Clinical utilization of a CLIA-certified cell-free DNA (cfDNA) blood test for identification of targetable molecular alterations in patients with non-small cell lung cancer (NSCLC).

Tumor Biology
Session Type and Session Title: 
This abstract will not be presented at the 2016 ASCO Annual Meeting but has been published in conjunction with the meeting.
Abstract Number: 


J Clin Oncol 34, 2016 (suppl; abstr e23064)
Hai T. Tran, Yasir Elamin, George R. Simon, George R. Blumenschein, Anne S. Tsao, Vassiliki Papadimitrakopoulou, Don Lynn Gibbons, Frank V. Fossella, Richard Burnham Lanman, Kimberly C. Banks, Lauren Averett Byers, Jianjun Zhang, John Heymach; The University of Texas MD Anderson Cancer Center, Houston, TX; Department of Thoracic/Head & Neck Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX; Department of Thoracic/Head and Neck Medical Oncology, Division of Cancer Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX; Guardant Health, Inc., Redwood City, CA

Abstract Disclosures


Background: The availability to have tumor genomic information from simple blood collection can significantly impact patient care. We report the clinical utility of a CLIA-certified cfDNA next generation sequencing (NGS) blood test in our patients (pts) with NSCLC. Methods: From April 2015 to January 2016, blood samples from 50 NSCLC pts were analyzed using cfDNA NGS with a panel of 70 cancer-related genes at a CLIA-certified lab (Guardant360, Guardant Health, Redwood City, CA) with reported sensitivity of 0.1% mutant allele fraction with high specificity ( > 99.9999%) (PLoS One, 10(10), 2015). Results: Fifty-three Guardant360 tests were completed in 50 pts (28/F:22/M); histology: adenocarcinoma(47), squamous(2) and sarcomatoid(1). Rationale for blood tests: insufficient tissue(32%), addition to tissue analysis(32%), alternative to tissue biopsy(13%), treatment evaluation/resistant(20.7%), no documentation(1.8%). Based on Guardant360 results, 37 pt samples demonstrated either no alterations(n = 8) or alterations that were not targetable(n = 29); concordance with at least 1 genomic alteration from paired tissue analysis in 8 pt samples and new genomic alterations dictating change in therapies in another 8 pts included: EGFR-T790M(n = 4), EML4-ALK fusion(n = 2), EGFR-e19del(n = 1), multikinase targets(n = 1). Serial testing was done in 2 cases, one had no targetable molecular alterations, with confirmation from tissue at second testing. The other pt had 3 serial tests over a 8-month period; while on erlotinib-based therapy, 1st test revealed EGFR-e19del at 0.31%, decreasing to 0.18% 4 months later; then, at progression, showed increased to 0.54% with appearance of EGFR-T790M (0.23%). At which time osimertinib was initiated. Complete clinical outcomes will be updated. Conclusions: Molecular testing of cfDNA is a simple, minimally invasive test when tissue sample is not available or inadequate for molecular analysis. It is particularly useful in the long-term management of patients for monitoring of emergence and confirmation of resistance-associated molecular alterations; such as EGFR-T790M.