What Was Approved?
On September 25, 2025, the U.S. Food and Drug Administration approved Inluriyo (imlunestrant) for adults with:
- Estrogen receptor-positive (ER-positive) breast cancer
- HER2-negative breast cancer
- An ESR1 mutation
- Advanced or metastatic disease
- Disease progression after at least one prior line of endocrine therapy
An FDA-approved test is used to identify eligible patients with an ESR1 mutation.
How Does Inluriyo Work?
Inluriyo is an estrogen receptor antagonist.
It is designed to block estrogen-receptor signaling that can help drive the growth of certain ER-positive breast cancers.
How Is Inluriyo Taken?
The recommended dose is:
400 mg by mouth once daily.
It should be taken on an empty stomach, at least 2 hours before food or 1 hour after food.
Treatment generally continues until disease progression or unacceptable toxicity.
What Did the Clinical Trial Show?
FDA approval was supported by the EMBER-3 clinical trial, which enrolled 874 patients with ER-positive, HER2-negative advanced or metastatic breast cancer previously treated with endocrine therapy.
The study evaluated whether imlunestrant could delay disease progression compared with standard endocrine therapy.
Trial results supported FDA approval in the subgroup of patients with ESR1-mutated tumors.
Who Is Inluriyo For?
Inluriyo is not approved for every patient with ER-positive breast cancer.
Eligibility depends on:
- ER-positive status
- HER2-negative status
- Presence of an ESR1 mutation
- Prior endocrine therapy
- Advanced or metastatic disease
Bottom Line
Inluriyo (imlunestrant) is an FDA-approved oral endocrine therapy for certain adults with ER-positive, HER2-negative, ESR1-mutated advanced or metastatic breast cancer after prior endocrine treatment.
Because eligibility depends on biomarker testing and prior treatment history, therapy should be guided by an oncology team.
Sources
- U.S. Food and Drug Administration (FDA) — FDA Approves Imlunestrant for ER-Positive, HER2-Negative, ESR1-Mutated Advanced or Metastatic Breast Cancer, September 25, 2025.
- U.S. Food and Drug Administration (FDA) — Drug Trials Snapshot: Inluriyo.
- U.S. Food and Drug Administration (FDA) — Inluriyo (imlunestrant) Prescribing Information, 2025.