EGFR-TKI rechallenge in patients with EGFR-mutated non-small-cell lung cancer who progressed after first-line osimertinib treatment: A multicenter retrospective observational study

Background: Rechallenge therapy with epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) is known to confer some clinical benefit for patients with metastatic EGFR-mutated non-small cell lung cancer (NSCLC). However, little is known about the efficacy of EGFR-TKI rechallenge after resistance to first-line (1L) osimertinib. This study aimed to assess the efficacy and safety of EGFR-TKI rechallenge therapy after resistance to 1L osimertinib in a Japanese clinical setting. Methods: Between April 2018 and August 2022, 26 patients who progressed after treatment with 1L osimertinib and received EGFR-TKI rechallenge were included in this multicenter retrospective analysis. Patients in whom 1L osimertinib was discontinued owing to toxicity and had subsequent disease progression were also included in the analysis. Results: Overall, the objective response rate for rechallenge therapy was 23.1%. The disease control rate was 53.9%, and the median progression-free survival (PFS) was 3.4 months. Patients who discontinued 1L osimertinib for toxicity had a higher response rate (42.9% vs. 15.8%) and longer PFS than those who discontinued it due to disease progression (median: 11.4 vs. 2.7 months, P = 0.001). Three patients (11.5%) developed rechallenge therapy-associated pneumonitis, two of which were grade >= 3. Conclusions: Rechallenge with EGFR-TKI after 1L osimertinib resistance showed limited clinical efficacy. However, it could be considered as a subsequent salvage therapeutic option for patients in whom 1L osimertinib was discontinued owing to toxicity.