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  P2.04 - Immunooncology (Not CME Accredited Session) (ID 953)

  • Event: WCLC 2018
  • Type: Poster Viewing in the Exhibit Hall
  • Track:
  • Presentations: 1
  • Moderators:
  • Coordinates: 9/25/2018, 16:45 - 18:00, Exhibit Hall

  • 26976

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    P2.04-01 - Associations Histological Subtype of Lung Adenocarcinoma and Programmed Death Ligand 1 (PD-L1) Expression in Tumor Cells. (ID 12995)

    16:45 - 18:00  |  Author(s): Edgar Vergara
    • Abstract
    • Slides

    Background
    

    The analysis by immunohistochemistry (IHC) of the programmed cell death-ligand 1 (PD-L1) protein expression is the most extensively explored biomarker for response to immunotherapy in non-small cell lung cancer (NSCLC). However, there are differences concerning diverse IHC assays and cut-off criteria: Pembrolizumab with the 22C3 assay with cut-off ranges of >1%, 1-49% and >50%; and Nivolumab with the 28-8 assay and ranges of <1%, 1-5%, 5 -10% and >10%. Furthermore, there is lack of information regarding the association between the histological subtype of adenocarcinoma and PD-L1 expression. In this work, we assessed the frequency of PD-L1 expression according with to histological subtype of adenocarcinoma.

    a9ded1e5ce5d75814730bb4caaf49419 Method
    

    PD-L1 expression was assessed using the PD-L1 IHC 22C3 pharmDx immunohistochemistry assay (Dako North America, Inc.). We correlated histological subtype of adenocarcinoma with the frequency and intensity of PD-L1 expression, smoking history, EGFR and ALK status.

    4c3880bb027f159e801041b1021e88e8 Result
    

    Tissue samples from one hundred and sixty-two were analyzed, of which 33 (20.4%) were excluded due to insufficient material for PD-L1asessment. Among them, 106 patients (71,55%) were female, the median age was 63 years (range 31-86 years), 69 (53.5%) were never-smokers with no exposition to wood smoke or asbestos (79,61.2% and 117, 90.7% respectively). Among the 129 adenocarcinomas, 31.0% were acinar histological subtype; 27.1% solid, 17.1% papillary, 3.9% lepidic, 1.6% micropapillary and 54.3% had a moderated tumor differentiation grade. According to PD-L1 score, 49 (38%) of the patients were classified as negative (PD-L1<1%), 71(55%) as poor PD-L1 expression (1 - 49%), and 9 (7%) as strong PD-L1 expression (≥50%). According to the IASLC/ATS adenocarcinoma histological subtype was associated with PD-L1 expression (p=0.003). Solid and acinar adenocarcinomas were more likely to present strong PD-L1 expression (55.6% & 33.3%, respectively) compared to lepidic, papillary, micropapillary and unspecified tumors, which presented a strong PD-L1 expression in up to 11.1%. Median PFS to first line therapy was 10.3 (95% CI: 6.1–14.5) months. Tobacco exposure was the only factor independently associated with an increase in the hazard of progression to first line therapy (either CT or TKI) from any cause among NSCLC patients (HR, 95% CI: 1.56-12.1). The median OS was 41.9 (95% CI: 10.9–72.9) months. Median OS differences were not found among PD-L1 (negative vs. positive: 60.6 vs. 31.3 months, p=0.685).

    8eea62084ca7e541d918e823422bd82e Conclusion
    

    Patients with adenocarcinoma tumors, solid histological subtype and poor differentiation grade can be more benefited with a PD-1 based immunotherapy. PD-L1 score can be a predictor factor for the response to first line chemotherapy.

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