SABCS 2021: Update From Phase III Trial of Oral SERD in Advanced Breast Cancer
Posted: Monday, December 20, 2021
Second- or third-line treatment with the oral selective estrogen receptor degrader (SERD) elacestrant significantly improved progression-free survival versus standard-of-care endocrine monotherapy in patients with estrogen receptor–positive, HER2-negative advanced or metastatic breast cancer, according to Aditya Bardia, MD, MPH, of Mass General Cancer Center, Boston, and colleagues. The results of the multicenter phase III EMERALD trial, which were presented during the 2021 San Antonio Breast Cancer Symposium (SABCS; Abstract GS2-02), suggested this agent was also well tolerated.
“Elacestrant is the first oral SERD that has demonstrated a statistically significant and clinically meaningful improvement in progression-free survival versus standard-of-care endocrine therapy in a randomized, global, phase III study,” said Dr. Bardia during a press conference prior to the meeting.
A total of 477 postmenopausal patients who experienced disease progression after endocrine and CDK4/6 inhibitor therapy were randomly assigned in a 1:1 ratio to receive elacestrant or fulvestrant or an aromatase inhibitor. A subgroup of 228 patients harbored ESR1 mutations.
The risk of disease progression or death was reduced by 30% in patients treated with elacestrant (hazard ratio = 0.697); in the ESR1-mutated subgroup, the risk was reduced by 45% (hazard ratio = 0.546). At 12 months, the rate of progression-free survival was 22.3% with elacestrant and 9.4% with the standard of care; the rates of progression-free survival were 26.8% and 8.2%, respectively, in the ESR1-mutated subgroup. The prespecified interim analysis of overall survival revealed a trend in favor of elacestrant in the entire patient population (hazard ratio = 0.751) and in the ESR1-mutated subgroup (hazard ratio = 0.592).
Nausea, vomiting, and fatigue were the most frequently reported grade 1 or 2 treatment-related adverse events with elacestrant. A total of 6.3% of patients treated with elacestrant and 4.4% of those treated with the standard of care experienced treatment-emergent adverse events leading to discontinuation of therapy. No treatment-related deaths were reported.
Disclosure: For full disclosures of the study authors, visit sabcs.org.
