Liquid biopsy on par with tissue testing in advanced lung cancer

By Megan Brooks

NEW YORK (Reuters Health) - 5/3/2019

In patients with newly diagnosed metastatic non-small-cell lung cancer (NSCLC), the Guardant360 liquid biopsy detects genomic biomarkers as well as standard-of-care tissue genotyping tests but with a faster turn-around time, new research suggests.

"Tissue biopsy-based tests are invasive, can have serious complications, are time-consuming, and the specimens are often inadequate to test for all the relevant mutations. Our study shows that Guardant360 test results can be obtained in about a week, are reliable, and in some respects a better alternative to the traditional tissue testing in ensuring guideline-complete molecular testing for all patients," Dr. Vassiliki Papadimitrakopoulou of The University of Texas MD Anderson Cancer Center said in a statement.

She presented topline results from the NILE study during a media briefing February 27 ahead of presentation at the upcoming American Association for Cancer Research (AACR) annual meeting.

Guardant360 utilizes cell-free tumor DNA (cfDNA) in blood to detect all seven guideline-recommended predictive biomarker mutations, known as the G7 (EGFR, ALK, ROS1, BRAF, RET, MET, ERBB2) and one prognostic biomarker mutation (KRAS).

The NILE study is a head-to-head study of standard tissued-based genomic testing versus cfDNA analysis using Guardant360 in 282 patients (54% women, 82% white) with newly diagnosed advanced NSCLC.

A G7 biomarker was detected in a higher proportion of liquid biopsies than standard tissue genotyping (77 patients, 27.3% vs. 60 patients, 21.3%; P<0.0001).

Additionally, the liquid-biopsy results were delivered significantly faster than the tissue testing results (median, nine days vs. 15 days), "a key factor to ensuring timely and appropriate therapy selection in these patients with advanced lung cancer," Dr. Papadimitrakopoulou told the briefing.

"When focusing on the guideline-recommended genomic biomarkers with FDA-approved therapies (EGFR, ALK and BRAF), if the biomarker was identified by cfDNA, it was also identified in tissue every time. Plasma cfDNA testing therefore had 100% positive predictive value," she reported.

"These results have very exciting implications for clinical practice, especially in light of the expanding list of genomic biomarkers to be assessed, which places strain on tissue availability and the importance of completing the assessment quickly to identify the right therapies for these newly diagnosed patients," Dr. Papadimitrakopoulou said.

"In the largest study of newly diagnosed advanced NSCLC patients, these study results demonstrate the clinical utility of a well-validated, comprehensive, sensitive cfDNA test to identify patients with guideline-recommended biomarker-positive tumor and it is an alternative to standard-of-care tissue testing in the first-line testing," she added.

Dr. John Carpten, briefing moderator and program chair for the AACR annual meeting, said this field is growing "rapidly" and the NILE study "really shows the power of these new approaches in allowing us to measure circulating cell free biomarkers (to guide) treatment choices. The results are really exciting and show that we can identify the mutations in the cancer that are important and do this in a much more non-invasive way."

Non-small-cell lung cancer has been a "scourge in the oncology community for so long, but now there are a number of targeted therapies available for these patients in addition to immunotherapy. Being able to use these new approaches for detecting cancer and identifying treatment choices is incredible," said Dr. Carpten of the University of Southern California Keck School of Medicine in Los Angeles.

The study was funded by Guardant Health Inc. Dr. Papadimitrakopoulou has received research support from the company.

SOURCE: http://bit.ly/2VzL5O8

AACR 2019.

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