The FDA approved Guardant Health’s Guardant360 CDx as a companion diagnostic for identifying BRAF V600E–mutant metastatic colorectal cancer patients eligible for Pfizer’s encorafenib (Braftovi) plus cetuximab and chemotherapy regimen. The decision was supported by phase 3 BREAKWATER data showing survival and response benefits and expands Guardant360’s portfolio of companion diagnostic indications. Guardant framed the approval as further validation of liquid biopsy utility for treatment selection and resistance monitoring. Regulators and clinicians continue to debate the incremental clinical utility of ctDNA versus tissue testing, but the authorization increases noninvasive options to match targeted therapies to genomic alterations.