Site-Specific Differences in PD-1 Blockade Success and Biomarkers in Urothelial Carcinoma Treated with Pembrolizumab

Introduction: Since tumors in different human organs may have different tumor microenvironments, we evaluate time-course changes in all tumor locations after pembrolizumab treatment in urothelial carcinoma (UC) to examine the differences in efficacy of pembrolizumab per organ. Further, we uncover the usefulness of inflammatory markers such as neutrophil-to-lymphocyte ratio (NLR), CRP, and kinetics of these markers to predict pembrolizumab success and relation to overall survival (OS) in UC. Patients and Methods: A total of 115 cancerous lesions from 44 UC patients were measurable based on RECIST 1.1 criteria. The serum CRP and NLR levels were measured at baseline prior to pembrolizumab treatment and at least every 3 weeks just prior to pembrolizumab administration. Results: Site-specific success (ie, patients with CR/PR/SD by RESIST 1.1) rates for pembrolizumab treatments were as follows: primary tumors: 67%, lymph node: 70%, lung: 44%, liver: 40%, and peritoneal metastasis: 56%. Focusing on the major metastasis sites, lymph nodes and lungs, we examined the relationships between NLR, CRP, or that kinetics and pembrolizumab success. In lymph nodes, both early NLR kinetics (P = .005) and CRP kinetics (P = .035) was a predictor for pembrolizumab success. On the other hand, none of 4 was not in lung metastases. Regarding to the mortality, the multivariate analysis revealed that early NLR kinetics was a prognostic biomarker for OS among the 4, independent of performance status and liver metastasis. Conclusion: We revealed that site-specific pembrolizumab success in UC. Early NLR kinetics was a predictor for lymph node pembrolizumab success and OS in our cohorts.