Real-world treatment outcomes before and after chemoimmunotherapy approval in EGFR-mutant NSCLC after EGFR-TKI failure: a Japanese cohort study

Background: In Japan, chemoimmunotherapy was approved as treatment for advanced or recurrent non-small-cell lung cancer (NSCLC), including for patients with epidermal growth factor receptor (EGFR) mutations, in December 2018. However, the impact of its approval on real-world clinical outcomes among patients with EGFR-mutant NSCLC remains unclear. The aim of our study was to assess that impact. Methods: We retrospectively assessed consecutive patients with advanced or recurrent EGFR-mutant NSCLC who received platinum-based cancer therapy after EGFR-tyrosine kinase inhibitors (TKIs) at 20 institutions in Japan from January 2017 to July 2022. Results: We evaluated 120 (27.2%) patients before the chemoimmunotherapy approval and 321 (72.8%) after. Overall, no significant differences in progression-free survival (PFS) or overall survival (OS) were observed between the pre- and post-approval groups (p = 0.72 and p = 0.89, respectively). In the subgroup with programmed cell death-ligand 1 (PD-L1) expression ≥ 50%, the post-approval group had a significantly longer PFS (p = 0.007) and OS (p = 0.048) than the pre-approval group. In contrast, in the PD-L1 < 50% cohort, no significant differences in the PFS (p = 0.54) or OS (p = 0.75) were noted between the groups. Conclusions: The approval of chemoimmunotherapy did not affect treatment outcomes among patients with EGFR-mutant NSCLC who received platinum-based therapy after EGFR-TKIs. However, patients with high levels of PD-L1 expression had improved outcomes post-approval, suggesting potential benefits in this subgroup.