Dr Ansley on the Role of Elacestrant in ER+/HER2– Advanced Breast Cancer

“One of the best things about elacestrant is how well it is tolerated. We didn’t see as many [adverse] effects because it is a more endocrine-based therapy. One thing we’re always looking for are drugs that work better with fewer AEs, and we are seeing that with these [treatments].”

Katherine C. Ansley, MD, a breast medical oncologist at the Atrium Health Wake Forest Baptist Hematology and Oncology – Cancer Center and an associate professor of cancer medicine at the Wake Forest University School of Medicine, highlighted the role of the oral selective estrogen receptor degrader (SERD) elacestrant (Oserdu) for the treatment of patients with estrogen receptor (ER)–positive, HER2-negative advanced or metastatic breast cancer who previously received 1 or 2 lines of therapy with a CDK4/6 inhibitor plus fulvestrant (Faslodex) or an aromatase inhibitor.

In January 2023, the FDA approved elacestrant for the treatment of patients with ER-positive, HER2-negative, ESR1-mutated advanced or metastatic breast cancer with disease progression after at least 1 line of endocrine therapy.

Based on findings from subgroup analyses of the phase 3 EMERALD trial (NCT03778931), there was some initial concern about using elacestrant in patients with bone, liver, or lung metastases, Ansley began. However, significant responses were observed among patients with liver and/or lung metastases who were treated with elacestrant, she explained. Specifically, in those with liver and/or lung metastases and ESR1-mutant disease, the median progression-free survival (PFS) was 7.3 months and 1.9 months with elacestrant vs standard of care (SOC), respectively (HR, 0.35; 95% CI, 0.21-0.59), she added. Furthermore, patients with bone metastases experienced a median PFS of 9.1 months with elacestrant compared with 1.9 months with SOC (HR, 0.38; 95% CI, 0.23-0.62), which is encouraging, according to Ansley.

Beyond the median PFS, Ansley also noted that elacestrant was well tolerated, with minimal adverse effects (AEs) observed because it is an endocrine-based therapy. Of note, the majority of AEs observed were grade 1/2 in the overall patient population. Treatment discontinuations due to any treatment-related AE occurred in 8 patients treated with elacestrant (n = 237) vs 2 treated with SOC (n = 230). No treatment-related deaths were reported in either arm. Additionally, the updated safety analysis revealed that the most common any-grade gastrointestinal AEs observed included nausea (elacestrant, 35%; SOC, 19%) and vomiting (19%; 9%).