Last reviewed 2026-04-20 · How we verify

Inluriyo (IMLUNESTRANT)

Inluriyo works by blocking estrogen receptors on cancer cells, preventing them from growing and spreading.

Inluriyo (imlunestrant) is a small molecule estrogen receptor antagonist developed by Eli Lilly And Co. It is used to treat ER-positive, HER2-negative, ESR1-mutated advanced or metastatic breast cancer, particularly in patients with disease progression following at least one line of endocrine therapy. Inluriyo was approved by the FDA in 2025 and is currently patented. Key safety considerations include its half-life of 30 hours. As a patented medication, there are currently no generic manufacturers.

At a glance

Mechanism of action

Imlunestrant is an estrogen receptor (ER) antagonist that binds to ERα. In vitro, imlunestrant induced degradation of ERα, leading to inhibition of ER-dependent gene transcription and cellular proliferation in ER+ breast cancer cells. Imlunestrant demonstrated in vitro and in vivo anti-tumor activity in ER+ breast cancer xenograft models, including models with ESR1 mutations.

Approved indications

• ER-positive, HER2-negative, ESR1-mutated advanced or metastatic breast cancer
• ER-positive, HER2-negative, ESR1-mutated advanced or metastatic breast cancer with disease progression following at least one line of endocrine therapy

Common side effects

• Musculoskeletal pain
• Fatigue
• Diarrhea
• Nausea
• Constipation
• Abdominal pain
• Hemoglobin decreased
• Neutrophils decreased
• Calcium decreased
• Platelets decreased
• ALT increased
• Triglycerides increased

Drug interactions

• Strong CYP3A Inhibitors
• Strong CYP3A Inducers
• Strong CYP3A Inhibitors
• Strong CYP3A Inducers
• P-gp or BCRP Substrates

Key clinical trials

• A Study of LOXO-783 in Patients With Breast Cancer/Other Solid Tumors (PHASE1)
• A Study of Imlunestrant (LY3484356) in Premenopausal Women With Estrogen Receptor-Positive (ER+) Human Epidermal Growth Factor Receptor 2 Negative (HER2-) Early Breast Cancer (PHASE2)
• A Study of LY4257496 in Participants With Cancer (OMNIRAY) (PHASE1)
• First-in-Human Study of STX-478 as Monotherapy and in Combination With Other Antineoplastic Agents in Participants With Advanced Solid Tumors (PHASE1,PHASE2)
• Neoadjuvant Imlunestrant Plus Abemaciclib Treatment Guided by Ki67 Index After 2 Weeks for ER-Positive HER2-Negative Breast Cancer (PHASE2)
• A Study of Imlunestrant Versus Standard Endocrine Therapy in Participants With Early Breast Cancer (PHASE3)
• A Study of Imlunestrant (LY3484356) in Female Healthy Participants (PHASE1)
• A Study of LY3484356 in Healthy Female Participants (PHASE1)

Patents

Primary sources

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