Clinical Course After Initiation of Nivolumab Therapy in Patients with EGFR-Mutated Non-Small Cell Lung Cancer With or Without Pd-L1 Expression

摘要

Introduction Nivolumab has been reported to be more effective in the subset of non-squamous non-small cell lung cancer (NSCLC) patients with tumors harboring wild-type epidermal growth factor receptor (EGFR) and/or expressing programmed death ligand-1 (PD-L1). However, it is unclear whether PD-L1 expression influences the efficacy of nivolumab in patients with EGFR-mutated NSCLC. Therefore, tumor PD-L1 expression was evaluated in five patients with EGFR-mutated NSCLC who had been treated with nivolumab. Methods We have identified patients with NSCLC harboring EGFR gene mutation retrospectively out of a group of 23 consecutive patients treated with nivolumab at our hospital between January 2016 and March 2017. The tumors of patients with EGFR-mutated NSCLC who had received nivolumab treatment based on clinical judgment were analyzed retrospectively. Tumor PD-L1 expression was evaluated by measurement of the tumor proportion score (TPS) using a rabbit antihuman PD-L1 antibody (clone 22C3). Results Three patients received the treatment with nivolumab as second line treatment, and two patients received the treatment as third line treatment. One out of five patients had a response with treatment with nivolumab and that was the only patient with a positive PD-L1 expression (TPS of 80–90%). Conclusion The results of the present study suggest that evaluation of tumor PD-L1 expression might be useful for predicting the efficacy of nivolumab, even in patients with EGFR-mutated NSCLC.