Comparing survival and treatment response of patients with acquired T790M mutation second-line osimertinib versus sequential treatment of chemotherapy followed by osimertinib: A real-world study

PURPOSE To investigate the survival benefit with first/second generation epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) and osimertinib in different treatment sequences. METHODS We retrospectively screened 3807 patients diagnosed with cancer between 2013 and 2019 at Kaohsiung Chang Gung Memorial Hospital. In total, 76 patients with EGFR T790M mutation who received osimertinib after re-biopsy or liquid biopsy were enrolled for the analysis. RESULTS The median progression-free survival (PFS), median overall survival (OS), and median OS2 of the 76 patients were 11.93, 66.53, and 29.57 months, respectively. A significant difference was observed in the disease control rate between those who received osimertinib treatment after chemotherapy (group A) and those who received osimertinib immediately following EGFR-TKI therapy (group B) (34 [94.4%] vs. 31 [77.5%], p = 0.036). In addition, chronic obstructive pulmonary disease tended to be a poor prognostic factor for PFS and OS. CONCLUSION This real-world analysis revealed that previous chemotherapy could affect the treatment outcomes of patients with non-small cell lung cancer treated with osimertinib. Osimertinib treatment following first/second generation EGFR-TKI treatment or chemotherapy resulted in improved survival benefit.