Multicenter Comparison of 22C3 PharmDx (Agilent) and SP263 (Ventana) Assays to Test PD-L1 Expression for NSCLC Patients to Be Treated with Immune Checkpoint Inhibitors

Antonio Marchetti, Massimo Barberis, Renato Franco, Graziano De Luca, Maria Vittoria Pace, Stefania Staibano, Marco Volante, Fiamma Buttitta, Elena Guerini-Rocco, Luisella Righi, Tommaso D'antuono, Giorgio V Scagliotti, Carmine Pinto, Gaetano De Rosa, Mauro Papotti

Research output: Contribution to journalArticlepeer-review


INTRODUCTION: Among the several agents targeting the programmed cell death 1 (PD-1) pathway, pembrolizumab is currently the only one approved for the treatment of patients with NSCLC in association with a companion diagnostic assay, the anti-PD-L1 immunohistochemical (IHC) 22C3 PharmDx (Agilent Technologies, Santa Clara, CA) using the Dako Autostainer (Dako, Carpinteria, CA). However, the Dako platform is not present in each pathology department, and this technical limitation is a major problem for the diffusion of the PD-L1 IHC predictive test for pembrolizumab.

METHODS: The Italian Society of Anatomic Pathology and Cytopathology and the Italian Association of Medical Oncology in an independent, multicenter study compared the in vitro diagnostics PD-L1 IHC 22C3 pharmDx test (Agilent) on the Dako Autostainer and the in vitro diagnostics Ventana PD-L1 (SP263) test on the Ventana BenchMark platform (Ventana Medical Systems, Tucson, AZ). Using serial sections from tissue microarrays, 100 lung adenocarcinomas were locally stained and scored in four centers with the same antibody batches.

RESULTS: A high analytical correlation (more than 90% at the lower 95% confidence interval [CI] value) between PD-L1 expression levels obtained with the 22C3 and SP263 assays was observed. At the proposed clinically relevant cutoffs (≥50% and ≥1%), the overall concordances between 22C3 and SP263 data were 0.99 (95% CI: 0.96-1) and 0.80 (95% CI: 0.68-0.91), respectively. The lower agreement between data obtained with the 22C3 and SP263 clones at the cutoff of 1% or higher was mainly related to the lower (about 80%) interrater agreement at this cutoff with each clone.

CONCLUSIONS: These results indicate a high correlation between PD-L1 IHC expression data obtained with the Agilent PD-L1 IHC 22C3 pharmDx and the Ventana PD-L1 (SP263) tests in NSCLC and suggest that the two assays could be utilized interchangeably as an aid to select patients for first-line and second-line treatment with pembrolizumab and potentially with other anti-PD-1/PD-L1 checkpoint inhibitors.

Original languageEnglish
Pages (from-to)1654-1663
Number of pages10
JournalJournal of Thoracic Oncology
Issue number11
Publication statusPublished - Nov 2017


  • Journal Article


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