Guardant Health, Inc. announced that the U.S. Food and Drug Administration (FDA) has approved its Guardant360® CDx liquid biopsy test as a companion diagnostic to identify advanced or metastatic breast cancer patients with ESR1 mutations who may benefit from treatment with ORSERDU™ (elacestrant), a nonsteroidal selective estrogen receptor degrader to be commercialized by Stemline Therapeutics, Inc., a wholly-owned subsidiary of Menarini Group. Breast cancer is the second leading cause of cancer death in women. The American Cancer Society estimates that about 297,790 new cases of invasive breast cancer will be diagnosed in women in 2023, and about 43,700 women will die from breast cancer.2 ORSERDU is the first therapy to be approved by the FDA for advanced breast cancer patients with ESR1 mutations, with disease progression following at least one line of endocrine therapy.

ESR1 mutations are present in approximately 40% of ER+/HER2- advanced breast cancers. The FDA approved Guardant360 CDx as a companion diagnostic (CDx) in conjunction with the approval of ORSERDU for postmenopausal women or adult men with estrogen receptor (ER)-positive, human epidermal growth factor receptor 2 (HER2)-negative, ESR1-mutated, advanced or metastatic breast cancer with disease progression following at least one line of endocrine therapy.