Pooled Analysis Of Pd-L1 Expression Across 6 Tumor Types In The Nivolumab Clinical Program

Introduction: Programmed death ligand 1 (PD-L1) is a key biomarker for PD-1 checkpoint inhibitors; PD-L1 evaluation is incorporated across the nivolumab clinical trial program. Understanding relative expression of PD-L1 for a specific tumor type is important in evaluating its predictive and prognostic value. In this analysis, we present prevalence data from 13 050 patients across 6 tumor types from 23 nivolumab clinical trials. Methods: PD-L1 expression on tumor cells was evaluated with the Dako PD-L1 IHC 28-8 pharmDx assay in select clinical studies: melanoma (MEL), non-small cell lung cancer (NSCLC), renal cell carcinoma (RCC), small-cell lung cancer (SCLC), urothelial cancer (UC), and squamous cell carcinoma of the head and neck (SCCHN). All tumor types included previously treated patients; MEL, NSCLC, and RCC trials also included treatment-naive. PD-L1 IHC staining and interpretation was conducted by reference laboratories. Interpretation was based on a scoring guideline developed for each tumor type, consistent with Dako development standards. Cut-off for data collection was November 23, 2016. Results: Across all tumor types, 93% of samples were evaluable for PD-L1 (Table). PD-L1 expression was evaluated in individual tumor types; proportion of samples with PD-L1 expression ≥1% varied by type (9.0% [SCLC] to 62.8% [MEL]). Proportion of samples at other expression levels also varied, with the highest proportion of ≥50% PD-L1 expression in NSCLC (28.4%). Evaluating the 3 largest nivolumab programs (MEL, NSCLC, and RCC), the profile of PD-L1 expression was significantly different between tumor types ( P Conclusion: Prevalence of PD-L1 expression ≥1% and expression levels for screened patients vary significantly by tumor type with minor differences between treatment-naive and overall population. PD-L1 prevalence in nivolumab NSCLC trials is consistent with previously published results, including those with other PD-L1 assays (Aggarwal et al, Ann Oncol 2016;27[s6]). Citation Format: Gabriel Krigsfeld, James Novotny, Emin Oroudjev, Josette Carnahan, Songlan Zuo, Steven D. Averbuch, Virginia Burns. Pooled analysis of PD-L1 expression across 6 tumor types in the nivolumab clinical program [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr CT143. doi:10.1158/1538-7445.AM2017-CT143