Osimertinib is a third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) that has exhibited efficacy in patients with EGFR-mutant non-small cell lung cancer (NSCLC). Interstitial lung disease (ILD) is a fatal adverse event of osimertinib treatment, and it requires treatment discontinuation. There are few reports regarding the safety and efficacy of osimertinib re-challenge in patients who experienced osimertinib-induced ILD. This retrospective study assessed this treatment option. We retrospectively collected data for patients treated with osimertinib who developed ILD at Shizuoka Cancer Center from April 2016 to March 2020. ILD was diagnosed by two doctors based on imaging tests and blood tests to exclude other causes. Among 215 patients treated with osimertinib, 28 developed ILD. The median age of patients with ILD was 69.5 years (range, 39.0-80.0). In addition, 29% of patients were men, and 46% had a history of smoking. Eleven patients were re-administered EGFR TKIs, including eight patients treated with osimertinib and three patients treated with alternative EGFR TKIs. Among patients re-challenged with osimertinib, none who previously experienced grade 1 ILD exhibited ILD relapse, even with the same osimertinib dose and without the concurrent administration of systemic steroids. Meanwhile, one of the four patients who previously exhibited grade 2 ILD experienced despite a dose reduction for osimertinib and systemic steroid administration. For patients with EGFR-mutant NSCLC who experience grade 1 ILD during osimertinib therapy, osimertinib re-challenge may be suitable when no other treatments are available.
Keywords: Adverse event; Epidermal growth factor receptor; Epidermal growth factor receptor mutation; Interstitial lung disease; NSCLC; Osimertinib.