ORSERDU (elacestrant) is an oral estrogen receptor antagonist indicated for ER-positive, HER2-negative, ESR1-mutated advanced or metastatic breast cancer in postmenopausal women or adult men following disease progression after prior endocrine therapy, demonstrating improved progression-free survival in clinical trials.

Therapeutic Efficacy and Clinical Application of Elacestrant in ESR1-Mutated Advanced Breast Cancer

ORSERDU (elacestrant) exerts its therapeutic effect by antagonizing estrogen receptor-alpha (ERα), inducing receptor degradation via the proteasomal pathway, thereby inhibiting estrogen-driven tumor proliferation. It is specifically effective in ER-positive, HER2-negative breast cancer harboring activating ESR1 mutations, a subgroup resistant to prior endocrine therapies, including CDK4/6 inhibitors. In the EMERALD trial, patients with ESR1 mutations treated with ORSERDU achieved a median progression-free survival (PFS) of 3.8 months versus 1.9 months in the control group (fulvestrant/aromatase inhibitors), with a hazard ratio of 0.55 (95% CI: 0.39–0.77).