Influence of PD‐L1 expression on the efficacy of EGFR‐TKIs in EGFR ‐mutant non‐small cell lung cancer

BACKGROUND: Evidence on the influence of programmed death‐ligand 1 (PD‐L1) expression on the efficacy of epidermal growth factor receptor tyrosine kinase inhibitors (EGFR‐TKIs) in EGFR‐mutant non‐small cell lung cancer (NSCLC) patients is at variance. METHODS: A single‐center retrospective study was conducted to evaluate the influence of PD‐L1 expression on the efficacy of EGFR‐TKIs for NSCLC patients with EGFR mutation. Clinical information was retrieved from electronic medical records. The patients were divided into three subgroups according to PD‐L1 expression level: PD‐L1 < 1% (negative), PD‐L1 1%–49% and PD‐L1 ≥ 50%. The clinicopathological features, overall response rate (ORR), progression‐free survival (PFS) and comutation information were collected and compared between the three subgroups. RESULTS: A total of 117 patients were included. For PD‐L1 < 1%, PD‐L1 1%–49% and PD‐L1 ≥ 50% group, there were 39 (33.3%), 51 (43.5%) and 27 (23.0%) patients respectively, and the ORR was 43.2%, 64.0%, and 51.9%, respectively (p = 0.162), and the median progression‐free survival (mPFS) was 22.0 months (95% CI: 14.0–29.9 months), 15.4 months (95% CI: 8.9–21.8 months) and 13.0 months (95% CI: 10.6–15.3 months), respectively (log‐rank, p = 0.01). The mPFS was negatively correlated with PD‐L1 expression level (r = −0.264, p = 0.041) and PD‐L1 expression was an independent risk factor for worse PFS of EGFR‐TKIs in multivariate Cox regression. Patients with concurrent TP53 mutation had shorter PFS (p = 0.039) and the patients harboring both mutant TP53 and positive PD‐L1 had the shortest PFS (p = 0.006). CONCLUSIONS: The efficacy of EGFR‐TKIs was influenced by the baseline PD‐L1 expression. Higher PD‐L1 expression was associated with shorter PFS. The combined indicators of TP53 and PD‐L1 identified subgroups showing divergent benefits from EGFR‐TKIs.