Neoantigen-based Peptide Vaccine and Conventional Third-line Therapy for CRC Progressed After Second-line Treatment

This study is conducted in accordance with the Declaration of Helsinki and the guidelines of the Consolidated Standards of Reporting Trials. 10 patients with CRC progressed after second-line therapy will be recruited in this study. With doctor's assessment, a combined treatment of conventional third-line therapy and personalized tumor neoantigen-based peptide vaccine treatment plan will be designed for each participant. Here are the steps for preparing the neoantigen-based peptide vaccine: Collecting venous blood samples; Blood PBMC exome sequencing; RNA transcriptome sequencing; Classifying HLA alleles; Performing bioinformatics analysis, finding meaningful mutations and about 20 neoantigen sequences for each patient; Synthesizing peptide neoantigens; Preparation of the personalized tumor neoantigen-based peptide vaccine. Participants will receive a conventional third-line therapy course and 10 subcutaneous injections of the vaccine within a treatment period of 21 weeks. After treatment, participants will be followed in every 6 weeks till the end of the study. Venous blood collection, physical examination, ECOG Performance Status Scale assessment, CT/MRI scan, X-ray examination, laboratory examination, and other necessary examinations are required at each follow-up visit.