Exploring a Patient Case: Biomarker Testing After Progression and Discussing Treatment Choices With Your Care Team

Clinical Brief: EMERALD Trial Insights for ESR1-Mutant Breast Cancer

Main Discussion Topics:

• Overview of EMERALD trial design and patient population
• Co-primary end points and efficacy outcomes for ESR1-mutant tumors
• Critical subset analyses identifying best responders (>12 months prior CDK4/6)
• Median PFS outcomes: 8.6 months versus 3.8 months in optimal patients
• Limited relevance of variant allele frequency (VAF) for treatment selection

Key Points for Physicians:

• Elacestrant approved specifically for ESR1-mutant metastatic breast cancer
• Prior CDK4/6 duration greater than 12 months predicts better response (8.6 versus 1.9 months PFS)
• Benefit maintained across visceral disease, multiple metastatic sites
• PIK3CA co-mutations do not negate elacestrant benefit
• VAF is not currently useful for treatment selection decision-making

The EMERALD trial established that patient selection based on endocrine sensitivity duration, rather than just mutation presence, optimizes treatment outcomes with elacestrant.