Clinical outcomes in patients with non-small cell lung cancer harboring EGFR Exon20 in-frame insertions in the near-loop and far-loop: Results from LC-SCRUM-Asia

Objectives: In this study, we explored the clinical outcomes of non-small cell lung cancer (NSCLC) patients with EGFR Exon20 in-frame insertions (Exon20ins), and the impact of the location of Exon20ins on these clinical outcomes. Materials and methods: The efficacies of current systemic therapies in NSCLC patients harboring Exon20ins were investigated using a large-scale clinico-genomic database of LC-SCRUM-Asia, and compared with that of amivantamab in the CHRYSALIS trial. Results: Of the 11,397 patients enrolled in LC-SCRUM-Asia, Exon20ins were detected in 189 patients (1.7 %). Treatment with classical EGFR tyrosine-kinase inhibitors (classical TKIs) was associated with a significantly shorter progression-free survival (PFS) in NSCLC patients with Exon20ins as compared with Exon19 deletions and L858R. Post platinum-based chemotherapy, classical TKIs and immune checkpoint inhibitors (ICIs) were associated with a shorter PFS than with docetaxel in patients with Exon20ins (HR [95 % CI]; TKIs vs docetaxel, 2.16 [1.35–3.46]; ICIs vs docetaxel, 1.49 [1.21–1.84]). Patients treated with amivantamab in the CHRYSALIS trial showed a risk reduction in PFS and overall survival as compared with LC-SCRUM-Asia patients treated with docetaxel, classical TKIs, or ICIs. Among the 189 patients, Exon20ins were classified as near-loop or far-loop insertions in 115 (61 %) and 56 (30 %) patients, respectively. Treatment with osimertinib was associated with a longer PFS in patients with Exon20ins in near-loop as compared with far-loop (median, 5.6 vs. 2.0 months; HR [95 % CI], 0.22 [0.07–0.64]). Conclusions: After platinum-based chemotherapy, classical TKIs and ICIs are less effective in NSCLC patients with Exon20ins, and amivantamab may be a promising targeted therapy. There is a possibility that the location of Exon20ins has an impact on the efficacy of TKIs.