To predict the response to EGFR tyrosine kinase inhibitor (TKI) therapy in non-small cell lung cancer (NSCLC) patients, formalin-fixed paraffin-embedded (FFPE) tumor tissue is routinely tested for the presence of somatic mutations in the epidermal growth factor receptor (EGFR) gene. Sufficient tumor tissue is not always available and ctEGFR testing from plasma is an alternative approach for the detection of EGFR mutations. Therefore, a fast and fully automated ctEGFR assay with minimal hands-on time should allow laboratories to quickly generate EGFR testing results.
IdyllaTM (Biocartis) is a fully integrated molecular diagnostics platform that combines speed and ease of use with high sensitivity and high multiplexing capabilities. In terms of ctDNA testing, it overcomes the time-consuming step of ctDNA extraction from plasma. After insertion of 2 ml of plasma into the cartridge, the complete process of ctDNA extraction, real-time PCR, data analysis and reporting is fully automated. The ctEGFR prototype assay allows the detection of 49 mutations including insertions and deletions in exons 18, 19, 20 and 21. The results obtained by the ctEGFR prototype assay were compared with NGS (sensitivity 2-5%).
Sixty-four NSCLC samples were tested with both assays. Overall, 34 mutations were detected by NGS and confirmed by the ctEGFR prototype assay. In 33 samples, NGS detected no mutation. The ctEGFR prototype assay detected 7 additional mutations in this cohort. Retesting with the cobas EGFR Mutation Test v2 confirmed the presence of these mutations. Analytical sensitivity was assessed for 20 mutations using plasma spiked with synthetic targets. Analytical sensitivities ranging from 1 to 4% were obtained for the tested mutations. Inclusivity was demonstrated for 49 mutations in total. The average turnaround time of a run was <2h 40 min and the hands-on time for the assay was <2 min.
This study shows that the Idylla™ platform enables the development of a prototype ctEGFR assay with high sensitivity and ease of use combined with a fast turnaround time for the testing of 49 relevant EGFR mutations in 2 ml of plasma from NSCLC patients.
Biocartis.
Biocartis.
M. Reijans: Full / Part-time employment: Biocartis. S.V. Gestel: Full / Part-time employment: Biocartis. E.D. Haes: Full / Part-time employment: Biocartis. C. Vandesteene: Full / Part-time employment: Biocartis. J.M. Castro Gomez: Full / Part-time employment: Biocartis. C. Gouedard: Full / Part-time employment: BioPath Innovations SA. S. Patera: Full / Part-time employment: BioPath Innovations SA. S. Murray: Full / Part-time employment: BioMarker Solutions Ltd. G.G. Maertens: Full / Part-time employment: Biocartis.