FDA Grants Accelerated Approval to AstraZeneca Etcamah (Camizestrant) Plus CDK4/6 Inhibitor for ESR1-Mutated HR+ HER2- Advanced Breast Cancer; Guardant360 CDx Approved as Companion Diagnostic
AstraZeneca (NASDAQ: AZN) announced Friday September 4, 2026 that the FDA granted accelerated approval to Etcamah (camizestrant, an oral selective estrogen receptor degrader) in combination with a CDK4/6 inhibitor (abemaciclib, palbociclib, or ribociclib) for adults with hormone-receptor-positive HER2-negative locally advanced or metastatic breast cancer upon detection of ESR1 mutation during aromatase inhibitor plus CDK4/6 inhibitor therapy. FDA also approved the Guardant360 CDx blood-based next-generation sequencing assay as a companion diagnostic to identify ESR1-mutant patients. Approval was based on the Phase 3 SERENA-6 trial that documented a 56% reduction in disease progression or death versus continued standard-of-care aromatase inhibitor plus CDK4/6 inhibitor treatment in the ESR1-mutated subgroup. SERENA-6 was presented at ASCO 2026 and simultaneously published in the New England Journal of Medicine. Etcamah becomes the first oral SERD approved for the switch-at-emergence-of-ESR1 setting, replacing the fulvestrant intramuscular injection historically used post-progression. AstraZeneca is positioning Etcamah alongside Trodelvy plus Datroway as anchors of the expanded breast-cancer franchise.