Early Phase Persistent Changes in the White Blood Cell Fraction in Patients With Advanced Urothelial Carcinoma Treated With Pembrolizumab: A Multicenter Retrospective Study.

BACKGROUND/AIM:The association of clinical outcomes with posttreatment persistent changes in eosinophils and other white blood cell (WBC) subtypes in patients with advanced urothelial cancer (UC) treated with pembrolizumab after the failure of platinum-based chemotherapy is unclear. PATIENTS AND METHODS:We retrospectively analyzed 87 patients with advanced UC who received pembrolizumab after the failure of platinum-based chemotherapy. The changes in WBC subtypes from pretreatment were evaluated three and six weeks after pembrolizumab administration. The association between the changes in the WBC subtypes and clinical outcomes was then evaluated using the Kaplan-Meier method and a Cox regression model. RESULTS:Among WBC subtypes, significant changes in the absolute (AEC) and relative eosinophil count (REC) and the neutrophil-to-eosinophil ratio (NER) were observed at three and six weeks compared with pretreatment (p<0.001). Multivariable Cox regression analyses revealed that a persistent decrease in AEC and REC and a persistent increase in NER were associated with poor overall survival. CONCLUSION:Persistent increase in AEC and REC and decrease in NER in the early phase after pembrolizumab may be significant early predictive markers of improved clinical outcomes in patients with advanced UC receiving pembrolizumab.