Abstract 3739: Comparison of technologies for EGFR analysis within a subset of a randomized clinical trial
Authors: Marabese Mirko , Broggini Massimo , Reijans Martin , Gouedard Cedric , Maertens Geert , Sablon Erwin , Ganzinelli Monica , Garassino Marina C. , Murray Samuel 
Published: July 2017

Background: EGFR mutation analysis is laborious often requiring &gt;5 working days and multiple slices of formalin-fixed paraffin-embedded (FFPE) tissue. Idylla™ is a fully integrated, automated molecular diagnostics platform combining speed, ease of use, high sensitivity, multiplexing capabilities, offering sensitive detection of 52 mutations including insertions and deletions in exons 18-21.

Methods: We assessed 149 cases from the phase III TAILOR study (Garassino et al, Lancet Oncology 2013;14:981-8), where EGFR was centrally assessed. Relative concordance between study entry classification to TAILOR (Sanger sequencing), Idylla™ and next generation sequencing (NGS) for EGFR were investigated. Single unprocessed sections were used per Idylla™ and NGS following pathological review. NGS was performed using the AmpliseqTM Colon and Lung Cancer Panel v2 on an Ion Torrent PGM™ (Thermo Fisher) in a reference laboratory3; Idylla™ (Biocartis NV) was performed at Biocartis1. Samples and study genotypes were blinded to NGS and Idylla™.

Results: There were 132 eligible calls to compare NGS vs Idylla™ (14 fails NGS, 1 Idylla™, 2 both); 108 to compare Sanger vs Idylla™ (38 fails Sanger, 2 Idylla™, 1 both); 101 to compare Sanger vs NGS (31 fails Sanger, 7 NGS, 9 both). For NGS, a minimum coverage of 500 reads was set at a clinically relevant LOD of 5% mutant allelic frequency for calls. Comparison NGS vs Idylla™: 46 EGFR (34.8%) mutation positive by Idylla™, 43 (32.6%) by NGS; Sensitivity 93.48%; Specificity 100.00 %. Comparison Sanger v Idylla™: 41 EGFR (38.0%) mutation positive by Idylla™, 38 (35.2%) by Sanger; Sensitivity 85.37%; Specificity 95.52 %. Sanger v NGS: 39 EGFR (38.6%) mutation positive by NGS, 39 (38.6%) by Sanger; Sensitivity 87.18%; Specificity 91.94 %. Of 16 NGS failures 14 were reportable by Idylla™.

Conclusions: Idylla™ proved to be a reliable platform for rapid EGFR mutational status evaluation. Compared to NGS and Sanger sequencing Idylla™ has several advantages: its ease of use, hands on time &lt;5 mins, all-inclusive lyophilized cartridge requiring only one section of 5μm FFPE, restricted secondary manipulation errors in a busy workflow. Positive and Negative predictive values for both Idylla™ and NGS were excellent. Although NGS offers significant additional clinical data availability through multiplexing, the number of samples classified as inadequate for NGS (14/16 giving result with Idylla™) indicates a likely requirement of more sample robust platforms in diagnostic workflows.

Citation Format: Mirko Marabese, Massimo Broggini, Martin Reijans, Cedric Gouedard, Geert Maertens, Erwin Sablon, Monica Ganzinelli, Marina C. Garassino, Samuel Murray. Comparison of technologies for EGFR analysis within a subset of a randomized clinical trial [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3739. doi:10.1158/1538-7445.AM2017-3739