Osimertinib, a third-generation EGFR tyrosine kinase inhibitor: A retrospective multicenter study of its real-world efficacy and safety in advanced/recurrent non-small cell lung carcinoma

Background Osimertinib is recommended for T790M mutation-positive advanced non-small cell lung cancer (NSCLC) resistant to first- and second-generation epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs). Recently, some reports exist on the real-world use of osimertinib; however, reports involving third/later-line use are few. Hence, this study was conducted to evaluate the efficacy and safety of osimertinib used in various treatment lines for T790M-positive NSCLC patients. Methods This retrospective, observational, multicenter study included T790M-positive advanced/recurrent NSCLC patients treated with osimertinib from May 2016 to March 2018. The clinical characteristics, efficacy, and adverse events were retrospectively investigated. The Kaplan-Meier method was used to analyze progression-free survival (PFS) and overall survival (OS). PFS-associated clinical characteristics were evaluated using the Cox proportional hazards model. Results The objective response rate (ORR) and disease control rate (DCR) were 60.7% and 91.1%, respectively; the median PFS was 11.0 months. There were no significant differences in the median PFS for patients treated with osimertinib as second-line and third-/later-line (14.5 vs. 11.0 months respectively, P = 0.327). Analysis using the Cox proportional hazards model for clinical features affecting PFS also revealed no significant factors. Adverse events of grade >= 3 were reported in 15 patients (26.8%); the most common were anemia (n = 3) and cutaneous toxicity (n = 3). Grade 4 neutropenia was observed in one patient; any-grade pneumonitis was observed in six patients (10.7%), including one with grade 3 pneumonitis. Conclusions Osimertinib demonstrated efficacy even when administered as third-/later-line treatment to NSCLC patients. Osimertinib-related pneumonitis was observed more frequently than previously reported. Key points Significant findings of the study Osimertinib shows efficacy even as later-line treatment in T790M mutation-positive NSCLC patients previously treated with EGFR-TKIs. However, the incidence of >= grade 3 adverse events, especially pneumonitis, was higher than that previously reported by other studies. What this study adds Osimertinib was approved for previously EGFR-TKI-treated EGFR T790M-positive NSCLC. With the increasing frequency of its use as first-line treatment, this study provides valuable evidence for the efficacy and safety of osimertinib for previously EGFR-TKI-treated NSCLC.