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

Abstract

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. 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). 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%). 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.