The purpose of this study is to evaluate the safety and immune response of different doses of RNF43-721 emulsified with Montanide ISA 51 in combination with S-1/CPT-11 chemotherapy.

RNF43 is a cancer testis antigen which express widely in colorectal cancer tissue but not in normal organs. RNF43-721 induces HLA A24 restricted specific cytotoxic T lymphocytes (CTL) against RNF43 expressed target. S-1/CPT-11 chemotherapy is performed unresectable advanced colorectal cancer in Japan and is reported to be obtained almost the same result compared with FOLFOX or FOLFIRI as first-line chemotherapy for advanced colorectal cancer. Because synergistic effect between vaccine therapy and chemotherapy will be expected, we plan phase I study to evaluate the safety and immune response of different doses of RNF43-721 emulsified with Montanide ISA 51 in combination with S-1/CPT-11 chemotherapy.

Inclusion Criteria:

• ECOG performance status 0-1
• Life expectancy > 3 months
• HLA A24 positive
• Histologically diagnosed as colorectal cancer with measurable lesion
• Laboratory values as follows:WBC>3000/mm3, Hb>10mg/dl, Plt>75000/mm3, Creatinine<1.2mg/dl, T. bil.<1.5mg/dl, AST, ALT<3x normal limits
• Able and willing to give valid written informed consent

Exclusion Criteria:

• Active other malignancy
• Active infection
• Immune deficiency
• Current treatment with steroids and immunosuppressive agents
• Pregnancy and breast feeding
• Inability oral intake
• Psychic disease
• Hepatitis B, C virus
• HIV infection