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Margueritta El Asmar

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    MA04 - Novel Approaches with IO (ID 900)

    • Event: WCLC 2018
    • Type: Mini Oral Abstract Session
    • Track: Immunooncology
    • Presentations: 1
    • Moderators:
    • Coordinates: 9/24/2018, 13:30 - 15:00, Room 107
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      MA04.11 - Neoantigen Targeting and T Cell Reshaping in Resectable NSCLC Patients Treated with Neoadjuvant PD-1 Blockade (ID 12605)

      14:40 - 14:45  |  Author(s): Margueritta El Asmar

      • Abstract
      • Presentation
      • Slides


      PD-1 blockade is now standard treatment for advanced non-small cell lung cancer (NSCLC) and has recently shown impressive efficacy in promoting major pathologic response (MPR) and delaying relapse in the neoadjuvant setting. The role of tumor mutational burden, and specifically T cells targeting neoantigens derived from these mutations, in facilitating tumor clearance has been demonstrated in advanced NSCLC. However, it is unknown how neoadjuvant PD-1 blockade impacts the frequency and function of tumor specific T cells and their ability to promote major pathologic response, or how these factors may synergize to prevent or delay relapse after surgical resection.

      a9ded1e5ce5d75814730bb4caaf49419 Method

      Whole exome sequencing and neoantigen prediction was performed on pre-treatment tumor biopsies and matched normal tissue from 11 patients with resectable NSCLC treated with neoadjuvant nivolumab as part of a clinical trial (NCT02259621). T cell recognition of peptides representing candidate neoantigens was evaluated using the MANAFEST assay, which identifies T cell receptor clonotypes corresponding to antigen specificities. T cell receptor sequencing was additionally performed on serial peripheral blood T cells, pre-treatment tumor biopsies, and resected post-treatment tissues. A bioinformatic platform was developed to evaluate the dynamics of intratumoral T cell clonotypes, and more specifically neoantigen-specific clonotypes detected before, during, and after treatment and during long-term follow-up.

      4c3880bb027f159e801041b1021e88e8 Result

      High-magnitude, polyclonal neoantigen-specific T cell responses were detected in the peripheral blood and persisted for many months after surgical resection and cessation of treatment. Binding to and stability with cognate HLA I molecules was validated for reactive neoantigens. Significant treatment-induced systemic perturbations in the tumor-specific T cell repertoire and an influx of peripheral T cell clonotypes into tumor tissue and lymph nodes was observed in patients regardless of pathologic response, whereas peripheral clonotypic reshaping of the anti-tumor repertoire and intratumoral T cell clonality were associated with MPR status.

      8eea62084ca7e541d918e823422bd82e Conclusion

      We show significant and systemic alterations in the peripheral anti-tumor T cell repertoire in NSCLC patients treated with neoadjuvant anti-PD-1 regardless of MPR status. Notwithstanding, the impaired restructuring of the anti-tumor T cell repertoire in patients without MPR highlights a potential immunological deficiency to overcome in future therapeutic approaches aiming to increase the MPR rate in NSCLC patients treated with neoadjuvant PD-1 blockade.


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