The U.S. Food and Drug Administration (FDA) has approved Inluriyo (imlunestrant, 200 mg tablets), a new oral treatment from Eli Lilly and Company, for adults with estrogen receptor-positive (ER+), HER2-negative (HER2–), ESR1-mutated advanced or metastatic breast cancer (MBC) whose disease has progressed following at least one line of endocrine therapy.
The approval is based on results from the Phase 3 EMBER-3 trial, which demonstrated that Inluriyo significantly improved progression-free survival compared to standard endocrine therapy. Patients receiving Inluriyo experienced a 38% reduction in risk of disease progression or death. In those with ESR1-mutated MBC, median progression-free survival was 5.5 months with Inluriyo, compared to 3.8 months with fulvestrant or exemestane.
“This therapy reflects our commitment to developing treatments that improve outcomes for people with breast cancer,” said Jacob Van Naarden, executive vice president and president of Lilly Oncology. “It represents an important step toward advancing innovative, all-oral treatment approaches.”
Targeting ESR1 Mutations
ESR1 mutations, which are found in nearly half of patients previously treated with hormone therapy, are known to contribute to treatment resistance. Inluriyo works by binding to and degrading estrogen receptors, helping to reduce cancer cell growth. Its once-daily oral dosing offers a more convenient option compared to injectable therapies.
“This represents an important advancement for patients with ESR1-mutated MBC,” said Dr. Komal Jhaveri of Memorial Sloan Kettering Cancer Center, a principal investigator in the EMBER-3 trial. “With its demonstrated efficacy, tolerability, and oral administration, this therapy provides a meaningful alternative.”
Safety and Side Effects
The majority of side effects observed in the trial were low-grade (Grade 1 or 2). Common adverse reactions included decreased hemoglobin, musculoskeletal pain, fatigue, diarrhea, and nausea. Treatment discontinuation due to side effects occurred in 4.6% of patients.
The drug’s label includes a warning for embryo-fetal toxicity, and prescribers are advised to consult full safety information before use.
Looking Ahead
Inluriyo is also under investigation in the ongoing EMBER-4 trial, a Phase 3 study evaluating its use in early-stage breast cancer at high risk of recurrence. That trial is enrolling approximately 8,000 patients globally.
“The approval of Inluriyo expands the metastatic breast cancer treatment landscape,” said Jean Sachs, CEO of Living Beyond Breast Cancer. “Eligible patients will now have access to an additional treatment option, offering them flexibility and hope.”
Eli Lilly expects Inluriyo to become available in the U.S. within the coming weeks.
About Inluriyo (imlunestrant):
- Class: Oral estrogen receptor antagonist
- Indication: ER+, HER2–, ESR1-mutated advanced/metastatic breast cancer
- Dosage: 200 mg tablets, once daily
- Manufacturer: Eli Lilly and Company