Expressions of PD-L1 and Nectin-4 in urothelial cancer patients treated with pembrolizumab.

Objectives: Recently, the standard of care for advanced urothelial cancer (UC) has been changed by developing immune-checkpoint inhibitors (ICIs). However, its response rate is limited to 20-30%. The identification of biomarkers to predict the therapeutic effects of ICIs is urgently needed. The present study explored the association between immunohistochemical biomarkers and clinical outcomes in UC patients treated with pembrolizumab.

Patients And Methods: A total of 85 patients with UC who received pembrolizumab after chemotherapy from January 2018 to May 2020 were retrospectively reviewed. Tumor tissues were obtained for immunohistochemical study from 47 out of 85 patients. The protein expressions of PD-L1, WT1, Nectin-4, CD4, CD8, Foxp3, and CD68 in tumor cells and/or tumor infiltrating lymphocytes were immunohistochemically examined. The associations between protein expressions and overall survival (OS), progression-free survival (PFS), and disease control rate (DCR) were statistically analyzed.

Results: Patients with positive PD-L1 in tumor cells showed significantly worse OS (Log-rank test: HR 5.146, p = 0.001, Cox regression analysis: HR 4.331, p = 0.014) and PFS (Log-rank test: HR 3.31. p = 0.022), along with significantly lower DCR (14.3%) compared to the PD-L1 negative patients (67.5%). In addition, patients with strong expression of Nectin-4 in tumor cells showed significantly higher DCR (100%) than the other patients (50%).

Conclusion: PD-L1 expression in tumor cells was associated with poor prognosis (OS and PFS) and low DCR. Interestingly, the strong expression of Nectin-4 was correlated with high DCR. PD-L1 and Nectin-4 expression in tumor cells could be prognostic biomarkers useful for pembrolizumab in patients with advanced UC.