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Study Comparing Imlunestrant with Standard Endocrine Therapy for Patients with Early ER+, HER2- Breast Cancer at Increased Risk of Recurrence

Verified siteRegistered drugNo placebo
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What is this trial about?

A plain-language summary of the goals, design and what participants do

This clinical trial is focused on studying treatments for early-stage breast cancer, specifically for patients who have a type of breast cancer known as ER-positive and HER2-negative. These terms refer to the presence of certain receptors on cancer cells that can influence how the cancer grows and responds to treatment. The study is comparing a new treatment called imlunestrant with standard treatments that are commonly used to block the effects of estrogen, a hormone that can promote the growth of some breast cancers. The standard treatments being compared include medications like tamoxifen, exemestane, anastrozole, letrozole, and gonadotropin-releasing hormone analogues.

The purpose of the study is to evaluate how effective imlunestrant is compared to these standard treatments in preventing the return of breast cancer in patients who have already received two to five years of standard endocrine therapy. Endocrine therapy is a treatment that helps to stop or slow the growth of cancer by blocking the body's natural hormones. Participants in the study will be randomly assigned to receive either imlunestrant or one of the standard treatments. The study will monitor participants over a period of time to see how well the treatments work in preventing cancer from coming back.

Throughout the study, participants will receive regular check-ups and assessments to monitor their health and the effectiveness of the treatment. The study aims to provide valuable information on whether imlunestrant can offer a better option for patients with this type of breast cancer, potentially improving outcomes and reducing the risk of cancer recurrence. The study will also look at the overall health and quality of life of participants while they are receiving treatment.

The research process

The trial runs in 6 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Enrollment and initial assessment

    Upon joining the study, an initial assessment will be conducted to confirm eligibility. This includes reviewing medical history and current health status.

    Participants must have early-stage ER+ HER2- breast cancer, have undergone surgery, and have been on estrogen-blocking medication for 2 to 5 years.

  2. Step 2

    Randomization

    Participants will be randomly assigned to one of two groups: one receiving imlunestrant and the other receiving standard endocrine therapy.

    This process ensures that each participant has an equal chance of being placed in either group.

  3. Step 3

    Treatment phase

    Participants in the imlunestrant group will take the medication orally as directed by the study team.

    Participants in the standard therapy group will continue with their prescribed endocrine therapy, which may include medications like tamoxifen, exemestane, anastrozole, or letrozole.

  4. Step 4

    Regular follow-up visits

    Regular follow-up visits will be scheduled to monitor health and response to treatment. These visits may include physical exams, blood tests, and questionnaires.

    Participants will be asked about any side effects or changes in health status.

  5. Step 5

    Completion of treatment

    The treatment phase will continue until the study's end date or until the participant's doctor advises otherwise.

    Participants will be informed about the next steps and any additional follow-up required after completing the treatment phase.

  6. Step 6

    Final assessment

    A final assessment will be conducted to evaluate the overall health and treatment outcomes.

    This may include a review of medical records, final questionnaires, and any necessary medical tests.

Who can join the trial?

7 criteria

  • Have early-stage ER+ HER2- breast cancer.
    • ER+: The cancer cells grow in response to the hormone estrogen.
    • HER2-: The cancer cells do not have an excess of the HER2 protein on their surface.
    • Have already had surgery to treat the breast cancer.
    • Have a higher-than-average risk for the breast cancer to come back.
    • Have been taking a drug that blocks the production or action of estrogen for the last two to five years.
    • Be able to walk and able to carry out light work.
    • Have adequate body organ function.

Who cannot join the trial?

4 criteria

  • Patients who have not received 2 to 5 years of standard ET (endocrine therapy) for ER+ (estrogen receptor-positive), HER2- (human epidermal growth factor receptor 2-negative) EBC (early breast cancer) with an increased risk of recurrence.
  • Patients who are not within the specified age range for the study.
  • Patients who do not meet the gender requirements for the study.
  • Patients who are considered part of a vulnerable population that the study does not include.
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Investigated drugs

  • Imlunestrant

    is a medication being studied for its potential to help patients with a specific type of breast cancer. This type of breast cancer is called ER+ and HER2-, which means that the cancer cells grow in response to the hormone estrogen but do not have too much of a protein called HER2. Imlunestrant works by blocking the effects of estrogen on the cancer cells, which may help to slow down or stop the growth of the cancer. In this trial, researchers are looking to see if imlunestrant can be more effective than the standard hormone treatments that patients usually receive after their initial therapy.

  • Standard Adjuvant Endocrine Therapy

    refers to the usual hormone treatments given to patients with ER+ and HER2- breast cancer after they have completed their initial therapy. These treatments are designed to lower the levels of estrogen in the body or block its effects on cancer cells, which can help prevent the cancer from coming back. The standard therapies often include medications like tamoxifen or aromatase inhibitors, which have been used for many years to help reduce the risk of breast cancer recurrence. In this trial, the standard therapy is being compared to imlunestrant to see which is more effective in preventing the cancer from returning.

What is already known about the treatment

Imlunestrant – Imlunestrant is administered orally and is being studied as a treatment for certain types of breast cancer. It is currently in a Phase 3 clinical trial, which means it is being tested for effectiveness and safety in a larger group of patients. The main use of imlunestrant is for patients with early-stage breast cancer that is estrogen receptor-positive (ER+) and human epidermal growth factor receptor 2-negative (HER2-), who have an increased risk of the cancer coming back. Imlunestrant works by blocking the effects of estrogen on cancer cells, which can slow down or stop the growth of these cells. It is classified as an endocrine therapy, which is a type of treatment that targets hormone-related cancers.

Investigated diseases

Breast Neoplasms – Breast neoplasms refer to abnormal growths of tissue in the breast, which can be benign or malignant. Malignant breast neoplasms, commonly known as breast cancer, can originate in different parts of the breast, such as the ducts or lobules. The disease progresses as cancer cells grow uncontrollably and can invade nearby tissues or spread to other parts of the body through the lymphatic system or bloodstream. Early stages may not show symptoms, but as the disease advances, symptoms like lumps, changes in breast shape, or skin dimpling may occur. The progression can vary widely, with some neoplasms growing slowly and others more rapidly. Understanding the specific type and characteristics of the neoplasm is crucial for determining its behavior and potential impact.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2022-501007-28-00Protocol codeJ2J-MC-JZLHEstimated enrolment8 082 patientsSponsorEli Lilly & Co.

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