Predicting Objective Response of Pembrolizumab in Platinum-Refractory Urothelial Carcinoma Based on Neutrophil-Lymphocyte Ratio Fluctuation and Liver Metastases

Introduction: It is well known that patients with objective response to pembrolizumab have a durable duration of response, leading to favorable survival outcomes.We investigated the possibility of predicting the objective response with concise indicators obtained from daily clinical practice. Methods: In our multi-institutional cohort, 220 platinum-refractory metastatic urothelial carcinoma (mUC) patients treated with pembrolizumab for at least 6 weeks with complete information of objective response were investigated. Results: The median follow-up was 7.3 months, and 119 patients deceased during the follow-up. A multivariate logistic regression analysis exhibited two independent variables predicting the objective response, including the neutrophil-lymphocyte ratio (NLR) change at 6 weeks of treatment and liver metastasis. We proposed a risk group using these two indicators. Patients with no predictive indicators/one of those were assigned to favorable (42%)/intermittent (47%) risk groups. Patients with both indicators were assigned to poor risk (11%). Notably, the objective response rate was well delineated in 41%, 25%, and 0% for favorable-, intermediate-, and poor-risk groups, respectively (p > 0.001). Distinct overall survival (OS) between the risk groups was also confirmed with the median OS of 14.1, 11.7, and 4.2 months in favorable-, intermediate-, and poor-risk groups, respectively. Conclusions: At the 6 weeks of the pembrolizumab treatment, our risk model predicts the objective response rate precisely. Notably, those classified as poor risk marked by liver metastasis and an increased NLR should be considered for alternative therapy with a different mode of action, highlighting a critical decision point in treatment optimization.