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  P2.09 - Pathology (ID 174)

  • Event: WCLC 2019
  • Type: Poster Viewing in the Exhibit Hall
  • Track: Pathology
  • Presentations: 1
  • Moderators:
  • Coordinates: 9/09/2019, 10:15 - 18:15, Exhibit Hall

  • 31232

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    P2.09-31 - High Concordance of PD-L1 Antibody Between Clone 22C3 and Clone E1L3N in Non-Small Cell Lung Cancer Biopsy Samples (ID 2058)

    10:15 - 18:15  |  Author(s): Wei Zhang
    • Abstract
    • Slides

    Background
    

    PD-L1 22C3 pharmDx was approved as a companion diagnostics for predicting response to pembrolizumab of advanced non-small cell lung cancer (NSCLC) patients. However, the laboratory developed tests (LDTs) for PD-L1 immunohistochemistry were widely available and urgently be standardized in clinical routine practice. We compared the concordance between PD-L1 antibody clone E1L3N and clone 22C3 expression on the DaKo AutostainerLink48 platform in NSCLC biopsy samples.

    Method
    

    171 non-small cell lung cancer (NSCLC) biopsy samples were recruited in this study, Serial sections of FFPE blocks were used for IHC staining. The staining protocol was performed according to the standard of PD-L1 IHC 22C3 pharmDx package.

    Result
    

    PD-L1 clone E1L3N and 22C3 distributed a similar pattern in NSCLC biopsy samples. The two assays scoring of E1L3N and 22C3 were highly concordant (lower Kappa value was 0.868 for two cutoff). There was very strong reliability among two pathologists in evaluating PD-L1 scoring with two assays (the lowest PPA was 88.9% for two cutoff). The PPA range was 85.7%-96.3% for all samples. In the Bland-Altman analysis, the mean difference in percentage of tumor cells positively stained for PD-L1 between the paired assay findings was 1.36% for all samples, and 0.57%, -0.66% between the two pathologists for 22C3 and E1L3N assay, respectively.

    

    Conclusion
    

    The results indicated that clone E1L3N assay has a high concordance with 22C3. PD-L1 clone E1L3N assay is reliable and cost-effective, which could be used as a primary screening agent for PD-L1 IHC staining in the pathological laboratory.

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