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Study of ribociclib combined with hormone therapy for patients with early-stage hormone receptor-positive, HER2-negative breast cancer

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 focuses on treating early breast cancer that is hormone receptor-positive and HER2-negative. The study evaluates the effectiveness and safety of using ribociclib (also known as LEE011) in combination with hormone therapy. The hormone therapy medications used in the study include anastrozole, letrozole, and goserelin.

The main purpose of this study is to determine if adding ribociclib to standard hormone therapy improves outcomes for patients with early breast cancer compared to hormone therapy alone. Ribociclib is given as a tablet that is taken by mouth, while goserelin is given as an injection under the skin. Anastrozole and letrozole are also taken as tablets.

During the study, patients will receive either the combination of ribociclib with hormone therapy or hormone therapy by itself. The treatment continues for up to 5 years, and patients will have regular check-ups to monitor their health. The study team will track how long patients remain free from cancer returning and assess the overall safety of the treatment combination.

The research process

The trial runs in 5 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Initial medical assessment

    Your medical condition will be confirmed as hormone receptor-positive, HER2-negative early breast cancer

    Basic health tests will be performed including blood tests, heart function (ECG), and kidney function assessment

  2. Step 2

    Treatment assignment

    You will be randomly assigned to one of two treatment groups

    Group 1: endocrine therapy alone

    Group 2: ribociclib plus endocrine therapy

  3. Step 3

    Treatment period

    The treatment will continue for 5 years from the start date

    Depending on your group, you will receive:

    - Endocrine therapy: oral medications (anastrozole or letrozole)

    - If applicable, goserelin will be given as an injection under the skin

    - If assigned, ribociclib will be taken by mouth

  4. Step 4

    Regular monitoring

    Regular health checks will include:

    Blood tests to monitor cell counts and organ function

    Heart monitoring with ECG

    Physical examinations

    Quality of life assessments

  5. Step 5

    Follow-up period

    The study will continue until April 2026

    Regular check-ups will monitor your health status

    Assessment of how well the treatment is working

    Monitoring for any side effects

Who can join the trial?

19 criteria

  • Must be at least 18 years old
  • Must sign an informed consent form before any study procedures
  • Must have completed radiation therapy (if required) before screening
  • Must be able to receive hormone therapy for at least 5 years
  • Must have good physical functioning status (ECOG 0 or 1, meaning able to perform daily activities)
  • Must have adequate blood test results, including:
    • Normal white blood cell counts
    • Normal platelet levels
    • Adequate hemoglobin levels
    • Normal kidney function
    • Normal liver function
    • Must have normal heart rhythm on ECG test
    • Must be willing to attend all scheduled visits and follow study procedures
    • Women who can become pregnant must have a negative pregnancy test and use effective birth control methods during the study
    • Must have confirmed breast cancer that is:
      • Hormone receptor-positive (responds to hormones)
      • HER2-negative (specific type of breast cancer)
      • Completely removed by surgery with clear margins
      • At specific disease stages (Stage IIA, IIB, or III) with certain risk factors
      • Must have completed chemotherapy (if required) before screening
      • Must have tumor tissue available for laboratory testing (except for patients in China)

Who cannot join the trial?

14 criteria

  • Previous treatment with CDK4/6 inhibitors (drugs that block specific proteins involved in cell growth)
  • Presence of metastatic disease (cancer that has spread to other parts of the body)
  • History of other malignancies within the past 5 years, except for adequately treated non-melanoma skin cancer or carcinoma in situ
  • Severe heart conditions including:
    • Uncontrolled high blood pressure
    • Heart attack within past 6 months
    • Unstable heart rhythm problems
    • Severe liver problems or abnormal liver function tests
    • Known hypersensitivity (allergic reaction) to the study medications
    • Pregnant or breastfeeding women
    • Participation in another clinical trial within 30 days before starting this study
    • Any condition that would make it unsafe for the patient to participate in the study, as determined by the study doctor
    • Unable to swallow oral medications
    • Major surgery within 14 days before starting the study treatment
    • Active or uncontrolled infections
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Investigated drugs

  • Ribociclib

    A medication used in combination with endocrine therapy for treating breast cancer. It belongs to a class of drugs called CDK4/6 inhibitors that help stop cancer cells from growing and dividing. This medication is taken orally and works by blocking specific proteins that promote cancer cell growth.

  • Endocrine Therapy (ET)

    A treatment that blocks or lowers the amount of hormones in the body to stop or slow down the growth of hormone receptor-positive breast cancer. This therapy can include different types of hormone-blocking medications that either lower estrogen levels or prevent estrogen from attaching to cancer cells.

What is already known about the treatment

  • Ribociclib

    A targeted therapy medication administered orally as tablets, used in combination with endocrine therapy for the treatment of hormone receptor-positive, HER2-negative early breast cancer. This drug belongs to the class of CDK4/6 inhibitors and works by blocking specific proteins that promote cancer cell growth, effectively slowing down or stopping the progression of cancer cells. Currently established in medical practice as an important component of breast cancer treatment, Ribociclib has shown promising results in clinical trials when used as an adjuvant therapy, particularly in early-stage breast cancer where it helps prevent cancer recurrence.

  • Endocrine Therapy (ET)

    A hormonal treatment approach administered either orally or through injection, designed to block or lower the levels of hormones that can stimulate cancer growth in hormone receptor-positive breast cancer. This well-established treatment works by either blocking hormone production or preventing hormones from binding to cancer cells, and it has been a cornerstone of breast cancer treatment for many years. Endocrine therapy includes various medications such as tamoxifen or aromatase inhibitors, which are typically prescribed for several years to reduce the risk of cancer recurrence.

Investigated diseases

  • Hormone Receptor-Positive Breast Cancer

    A type of breast cancer where cancer cells grow in response to hormones estrogen and progesterone. The cancer cells have proteins called hormone receptors that become activated when hormones attach to them. This disease typically develops in the breast tissue and can spread to nearby lymph nodes. The cancer cells display specific receptors on their surface that respond to natural hormones in the body. This condition represents the most common form of breast cancer.

  • HER2-Negative Breast Cancer

    A form of breast cancer where the cancer cells do not have high amounts of a protein called HER2 on their surface. This cancer tends to grow more slowly than HER2-positive cancers. The disease develops when breast cells begin to divide uncontrollably without elevated levels of the HER2 protein. This type of breast cancer typically responds differently to treatments compared to HER2-positive cases.

  • Early Breast Cancer

    A stage of breast cancer where the disease is contained within the breast or has only spread to nearby lymph nodes. At this stage, the cancer is localized and has not spread to distant parts of the body. The disease is typically discovered during early screening or when a small lump is detected. This represents the initial phase of breast cancer development.

Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2023-510357-42-00Protocol codeCLEE011O12301CEstimated enrolment4 992 patientsSponsorNovartis Pharma AG

sourced from the EU Clinical Trials Register and site verification

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