Detection of activating and acquired resistant mutation in plasma from EGFR-mutated NSCLC patients by peptide nucleic acid (PNA) clamping-assisted fluorescence melting curve analysis.

Chang Gon Kim,Hye Ryun Kim,Jee Hung Kim,Min Hee Hong,Chang Young Lee,Yoon Jin Cha,Byoung Chul Cho,Hyo Sup Shim,Su Jin Heo,Jin Gu Lee,Hyung Soon Park

doi:10.18632/oncotarget.17786

Abstract

This study was designed to prospectively examine whether peptide nucleic acid clamping-assisted fluorescence melting curve analysis (PANAMutyper™) is feasible for the detection of activating and acquired resistant epidermal growth factor receptor (EGFR) mutation in plasma. Patients with non-small cell lung cancer harboring activating EGFR mutations who were scheduled to undergo EGFR-tyrosine kinase inhibitors (EGFR-TKIs) were enrolled between September 2011 and March 2015. A total of 102 patients with EGFR-mutated lung cancer were enrolled, 53 had available plasma samples at disease progression, and 28 underwent serial plasma sampling during EGFR-TKI treatment. EGFR-TKI-sensitizing and T790M mutations were detected in the plasma of 68.6% (70/102) at baseline and 30.2% (16/53) at disease progression, respectively. The concordance rates for matched tissue and plasma samples were 80.4% and 90.2% for E19del and L858R mutations at baseline and 56.3% for T790M mutation at disease progression. The sustained presence of plasma EGFR mutations four weeks after EGFR-TKI predicted a poor objective response rate (30.0% vs. 87.5%, P = 0.025), as well as worse progression-free survival (hazard ratio [HR], 4.381) and overall survival (HR, 5.475). Longitudinal analysis could detect T790M mutations earlier than disease progression based on imaging study (median time from appearance of T790M in plasma samples to progression at imaging scan, 103 days). In conclusion, PANAMutyper™ is reliable for detecting activating and acquired resistant EGFR mutation in plasma, and predicts responses to EGFR-TKI via longitudinal monitoring of EGFR mutation during treatment.

Highlights

Activating epidermal growth factor receptor (EGFR) mutations are predictive biomarkers for response to EGFR-tyrosine kinase inhibitors (EGFR-TKIs; e.g., erlotinib, gefitinib or afatinib) and EGFR-TKIs are the standard first-line therapy for non-small cell lung cancer (NSCLC) with activating EGFR mutations [1,2,3]
We prospectively evaluated whether Peptide nucleic acids (PNA) clamping-assisted fluorescence melting curve analysis (PANAMutyperTM) can accurately detect activating and acquired resistance EGFR mutations in plasma circulating free tumor DNA (ctDNA) derived from NSCLC patients
The benefits of liquid biopsy including delicate reflection of tumor heterogeneity as well as fast turn-around time can be seen in this case. This is the first prospective study demonstrating the feasibility of PNA clamping-assisted fluorescence melting curve analysis (PANAMutyperTM) of plasma ctDNA derived from NSCLC patients with activating and acquired resistant EGFR mutations

Summary

Introduction

Activating epidermal growth factor receptor (EGFR) mutations are predictive biomarkers for response to EGFR-tyrosine kinase inhibitors (EGFR-TKIs; e.g., erlotinib, gefitinib or afatinib) and EGFR-TKIs are the standard first-line therapy for non-small cell lung cancer (NSCLC) with activating EGFR mutations [1,2,3]. Randomized phase III studies have consistently demonstrated that first-line EGFR-TKI therapy improves progression-free survival (PFS) compared with standard cytotoxic chemotherapy in EGFR mutated lung cancer patients [2,3,4]. Most patients treated with EGFR-TKI develop disease progression due to acquired resistance via multiple mechanisms [5,6,7]. Of these mechanisms, EGFR T790M mutation accounts for more than 50% of the acquired resistance [8]. In the era of third generation EGFR-TKI, the detection of EGFR T790M mutation in repeated biopsies at the time of EGFR-TKI failure is indispensable to improving survival outcomes in EGFR mutated patients

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