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Nivolumab response rate is 40% in metastatic melanoma. Few studies have evaluated pre-treatment biomarkers predictive of response. The aim of this study was to identify potential peripheral blood biomarkers associated with survival in patients with advanced melanoma treated with nivolumab. All advanced melanoma cases treated with anti-programmed cell death protein 1 (anti-PD1) over a 3-year period in the Dermato-Oncology Department, Nantes, France were identified. For each case, 9 potential blood biomarkers were identified. Bivariate and multivariate analyses, adjusted for the American Joint Committee on Cancer (AJCC) classification stage, Eastern Cooperative Oncology Group (ECOG) performance status, lactate dehydrogenase (LDH) level and failure to respond to first-line therapy, were used to test the association between biomarkers and overall survival (primary outcome) or progression-free survival (secondary outcome). Increased monocyte count, leukocyte/lymphocyte ratio and neutrophil/lymphocyte ratio were significantly associated with decreased overall survival after bivariate and multivariate analyses. Increased monocyte count was also significantly associated with decreased progression-free survival. These blood variables are easily measured and could help to predict patient response before the introduction of anti-PD1 therapy.

Therapeutic strategies using anti-PD-1-blocking antibodies reported unparalleled effectiveness for melanoma immunotherapy, but deciphering immune responses modulated by anti-PD-1 treatment remains a crucial issue. Here, we analyzed the composition and functions of the large Melan-A-specific T-cell repertoire in the peripheral blood of 9 melanoma patients before and after 2 months of treatment with anti-PD-1. We observed amplification of Melan-A-specific Vß subfamilies undetectable before therapy (thereafter called emerging Vß subfamilies) in responding patients, with a predominant expansion in patients with a complete response. These emerging Vß subfamilies displayed a higher functional avidity for their cognate antigen than Vß subfamilies not amplified upon anti-PD-1 therapy and could be identified by a sustained coexpression of PD-1 and TIGIT receptors. Thus, in addition to the emergence of neoantigen-specific T cells previously documented upon anti-PD-1 therapy, our work describes the emergence of high-avidity Melan-A-specific clonotypes as a surrogate marker of treatment efficacy. Cancer Res; 77(24); 7083-93. ©2017 AACR ., (©2017 American Association for Cancer Research.)