- On September 25, 2025, U.S. Food and Drug Administration (FDA) approved Imlunestrant for adults with estrogen receptor-positive (ER+), HER2-negative advanced or metastatic breast cancer who have an ESR-1 mutation and whose cancer progressed after at least one prior line of endocrine therapy.
- The FDA approval was based on data from the EMBER-3 Phase 3 clinical trial.
In the trial, imlunestrant showed a statistically significant improvement in investigator-assessed PFS compared to other endocrine therapies for patients with ESR1-mutated breast cancer.
ESR1mutational status was determined by blood circulating tumor deoxyribonucleic acid (ctDNA) analysis using the Guardant360 CDx assay and was specific to ESR-1 mutations in the ligand-binding domain.
- Any-grade adverse events occurred in 83% of patients in the trial.
Most common adverse events included fatigue, diarrhea, nausea, and elevated liver enzymes.
- The recommended imlunestrant dose is 400 mg orally once daily (on an empty stomach)
https://www.fda.gov/drugs/resources-information-approved-drugs/fda-approves-imlunestrant-er-positive-her2-negative-esr1-mutated-advanced-or-metastatic-breast
