# EGFR exon 20 insertion

Source: https://onco.cc/biomarkers/egfr-exon-20-insertion/  
OnCo record `egfr-exon-20-insertion` (Biomarker). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Exon 20 insertions add amino acids after the C-helix of EGFR and make the kinase resistant to the usual EGFR tablets. They account for about a tenth of EGFR mutations and have their own drugs: amivantamab with chemotherapy and sunvozertinib.

## Summary

In-frame insertions or duplications in exon 20 (A767_V769dup, D770_N771insSVD and others) are structurally distinct from the classical mutations and do not respond to first- or third-generation TKIs at tolerated doses. Amivantamab is labelled with carboplatin and pemetrexed for first-line NSCLC with EGFR exon 20 insertion mutations (PAPILLON) and alone after platinum chemotherapy; sunvozertinib (Zegfrovy, 2025) is labelled after platinum chemotherapy with the Oncomine Dx Express Test as companion; mobocertinib was withdrawn in 2023. Guardant360 CDx and the Oncomine Dx Target Test carry exon 20 insertion claims for amivantamab. PCR hotspot kits miss many exon 20 insertions, so sequencing is preferred.

## Fields

- Kind: Biomarker
- Last checked: 2026-09-23
- Also known as: EGFR ex20ins; exon 20 insertion; EGFR exon 20 insertion mutation; EGFR ex20ins NSCLC
- Tags: biomarker; egfr

## Sources

- Rybrevant prescribing information (DailyMed): https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=1466c070-9f97-4fa4-a955-6a6b59981fb8

## Connected records

- biomarkers: [EGFR exon 19 deletion](https://onco.cc/biomarkers/egfr-exon-19-deletion/), [HER2 (ERBB2) activating mutation](https://onco.cc/biomarkers/her2-mutation/)
- cancers: [Non-small-cell lung cancer](https://onco.cc/cancers/nsclc/)
- drugs: [Amivantamab](https://onco.cc/drugs/amivantamab/), [Guardant360 CDx](https://onco.cc/drugs/guardant360-cdx/), [Mobocertinib](https://onco.cc/drugs/mobocertinib/), [Oncomine Dx Target Test](https://onco.cc/drugs/oncomine-dx-target-test/), [Sunvozertinib](https://onco.cc/drugs/sunvozertinib/), [Zipalertinib](https://onco.cc/drugs/zipalertinib/)
- terms: [EGFR exon 20 insertion](https://onco.cc/terms/egfr-exon20-insertion/), [EGFR mutation subtypes (exon 19 deletion, L858R, exon 20 insertion, T790M)](https://onco.cc/terms/egfr-mutation-subtypes/), [Next-generation sequencing (NGS)](https://onco.cc/terms/ngs/)
- targets: [EGFR](https://onco.cc/targets/egfr/)

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JSON: https://onco.cc/api/v1/entities/egfr-exon-20-insertion.json