Predictors of Efficacy of Immune Checkpoint Inhibitors in Patients With Advanced Urothelial Carcinoma: A Systematic Review and Meta-Analysis

Introduction: Several programmed death ligand-1 (PD1/L1) immune checkpoint inhibitors (ICIs) are approved in urothelial carcinoma (UC). Patients and Methods: To address the need for predictors of the efficacy of ICIs in metastatic urothelial carcinoma (mUC), randomized controlled trials of PD1/L1 inhibitors alone or in combination with chemotherapy in this patient population were systematically reviewed, and differences in ICI-associated survival outcomes according to available baseline variables were quantitatively assessed. Results: The quantitative analysis included 6524 patients with mUC. No visceral metastatic site (HR 0.67; 95% CI, 0.76-0.90) and high PDL-1 expression (HR 0.74; 95% CI, 0.640.87) were significantly associated with a reduced risk of death. Conclusion: Treatment with an ICI-containing regimen was associated with a reduced risk of death in mUC patients, which was associated with PDL-1 expression and metastatic site. Further research is warranted.