# EGFR exon 20 insertion

Source: https://onco.cc/terms/egfr-exon20-insertion/  
OnCo record `egfr-exon20-insertion` (Term). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

A rarer EGFR mutation (~2% of lung cancers) that does not respond to standard EGFR pills and needs its own drugs.

## Summary

EGFR exon 20 insertions are a rarer class of EGFR mutation in non-small-cell lung cancer, making up a minority of EGFR-mutant disease. Structurally the insertion blocks first- to third-generation EGFR tyrosine kinase inhibitors, so the standard EGFR pills that work for exon 19 deletions and L858R do not work here. Amivantamab with chemotherapy, tested in PAPILLON, is the first-line standard, and sunvozertinib, approved in 2025, is the oral option following the withdrawal of mobocertinib. Readers meet the term on the drug pages for amivantamab, mobocertinib and sunvozertinib and within the receptor tyrosine kinase activation pathway. It matters because it is the clearest example of an EGFR alteration that needs its own drugs rather than the class default.

## Fields

- Kind: Term
- Last checked: 2026-09-06

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Epidermal_growth_factor_receptor
- CHRYSALIS: amivantamab in EGFR exon 20 insertion-mutated non-small-cell lung cancer (Journal of Clinical Oncology 2021): https://doi.org/10.1200/JCO.21.00662

## Connected records

- cancers: [EGFR-mutated non-small-cell lung cancer](https://onco.cc/cancers/egfr-mutant-nsclc/), [Lung cancer (all types)](https://onco.cc/cancers/lung-cancer/), [Non-small-cell lung cancer](https://onco.cc/cancers/nsclc/)
- targets: [EGFR](https://onco.cc/targets/egfr/)
- drugs: [Amivantamab](https://onco.cc/drugs/amivantamab/), [Mobocertinib](https://onco.cc/drugs/mobocertinib/), [Sunvozertinib](https://onco.cc/drugs/sunvozertinib/)
- key papers: [Amivantamab in EGFR Exon 20 Insertion-Mutated Non-Small-Cell Lung Cancer Progressing on Platinum Chemotherapy: Initial Results From the CHRYSALIS Phase I Study](https://onco.cc/key-papers/paper-park-j-clin-oncol/)
- pathways: [Receptor tyrosine kinase activation](https://onco.cc/pathways/rtk-activation/)
- biomarkers: [EGFR exon 20 insertion](https://onco.cc/biomarkers/egfr-exon-20-insertion/), [HER2 (ERBB2) activating mutation](https://onco.cc/biomarkers/her2-mutation/)

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