High-dose furmonertinib in combination with intraventricular chemotherapy for EGFR exon 20 insertion mutated lung adenocarcinoma with leptomeningeal metastasis.

• DOI: 10.1200/jco.2024.42.16_suppl.e20555
• Publication Date: 2024-07-03T20:03:01Z
• Authors: Shencun Fang; Hehui Fang; Ting Xu; Liangfeng Yang; Xiaoyue Wang; Na Liu; Xing Zhang; Bei Zhang
• Keywords: 03 medical and health sciences; 0302 clinical medicine

e20555 Background: Leptomeningeal metastasis (LM) is a severe complication of advanced lung adenocarcinoma (LUAD) and always has dismal prognosis. EGFR exon 20 insertion ( 20ins) the third most common mutations; however, there are currently no reports focusing on LM with 20ins, optimal therapy for these patients remains unclear. This retrospective study aimed to evaluate efficacy safety high-dose furmonertinib in combination intraventricular chemotherapy 20ins mutated LUAD LM. Methods: Weretrospectively enrolled 10 who had failed multiline treatment between May 2021 June 2023 at Nanjing Chest Hospital. All them confirmed by next generation sequencing. received via Ommaya reservoir. Furmonertinib was taken 160 mg once daily. The regimen consisted 30mg pemetrexed 5 dexamethasone administered twice weekly 2 weeks during consolidation phase, followed maintenance phase every 3-4 until disease progression or unacceptable toxicity, patient refusal. Results: median age 53.5 years (range: 39-66), six (60%) were males. Four (40%) an ECOG 3, 4. intracranial ORR (iORR) 60% (6/10) DCR (iDCR) 90% (9/10). PS improved 80% after treatment. With follow-up 9.3 months, progression-free survival (iPFS) 7.3 months (95% CI, 3.3-NR) overall (OS) 8.8 4.9-NR), respectively. Treatment related adverse events ≥ grade 3 occurred only patients, which nausea rash. Conclusions: tolerable breakthrough clinical harboring 20ins.