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MP26-01 PRETREATMENT NEUTROPHIL-TO-LYMPHOCYTE RATIO IS A NOVEL BIOMARKER FOR PREDICTING WORSE CLINICAL OUTCOME IN CHEMO-RESISTANT UROTHELIAL CARCINOMA PATIENTS TREATED WITH PEMBROLIZUMAB

INTRODUCTION AND OBJECTIVES: No reliable biomarker is available for predicting worse clinical outcome in chemo-resistant urothelial carcinoma (UC) patients treated with pembrolizumab. We focused on the neutrophil-lymphocyte ratio (NLR), which is reported to be a simple index of systemic inflammation and a possible biomarker for predicting prognosis in various malignancies, including UC. Our aim was to evaluate whether a high pretreatment NLR level (pre-NLR) could predict subsequent clinical outcomes in chemo-resistant UC patients treated with pembrolizumab. METHODS: We identified 50 cases treated with pembrolizumab for chemo-resistant UC between December 2017 and August 2018 at our 5 institutions. We investigated the association between pre-NLR levels and their prognosis. We defined patients with NLR of >3.90 as the high pre-NLR group according to a calculation by receiver-operating curve analysis. RESULTS: The high pre-NLR group consisted of 13 cases (26.0%). In the 45 cases who had measurable lesions, at the point of maximum effect the sum of the target lesion longest diameter (SLD) was decreased in 17 cases (37.8%) compared to baseline. SLD was decreased in 2 cases (15.4%) in the high pre-NLR group, which was significantly lower than that in the low pre-NLR group (15 cases, 46.9%, p=0.048). The disease control rate defined by RECIST ver. 1.1 at best response in the high pre-NLR group was 15.4%, which was significantly lower than that in their counterpart (45.9%, p=0.049). No association was observed between pre-NLR levels and the occurrence of adverse events. The 6-month progression-free survival (PFS) rate for the high pre-NLR group was 10.3±9.4%, which was significantly lower than that for their counterpart (31.9±9.2%, p=0.001). Multivariate Cox regression analysis revealed that pre-NLR level was the only independent indicator for disease progression (p=0.004). Furthermore, the 6-month cancer-specific survival (CSS) rate for the high pre-NLR group (53.7±15.7%) was significantly lower than that for their counterpart (90.0±6.7%, p<0.001). Multivariate analysis revealed that an elevated pre-NLR was the only independent indicator for cancer-specific death (p=0.007). The change of NLR level before and after pembrolizumab was elevated in 28 cases (56.0%). However, there was no association between clinical outcome of PFS and CSS and the change of NLR level. CONCLUSIONS: Elevated pre-NLR could identify a population with a poor response to pembrolizumab treatment among chemo-resistant UC patients. Source of Funding: none