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Mario Colombo



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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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      MA04.06 - PD-1 Blockade Promotes Hyperprogressive Disease inĀ NSCLC Through Macrophages Activation via Antibody-Fc/FcR Interaction (ID 12334)

      14:05 - 14:10  |  Author(s): Mario Colombo

      • Abstract
      • Presentation
      • Slides

      Background

      In a subset of patients, named hyperprogressors (HPs), immunotherapy seems to paradoxically boost tumor growth. However, neither pathological and clinical features nor the underlying biological mechanism have been identified. We dissected the role of tumor-myeloid cells crosstalk as possible players.

      a9ded1e5ce5d75814730bb4caaf49419 Method

      HPs were defined on the basis of clinical and radiological features. Baseline histological samples from patients treated with immune checkpoints inhibitors (ICI) were evaluated by immunohistochemistry for myeloid and lymphoid markers. We tested the effect on tumor growth of murine and human ICI in T-cell deficient mice injected with human lung cancer cell lines and PDXs bearing different genotypes (EGFR+, KRAS+, STK11+ and wt). Innate immune microenvironment was evaluated by FACS analysis and immunohistochemistry. In vitro studies of ICI binding functional modulation were performed in human myeloid cells from patients and healthy donors.

      4c3880bb027f159e801041b1021e88e8 Result

      In a clinical series of 187 patients treated with ICI, hyperprogression was observed in 40 (26.3%) cases. All available HP pre-treatment tissue samples (11 cases) showed CD163+CD33+PD-L1+Arginase-A1+ clustered epithelioid macrophages infiltrating the tumor foci also expressing FcRs including CD32b. No differences in T cell compartment were observed. Murine and human PD1 blocking mAbs induced a boost of tumor growth in H460 xenografs in imunocompromised mice. A similar effect was observed in EGFR+ but not in KRAS+ and wt PDXs treated with human anti-PD1. Notably, no hyperprogression was observed after treatment with murine and human anti PD-1 F(ab)2. Hyperprogressive tumors were enriched in arginase+ myeloid-macrophage cells and fibrotic features. ICI bind in vitro to human macrophages and monocytes via Fc/FcR interactions, likely involving CD32b (FcgRIIb) and triggering functional polarization.

      8eea62084ca7e541d918e823422bd82e Conclusion

      Our results provide evidence that FcR triggering on macrophages by ICI delivers a signaling cascade promoting a functional reprogramming of these cells toward a more aggressive pro-tumorigenic behavior eventually inducing hyperprogression in a subset of patients with distinctive immune and genetic profile. A validation prospective study in ongoing.

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