FDA Grants Accelerated Approval to AstraZeneca's Etcamah (Camizestrant) — First-Ever Cancer Therapy Approved on ctDNA-Guided Treatment Switching, Overriding a 6-3 Adverse ODAC Vote

The FDA granted accelerated approval to Etcamah (camizestrant), AstraZeneca's oral selective estrogen receptor degrader (SERD), in combination with a CDK4/6 inhibitor (abemaciclib, palbociclib, or ribociclib) for adults with HR-positive, HER2-negative locally advanced or metastatic breast cancer upon detection of an ESR1 mutation via blood-based circulating tumor DNA (ctDNA) testing — before imaging shows radiologic progression. The FDA simultaneously approved Guardant360 CDx as the companion diagnostic. In the Phase 3 SERENA-6 trial, switching to Etcamah plus a CDK4/6 inhibitor at ctDNA-detected molecular progression cut the risk of disease progression or death by 56% versus continuing an aromatase inhibitor (median PFS 16.0 vs. 9.2 months). The approval is notable because FDA's Oncologic Drugs Advisory Committee (ODAC) voted 6-3 against it, arguing the trial did not prove that switching at molecular detection is superior to switching at radiologic progression — the FDA proceeded to accelerated approval anyway, citing patient-reported benefits including delayed time to chemotherapy and preserved quality of life in the early-switch arm.