Elacestrant for ER-Positive HER2-Negative Advanced Breast Cancer.

Objective: This article aims to discuss elacestrant, an oral selective estrogen receptor downregulator approved by the Food and Drug Administration (FDA) in January 2023 for the treatment of hormone receptor positive (HR+) human epidermal growth factor receptor 2 negative (HER2-) advanced breast cancer.

Data sources: PubMed, Embase, Medline, Clinicaltrials.gov, and the National Comprehensive Cancer Network (NCCN) were searched from inception to August 31, 2023.

Study selection and data extraction: Clinical trials published in English were included and relevant information regarding methodology and results were extracted.

Data synthesis: Phase 1 and 3 trials showed elacestrant was safe and improved progression-free survival in patients with endocrine receptor 1 (ESR1) mutations who failed cyclin-dependent kinase 4/6 inhibitor (CDK 4/6i) plus 1 prior endocrine therapy compared with standard of care (SOC) (fulvestrant, anastrozole, letrozole, or exemestane monotherapy).

Relevance to patient care and clinical practice in comparison to existing drugs: Elacestrant maintains a comparable adverse event profile with other endocrine therapies and offers an alternative to typical sequential therapy which can delay the use of or be used after traditional chemotherapy. Elacestrant is currently being studied in CDK 4/6 inhibitor naïve patients and as a component of combination therapy for first-line use which could lead to future indications.

Conclusions: Elacestrant gained FDA approval in January 2023 and can be considered in patients with HR+ HER2- advanced breast cancer and ESR1 mutations who have progressed despite therapy with either CDK 4/6i plus aromatase inhibitors (AI) or fulvestrant or chemotherapy.