Guardant Health buoyed by positive study results for liquid biopsy testing

(University of Pennsylvania)

Guardant Health is celebrating study results showing that its liquid biopsy tests may work better than standard tissue biopsy in advanced lung cancer patients who can’t undergo traditional testing.

Guardant’s liquid biopsy tests identified cell-free tumor DNA (ctDNA) mutations similar to those found by next-generation sequencing tests, according to results from scientists at the University of Pennsylvania. Liquid biopsies also picked up on mutations in patients with non-small cell lung cancer (NSCLC) that tissue biopsies didn’t uncover, researchers said in a statement. Scientists recently published their findings in Clinical Cancer Research.

The results represent "a bit of a paradigm shift,” Erica Carpenter, senior author of the study, said in a statement. “The tissue biopsy sequencing result has been considered the gold standard against which one compares the ctDNA result. Our work suggests that one can act on a ctDNA result, even in the absence of the so-called gold standard, and get a clinical response in these patients,” Carpenter said.

The study included 102 patients with NSCLC receiving treatment at Penn between Feb. 2015 and March 2016. 50 patients could only provide tissue samples. Liquid biopsy samples were sent back to California-based Guardant for testing. 

Out of those 50 patients, tissue samples turned up 24 mutations linked to lung disease, while liquid biopsy samples identified 19 of those mutations. 

Six patients also had serial liquid biopsies to monitor the disease. The tests helped guide treatment in every case, the researchers said, whether by identifying a mutation linked to specific therapy or by ruling out chemo for some patients who can’t have tissue biopsies.

Next up, researchers want to carry out larger scale studies that look at how liquid biopsy tests could help refine treatment. Scientists will look at how the tests would work in patients who don’t have mutations linked to certain therapies.

“The ever-expanding number of targeted therapies for lung cancer patients has been accompanied by a need for diagnostics with real-time detection of therapeutically targetable mutations. More and more, liquid biopsies are proving to help fill this need,” Corey Langer, co-author on the study, said in a statement. “While tissue samples will likely remain a major part of the initial diagnostic process, this non-invasive approach appears to be another powerful tool in our toolbox to help determine the best course of treatment for lung cancer patients.”