Incidence and Risk of Colitis with Programmed Death 1 Versus Programmed Death Ligand 1 Inhibitors for the Treatment of Cancer

Colitis is a major immune-related adverse event associated with programmed death 1 (PD-1) and programmed death-ligand 1 (PD-L1) inhibitors, but the risk of colitis with PD-1 versus PD-L1 inhibitors is not well characterized. We performed a meta-analysis for the incidence of all grade and grade 3-4 colitis with PD-1 inhibitor (nivolumab, pembrolizumab, and cemiplimab) or PD-L1 inhibitor (atezolizumab, avelumab, and durvalumab) monotherapy using a fixed effects model. We also conducted subgroup meta-analyses of non-small cell lung cancer (NSCLC) or urothelial carcinoma (UC) trials, and a network meta-analysis of randomized trials comparing PD-1 or PD-L1 inhibitors with docetaxel for NSCLC. We also analyzed the Food and Drug Administration Adverse Event Reporting System database to estimate the reporting odds ratio of each medication. PD-1 inhibitors were associated with a higher incidence of all grade and grade 3-4 colitis compared with PD-L1 inhibitors in the analysis of all cancer types [1.49% vs. 0.83%, relative risk; 1.80, 95% confidence interval (CI); 1.22-2.67 for all grade colitis, and 0.85% vs. 0.34%, relative risk; 2.52, 95% CI; 1.46-4.37 for grade 3-4 colitis]. The meta-analyses of NSCLC and UC trials, and the network meta-analysis of NSCLC trials were also suggestive of a higher risk of colitis with PD-1 versus PD-L1 inhibitors. The reporting odds ratio of colitis with PD-1 versus PD-L1 inhibitors was 1.80 (95% CI; 1.53-2.14). In this meta-analysis of clinical trials exploring PD-1 and PD-L1 inhibitors in solid tumors, PD-1 inhibitors were associated with a higher risk of colitis.