Effect of strong programmed cell death ligand-1 (PD-L1) expressions on clinical outcomes in advanced non-small cell lung cancer treated with third-generation epidermal growth factor receptor-tyrosine kinase inhibitors.

Abstract

e20500 Background: Third-generation tyrosine kinase inhibitors (TKIs) are the standard treatment for advanced epidermal growth factor receptor (EGFR) mutation-positive lung adenocarcinoma. In first/second generation EGFR-TKIs, strong programmed death ligand 1 (PD-L1) expression contributes to primary resistance, significantly affecting patient prognosis. Despite this, the relationship between PD-L1 expression levels and third-generation TKIs remains unclear. Methods: This retrospective cohort study reviewed patients with advanced NSCLC who received third-generation EGFR-TKIs as first-line systemic therapy at the Shandong Cancer Hospital between March 2019 and June 2022. The EGFR status of the patients was assessed using amplification refractory mutation system fluorescence quantitative polymerase chain reaction, and the PD-L1 expression level was evaluated using Dako 22 C3 immunohistochemical staining. The Kaplan–Meier method was used for survival analysis. The log-rank test was used to compare differences in survival curves between the two groups. Results: Overall, 150 patients were included in this study. PD-L1 expression was negative (PD-L1 tumor proportion score < 1%) in 89 cases, weak (1–49%) in 42 cases, and strong (≥50%) in 19 cases. The median follow-up period for the entire cohort was 22.12 months (median progression-free survival [mPFS]: 24.33 months); the median overall survival was not reached. mPFS for patients with negative, weak, and strong PD-L1 expressions was 23.60, 26.12, and 16.60 months, respectively. The mPFS for strong PD-L1 expression was significantly shorter than that for with weak PD-L1 expression but was not associated with negativity, particularly in the 19DEL and 21L858R subgroups. PFS was significantly shorter in patients with strong PD-L1 expression in both subgroups (19DEL and 21L858R) than in those with weak PD-L1 expression. Conclusions: Strong PD-L1 expression in tumor cells influenced the clinical outcomes of patients with advanced NSCLC treated with third-generation EGFR-TKIs. Stronger PD-L1 expression in TKI-treated patients with advanced first-line EGFR-mutated NSCLC was associated with worse PFS.