Amivantamab in advanced non–small cell lung cancer with epidermal growth factor receptor exon 20 insertion mutations: Real‐world data from the Italian ATLAS Registry

Background: The treatment landscape for metastatic non-small cell lung cancer (NSCLC) with EGFR exon 20 insertion (ex20ins) is rapidly evolving, with the development of specific targeted therapies. The bispecific antibody amivantamab is the new standard of care for this population but real-world safety and efficacy data are lacking. Methods: This is a multicenter, retrospective, observational study conducted on advanced NSCLC patients harboring EGFRex20ins who were included within the ATLAS Italian real-world registry between January and December 2024. Clinical-pathological features, treatment effectiveness, and safety outcomes were retrospectively collected and analyzed. Results: A total of 119 advanced NSCLC patients harboring EGFRex20ins mutations were included. Seventy-six (63.9%) and 24 (20.2%) received first-line platinum-based chemotherapy with or without immunotherapy, respectively. Overall 64 of 119 patients received single agent amivantamab in the subsequent lines. Treatment-related adverse events (TRAEs) of any grade and grade 3-4 were reported in 68.8% and 10.9%, respectively, including skin rash (56%, G3 9.4%), asthenia (9%), peripheral edema (8%), and infusion-related reactions (9.4%, G3 1.5%). Dose interruptions, reductions, and discontinuations due to TRAEs occurred in 20.3%, 12.5%, and 3.1% patients, respectively. The objective response rate was 37.5%, the DCR was 66.2%, the median progression-free survival (mPFS) was 9.6 months, and the median overall survival was 16.9 months under amivantamab. Among the 23 patients with brain metastasis, 13% achieved a partial intracranial (ic) response and 43.5% a stable disease. The ic mPFS was 11.6 months. Conclusion: This data confirms the efficacy and safety profile of amivantamab observed in the CHRYSALIS trial, showing a meaningful clinical benefit in a heavily pretreated real-world population.