501P - Clinical characteristics and efficacy in non-small cell lung cancer patients with EGFR exon 20 insertion and EGFR amplification

Background

Previous studies have proved that EGFR exon 20 insertion (EGFRex20ins) mutation present in about 1.8% of non-small cell lung cancer (NSCLC). 22% of EGFRex20ins are co-occurring with EGFR amplification. The aim of this study is to investigate the clinical characteristics and efficacy in Chinese NSCLC patients harboring EGFRex20ins and EGFR amplification.

Methods

A total of 1483 patients with advanced NSCLC were screened. All variants of EGFRex20ins and other oncogenic drivers were identified by next-generation sequencing (NGS).

Results

EGFRex20ins were found in 2.2% of patients and a total of 38 patients were included in clinical characteristics analysis. Various EGFRex20ins were identified, most commonly V769_D770dup (26.3%) and D770_N771dup (23.7%). Interestingly, co-occurring EGFR amplification was found in 39.5% of patients (15/38). In patients with EGFR amplification, the median age was 58 years (range, 38 to 75 years), and 66.7% were female. Most of them were never-smokers (86.7%) and had adenocarcinoma (93.3%). These clinical characteristics were not significantly different from those without EGFR amplification (P > 0.05). Except for patients with EGFR-sensitive mutations, a total of 25 patients who had used EGFR-tyrosine kinase inhibitors (TKIs) were included in the survival analysis. Although there were no statistically differences in two group, a tendency of prolonged median progression-free survival (mPFS) in patients without EGFR amplification was found (80.5 versus 30.0 days, P = 0.175).

Conclusions

EGFR amplification often co-occur with EGFRex20ins in Chinese NSCLC, and the ratio is higher than previous studies in Caucasian. Although there was no difference in clinical characteristics and efficacy between patients with and without EGFR amplification, a tendency of prolonged mPFS in patients without EGFR amplification was found. Future prospectively large-sample-size studies are needed to evaluate this finding.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

Guangdong Lung Cancer Institute.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.