Serum Antibody Against NY-ESO-1 and XAGE1 Antigens Potentially Predicts Clinical Responses to Anti-Programmed Cell Death-1 Therapy in NSCLC.

INTRODUCTION: Programmed cell death-1 (PD-1) inhibitors effectively treat NSCLC and prolong survival. Robust biomarkers for predicting clinical benefits of good response and long survival with anti-PD-1 therapy have yet to be identified; therefore, predictive biomarkers are needed to select patients with benefits. METHODS: We conducted a prospective study to explore whether serum antibody against NY-ESO-1 and/or XAGE1 cancer-testis antigens predicted primarily good clinical response and secondarily long survival with anti-PD-1 therapy for NSCLC. The serum antibody was detected by enzyme-linked immunosorbent assay, and tumor immune microenvironment and mutation burden were analyzed by immunohistochemistry and next-generation sequencing. RESULTS: In the discovery cohort (n = 13), six antibody-positive NSCLC cases responded to anti-PD-1 therapy (two complete and four partial responses), whereas seven antibody-negative NSCLC cases did not. Antibody positivity was associated with good response and survival, regardless of tumor programmed death ligand 1 (PD-L1) expression, mutation burden, and CD8+ T-cell infiltration. In the validation cohort (n = 75), 17 antibody-positive NSCLC cases responded well to anti-PD-1 therapy as compared with 58 negative NSCLC cases (objective response rate 65% versus 19%, p = 0.0006) and showed significantly prolonged progression-free survival and overall survival. Antibody titers highly correlated with tumor reduction rates. In the multivariate analysis, response biomarkers were tumor programmed death ligand 1 expression and antibody positivity, and only antibody positivity was a significantly better predictive biomarker of progression-free survival (hazard ratio = 0.4, p = 0.01) and overall survival (hazard ratio = 0.2, p = 0.004). CONCLUSIONS: Our results suggest that NY-ESO-1 and/or XAGE1 serum antibodies are useful biomarkers for predicting clinical benefits in anti-PD-1 therapy for NSCLC and probably for other cancers.

Survival of Lung Adenocarcinoma Patients Predicted from Expression of PD-L1, Galectin-9, and XAGE1 (GAGED2a) on Tumor Cells and Tumor-Infiltrating T Cells.

The immune status of tumors varies, and this may affect the overall survival (OS) of patients. We examined tumors from 120 patients with lung adenocarcinomas with a tissue microarray for T-cell infiltration and the expression of PD-L1 and Galectin-9 (both ligands for inhibitory receptors on T cells), and cancer/testis (CT) antigen XAGE1 (GAGED2a; a tumor antigen often found on lung tumors) expression, to determine their relevance to OS. Patients defined as pStage I-IIIA could be grouped, based on the expression profiles of PD-L1, Galectin-9, and XAGE1, into cluster A, who had prolonged survival, and cluster B, who had shorter survival. The difference in survival of the clusters was confirmed separately for pStage I and pStage II-IIIA patients. Cluster A patients who also had CD4 and CD8 T-cell infiltration showed even better survival, as expected. The findings were confirmed by examining an independent validation cohort of 68 pStage I lung adenocarcinoma patients. Our data showed that PD-L1 expression was a positive indicator, whereas Galectin-9 and XAGE1 expression was negative. In vitro analyses suggested that PD-L1 expression was upregulated by IFNγ secreted from activated T cells in the tumor and Galectin-9 expression was counteracting those T cells. Thus, use of these immune markers enables the creation of a discriminant function with which to classify tumors and predict survival. Cancer Immunol Res; 4(12); 1049-60. ©2016 AACR.