Epidermal growth factor receptor (EGFR) exon 20 insertion mutants (EGFR ex20ins)

Epidermal growth factor receptor (EGFR) exon 20 insertion mutants are a heterogeneous group of oncogenic alterations found in approximately 1% to 12% of EGFR-mutant non-small cell lung cancers (NSCLC) (Source: Remon et al., Cancer Treatment Reviews, 2020). These mutations occur within the C-helix and the loop following the C-helix of the kinase domain, resulting in a stabilized active conformation that drives uncontrolled cell proliferation and survival through the MAPK and PI3K pathways (Source: NIH/NCI, 2024). Historically, these mutants have been challenging to treat because the structural changes in the ATP-binding pocket prevent effective binding of early-generation tyrosine kinase inhibitors (TKIs) like erlotinib or osimertinib (Source: Vyse and Huang, Signal Transduction and Targeted Therapy, 2019). Furthermore, the structural similarity between the mutant kinase domain and the wild-type EGFR kinase domain often leads to significant off-target toxicities when using non-selective inhibitors. Recent therapeutic advancements have introduced bispecific antibodies, such as amivantamab, which targets both EGFR and MET, and next-generation TKIs like sunvozertinib specifically engineered to overcome these structural hurdles (Source: FDA, 2021; Wang et al., Lancet Oncology, 2022). Accurate identification of these mutations via next-generation sequencing is critical for clinical decision-making, as they do not respond to standard EGFR-targeted therapies (Source: IASLC, 2023).

Other names

EGFR exon 20 insertionsERBB1 exon 20 insertionHER1 exon 20 insertionEGFR ex20insEGFR exon 20 ins

Small-molecule tyrosine kinase inhibition (TKI) and bispecific antibody-mediated receptor degradation and signaling blockade (Source: Meador et al., Journal of Thoracic Oncology, 2021).