Objectives: A minority of NSCLC patients benefit from anti-PD1 immune checkpoint inhibitors. A rational combination of biomarkers is needed. The objective was to determine the predictive value of tumor mutational load (TML), CD8+ T cell infiltration, HLA class-I and PD-L1 expression in the tumor. Materials and methods: Metastatic NSCLC patients were prospectively included in an immune-monitoring trial (NTR7015) between April 2016-August 2017, retrospectively analyzed in FFPE tissue for TML (NGS: 409 cancer-related-genes) and by IHC staining to score PD-L1, CD8+ T cell infiltration, HLA class-I. PFS (RECISTv1.1) and OS were analyzed by Kaplan–Meier methodology. Results: 30 patients with adenocarcinoma (67%) or squamous cell carcinoma (33%) were included. High TML was associated with better PFS (p = 0.004) and OS (p = 0.025). Interaction analyses revealed that patients with both high TML and high total CD8+ T cell infiltrate (p = 0.023) or no loss of HLA class-I (p = 0.026), patients with high total CD8+ T cell infiltrate and no loss of HLA class-I (p = 0.041) or patients with both high PD-L1 and high TML (p = 0.003) or no loss of HLA class-I (p = 0.032) were significantly associated with better PFS. Unsupervised cluster analysis based on these markers revealed three sub-clusters, of which cluster-1A was overrepresented by patients with progressive disease (15 out of 16), with significant effect on PFS (p = 0.007). Conclusion: This proof-of-concept study suggests that a combination of PD-L1 expression, TML, CD8+ T cell infiltration and HLA class-I functions as a better predictive biomarker for response to anti-PD-1 immunotherapy. Consequently, refinement of this set of biomarkers and validation in a larger set of patients is warranted.

Biomarker, Nivolumab, NSCLC, TMB, Tumor microenvironment
dx.doi.org/10.1007/s00262-020-02506-x, hdl.handle.net/1765/124864
Cancer Immunology, Immunotherapy: other biological response modifications
Department of Pulmonology

Hurkmans, D.P. (Daan P.), Kuipers, M.E. (Merian E.), Smit, J. (Jasper), van Marion, R, Mathijssen, A.H.J, Postmus, P.E. (Piet E.), … van der Burg, S.H. (2020). Tumor mutational load, CD8+ T cells, expression of PD-L1 and HLA class I to guide immunotherapy decisions in NSCLC patients. Cancer Immunology, Immunotherapy: other biological response modifications. doi:10.1007/s00262-020-02506-x