Prognostic Implication of PD-L1 Expression on Osimertinib Treatment for<i>EGFR</i>-mutated Non-small Cell Lung Cancer
Toshihiro Shiozawa, Takeshi Numata, Tomohiro Tamura, Takeo Endo, Takayuki Kaburagi, Yusuke Yamamoto, Hideyasu Yamada, Norihiro Kikuchi, Kazuhito Saito, Masaharu Inagaki, Koichi Kurishima, Yasunori Funayama, Kunihiko Miyazaki, Nobuyuki Koyama, Kinya Furukawa, Hiroyuki Nakamura, Shinji Kikuchi, Hideo Ichimura, Yukio Sato, Ikuo Sekine, Hiroaki Satoh, Nobuyuki Hizawa
Abstract
BACKGROUND/AIM: Real-world data on the clinical outcomes of first-line osimertinib treatment for non-small cell lung cancer (NSCLC) with epidermal growth factor receptor (EGFR) mutations is lacking. This study aimed to reveal the treatment outcomes and prognostic factors of osimertinib as first-line therapy in clinical practice settings. PATIENTS AND METHODS: We retrospectively evaluated clinical outcomes of patients with EGFR-mutated NSCLC treated with osimertinib as first-line therapy across 12 institutions in Japan between August 2018 and March 2020. RESULTS: Among 158 enrolled patients, the objective response rate (ORR) was 68%, and the estimated median progression-free survival (PFS) was 17.1 months [95% confidence interval (CI)=14.5-19.7]. Subgroup analysis showed that PFS in the group with high programmed death-ligand 1 (PD-L1) expression was significantly shorter than that in groups with low or no PD-L1 expression (10.1 vs. 16.1 vs. 19.0 months; p=0.03). Univariate and multivariate analyses demonstrated that high PD-L1 expression was the only independent adverse prognostic factor of osimertinib outcome related to PFS (hazard ratio=2.71; 95%CI=1.26-5.84; p=0.01). In terms of anti-tumor response, there was no statistically significant correlation between PD-L1 expression and the ORR (67% vs. 76% vs. 65%; p=0.51). No significant correlation was also found between PD-L1 and the incidence of de novo resistance to osimertinib (p=0.39). CONCLUSION: Although PD-L1 expression was not associated with either the ORR or frequency of de novo resistance, high PD-L1 expression could be an independent adverse prognostic factor related to PFS in osimertinib treatment.