EGFR exon 20 insertions mutation in lung adenocarcinoma and its response by high-dose of Furmonertinib: a real-world study

BackgroundLUAD patients with EGFR exon 20 insertions (ex20ins) have a poorer prognosis than those with EGFR 19del or L858R mutations. The FAVOUR study showed high-dose furmonertinib's efficacy in ex20ins patients. However, more real-world data are needed to validate these findings.MethodsWe summarized LUAD patients who underwent NGS testing at Henan Cancer Hospital from January 1, 2020, to December 31, 2022. We then reviewed cases of patients with EGFR exon 20 insertion (ex20ins) mutations who received high-dose furmonertinib (240 mg/day) and had follow-up data. We assessed the objective response rate (ORR), disease control rate (DCR), progression-free survival (PFS), time to treatment failure (TTF), overall survival (OS), and treatment-related adverse events (TRAEs).ResultsA total of 3,571 patients underwent NGS testing, with 1,632 (45.70%) identified as having EGFR mutations, including 87 (2.44%) with exon 20 insertions (ex20ins). Follow-up data were complete for 21 ex20ins patients treated with 240 mg/d of furmonertinib. Thirteen had prior treatments, including targeted therapy, and four had received EGFR-TKI. By March 1, 2024, 18 patients progressed, and 13 died. The ORR was 52.40% (11/21), DCR was 100%, median PFS was 6.15 months, TTF was 10.78 months, and OS was 21.67 months. Among the 18 progressing patients, 11 had neurological progression, six had thoracic progression, and two had liver progression. Diarrhea was the most common adverse event, and no patients discontinued treatment due to AEs.ConclusionsAmong LUAD patients, 2.44% harbored EGFR exon 20 insertions (ex20ins), and furmonertinib at 240 mg/d demonstrated efficacy and was well-tolerated in this real-world study of LUAD patients with EGFR ex20ins mutations.