Comprehensive Liquid Biopsy Guides Metastatic Cancer Treatment

Liquid biopsies offer a promising approach for identifying druggable genomic alterations, which is the ability of a portion of a genome to be targeted by a drug, especially by a small molecule drug, without the need for costly and invasive tissue biopsies.

The results of the first prospective clinical trial using a comprehensive liquid biopsy test as the sole diagnostic tool used by doctors to guide metastatic cancer patients to matched therapy across multiple cancers has been recently announced.

Scientists at the Samsung Medical Center (Sungkyunkwan University School of Medicine, Seoul, Korea) and a commercial company collaborated in the first prospective study to evaluate the response of advanced cancer patients to matched therapy based on circulating tumor DNA (ctDNA)-detected alterations across different solid tumor cancers without tissue biopsies available for molecular testing. The study of 200 patients demonstrated high actionability in matching patients to targeted therapies, as well as statistically significant response rates in lung (88%) and gastric (60%) cancers.

The study used Guardant360 (Guardant Health, Inc, Redwood city, CA, USA), the first and only comprehensive liquid biopsy that covers all guideline recommended biomarkers in a single test. Guardant360 is a biopsy‐free, simple blood test for tumor genomic profiling. It takes 14 days or less from the time it is received at the laboratory for a full report to reach the ordering doctor. This is two full weeks sooner than with a tissue sample from a best in class cancer center. The Guardant360 blood test also provides samples with an adequate level of cell free DNA to test 99.8% of the time. In contrast, the samples used for tissue sequencing typically have insufficient DNA from 20% to 40% of the time. This adds further delays as either a new sample from the original tumor block must be present or another biopsy must be done to get enough tissue to test.

Jeeyun Lee, MD, the primary investigator on the study, said, “The genomic landscape of variants we found with Guardant360 were comparable to what we saw in a tissue-based prospective clinical utility study. When these patients are then guided to matched therapy based on ctDNA profiling, the response rate was again comparable to what we see when selection is based on tumor specimens. This blood-based technology also overcomes tumor heterogeneity by providing a more global summary of all the aberrations in different metastatic sites. It also may reduce harm to patients by obviating the need for invasive biopsy. The study was presented on June 6, 2016, at the American Society of Clinical Oncology Annual Meeting held in Chicago, IL, USA.

Related Links:
Samsung Medical Center
Guardant Health