WCLC 2025 - Posters & ePosters-EP.12.22 Clinical Treatment Outcomes of Erlotinib in Metastatic Non-Small Cell Cancer Harboring Uncommon EGFR Mutations

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This retrospective study at Chonburi Hospital (2020-2023) examined clinical outcomes in 193 treatment-naïve patients with metastatic non-small-cell lung cancer (NSCLC) harboring EGFR mutations treated first-line with erlotinib. Patients were stratified by EGFR mutation types as common (89.6%), uncommon (10.3%), and compound mutations (4.1%). Mutation subtypes were identified using cobas EGFR Mutation Test v2 and real-time PCR.<br /><br />Common mutations included Exon 19 deletion (54.4%) and L858R in Exon 21 (35.2%), while uncommon mutations comprised G719X, S768I, Exon 20 insertions, and L861Q. Compound mutations combined various uncommon and common alterations.<br /><br />Erlotinib was administered at 150 mg daily until disease progression or intolerance, with response assessed every 1-3 months by imaging. Outcomes measured were objective response rate (ORR), progression-free survival (PFS), and overall survival (OS).<br /><br />Key findings showed significantly better outcomes for patients with common mutations, achieving median OS of 19.5 months, compared to only 6.0 months for uncommon mutations and 7.6 months for compound mutations (p=0.001). Compound mutations had modestly better OS than single uncommon mutations but were still inferior to common mutations.<br /><br />The study highlights that uncommon and compound EGFR mutations predict poorer responses and survival with erlotinib treatment. These results align with prior literature suggesting the need for mutation-tailored therapy. The authors advocate improved access to other EGFR TKIs such as afatinib and osimertinib, which have demonstrated efficacy in uncommon mutation subsets, to enhance clinical outcomes.<br /><br />In conclusion, erlotinib shows limited effectiveness in NSCLC patients with uncommon or compound EGFR mutations. Personalized approaches based on mutation type are essential to optimize targeted therapy strategies in this population. The study emphasizes the clinical importance of distinguishing mutation subtypes for appropriate treatment selection in EGFR-mutant NSCLC.

Asset Subtitle

Chalita Lagampan

Meta Tag

Speaker Chalita Lagampan

Topic Metastatic Non-small Cell Lung Cancer – Targeted Therapy

Keywords

metastatic non-small-cell lung cancer

NSCLC

EGFR mutations

erlotinib

common EGFR mutations

uncommon EGFR mutations

compound EGFR mutations

progression-free survival

overall survival

targeted therapy