Advanced Non-small Cell Lung Cancer: EGFR Mutation Analysis Using Pyrosequencing and the Fully Automated qPCR-Based IdyllaTM System

Osimertinib in uncommon EGFR exon 21 L861R and EGFR exon 18 deletion-insertion mutant non-small cell lung cancer-case report

Background

Tyrosine kinase inhibitors (TKIs) have changed the treatment landscape for patients with advanced non-small cell lung cancer (NSCLC) found to have oncogene-driven activating epidermal growth factor receptor (EGFR) mutations. Whilst there have been a handful of case reports of sensitivity to first-generation TKIs in EGFR L861R mutations, the efficacy of the third-generation TKI osimertinib in NSCLC patients with EGFR L861R and EGFR exon 18 deletion-insertion mutations is limited.

Case Description

We report two patients from our institution with uncommon EGFR mutations treated with first-line osimertinib. Our first patient, a 72-year-old male with metastatic lung adenocarcinoma was identified to harbour a rare EGFR L861R mutation and was commenced on osimertinib. After a follow-up period of 18 months, the patient is continuing to experience treatment benefit with imaging showing a good partial response. The second patient, a 60-year-old male also with metastatic lung adenocarcinoma and an EGFR exon 18 deletion-insertion mutation achieved a partial response for 6.6 months. Upon progression, he was commenced on carboplatin and pemetrexed chemotherapy however died from subsequent pneumonia. He had an overall survival (OS) from time of diagnosis of 7.6 months.

Conclusions

We demonstrate clinical efficacy of first-line osimertinib in the treatment of advanced NSCLC harbouring uncommon EGFR L861R and EGFR exon 18 deletion-insertion mutations. These results may be suggestive of the wider applicability of osimertinib in the treatment of uncommon EGFR mutant NSCLC.

Rapid and reliable testing for clinically actionable EGFR mutations in non-small cell lung cancer using the IdyllaTM platform: a real-world two-center experience in Greece

BACKGROUND

Limited information exists on epidermal growth factor receptor (EGFR) molecular epidemiology in Greece. Next-generation sequencing (NGS) is the recommended method for EGFR genotyping in NSCLC. The Idylla Biocartis platform is a fully automated system for actionable EGFR mutation detection.

RESEARCH DESIGN AND METHODS

We describe the prevalence of EGFR mutations in NSCLC patients in two high-volume clinical centers in Greece and compare key methods used for their determination. Eight hundred and fifty-seven FFPE samples from NSCLC patients were tested for EGFR mutations at University of Crete (UoC; n = 324) and at Evangelismos Hospital, Athens (Evangelismos; n = 503).

RESULTS

The prevalence of EGFR mutations was 11.1% in the whole cohort (11.5% in non-squamous). The detection rate was 11.0% by NGS, 9.8% by Sanger and 11.3% by Idylla for the whole cohort (12.0% in non-squamous). The agreement between Idylla and Sanger was 93.2%. A targetable EGFR mutation was detected in 10.0% using tissue NGS alone, and in 16.0% using concurrent Idylla ctEGFR testing.

CONCLUSION

The frequency of EGFR mutations was as expected for a Caucasian population. The Idylla EGFR test performance is comparable to reference methods and with a shorter TAT. Adding a concurrent plasma Idylla test to tissue NGS testing increases the detection rate of EGFR mutations in NSCLC.