Epidermal growth factor receptor exon 20 insertions in advanced lung adenocarcinomas: Clinical outcomes and response

Cancer
|June 23, 2015
PubMed
Abstract

Insights

Epidermal growth factor receptor (EGFR) exon 20 insertions (exon20ins) in lung cancer are resistant to EGFR tyrosine kinase inhibitors (TKIs). Standard chemotherapy is recommended as first-line treatment for these patients.

Area of Science:

  • Oncology
  • Genetics
  • Pharmacology

Background:

  • Epidermal growth factor receptor (EGFR) exon 20 insertions (exon20ins) constitute about 10% of EGFR-mutant lung adenocarcinomas.
  • These mutations are linked to resistance against EGFR tyrosine kinase inhibitors (TKIs).
  • Clinical outcomes for patients with exon20ins compared to sensitizing EGFR mutations are not well-defined.

Purpose of the Study:

  • To compare the clinical outcomes of patients with stage IV lung adenocarcinomas harboring EGFR exon20ins versus those with EGFR exon 19 deletion (exon19del)/L858R mutations.
  • To evaluate the efficacy of EGFR TKIs and chemotherapy in patients with EGFR exon20ins.

Main Methods:

  • Retrospective analysis of patients with stage IV lung adenocarcinomas identified via molecular testing.
  • Collection of clinicopathologic data, including overall survival (OS) from stage IV diagnosis and time to progression (TTP) on erlotinib.
  • Comparison of outcomes between patients with EGFR exon20ins and those with EGFR exon19del/L858R mutations.

Main Results:

  • Out of 1882 patients, 46 had EGFR exon20ins (2%) and 258 had EGFR exon19del/L858R (14%).
  • Among 11 patients with exon20ins treated with erlotinib, 3 (27%) showed partial response.
  • TTP on erlotinib was 3 months for exon20ins versus 12 months for exon19del/L858R (P < .01).
  • Chemotherapy response was similar between groups.
  • Median OS was 26 months for exon20ins and 31 months for exon19del/L858R (P = .53).

Conclusions:

  • Most patients with advanced lung adenocarcinoma and EGFR exon20ins do not respond to EGFR TKI therapy.
  • Standard chemotherapy is recommended as the preferred first-line treatment.
  • Patients with EGFR exon20ins have an OS comparable to those with sensitizing EGFR mutations.
  • Certain variants like FQEA and ASV may exhibit response to erlotinib.