The ratio of T790M to EGFR-activating mutation predicts response of osimertinib in 1st or 2nd generation EGFR-TKI-refractory NSCLC

Efficacy of epidermal growth factor receptor tyrosine kinase inhibitor in the treatment of patients with nonsmall cell lung cancer

This study aimed to examine the effectiveness of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) in treating patients with nonsmall cell lung cancer (NSCLC), and the association between clinical characteristics and effectiveness. This retrospective study included 140 patients with NSCLC admitted to our hospital between July 2020 and July 2022. The patients were categorized into 2 groups according to the treatment that they received: a comparison group (67 patients) and a research group (73 patients). The comparison group received conventional chemotherapy, and the research group received conventional chemotherapy and EGFR-TKI-targeted therapy. The immune and tumor marker levels, clinical response, and relationship between clinical characteristics and response to therapy were compared between the 2 groups before and after treatment. After treatment, the levels of neuron-specific enolase and carcinoembryonic antigen (CEA) and CD8+ count were significantly lower, and forced vital capacity, forced expiratory volume in 1 second, and CD4+ count were significantly higher in the research group than in the comparison group. After treatment, the clinical effectiveness in the 2 groups significantly improved, and the disease control rate in the research group was significantly higher than that in the comparison group (89% vs 69%, P = .014). The bivariate analysis revealed that smoking history, ECOG Performance Status score, and CEA level were significantly associated with clinical effectiveness. Conventional chemotherapy combined with EGFR-TKI-targeted therapy is effective in patients with NSCLC and has a clinically significant effect on improving patients' immune function and lung function.

Epidermal growth factor receptor tyrosine kinase inhibitors for de novo T790M mutation: A retrospective study of 44 patients

Background

This study aimed to evaluate possible treatment strategies for patients with de novo T790M mutation‐positive (T790M+) non‐small‐cell lung cancer (NSCLC).

Methods

Patients diagnosed with de novo T790M+ NSCLC and treated with epidermal growth factor receptor tyrosine kinase inhibitors (EGFR‐TKIs) between 2011 and 2018 at a regional hospital in Taiwan were retrospectively reviewed. Their clinicopathological characteristics and subsequent treatment information were collected, and potential prognostic factors were identified using univariate and multivariate analyses.

Results

All tumors with T790M mutations coexisted with sensitizing mutations. Through the last follow‐up in May 2021, afatinib and osimertinib demonstrated better progression‐free survival (PFS, p < 0.01) and overall survival (OS, p < 0.01) than gefitinib and erlotinib. Additionally, patients with low T790M ratios had better PFS than those with high T790M ratios, implying that the proportion of T790M+ tumors determined the response to EGFR‐TKIs. Multivariate analysis confirmed that both EGFR‐TKI treatment (osimertinib hazard ratio [HR] 0.06, 95% confidence interval [CI] 0.01–0.30; afatinib HR 0.09, 95% CI 0.02–0.39) and a low T790M ratio (HR 0.29, 95% CI 0.12–0.69) were independently favorable prognostic factors for patients with de novo T790M+ NSCLC. Median PFS was 6.1 (95% CI 4.4–7.8) months. In addition, patients treated with first‐generation (1G)/second‐generation (2G) EGFR‐TKIs followed by osimertinib (n = 8) demonstrated the best OS compared with patients treated with frontline osimertinib (n = 5) or 1G/2G EGFR‐TKIs without osimertinib (n = 28, p < 0.01).

Conclusion

Sequential TKIs may represent an alternative option for de novo T790M mutation, particularly frontline afatinib and tumors with low T790M ratios.