WCLC 2025 - Posters & ePosters-EP.12.02 Efficacy and Safety of Firmonertinib for EGFR Exon 21 L858R Mutation-Positive NSCLC Patients With Brain Metastases

EP.12.02 Efficacy and Safety of Firmonertinib for EGFR Exon 21 L858R Mutation-Positive NSCLC Patients With Brain Metastases

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This study evaluates the efficacy and safety of firmonertinib, a pan-EGFR tyrosine kinase inhibitor (TKI) with high brain penetration, in treating non-small cell lung cancer (NSCLC) patients harboring the EGFR exon 21 L858R mutation and brain metastases. Brain metastases are common in advanced NSCLC with EGFR mutations, and patients with the L858R mutation typically have poorer outcomes compared to those with exon 19 deletions.  <br /><br />Ten patients from Tang-Du Hospital (median age 64, 60% female, 70% non-smokers) with brain metastases and the EGFR exon 21 L858R mutation were enrolled, all receiving first-line firmonertinib at either 80mg (60%) or 160mg (40%). Notably, 40% had a poor Eastern Cooperative Oncology Group performance status (ECOG PS 2). The median follow-up was 16.8 months.<br /><br />Results showed a high intracranial objective response rate (iORR) of 80% and intracranial disease control rate (iDCR) of 100%. The median intracranial progression-free survival (iPFS) and overall progression-free survival (PFS) were not reached, suggesting durable responses. Overall objective response rate (ORR) was 90% with 100% disease control. The 160mg dose group achieved 100% ORR and DCR, while all patients with ECOG PS 2 achieved partial responses both intracranially and overall. <br /><br />In terms of safety, treatment-related adverse events (TRAEs) were mild, with only Grade 1 events reported, including decreased white blood cells (10%), rash (20%), and nausea (20%). No Grade 2 or higher TRAEs were observed.<br /><br />In conclusion, firmonertinib demonstrated promising anti-tumor activity and a favorable safety profile in this difficult-to-treat NSCLC population with the EGFR exon 21 L858R mutation and brain metastases, including patients with poor performance status. Further studies could confirm these encouraging preliminary findings.

Asset Subtitle

Haichuan Su

Meta Tag

Speaker Haichuan Su

Topic Metastatic Non-small Cell Lung Cancer – Targeted Therapy

Keywords

firmonertinib

pan-EGFR tyrosine kinase inhibitor

non-small cell lung cancer

NSCLC

EGFR exon 21 L858R mutation

brain metastases

intracranial objective response rate

progression-free survival

Eastern Cooperative Oncology Group performance status

treatment-related adverse events