Impact of First-Line Osimertinib and Other EGFR-Tyrosine Kinase Inhibitors on Overall Survival in Untreated Advanced EGFR-Mutated Non-small Cell Lung Cancer in Japan: Updated Data from TREAD Project 01.

Background: Osimertinib shows higher effectiveness than first-generation epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs) in the initial treatment of EGFR-mutated non-small cell lung cancer. However, its superiority in terms of overall survival in the Asian population, especially Japanese patients, remains uncertain.

Objective: To evaluate the survival benefit of osimertinib over other EGFR-TKIs in Japanese patients, using real-world data. METHODS : As part of the Tokushukai REAl-world Data project, a retrospective multi-institutional study across 46 hospitals in Japan was conducted to evaluate the overall survival of patients with advanced EGFR-mutated non-small cell lung cancer using propensity score matching. The study involved patients receiving osimertinib as the first-line treatment (1L-Osi), those initially treated with other EGFR-TKIs (1L-non-Osi), and those receiving osimertinib after initial EGFR-TKI treatment (2L/later-Osi) between April 2010 and December 2022 and followed up until April 2023.

Results: Among 1062 Japanese patients with EGFR-mutated non-small cell lung cancer, 416 (39.2%) received 1L-Osi, while 646 (60.8%) received 1L-non-Osi, including 139 (13.1%) who received 2L/later-Osi. Within these groups, 416 (39.2%), 293 (27.6%), and 75 (7.1%) patients received first-line EGFR-TKI treatment post-osimertinib approval as a later-line treatment in Japan (March 2016). After propensity score matching, the overall survival of the 1L-Osi group was comparable to that of the 1L-non-Osi group in the post-March 2016 subset (n = 283, 42.0 vs 42.4 months). Similar trends were observed in the Del19 and L858R subgroups. The median overall survival of the 2L/later-Osi group was notably long: 60.2 months post-March 2016 (n = 75). A subgroup analysis based on initial EGFR-TKI treatment in the 1L-non-Osi and 2L/later-Osi groups revealed no significant differences among the gefitinib, erlotinib, and afatinib groups.

Conclusions: Based on real-world data, osimertinib did not show a significant improvement in overall survival compared to other EGFR-TKIs as a first-line treatment for EGFR-mutated advanced non-small cell lung cancer in the Japanese (Asian) population.

Clinical trial registration: This study was registered at the University Hospital Medical Information Network Clinical Trials Registry on 9 March, 2023 (identification UMIN000050552).