129P - The role of PD-L1 expression as a predictive biomarker in advanced renal cell carcinoma: A meta-analysis of randomized clinical trials

Abstract

BackgroundImmune checkpoint inhibitors (ICIs) are beneficial in a subset of metastatic renal cell carcinoma (mRCC) patients. However, no biomarker has been shown to be useful to select which patient benefits and the role of programmed death-ligand 1 (PD-L1) expression on tumor samples is controversial. MethodsWe assessed the potential role of PD-L1 expression according to Cochrane Collaboration’s Guidelines. Search of randomized clinical trials (RCTs) comparing ICIs (monotherapy or in combination with other therapies) to standard of care (SoC) in mRCC patients was performed. Trials must have included subgroup analysis evaluating the selected outcomes (progression-free survival-PFS- and overall survival-OS-) in different subsets of patients according to PD-L1 expression on tumor samples. Hazard ratios (HR) with confidence intervals (CI) were used as the measure of efficacy between groups. ResultsA total of 3,720 patients (5 studies) were included (ICIs arm: 1,913 patients; SoC arm: 1,807 patients). Globally, PFS and OS results favored ICIs. Differential expression of PD-L1 on tumor samples could select a subset of patients who could benefit more in terms of PFS (those with higher levels; p-value for difference between subgroups: 0.003) but it did not seem to impact in OS results (p-value for difference: 0.29).Table: 129PValue of PD-L1 expression as a predictive biomarker for ICIs. HR: Hazard ratio. CI: Confidence intervalTable: 129PTotal populationHigh PD-L1Low PD-L1p-value for differencePFSHR 0.72; 95% CI 0.58-0.90HR 0.63; 95% CI 0.51-0.77HR 0.96; 95% CI 0,79-1.160.003OSHR 0.69; 95% CI 0.61-0.78HR 0.64; 95% CI 0.54-0.77HR 0.73; 95% CI 0.62-0.870.29 ConclusionsPD-L1 could represent a biomarker to test PFS in clinical trials but its value for OS is less clear. Legal entity responsible for the studyThe authors. FundingHas not received any funding. DisclosureAll authors have declared no conflicts of interest.