Efficacy and safety of PD-1/PD-L1 and CTLA-4 immune checkpoint inhibitors in colorectal cancer: a meta-analysis

Aims: To evaluate the efficacy and safety of PD-1/PD-L1 and/or CTLA-4 inhibitors in the treatment of colorectal cancer (CRC) by meta-analysis. Methods: Electronic databases were searched. Eligible studies included investigations of efficacy and safety of anti-PD-1/PD-L1 or anti-CTLA-4 agents in patients with CRC. Corresponding indicators were calculated. Results: A total of 15 articles were included. The pooled objective response rate, overall survival rate, progression-free survival rate and adverse event rate were 33, 56, 46 and 59%, respectively. The objective response rates for CRC with deficient mismatch repair and CRC with proficient mismatch repair were 43 and 3%, respectively, in patients treated with PD-1 inhibitors. Conclusion: The authors' study indicates that PD-1/PD-L1 inhibitors manifest promising clinical responses in the treatment of CRC with deficient mismatch repair with acceptable treatment-related adverse events.