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C. Teixido



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    P1.07 - Immunology and Immunotherapy (ID 693)

    • Event: WCLC 2017
    • Type: Poster Session with Presenters Present
    • Track: Immunology and Immunotherapy
    • Presentations: 1
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      P1.07-015 - Interferon-Gamma (INFG) as a Biomarker to Guide Immune Checkpoint Blockade (ICB) in Cancer Therapy (ID 8939)

      09:30 - 09:30  |  Author(s): C. Teixido

      • Abstract
      • Slides

      Background:
      PD-L1 is induced by oncogenic signals or via INFG. STAT3, through DNMT1, epigenetically silences STAT1 and RIG-I and opposes INFG signaling. TET1 is a DNA demethylase. I kappa B kinase epsilon (IKBKE), a noncanonical I-kappa-B kinase, is essential for INFG induction, but can also promote NFATc1 phosphorylation and T cell response inhibition. Eomesodermin (Eomes) regulates T cell exhaustion. CCL5 (or Rantes), dependent on STAT3, causes myeloid-derived suppressor cell (MDSC) recruitment. YAP1 can also drive MDSC recruitment via CXCL5 signaling. We have explored whether the expression of genes related to INFG signaling, T cell exhaustion and MDSC recruitment is associated with response to ICB.

      Method:
      Total RNA from pre-treatment tissue samples of 17 NSCLC and 21 melanoma patients treated with nivolumab and pembrolizumab respectively, was analyzed by qRT-PCR. INFG, STAT3, IKBKE, STAT1, RIG-I and PD-L1 mRNA were examined. CCL5, YAP1, CXCL5, NFATC1, EOMES and TET1 expression was additionally assessed. Gene expression was categorized with respect to tertiles and patients were divided into two risk groups (low and intermediate/high). CD8[+ ]tumor-infiltrating lymphocytes (TILs) and PD-L1 protein expression in tumor and CD8[+ ]TILs were examined by immunohistochemistry (SP57 and SP142 assay, respectively). Progression free survival (PFS), overall survival (OS) and Disease Control Rate (DCR) were estimated.

      Result:
      Seventeen NSCLC patients, previously treated with one or more prior systemic therapies, received nivolumab. IKBKE was positively correlated with INFG (r=0.65, p=0.0124) and PD-L1 (r=0.58, p=0.0225) expression. RIG-I was loosely anticorrelated with NFATc1 (r=-0.55, p=0.0518). Among all biomarkers explored, only INFG was associated with PFS, OS and DCR. Specifically, PFS was significantly longer for nivolumab-treated patients with intermediate/high versus low INFG expression (5.1 versus 2.0 months, p=0.0124). OS was longer (though not statistically significant) for patients with intermediate/high versus low INFG expression (10.2 versus 4.9 months, p=0.0687). DCR to nivolumab was 71.43% for patients with intermediate/high INFG versus 0% for patients with low INFG expression. Neither PD-L1 immunohistochemistry expression nor CD8[+ ]TILs were related to nivolumab outcome. The same results were observed for 21 melanoma patients treated with pembrolizumab.

      Conclusion:
      IFNG production by T-cells plays critical roles in anti-cancer immune responses by augmentation of MHC Class I expression, growth arrest, post-proteasomal trimming of antigen epitopes, recruitment of effector cells, induction of T-regs fragility and PD-L1 expression. Further research is warranted in order to validate whether INFG is more accurate than PD-L1.

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    P3.01 - Advanced NSCLC (ID 621)

    • Event: WCLC 2017
    • Type: Poster Session with Presenters Present
    • Track: Advanced NSCLC
    • Presentations: 1
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      P3.01-045 - Correlation of EGFR Mutation Detection in CtDNA by Two Different Platforms in Advanced NSCLC Patients from a Single Institution (ID 9475)

      09:30 - 09:30  |  Author(s): C. Teixido

      • Abstract

      Background:
      Circulating-free tumor DNA (ctDNA) has emerged as a sensitive and feasible non-invasive blood-based approach alternative to tissue biopsies to screen for genetic drivers in advanced non-small cell lung cancer (NSCLC) patients. Recently, the COBAS Mutation Test has been FDA-approved for the detection of EGFR mutation (EGFRm) in peripheral blood but other approaches are currently used in clinical practice. Here, we aimed to correlate two different platforms for EGFRm monitoring ctDNA in an enriched cohort of tissue-genetically phenotyped EGFRm advanced NSCLC patients.

      Method:
      Blood samples were prospectively obtained from an enriched cohort of EGFR+ advanced NSCLC patients. Formalin-fixed paraffin-embedded (FFPE) tumor was characterized by NGS (Ion AmpliSeq Lung Cancer Research Panel v.2) in all patients at diagnose. Plasma ctDNA derived from peripheral whole blood was evaluated by COBAS EGFR Mutation Test v2 and a Peptide Nucleic Acid (PNA) probe–based real-time polymerase chain reaction blinded to baseline tumor genotype. Diagnostic accuracy and concordance of both blood techniques was used for direct comparison with respect to the molecular status of FFPE tissue.

      Result:
      A total of 80 matched pairs of peripheral blood samples from 40 patients were collected. Baseline tissue NGS reported mutations at exon 19 del (n=23), exon 21 (n=10), exon 18 (n=2), exon 20 (n=2) and T790M (n=3). Four wild-type EGFR tumors were used as controls. Blood samples were obtained at diagnose (n=12) and during tyrosine-kinase inhibitor (TKi) treatment for monitoring (n=28). Overall, concordance between both blood-based techniques with respect tissue-NGS was 100% (4/4) for negative controls and 55% (20/36) for positive tissue-NGS samples. Detection based on PNA and COBAS was negative in 60% (24/40) and 32.5% (13/40) patients respectively. Among 19 samples negative by PNA at monitoring, COBAS allowed plasma EGFRm detection in 11 patients. At baseline, the only two negative samples patients by both techniques were found in patients with localized brain disease. Six patients had detectable driver T790M mutation; among three patients with T790M+ in tissue, COBAS allowed detection in plasma in one patient whereas none was identified with PNA. The other three patients had acquired T790M mutations identified only in blood, all by COBAS.

      Conclusion:
      In this prospective blinded validation cohort, both methods retained high specificity. However, major differences between techniques were observed for longitudinal monitoring of EGFRm in blood.