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Aromatase Inhibitor

Imlunestrant + Abemaciclib for Breast Cancer (EMBER-3 Trial)

Phase 3
Research Sponsored by Eli Lilly and Company
Eligibility Criteria Checklist
Specific guidelines that determine who can or cannot participate in a clinical trial
Must have
Have a diagnosis of ER+, HER2- locally advanced or metastatic breast cancer
Have disease that has demonstrated progression on or after an aromatase inhibitor alone or in combination with a cyclin-dependent kinase (CDK)4/6 inhibitor
Must not have
Have received prior treatment with chemotherapy (except for neoadjuvant/ adjuvant chemotherapy), fulvestrant, or any investigational-ER-directed therapy (including SERDs and non-SERDs), any PI3K-, mTOR- or AKT- inhibitor
Have visceral crisis, lymphangitic spread within the lung, or any evidence of leptomeningeal disease
Screening 3 weeks
Treatment Varies
Follow Up randomization until death from any cause (estimated as up to 5 years)
Awards & highlights


This trial is testing a new drug to see if it's more effective than standard hormone therapy for treating breast cancer.

Who is the study for?
This trial is for postmenopausal women with advanced breast cancer that's ER+ and HER2-. They should have seen their cancer progress after aromatase inhibitor treatment, possibly combined with a CDK4/6 inhibitor. Participants must be able to take pills, have measurable disease or bone-only disease, and be in good physical condition (ECOG 0-1). They can't join if they've had certain prior treatments like chemotherapy or specific inhibitors, have severe brain metastasis, visceral crisis, lung complications from cancer spread, or serious medical conditions.Check my eligibility
What is being tested?
The study tests the effectiveness of Imlunestrant against standard hormone therapy and combines Imlunestrant with Abemaciclib versus Imlunestrant alone in treating ER+, HER2- advanced breast cancer. The goal is to see which treatment works better for patients whose cancer has spread. Participation could last up to five years.See study design
What are the potential side effects?
Potential side effects may include typical reactions associated with hormone therapies such as hot flashes, fatigue, joint pain; and those related to Abemaciclib like diarrhea, low white blood cell counts increasing infection risk. Each patient's experience may vary.

Eligibility Criteria

Inclusion Criteria

You may be eligible if you check “Yes” for the criteria below
My breast cancer is ER+ and HER2-, and has spread beyond the breast.
My cancer progressed after treatment with an aromatase inhibitor and possibly a CDK4/6 inhibitor.
I am fully active or restricted in physically strenuous activity but can do light work.
My cancer progressed after treatment with an aromatase inhibitor and possibly a CDK4/6 inhibitor.
I can swallow pills.
I am postmenopausal.

Exclusion Criteria

You may be eligible for the trial if you check “No” for criteria below:
I have previously been treated with specific cancer therapies, excluding early-stage chemotherapy.
My cancer has spread to my organs, lungs, or brain/spinal cord linings.
I have brain metastasis that is causing symptoms or has not been treated.


Screening ~ 3 weeks
Treatment ~ Varies
Follow Up ~randomization until death from any cause (estimated as up to 5 years)
This trial's timeline: 3 weeks for screening, Varies for treatment, and randomization until death from any cause (estimated as up to 5 years) for reporting.

Treatment Details

Study Objectives

Outcome measures can provide a clearer picture of what you can expect from a treatment.
Primary outcome measures
PFS in the Estrogen Receptor 1 (ESR1)-mutation Detected Population
Progression Free Survival (PFS) in the Intent-to-Treat (IIT) Population
Secondary outcome measures
Clinical Benefit Rate (CBR): Percentage of Participants Who Achieve a Best Overall Response of CR, PR or Stable Disease for Greater than or Equal to (≥) 24 Weeks
Duration of Response (DoR)
OS in the ESR1-mutation Detected Population
+6 more

Trial Design

3Treatment groups
Experimental Treatment
Active Control
Group I: Imlunestrant plus AbemaciclibExperimental Treatment2 Interventions
Imlunestrant plus abemaciclib administered orally.
Group II: ImlunestrantExperimental Treatment1 Intervention
Imlunestrant administered orally.
Group III: Investigator's Choice of Endocrine TherapyActive Control2 Interventions
Investigator's choice of exemestane administered orally or fulvestrant administered intramuscularly (IM). See local approved label for additional instructions.
First Studied
Drug Approval Stage
How many patients have taken this drug
Completed Phase 1
Completed Phase 2

Research Highlights

Information in this section is not a recommendation. We encourage patients to speak with their healthcare team when evaluating any treatment decision.
Mechanism Of Action
Side Effect Profile
Prior Approvals
Other Research
Selective Estrogen Receptor Degraders (SERDs) like Imlunestrant work by binding to estrogen receptors on cancer cells, causing receptor degradation and inhibiting estrogen-driven cancer cell growth. CDK4/6 inhibitors like Abemaciclib block cyclin-dependent kinases 4 and 6, essential for cell cycle progression, thereby preventing cancer cell division. These targeted therapies are crucial for breast cancer patients as they disrupt specific pathways critical for cancer cell survival, offering more effective and personalized treatment options.

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Who is running the clinical trial?

Eli Lilly and CompanyLead Sponsor
2,629 Previous Clinical Trials
3,217,250 Total Patients Enrolled
64 Trials studying Breast Cancer
36,904 Patients Enrolled for Breast Cancer
Study DirectorEli Lilly and Company
1,351 Previous Clinical Trials
415,616 Total Patients Enrolled
21 Trials studying Breast Cancer
10,608 Patients Enrolled for Breast Cancer

Media Library

Exemestane (Aromatase Inhibitor) Clinical Trial Eligibility Overview. Trial Name: NCT04975308 — Phase 3
Breast Cancer Research Study Groups: Imlunestrant, Investigator's Choice of Endocrine Therapy, Imlunestrant plus Abemaciclib
Breast Cancer Clinical Trial 2023: Exemestane Highlights & Side Effects. Trial Name: NCT04975308 — Phase 3
Exemestane (Aromatase Inhibitor) 2023 Treatment Timeline for Medical Study. Trial Name: NCT04975308 — Phase 3
Breast Cancer Patient Testimony for trial: Trial Name: NCT04975308 — Phase 3
~229 spots leftby Jul 2025