Can Liquid Biopsy Predict Benefit From Immunotherapy in Lung Cancer?
Posted: Friday, September 7, 2018
A blood-based assay used to measure tumor mutational burden may be able to accurately identify patients with advanced non–small cell lung cancer (NSCLC) who may benefit from checkpoint inhibitors. It also represents a less invasive alternative to tissue testing. These findings, which were based on a retrospective analysis of two large randomized trials—OAK and POPLAR—were reported in Nature Medicine by David Gandara, MD, of UC Davis Comprehensive Cancer Center, and colleagues.
“We succeeded [in] establishing a [tumor mutational burden] level in blood that correlates well with similar levels in tissue and was associated with favorable patient outcomes,” revealed Dr. Gandara in a UC Davis press release. “There are patients for whom the biopsy is inadequate from the start, or the tissue is used for routine pathology and we don’t have enough tissue left to do either genomic testing or tissue [tumor mutational burden]. If we can do it in blood in one test, that offers many advantages for patients who have had an inadequate biopsy.”
To determine whether blood could measure tumor mutational burden as effectively as tumor tissue, the researchers examined more than 1,000 blood samples from patients with advanced NSCLC and compared them with tumor tissue samples. They found that tumor mutational burden in plasma accurately and “consistently” identified patients who derived improved response and progression-free survival from atezolizumab in second-line and higher treatment settings for NSCLC.
“Collectively, our data show that high [tumor mutational burden in plasma] is a clinically actionable biomarker for atezolizumab in NSCLC,” the investigators wrote in their article. The blood-based assay has received Breakthrough Therapy designation from the U.S. Food and Drug Administration.
