Chen Y, et al. Target Oncol 2020.
BACKGROUND: Osimertinib is a standard therapy for advanced non-small cell lung cancer (NSCLC) patients with an acquired epidermal growth factor receptor (EGFR) T790M mutation; however, the exploration of clinical characteristics that may affect prognosis and long-term survival is still lacking.
OBJECTIVE: This retrospective study aimed to provide long-term survival data and explore meaningful prognostic factors in patients treated with osimertinib.
PATIENTS AND METHODS: A total of 246 patients with acquired EGFR T790M mutation who were treated with osimertinib were included in this study. Progression-free survival (PFS), overall survival from osimertinib initiation (OS1), overall survival from diagnosis of advanced disease (OS), and possible prognostic clinical features were analyzed.
RESULTS: The median PFS, OS1, and OS values were 12.17, 24.33, and 47.86 months, respectively. The median PFS of patients harboring EGFR exon 19 deletions/T790M (19del/T790M) and those harboring EGFR 21 L858R/T790M were 13.27 and 9.77 months (p = 0.001), respectively, while the median OS1 values were 25.03 and 18.30 months (p = 0.023), respectively; however, no significant difference was found in median OS (p = 0.060). Cox regression analysis revealed that coexisting mutation type and extrathoracic metastasis affected survival (PFS, OS1). In addition, gene biopsy specimen type (tissue or blood sample) was related to PFS (p = 0.032), which implied that liquid biopsy may be an independent poor prognostic factor.
CONCLUSIONS: This is the first reported survival analysis of osimertinib-treated Chinese patients, which indicates a median OS of 47.86 months. The EGFR T790M mutation is likely to coexist with 19del and indicate longer PFS and OS1 than EGFR 21 L858R/T790M. Additionally, the extrathoracic metastasis status and biopsy specimen type might also affect the survival of patients treated with osimertinib.