Prognostic Value of Serum Soluble PD-L1 in Metastatic Renal Cell Carcinoma Patients Treated With Nivolumab.

BACKGROUND/AIM:Increasing availability of effective treatment options for metastatic renal cell carcinoma (mRCC) has highlighted the importance of identifying predictors of treatment response. Although PD-L1 expression in renal cancer has been reported as a predictor of treatment response and prognosis, its assessment by immunohistochemistry is invasive and difficult to perform repeatedly. Soluble PD-L1 (sPD-L1) has recently been proposed as a predictive biomarker for several tumour types. Therefore, we evaluated sPD-L1 levels in patients with mRCC treated with nivolumab and investigated its association with treatment response. PATIENTS AND METHODS:We performed a prospective single-arm study in patients with mRCC treated with nivolumab as second line or later therapy. We measured serum sPD-L1 before and during treatment, classified patients based on baseline values (sPDL1 ≥0.23 ng/ml vs. <0.23 ng/ml) and compared outcomes between the two groups. RESULTS:A total of 43 patients with mRCC were included in this study, with 17 (39.5%) classified as low sPD-L1 and 26 (60.5%) as high sPD-L1. The International Metastatic RCC Database Consortium risk score was significantly poorer in the high sPD-L1 group. The objective response rate was significantly higher (41.2% vs. 7.7%) and overall survival significantly longer (p=0.0323) in the low group compared to the high group. There were no significant differences in progression-free survival between the two groups. CONCLUSION:Our study findings indicate that sPD-L1 might be a predictor of treatment response to nivolumab in patients with mRCC.