The Aim of This Study is to Assess the Efficacy and Safety of Chidamide, Regorafenib in Combination With Iparomlimab and Tuvonralimab for the Treatment of Advanced Colorectal Cancer in Third-line Therapy and Subsequent Lines.

Patients with advanced colorectal cancer, particularly those of the pMMR/MSS type, exhibit suboptimal therapeutic responses in the third-line and subsequent treatments. The efficacy of the existing standard treatment regimens is highly restricted. In the CORRECT study, the median overall survival (OS) of regorafenib was 6.4 months, the median progression-free survival (PFS) was 1.9 months, and the objective response rate (ORR) was 1%. In the CONCUR study targeting the Asian population, the median OS of the regorafenib group was 8.8 months, the median PFS was 3.2 months, and the ORR was 4%. In the FRESCO study, the median OS of fruquintinib was 9.3 months, the median PFS was 3.7 months, and the ORR was 4.7%. In the TERRA study, the median OS of trifluridine/tipiracil (TAS-102) was 7.8 months, the median PFS was 2.0 months, and the ORR was 1.1%. The SUNLIGHT study explored the combined treatment modality of TAS-102 plus bevacizumab, where the median OS of the combined regimen was 10.8 months, the median PFS was 5.6 months, and the ORR was 6.1%. Evidently, the therapeutic efficacy of advanced colorectal cancer in the third-line and beyond has plateaued. In recent years, fundamental research has discovered that epigenetic regulation significantly synergizes with anti-angiogenesis and immune checkpoint inhibition therapy. Small-scale clinical explorations have also indicated favorable efficacy and clinical prospects, warranting further investigation. Hence, we contemplate employing the combination of chidamide, regorafenib, and iparomlimab/tuvonralimab to investigate its efficacy and safety in the treatment of advanced colorectal cancer in the third-line and beyond, and to explore novel breakthroughs for refractory colorectal cancer after multiple lines of treatment. The aim of this study is to assess the efficacy and safety of the combination regimen of chidamide, regorafenib, and iparomlimab/tuvonralimab in patients with advanced colorectal cancer in the third-line an