# Imlunestrant

Source: https://onco.cc/drugs/imlunestrant/  
OnCo record `imlunestrant` (Treatment). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Imlunestrant is Lilly's oral oestrogen-receptor degrader, approved in 2025 for ESR1-mutant breast cancer and shown to work with abemaciclib regardless of mutation.

## Summary

EMBER-3: monotherapy PFS benefit confined to ESR1-mutant tumours (HR 0.62; OS 34.5 vs 23.1 months in update); imlunestrant + abemaciclib beat imlunestrant alone in all patients (PFS 10.9 vs 5.5 months, HR 0.59). FDA approved 25 September 2025 for ESR1-mutant disease after ≥1 endocrine line. EMBER-4 tests it as adjuvant therapy.

## Fields

- Kind: Treatment
- Status: approved
- Last checked: 2026-09-07
- Brand: Inluriyo
- Code: LY3484356
- Modality: Oral SERD
- Mechanism: Brain-penetrant oral SERD; pure antagonist that degrades ER.
- Approvals: US 2025: ER+/HER2- ESR1-mutated advanced breast cancer after ≥1 line of endocrine therapy; EU 2026: ESR1-mutant ER+/HER2- mBC; 9 Jan 2026
- Dosing: Oral; 400 mg once daily (approved as monotherapy); combination with abemaciclib studied
- Toxicity (grade 3+): Diarrhoea (with abemaciclib) 8%

## Sources

- FDA label (DailyMed): https://dailymed.nlm.nih.gov/dailymed/search.cfm?query=Imlunestrant

## Connected records

- biomarkers: [ESR1 mutation (ligand-binding domain, usually in ctDNA)](https://onco.cc/biomarkers/esr1-mutation-ctdna/)
- cancers: [HR-positive / HER2-negative breast cancer](https://onco.cc/cancers/breast-hr-positive/), [HR-positive metastatic breast cancer after CDK4/6 inhibitors](https://onco.cc/cancers/hr-positive-metastatic-post-cdk46/)
- technologies: [Endocrine therapy (SERMs, AIs, SERDs)](https://onco.cc/technologies/endocrine-therapy/), [Oral SERDs](https://onco.cc/technologies/oral-serds/)
- targets: [Estrogen receptor (ERα)](https://onco.cc/targets/estrogen-receptor/)
- companies: [Eli Lilly (incl. Loxo)](https://onco.cc/companies/eli-lilly/)
- terms: [ESR1 mutation](https://onco.cc/terms/esr1-mutation/), [Oral SERD](https://onco.cc/terms/oral-serd/)
- trials: [A Study of Imlunestrant (LY3484356) in Premenopausal Women With Estrogen Receptor-Positive (ER+) Human Epidermal Growth Factor Receptor 2 Negative (HER2-) Early Breast Cancer](https://onco.cc/trials/nct07287098/), [A Study of Imlunestrant Versus Standard Endocrine Therapy in Participants With Early Breast Cancer](https://onco.cc/trials/nct05514054/), [EMBER-3](https://onco.cc/trials/ember-3/)
- pairings: [Oral SERD + CDK4/6 inhibitor after ESR1 emergence](https://onco.cc/pairings/oral-serd-plus-cdk46-after-esr1/)
- roadmaps: [Hormonal therapy roadmap: removing the ovaries → tamoxifen → oral degraders switched by a blood test](https://onco.cc/roadmaps/hormonal-therapy-roadmap/)
- pathways: [Breast cancer (KEGG map)](https://onco.cc/pathways/breast-cancer-signalling/)

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