33P Real-world data of furmonertinib for patients with advanced non-small cell lung cancer with EGFR exon 20 insertion mutations

EGFR exon 20 insertions (ex20ins) -positive non-small cell lung cancer (NSCLC) is an uncommon disease with limited therapeutic options and a dismal prognosis. Furmonertinib is a novel 3rd generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor designed with a unique chemical structure to improve potency and specificity targeting various EGFR mutations and has been verified its superior efficacy and favorable safety profile in previous studies. We performed this study to investigate the efficacy and safety of furmonertinib for advanced NSCLC patients harboring EGFR ex20ins mutations. We retrospectively collected data of metastatic NSCLC patients with EGFR ex20ins mutations treated with furmonertinib 80 mg or 160 mg once daily in our center in South China from June 2022 to May 2023. Progression-free survival (PFS), objective response rate (ORR), and treatment-related adverse events (TRAEs) were assessed. A total of 48 patients with EGFR ex20ins mutations were included, and the major insertion variants were H773V774ins (12. 5%) and V769D770insASV (14. 58%). Eleven patients showed partial response, 30 patients with stable disease and 3 showed progressive disease as the best response to furmonertinib (ORR 22. 92%, DCR 85. 42%). The median PFS (mPFS) in all patients was 7. 93 months (95%CI 6. 57-14. 8). Median PFS was not significantly different between patients who received furmonertinib 80mg or 160mg once daily (10. 4 vs 7. 53 months, P=0. 49), neither with significance in first-line setting or above (10. 4 vs. 6. 5 months, P=0. 069). Patients with brain metastases at baseline responded similarly to those without brain metastases (PFS 7. 93 vs. 6. 93 months, ORR 23. 81% vs. 22. 22%, P = 0. 29). Patients in the near loop region showed a better mPFS in the first-line setting than in the second-line or above (10. 2 vs 6. 5 months, P= 0. 043). No grade≥3 TRAEs were observed. Furmonertinib showed encouraging anti-tumor activity and an acceptable safety profile in NSCLC patients with EGFR ex20ins mutation.