Subgroup Analysis From the Phase 3 EMERALD Trial by Prior Duration of Endocrine Therapy Plus CDK4/6 Inhibitor

An additional subgroup analysis examined outcomes based on prior endocrine therapy (ET) duration and CDK4/6 inhibitor exposure. Patients with a longer prior duration of ET plus CDK4/6 inhibitor showed a clinically meaningful improvement in PFS when treated with elacestrant compared to standard of care. This suggests that tumors retaining partial endocrine sensitivity—particularly with ESR1 mutations—derive the greatest benefit from selective estrogen receptor degrader-based therapy.