Clinical significance of ≥ 50% PD‐L1 expression with the SP263 monoclonal antibody in non‐small cell lung cancer patients

BACKGROUND: PD‐L1 expression in tumor cells has been associated with the efficacy of immune checkpoint inhibitors in non‐small cell lung cancer (NSCLC). The aim of this study was to explore correlations between smoking, genetic profiles, patient outcomes, and PD‐L1 expression in NSCLC. METHODS: PD‐L1 expression was evaluated in 241 surgically resected specimens by immunostaining and 50% was set as the cutoff value. RESULTS: Of the 241 tumors analyzed, a PD‐L1 tumor proportion score (TPS) of ≥ 50% was detected in 35 cases (14.5%) and a TPS of < 50% in 206 cases (85.5%). A PD‐L1 TPS ≥ 50% was significantly associated with smoking and EGFR wild‐type status (P < 0.001 and P = 0.039, respectively). Detailed assessment of smoking variables showed that total smoking duration was a predictor of a PD‐L1 TPS ≥ 50% (P = 0.001). Univariate and multivariate survival analyses revealed that patients with a PD‐L1 TPS ≥ 50% had poorer disease‐free and overall survival than those with a PD‐L1 TPS < 50% (P = 0.001 and P < 0.001, respectively). CONCLUSION: The incidence of a PD‐L1 TPS ≥ 50% was significantly higher in smoking and EGFR wild‐type NSCLC patients, particularly in long‐term smokers. A PD‐L1 TPS of ≥ 50% was an independent adverse prognostic factor for survival in patients with NSCLC.