Abstract 5601: Oncomine™ dx express CE-IVD liquid biopsy assay for non-small cell lung cancer: Performance review and analytical validation
Authors: Siepert Nicholas , Schageman Jeoffrey , Gu Jian , Jayaweera Thilanka , Jasti Madhu , He Luming , Wunch Stephen , Ostrowska Emilia , Delacour Tasha , Hassell Diarra , Bowden Thomas , Garcia Daniela , Tong Stephanie , Raut Swasti , Ezzedine Nader , Martinez Elliott , Bramlett Kelli 
Published: April 2023

Abstract
Introduction - Clinical diagnostics assays for oncology are becoming more readily available due to the advancement and democratization of Next-Generation Sequencing (NGS). Additionally, liquid biopsy can be used in NGS to detect genetic variants in circulating tumor DNA and RNA. Liquid biopsy is a less invasive option compared to traditional biopsy methods for early detection and continuous monitoring of cancer treatment outcomes. Here, we discuss screening of over 3,500 non-small cell lung cancer (NSCLC) samples, and the analytical validation of the Oncomine™ Dx Express Test (ODxET) and Genexus™ Dx Integrated Sequencer for detection of clinically significant variants in liquid biopsy samples.
Methods - Our team screened over 3,500 NSCLC liquid biopsy samples in search of high priority clinical variants. Variants selected for analytical validation studies included ERBB2 exon 20 insertion, EGFR exon 20 insertion, EGFR exon 19 deletion, EGFR T790M, KRAS G12C, BRAF V600E, and RNA fusion isoforms including ALK, NTRK1/2/3, RET, and ROS1 oncogenic drivers. Over 550 screened samples were found to be positive for these variants of interest. This screening was performed on the Genexus™ Dx Integrated Sequencer according to the user guide.
Results - The Genexus™ Dx Integrated Sequencer automates library preparation, sequencing, analysis, and reporting QC metrics and variant calls. Sequencing run setup is quick and straightforward, taking less than 15 minutes to start a run and just over 24 hours to go from nucleic acid to report. Limit of detection (LoD) for DNA SNVs, insertions, and deletions at 5 ng DNA input level ranged from 0.65% to 1.82% allelic frequency (AF), depending on the variant. The higher DNA input of 30 ng resulted in a lower LoD range, from 0.31% to 0.42% AF. RNA fusion and splice variant LoD at 5 ng sample input ranged from 9.9 to 19.6 molecular counts. The higher 30 ng input resulted in a lower LoD range for RNA variants as well, ranging from 6.4 to 8.0 molecular counts. In the analytical accuracy study, the false positive rate was found to be 0.2% for SNVs, 0% for insertions/deletions, and 0% for fusion targets. In the analytical reproducibility study, the average with-in run repeatability call rate (No Calls excluded) was 99.64% for DNA variants and 98.75% for RNA variants.
Conclusion - Here, we demonstrated that the ODxET workflow on Genexus™ Dx Integrated Sequencer is a fast and efficient tool for testing clinical NSCLC liquid biopsy samples with high sensitivity and specificity.
For in vitro diagnostic use. Not available in all regions including the United States.
Citation Format: Nicholas Siepert, Jeoffrey Schageman, Jian Gu, Thilanka Jayaweera, Madhu Jasti, Luming He, Stephen Wunch, Emilia Ostrowska, Tasha Delacour, Diarra Hassell, Thomas Bowden, Daniela Garcia, Stephanie Tong, Swasti Raut, Nader Ezzedine, Elliott Martinez, Kelli Bramlett. Oncomine™ dx express CE-IVD liquid biopsy assay for non-small cell lung cancer: Performance review and analytical validation. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5601.