FDA Approval Summary: Elacestrant for ER–Positive, HER 2–Negative, ESR1-Mutated Advanced or Metastatic Breast Cancer
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Purpose
The U.S. Food and Drug Administration approved elacestrant for the treatment of postmenopausal women or adult men with estrogen receptor–positive (ER+), human epidermal growth factor receptor 2–negative (HER2–), estrogen receptor 1 (ESR1)–mutated advanced or metastatic breast cancer with disease progression after at least one line of endocrine therapy (ET).
Patients and Methods
Approval was based on EMERALD (Study RAD1901-308), a randomized, open-label, active-controlled, multicenter trial in 478 patients with ER+, HER2– advanced or metastatic breast cancer, including 228 patients with ESR1 mutations. Patients were randomly assigned (1:1) to receive either elacestrant 345 mg orally once daily (n = 239) or investigator's choice of ET (n = 239).
Results
In the ESR1-mut subgroup, EMERALD demonstrated a statistically significant improvement in progression-free survival (PFS) by blinded independent central review assessment (n = 228, hazard ratio [HR] 0.55, 95% CI 0.39-0.77, P value=0.0005). Although the overall survival (OS) end point was not met, there was no trend toward a potential OS detriment (HR 0.90, 95% CI 0.63-1.30) in the ESR1-mut subgroup. PFS also reached statistical significance in the intention-to-treat (ITT) population (n = 478; HR 0.70, 95% CI 0.55-0.88]; P value=0.0018). However, improvement in PFS in the ITT population was primarily attributed to results from patients in the ESR1-mut subgroup. More patients who received elacestrant experienced nausea, vomiting, and dyslipidemia.
Conclusion
The approval of elacestrant in ER+, HER2– advanced or metastatic breast cancer was restricted to patients with ESR1 mutations. Benefit-risk assessment in the ESR1-mut subgroup was favorable on the basis of a statistically significant improvement in PFS in the context of an acceptable safety profile including no evidence of a potential detriment in OS. By contrast, the benefit-risk assessment in patients without ESR1 mutations was not favorable. Elacestrant is the first oral estrogen receptor antagonist to receive FDA approval for patients with ESR1 mutations.
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FDA Approval Summary: Elacestrant for ER–Positive, HER 2–Negative, ESR1-Mutated Advanced or Metastatic Breast Cancer
Primary Source
Journal of Clinical Oncology
Source Reference: