Tumor LAG-3 and NY-ESO-1 expression predict durable clinical benefits of immune checkpoint inhibitors in advanced non-small cell lung cancer

Background Immune checkpoint inhibitors (ICIs) are an established treatment for non-small cell lung cancer (NSCLC) that have demonstrated durable clinical benefits (DCBs). Previous studies have suggested that NY-ESO-1 and LAG-3 could be surrogate markers of ICI responses in NSCLC; therefore, we explored the predictive value of NY-ESO-1 and LAG-3 expression in NSCLC. Methods We retrospectively reviewed the records of 38 patients with advanced NSCLC treated with anti-PD-1 monoclonal antibodies from 2013 to 2016 at Seoul National University Hospital and Seoul National University Bundang Hospital after failed platinum-based chemotherapy. Tumor tissues from each patient were subjected to immunohistochemical analysis to determine NY-ESO-1, LAG-3, and PD-L1 expression, whose ability to predict progression-free survival (PFS) and overall survival (OS) was then analyzed alongside their positive (PPV) and negative (NPV) predictive values. Results NY-ESO-1 or LAG-3 expression was detected in all tumor samples from patients with high PD-L1 expression and was significantly associated with favorable patient outcomes, unlike PD-L1 expression. Patients whose tumors expressed both NY-ESO-1 and LAG-3 had a high DCB rate and those with triple-positive PD-L1, LAG-3, and NY-ESO expression had a superior median OS and PFS compared to those in patients with triple-negative expression. Furthermore, LAG-3 and NY-ESO-1 co-expression was an independent predictor of both PFS and OS, while LAG-3 displayed a good NPV. Conclusion Therefore, patients with NSCLC who co-express NY-ESO-1 or LAG-3 with PD-L1 exhibit greater DCBs and improved long-term survival following anti-PD-1 therapy. Moreover, NY-ESO-1 and LAG-3 could be novel predictive biomarkers of survival and should be considered in the future use of ICIs.