Guardant Health, Inc. (NASDAQ:GH) today announced a strategic collaboration with Radius Health, Inc. ((Radius, NASDAQ:RDUS) to pursue regulatory approval of the Guardant360® CDx as a companion diagnostic for elacestrant (RAD1901), an investigational selective estrogen receptor degrader (SERD) being studied in the treatment of advanced ER-positive, HER2-negative breast cancer resistant to CDK4/6 inhibitors in combination with hormone therapy.
The phase III clinical trial, EMERALD, is currently underway to assess the efficacy of elacestrant versus standard of care endocrine therapy in the overall population, as well as in patients who have been comprehensively genotyped using the Guardant360 test and harbor ESR1 mutations. Radius recently signed a global exclusive development and commercialization licensing agreement with Menarini Group for elacestrant. Radius will continue to conduct and complete the ongoing EMERALD trial through U.S. Food and Drug Administration (FDA) New Drug Application (NDA) filing.
“Given breast cancer’s inherent tumor heterogeneity and the high prevalence of bone metastasis in advanced disease, our Guardant360 liquid biopsy can help overcome the challenges of tissue and bone biopsies to reveal significantly more actionable mutations, including ESR1 mutations, which may play a role in resistance and which are being studied in Radius’ EMERALD trial,” said AmirAli Talasaz, Ph.D., Guardant Health President. “For patients with CDK4/6 resistant tumors, for whom few other treatment options exist, potential therapies such as elacestrant may represent a promising option.”
The Guardant360 blood test is increasingly being used to guide treatment in metastatic breast cancer, as the number of treatment-relevant genomic alterations continues to grow. Using next-generation sequencing, the Guardant360 test analyzes 74 genes using cell-free tumor DNA from patient blood samples. The Guardant360 test is broadly covered by Medicare for use across the vast majority of advanced solid tumors and many private payers.