REDWOOD CITY, Calif., Oct. 2, 2017 /PRNewswire/ -- Oncologists may get a new tool for identifying which of their cancer patients are most likely to respond to widely prescribed immunotherapies, recent research suggests. In a paper published in Clinical Cancer Research, researchers from the University of California, San Diego Moores Cancer Center showed that response to treatment with a checkpoint inhibitor-based immunotherapy correlated with the number of genomic alterations detected by the Guardant360 assay.

Clinical adoption of checkpoint inhibitors to treat a variety of solid tumor types has changed the way oncologists treat cancer in recent years. Although some patients respond dramatically to these drugs, many do not. While existing biomarkers such as PD-L1 expression are being used to help identify some patients well-suited for these drugs, these tests may be either imperfect predictors or infeasible to use due to limited tumor biopsy tissue. Now, UC San Diego investigators have demonstrated that the Guardant360 assay, the leading comprehensive liquid biopsy, may be able to non-invasively identify patients who benefit most from these drugs.

"Considering the high costs and complications associated with immunotherapy, finding biomarkers that predict which patients will respond best to immunotherapy is of utmost importance," said Razelle Kurzrock, MD, Director of the Center for Personalized Cancer Therapy at the University of California San Diego Moores Cancer Center and the study's senior author. "We show, for the first time, that a blood test that measures genomic alterations shed from the tumor into the circulation can help determine which patients are likely to respond."
Genomic testing in several advanced cancer types helps doctors match their patients to targeted therapies that are often more effective and less toxic than traditional chemotherapy. "These results also show the potential use of liquid biopsies for assisting immunotherapy decision making," said Richard Lanman, MD, Guardant Health's Chief Medical Officer. "Comprehensive genotyping before first-line immunotherapy is critical to identify EGFR, ALK, ROS1, and MET alterations, as these predict lack of response to checkpoint inhibitors while providing patients with a targeted therapy treatment option," Lanman said. "Here Dr. Yulian Khagi, Dr. Kurzrock, and team have shown that Guardant360 may help predict benefit of immunotherapy with a single blood test, by identifying hyper-mutated tumors noninvasively."

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