The US Food and Drug Administration approved Guardant360 CDx as a companion diagnostic to identify patients with hormone receptor–positive, HER2-negative advanced or metastatic breast cancer whose tumors harbor ESR1 mutations before radiographic disease progression and who may benefit from camizestrant (ETCAMAH), according to a Guardant Health press release.
The approval recommends testing every 3 months during therapy to detect emerging ESR1 mutations. Guardant360 CDx is a liquid biopsy for comprehensive genomic profiling that detects multiple genomic alterations across solid tumors.
The approval was based on data from the phase 3 SERENA-6 trial. Patients underwent Guardant360 CDx testing every 3 months while receiving an aromatase inhibitor plus a cyclin-dependent kinase 4/6 inhibitor. Following detection of an ESR1 mutation before radiographic progression, eligible patients switched to camizestrant while continuing the cyclin-dependent kinase 4/6 inhibitor.
Patients who switched to camizestrant plus a cyclin-dependent kinase 4/6 inhibitor had a 56% lower risk of disease progression or death compared with patients who continued the aromatase inhibitor plus the cyclin-dependent kinase 4/6 inhibitor.
Guardant Health reported a 47% reduction in the risk of deterioration in global health status and quality of life among patients treated under the circulating tumor DNA–guided treatment approach.
SERENA-6 evaluated circulating tumor DNA surveillance during first-line endocrine therapy to identify emerging ESR1 resistance mutations before radiographic disease progression. According to Guardant Health, biomarker testing in advanced cancer has historically occurred most often following clinical or radiographic progression.
Guardant360 CDx detects multiple genomic alterations across solid tumors and is approved as a companion diagnostic for therapies in non–small cell lung cancer, breast cancer, and colorectal cancer. Guardant Health reported that the latest approval represents the test’s 29th companion diagnostic indication across multiple tumor types globally.
Source: Guardant Health, Inc
