Abstract 5681: Utility of a targeted NSCLC genomic test for cfDNA variants in the community setting

Time to treatment can have significant impact on progression of cancer, and treatment decisions rely heavily upon genomic and proteomic testing. However, multiple factors can delay the availability of molecular diagnostic test results, including the use of tissue-based testing. Almost one third of patients with non-small cell lung cancer (NSCLC) are either not candidates for biopsies, or have insufficient tissue samples from their initial biopsy. Additionally, most physicians in the community setting want to initiate treatment quickly but do not have access to on-site molecular testing at their practice. As a result, physicians may delay their decision to commence treatment with specific targeted therapies or treat before the mutation status is known. The goal of this study was to assess the utility of a blood-based cell-free (cf) nucleic acid Laboratory Developed Test (LDT) in the community setting. The tests utilize Droplet Digital™ PCR (ddPCR) technology to detect the EGFR sensitizing mutations L858R and exon 19 deletion (E746 - A750), the EGFR resistance mutation (T790M), the KRAS mutations G12C, G12V and G12D, and the BRAF V600E mutation. Patient samples for testing were collected and shipped at ambient room temperature using a Biodesix® whole blood sample collection kit and processed at the Biodesix laboratory. Metrics were reviewed from the real-time measurement of established molecular diagnostic markers in the plasma of patients with NSCLC. For this study we analyzed results from greater than 4,000 patient cases (~24,000 individual variants). Greater than 70% of test orders were received from physician practices that self-identified as community based. Test mutation status results were reported within 72 hours of sample receipt from the physician’s office (95%). The percentage of tests requested that were positive for each variant category were 9% for EGFR sensitizing, 9% for EGFR resistance, 11% for KRAS, and 1% for BRAF. Notably, we generated test results successfully for 98% of tests submitted. We have developed fast, highly robust and sensitive blood-based assays to expedite time to treatment and expand the laboratory testing options for patients with NSCLC. Citation Format: Westen Hahn, Scott Thurston, Leisa Jackson, Amanda Weaver, Cherie Tschida, Brent Sage, Kristin Alexander, Tunee Pelletier, Nia Charrington, Samantha Cooper, Dianna Marr, Paul M. Bowling, Hestia Mellert, Gary Pestano. Utility of a targeted NSCLC genomic test for cfDNA variants in the community setting [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 5681. doi:10.1158/1538-7445.AM2017-5681