Imlunestrant
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.
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.
- Route
- Oral
- Schedule
- 400 mg once daily (approved as monotherapy); combination with abemaciclib studied
- Monitoring
- Liver enzymes; diarrhoea with abemaciclib
- Medicare
- Part D (self-administered)
Oral, self-administered, so it is a Part D drug: covered through a stand-alone Part D plan or Medicare Advantage drug benefit, usually on the specialty tier with 25 to 33% coinsurance until the annual cap ($2,000 in 2025, $2,100 in 2026). FDA-approved 2025.
- Commercial insurance
- covered with prior authorisation
Covered for FDA-labelled and NCCN-listed uses, but almost always behind prior authorisation confirming diagnosis, biomarker and line of therapy; dispensed through a specialty pharmacy. ESR1 mutation documentation required; plan policies are still being written.
- Assistance programmes
- Lilly Cares Foundation
- PAN Foundation — Disease-specific co-pay and premium funds; open and closed funds change monthly.
- HealthWell Foundation
- CancerCare Co-Payment Assistance Foundation
- Patient Advocate Foundation Co-Pay Relief
Part D out-of-pocket capped at $2,000 (2025) / $2,100 (2026). Medicare patients cannot use manufacturer co-pay cards; charity funds (PAN, HealthWell, CancerCare) and the Extra Help subsidy are the routes.
Sources: Medicare.gov: Drug coverage (Part D) · Medicare.gov: Costs for Medicare drug coverage (annual out-of-pocket cap). Not medical or financial advice; verify with your plan.
- Notes
- Recently licensed; a NICE appraisal is scheduled or in progress. Interim access may be possible via the CDF interim funding route once NICE issues positive draft guidance.
Sources: NICE search: imlunestrant. Funding decisions are indication-specific and change monthly; verify with NICE and your treating team.
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- 25 Sept 2025ApprovalUS
Approved as Inluriyo source
Approvals
| Region | Year | Indication |
|---|---|---|
| US | 2025 | ER+/HER2- ESR1-mutated advanced breast cancer after ≥1 line of endocrine therapy |
| Adverse event | Any grade | Grade 3+ |
|---|---|---|
| Diarrhoea (with abemaciclib) | 86% | 8% |
| Nausea (monotherapy) | 17% | — |
| Fatigue | 23% | — |
Events listed without rates were not read from a primary source; see the label. Blank cells mean the figure was not sourced, not that it is zero.
Trials
topRecruiting now (live from ClinicalTrials.gov)
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Landmark trials in OnCo
Latest papers
topQuery for this drug: (TITLE:"Imlunestrant" OR ABSTRACT:"Imlunestrant" OR TITLE:"Inluriyo" OR ABSTRACT:"Inluriyo" OR TITLE:"LY3484356" OR ABSTRACT:"LY3484356") AND (cancer OR tumor OR tumour OR oncology OR carcinoma OR lymphoma OR leukemia OR leukaemia OR myeloma OR sarcoma OR melanoma OR glioma). Results are unfiltered search hits about Imlunestrant, not a curated reading list.