A prospective, open-label, interventional study protocol to evaluate treatment efficacy of nivolumab based on serum-soluble PD-L1 concentration for patients with metastatic and unresectable renal cell carcinoma

Introduction Nivolumab has been proven to prolong overall survival as a second-line therapy for patients with advanced renal cell carcinoma (RCC) in a phase III clinical trial. However, versatile biomarkers have not been established to predict the efficacy of nivolumab against target disease. Methods and analysis After registration, screening test and serum-soluble programmed cell death 1-ligand 1 (sPD-L1) measurement will be performed by using the ELISA; patients will be grouped into high sPD-L1 or low sPD-L1 groups. Nivolumab (240 mg every 2 weeks by intravenous drip infusion) will be administered to each participant. For this prospective study, statistical power calculation indicated that 48 participants with metastatic or unresectable RCC are needed to assess the efficacy of this method. The participants must be at the age of at least 20 years at the time of informed consent and require second-line therapy after failure of first-line therapy or discontinuation due to adverse effects. All data will be collected in our institution. The primary endpoint is progression-free survival, and secondary endpoints are overall survival and objective response rate. In this protocol, we will examine sPD-L1 as a promising predictive marker. Ethics and dissemination This protocol was approved by the Kobe University Clinical Research Ethical Committee (C180067). Findings of this study will be widely disseminated through conference presentations, reports, factsheets and academic publications; further generalisation will also be discussed. Trial registration number UMIN000027873.