NEW YORK – Guardant Health said Monday that its liquid biopsy assay Guardant360 CDx has been approved by the US Food and Drug Administration as a companion diagnostic to identify individuals with ESR1 mutant breast cancer who may benefit from treatment with Menarini's Orserdu (elacestrant).
The drug, a nonsteroidal selective estrogen receptor degrader, is the first therapy approved by the FDA that targets cancers with this genomic alteration, which Guardant said is present in approximately 40 percent of ER-positive HER2-negative advanced breast cancers.
Guardant co-CEO Helmy Eltoukhy called the approval "great news" for patients. The FDA has approved Orserdu specifically for postmenopausal women or adult men with ESR1-mutated, advanced or metastatic breast cancer who have seen their cancer progress after at least one line of endocrine therapy.
In Menarini's Phase III EMERALD trial, the drug demonstrated statistically significant improvement in progression-free survival compared to standard-of-care endocrine monotherapy. In patients whose tumors had an ESR1 mutation, there was a 45 percent reduction of death or progression compared to standard treatment.
The CDx approval is Guardant Health’s fifth overall and its first in breast cancer.