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.