Immune Checkpoint Inhibitors in MSI-H/dMMR Colorectal Cancer: A Mini-Review

Microsatellite instability-high/mismatch repair deficient (MSI-H/dMMR) colorectal cancer accounts for 15% of all colorectal cancer cases and 5% of metastatic colorectal cancer. Although cancer immunotherapy has been effective in various cancer, its activity has been limited in colorectal cancer. However, cancer immunotherapy has been shown to be effective in MSI-H/dMMR colorectal cancer. Specifically, among immunotherapeutic modalities, immune checkpoint inhibitors have shown the most promising results in MSI-H/dMMR colorectal cancer and to date, the Food and Drug Administration (FDA) has approved three checkpoint inhibitors for the treatment of metastatic MSI-H/dMMR colorectal cancer. With the recent advances, checkpoints inhibitors can now be considered as the first line of therapy in advanced dMMR/MSI-H colorectal cancer, and in this review, we will examine the development and use of immune checkpoint inhibitors in the treatment of metastatic colorectal cancer.

Keywords: Colorectal cancer; Immunotherapy; Immune Checkpoint Inhibitor; Microsatellite instability; Mismatch repair deficiency

Abbreviations: MSI-H/dMMR: Microsatellite instability-high/mismatch repair; FDA: Food and Drug Administration; ORR: Objective response rate; PFS: Progression-free survival; OS: Overall survival