P76.37 Comprehensive Investigation of Uncommon EGFR Mutations in 14,429 Chinese Lung Cancer Patients

EGFR uncommon alterations in advanced non-small cell lung cancer and structural insights into sensitivity to diverse tyrosine kinase inhibitors

Background: Approximately 10% of patients with non-small cell lung cancer (NSCLC) harbor uncommon epidermal growth factor receptor (EGFR) alterations. This study aims to investigate the therapeutic responses and predict the binding activity of different tyrosine kinase inhibitors (TKIs) for EGFR uncommon alterations.

Methods: Between May 2014 and June 2021, clinical outcomes of NSCLC patients harboring EGFR uncommon alterations who received diverse treatment modalities: first-generation (1G) EGFR-TKI, second-generation (2G) EGFR-TKI afatinib, chemotherapy, and 1G TKI in combination with chemotherapy as the initial therapy were retrospectively analyzed, and structural analysis for the binding activity of major uncommon subtypes G719A, S768I, and L861Q to different TKIs were predicted.

Results: A total of 102 NSCLC patients harboring EGFR uncommon alterations with treatment and survival outcomes were included and analyzed. The majority of patients presented compound mutations (54.9%), and G719X plus S768I was the predominant subtype (n = 33, 32.3%). There was a significant difference in median progression-free survival (mPFS) between therapeutic patterns (p = 0.015) and EGFR alteration subtypes (p = 0.017). Rather than almonertinib and furmonertinib, afatinib, dacomitinib and osimertinib revealed favorable binding activity to G719A mutation. In contrast, S768I and L861Q mutation indicated an unaffected binding activity to these diverse kinds of EGFR TKIs.

Conclusion: Together with afatinib, 1G-TKIs combined with chemotherapy might be another effective option for NSCLC patients harboring EGFR uncommon alterations. Based on computational findings, afatinib, dacomitinib, and osimertinib might confer favorable activity to G719A, S768I, and L861Q, whereas almonertinib and furmonertinib revealed less activity to G719A.

EGFR Exon 18 Mutations in Advanced Non-Small Cell Lung Cancer: A Real-World Study on Diverse Treatment Patterns and Clinical Outcomes

Background

Approximately 3–5% of patients with epidermal growth factor receptor (EGFR) mutation-positive non-small cell lung cancer (NSCLC) harbor exon 18 mutations. The appropriate treatment for such patients has not been clarified. The aim of this study was to investigate the response of patients with NSCLC harboring EGFR exon 18 mutations to different therapeutic options.

Methods

Between May 2014 and September 2020, the clinical outcomes of 82 patients harboring EGFR exon 18 mutations who received first-generation (1G) EGFR-tyrosine kinase inhibitor (TKI), second-generation (2G) EGFR-TKI afatinib, chemotherapy, and 1G TKI in combination with chemotherapy as the initial therapy were retrospectively analyzed.

Results

A total of 82 NSCLC patients harboring EGFR 18 mutations with whose treatment and survival outcomes were available were analyzed. The median age was 59 years, and 47 (57.3%) were female. The most common kind of EGFR exon 18 mutation was G719X (75.6%), followed by E709X (15.9%), E709_T710delinsD (3.6%), and other subtypes (4.9%). There was a significant difference in median progression-free survival (mPFS) by therapeutic strategy (P = 0.017). The mPFS of 1G TKI, 2G TKI afatinib, chemotherapy, and 1G TKI in combination with chemotherapy were 7.7 (95% CI, 4.2–11.2), 11.3 (95% CI, 5.6–17.0), 5.0 (95% CI, 2.3–17.7), and 11.1 (95% CI, 5.9–16.4) months, respectively. No significant difference in PFS was observed between afatinib and 1G TKI in combination with chemotherapy (P = 0.709).

Conclusions

Like afatinib, 1G TKI in combination with chemotherapy might be an effective treatment option for patients harboring EGFR exon 18 mutations.