To provide methods for treating cancer patients.SOLUTION: Provided is a pharmaceutical composition for administering to a cancer patient to treat a cancer patient, which comprises an immune checkpoint inhibitory antibody which blocks immune checkpoint, such as cytotoxicity T-lymphocyte antigen-4 (CTLA-4) and programmed death-1 (PD-1), the cancer is selected from the group consisting of colon cancer, stomach cancer, endometrial cancer, bile duct cancer, pancreatic cancer, and prostate cancer, and the cancer patient having a microsatellite instable cancer (MSI).SELECTED DRAWING: None【課題】癌患者の治療方法の提供。【解決手段】細胞傷害性Ｔ－リンパ球抗原－４（ＣＴＬＡ－４）およびプログラム死－１（ＰＤ－１）等の免疫チェックポイントを遮断する免疫チェックポイント阻害抗体を含む、癌患者を治療するための癌患者への投与用の薬学的組成物であって、前記癌が結腸癌、胃癌、子宮内膜癌、胆管癌、膵臓癌、および前立腺癌からなる群から選択され、前期癌患者はマイクロサテライト不安定性癌（ＭＳＩ）を有する、前記薬学的組成物。【選択図】なし
