Plasma GDF15 Levels Associated with Circulating Immune Cells Predict the Efficacy of PD-1/PD-L1 Inhibitor Treatment and Prognosis in Patients with Advanced Non-Small Cell Lung Cancer

Although increased plasma growth differentiation factor-15 (GDF15) levels have been reported in patients with various cancers, the predictive role of PD-1/PD-L1 inhibitors in advanced cancers remains unknown. This study aimed to investigate GDF15 levels as a predictive marker in advanced non-small cell lung cancer (NSCLC) treated with PD-1/PD-L1 inhibitors and analyze their association with immune cell populations. This study included 87 patients with advanced NSCLC receiving anti-PD-1/PD-L1 inhibitors between March 2018 and May 2020. Blood samples were obtained immediately before and months after PD-1/PD-L1 inhibitor administration. The objective response rate (ORR) was significantly higher in the low GDF15 than in the high GDF15 group (39.2