防及び／又は治療剤として使用できる。【選択図】なし
