IMPORTANCE Immunotherapy with checkpoint inhibitors targeting the PD-1 (programmed cell death 1) axis has brought notable progress in patients with non-small cell lung cancer (NSCLC) and other cancers. However, autoimmune toxic effects are frequent and poorly understood, making it important to understand the pathophysiologic processes of autoimmune adverse effects induced by checkpoint inhibitor therapy. OBJECTIVE To gain mechanistic insight into autoimmune skin toxic effects induced by anti-PD-1 treatment in patients with non-small cell lung cancer. DESIGN, SETTING, AND PARTICIPANTS This prospective cohort study was conducted from July 1, 2016, to December 31, 2018. Patients (n = 73) with non-small cell lung cancer who received anti-PD-1 therapy (nivolumab or pembrolizumab) were recruited from 4 different centers in Switzerland (Kantonsspital St Gallen, Spital Grabs, Spital Wil, and Spital Flawil). Peripheral blood mononuclear cells, tumor biopsy specimens and biopsies from sites of autoimmune skin toxic effects were collected over a 2-year period, with patient follow-up after 1 year. MAIN OUTCOMES AND MEASURES Response to treatment, overall survival, progression-free survival, and development of autoimmune toxic effects (based on standard laboratory values and clinical examinations). RESULTS Of the cohort of 73 patients with NSCLC (mean [SD] age, 68.1 [8.9] years; 44 [60%] men), 25 (34.2% [95% CI, 24.4%-45.7%]) developed autoimmune skin toxic effects, which were more frequent in patients with complete remission or partial remission (68.2% [95% CI, 47.3%-83.6%]) than those with progressive or stable disease (19.6% [95% CI, 11.0%-32.5%]) (χ 2 = 14.02, P < .001). Nine T-cell antigens shared between tumor tissue and skin were identified. These antigens were able to stimulate CD8 + and CD4 + T cells in vitro. Several of the antigen-specific T cells found in blood samples were also present in autoimmune skin lesions and lung tumors of patients who responded to anti-PD-1 therapy. CONCLUSIONS AND RELEVANCE These findings highlight a potential mechanism of checkpoint inhibitor-mediated autoimmune toxic effects and describe the association between toxic effects and response to therapy; such an understanding will help in controlling adverse effects, deciphering new cancer antigens, and further improving immunotherapy.

Background: Checkpoint inhibitors (CIs) are highly effective but can induce severe immune-related adverse events (irAEs), which cannot be predicted. We investigated whether human leukocyte antigen (HLA) genes predispose to developing of irAEs during therapy and thus hold a predictive role. Methods: We established a prospective observational single-centre study and collected data from patients with either metastatic nonesmall cell lung cancer (NSCLC) or metastatic melanoma, who were treated with antiePD-1 (programmed cell death receptor 1), anti-CTLA4 (cytotoxic T-lymphocyteeassociated protein 4) or both CIs combined. Data include irAEs and ranges from 15th July 2016 until 10th May 2018. In addition, we performed HLA typing via next generation sequencing. Results: We enrolled 102 patients (median [range] age, 68 [62e74] years) with metastatic cancer in our study who received CI therapy. Of these patients, 59 (58%) developed one or more irAEs, among which pruritus (n Z 32 (54%)) and rash (n Z 24 (41%)) had the highest rates. We did not find evidence for a single HLA gene being associated with all irAEs (all P > .05). When assessing each irAE individually, we found a significant association between HLA-DRB1*11:01 and pruritus (OR Z 4.53, X 2 1,95 Z 9.45, P < .01) as well as a nominally

Background: Anti-programmed cell death protein 1 (PD1)/programmed death-ligand 1(PD-L1) therapy frequently entails immune-related adverse events (irAEs), and biomarkers to predict irAEs are lacking. Although checkpoint inhibitors have been found to reinvigorate T cells, the relevance of autoantibodies remains elusive.Objective: Our aim was to explore whether IgG autoantibodies directed against coexpressed antigens by tumor tissue and healthy skin correlate with skin irAEs and therapy outcome.Methods: We measured skin-specific IgG via enzyme-linked immunosorbent assay in patients with nonsmall cell lung cancer (NSCLC) who received anti-PD1/PD-L1 treatment between July 2015 and September 2017 at the Kantonsspital St. Gallen. Sera were sampled at baseline and during therapy after 8 weeks.Results: Analysis of publicly available tumor expression data revealed that NSCLC and skin coexpress BP180, BP230, and type VII collagen. A skin irAE developed in 16 of 40 recruited patients (40%). Only elevated anti-BP180 IgG at baseline significantly correlated with the development of skin irAEs (P = .04), therapy response (P = .01), and overall survival (P = .04). Limitations:The patients were recruited in a single tertiary care center.Conclusions: Our data suggest that the level of anti-BP180 IgG of NSCLC patients at baseline is associated with better therapy response and overall survival and with a higher probability to develop skin irAEs during anti-PD1/PD-L1 treatment.

Background: Long-term survival of stage IV melanoma patients has improved significantly with the development of immune checkpoint inhibitors (CIs). Reliable biomarkers to predict response and clinical outcome are needed. Methods: We investigated the role of melanoma-associated antibodies as predictive markers for CI therapy in two independent cohorts. In cohort 1, a prospective study, we measured specific antibodies before treatment, after one week and after six to nine weeks of treatment. Cohort 2 consisted of serum samples prior to CI therapy initiation. ELISA assays were performed to quantify specific IgG directed against melanocyte differentiation antigens tyrosinase-related proteins 1 and 2 (TRP1/TYRP1 and TRP2/TYRP2), glycoprotein 100 (gp100), MelanA/MART1, and the cancer-testis antigen NY-ESO-1. Response was defined as either complete or partial remission on CT scan according to RECIST 1.1. Results: In cohort 1, baseline levels of these antibodies were higher in the responder group, although statistical significance was only reached for NY-ESO-1 (p = 0.007). In cohort 2, significantly higher antibody baseline levels for MelanA/MART1 (p = 0.003) and gp100 (p = 0.029) were found. After pooling the results from both cohorts, higher levels of MelanA/MART1 (p = 0.013), TRP1/TYRP1 (p = 0.048), TRP2/TYRP2 (p = 0.047) and NY-ESO-1 (p = 0.005) specific antibodies at baseline were independently associated with response. Conclusions: Melanoma-associated antibodies may be candidate biomarkers for response and survival in metastatic melanoma patients being treated with CIs. These markers may be used to complement patient assessment, in combination with PD-L1 status, tumor-infiltrating lymphocytes and tumor mutational burden, with the aim to predict outcome of CI treatment in patients with metastatic melanoma. Trial registration: Ethikkommission Ostschweiz, EKOS 16/079 https://ongoingprojects.swissethics.ch/runningProjects_list. php?q=%28BASECID~contains~2016-00998%29&orderby=dBASECID.

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