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Study of ribociclib with or without chemotherapy for patients with hormone receptor positive, HER2 negative early breast cancer at intermediate risk

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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 studying breast cancer that is hormone receptor-positive and HER2-negative at intermediate risk of coming back after surgery. The study will compare two treatment approaches in patients who are eligible for chemotherapy. One group will receive ribociclib combined with hormone therapy without chemotherapy, while the other group will receive chemotherapy first, followed by ribociclib and hormone therapy. The chemotherapy medications that may be used include doxorubicin, epirubicin, cyclophosphamide, paclitaxel, paclitaxel albumin-bound, and docetaxel, which are given through a vein. The hormone therapy medications include letrozole, anastrozole, and exemestane, which are taken by mouth. Some patients may also receive medications called goserelin, leuprorelin, or triptorelin to suppress ovarian function, which are given as injections under the skin.

The purpose of this study is to find out if treatment with ribociclib and hormone therapy alone works as well as treatment that includes chemotherapy followed by ribociclib and hormone therapy in preventing breast cancer from returning. The study will look at how long patients remain free from invasive breast cancer coming back, including cancer returning in the same breast, nearby areas, the opposite breast, spreading to other parts of the body, or death from any cause. The study will also examine other outcomes such as survival without distant disease spread, overall survival, and what types of cancer recurrence occur.

Patients in the study will have already had surgery to remove their breast cancer with clear margins. They will be randomly assigned to one of the two treatment groups. Treatment with ribociclib will be given for a specific period, and hormone therapy is planned to continue for at least five years. Throughout the study, patients will be monitored for side effects and their quality of life will be assessed using questionnaires. Regular blood tests and heart monitoring will be performed to check for any problems related to the treatment. The study will follow patients over several years to compare how well each treatment approach works in preventing the cancer from returning.

The research process

The trial runs in 9 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Initial Assessment and Baseline Tests

    Blood tests will be performed to check blood cell counts, kidney function, and liver function. Specific measurements include white blood cells, platelets, red blood cells, kidney markers, liver enzymes, bilirubin (a substance produced by the liver), and electrolytes such as potassium, calcium, and magnesium.

    A heart tracing test called an electrocardiogram (ECG) will be performed to measure the heart's electrical activity and rhythm. The heart rate should be between 50 and 100 beats per minute, and the QTcF interval (a measurement of the heart's electrical cycle) should be less than 450 milliseconds.

    For women who can become pregnant, a blood pregnancy test will be performed to confirm that pregnancy is not present.

    Physical examination and performance status assessment will be completed to evaluate overall health and ability to carry out daily activities.

  2. Step 2

    Random Assignment to Treatment Group

    Assignment will be made to one of two treatment groups. The assignment is random, meaning it is determined by chance, similar to flipping a coin.

    Arm A: Treatment with ribociclib (a medication that blocks certain proteins that help cancer cells grow) combined with endocrine therapy (hormone-blocking treatment).

    Arm B: Treatment with chemotherapy first, followed by ribociclib combined with endocrine therapy.

  3. Step 3

    Treatment Phase for Arm A

    Treatment will begin with ribociclib taken by mouth combined with endocrine therapy.

    The endocrine therapy may include one of the following medications taken by mouth: letrozole, anastrozole, or exemestane. These medications work by reducing the amount of estrogen in the body or blocking estrogen from reaching cancer cells.

    If premenopausal at diagnosis, additional medications may be given by injection under the skin to suppress ovarian function. These include goserelin, leuprorelin, or triptorelin.

    The endocrine therapy treatment is planned to continue for at least 5 years from the start of treatment.

  4. Step 3

    Treatment Phase for Arm B - Chemotherapy

    Treatment will begin with chemotherapy, which uses medications to kill cancer cells or stop them from growing.

    Chemotherapy medications may include combinations of the following, given through a vein (intravenously): doxorubicin, epirubicin, cyclophosphamide, paclitaxel, paclitaxel albumin-bound, or docetaxel.

    The specific chemotherapy regimen, dosage, frequency, and duration will be determined based on standard treatment protocols.

    After completing chemotherapy, treatment will continue with ribociclib and endocrine therapy as described for Arm A.

  5. Step 4

    Treatment Phase for Arm B - Ribociclib and Endocrine Therapy

    Following completion of chemotherapy, treatment with ribociclib taken by mouth will begin, combined with endocrine therapy.

    The endocrine therapy may include one of the following medications taken by mouth: letrozole, anastrozole, or exemestane.

    If premenopausal at diagnosis, additional medications may be given by injection under the skin to suppress ovarian function. These include goserelin, leuprorelin, or triptorelin.

    The endocrine therapy treatment is planned to continue for at least 5 years from the randomization date.

  6. Step 5

    Regular Monitoring During Treatment

    Regular clinic visits will be scheduled throughout the treatment period.

    Blood tests will be performed periodically to monitor blood cell counts, kidney function, liver function, and electrolyte levels.

    Heart monitoring with electrocardiograms (ECG) will be performed at regular intervals to check heart rhythm and electrical activity.

    Physical examinations will be conducted to assess overall health and check for any side effects.

    Any side effects or adverse events will be recorded and evaluated according to standard toxicity criteria.

  7. Step 6

    Quality of Life Assessments

    Questionnaires will be completed at specific time points to assess quality of life and symptoms.

    The EORTC QLQ-C30 questionnaire evaluates general quality of life, including physical, emotional, and social well-being.

    The EORTC QLQ-BR42 questionnaire specifically assesses breast cancer-related symptoms and concerns.

    These assessments help track how treatment affects daily life and overall well-being.

  8. Step 7

    Contraception Requirements

    Women who can become pregnant must use one effective form of contraception during the entire treatment period.

    Contraception must continue for at least 21 days after the last dose of study medications, or longer if required by standard medical practice.

    This requirement is necessary because the study medications could harm an unborn baby.

  9. Step 8

    Long-Term Follow-Up

    After completing the active treatment phase, regular follow-up visits will continue.

    Follow-up assessments will monitor for any signs of cancer recurrence, including local recurrence, regional recurrence, distant spread, or new breast cancer in the opposite breast.

    Overall health status and survival will be tracked throughout the follow-up period.

    The study is expected to continue follow-up until November 2037.

Who can join the trial?

20 criteria

  • You must sign a written informed consent form before any screening procedures for the trial
  • You must be at least 18 years old
  • You must be female and have gone through menopause, which means your menstrual periods have permanently stopped. This can be confirmed by having had both ovaries surgically removed, being 60 years or older, or having specific blood test results that show menopause
  • You must have been diagnosed with invasive breast cancer, which is cancer that has spread into surrounding breast tissue, confirmed by laboratory examination of tissue samples
  • Your breast cancer must be HR-positive, meaning the cancer cells have receptors for hormones like estrogen, with at least 10% of tumor cells showing positive staining
  • Your breast cancer must be HER2-negative, meaning the cancer cells do not have too much of a protein called HER2
  • Your cancer must be at a specific stage based on tumor size, lymph node involvement, and how abnormal the cancer cells look under a microscope
  • Your doctor must determine that you are suitable for chemotherapy, which is a type of cancer treatment using strong medicines to kill cancer cells
  • You must have no medical reasons preventing you from receiving hormone therapy or chemotherapy, and you must be planned to receive hormone therapy for at least 5 years
  • You must have had surgery to remove the cancer within 12 weeks before joining the study, with clear margins meaning no cancer cells at the edges of removed tissue. If margins were positive, additional surgery or radiation treatment must be planned
  • Your overall health and ability to carry out daily activities must be good, scoring 0 or 1 on a scale called ECOG performance status
  • Your blood tests must show adequate levels of white blood cells, red blood cells, and platelets, which are cells that help your blood clot
  • Your kidney and liver function tests must be within acceptable ranges
  • Your blood levels of potassium, calcium, and magnesium must be normal or corrected to normal before starting treatment
  • Your heart rhythm test called an ECG must show normal results with heart rate between 50 and 100 beats per minute
  • If you are able to become pregnant, you must have a negative pregnancy test before starting treatment
  • If you are able to become pregnant, you must agree to use effective birth control during treatment and for at least 21 days after the last dose
  • You must be willing and able to attend all scheduled visits, follow the treatment plan, and complete required laboratory tests
  • You must not have any mental, family, or geographical situations that would prevent you from following the study requirements
  • You must be registered with a Social Security System or equivalent health insurance based on local requirements

Who cannot join the trial?

5 criteria

  • Men cannot participate in this study, as it is only for female patients
  • Children and young people under 18 years of age cannot participate in this study
  • Patients who do not have HR+ HER2- early breast cancer cannot participate. This means the breast cancer must have certain markers: it must be positive for hormone receptors (proteins that respond to hormones like estrogen or progesterone) and negative for HER2 (a protein that can make cancer grow faster)
  • Patients whose breast cancer is not at intermediate risk of recurrence cannot participate. This means the cancer must have a medium chance of coming back after treatment, not a low or high chance
  • Patients who are not eligible for adjuvant chemotherapy cannot participate. Adjuvant chemotherapy means cancer-fighting medication given after surgery to reduce the risk of cancer returning
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Investigated drugs

  • Ribociclib

    is a targeted cancer medication that works by blocking certain proteins that help cancer cells grow and divide. It is used in combination with hormone therapy to treat hormone receptor-positive, HER2-negative breast cancer. In this trial, ribociclib is being tested to see if it can be effective without the need for chemotherapy in patients with intermediate-risk early breast cancer.

  • Endocrine therapy

    (also called hormone therapy) is a treatment that blocks or lowers the amount of hormones in the body that can help certain types of breast cancer grow. This type of therapy is specifically designed for breast cancers that are hormone receptor-positive, meaning the cancer cells grow in response to hormones like estrogen or progesterone.

  • Chemotherapy

    is a traditional cancer treatment that uses strong medications to kill fast-growing cells in the body, including cancer cells. In this trial, chemotherapy is being compared to treatment without chemotherapy to determine if patients with intermediate-risk breast cancer can achieve similar results without undergoing chemotherapy.

What is already known about the treatment

Ribociclib – Ribociclib is a medication taken by mouth in tablet form that belongs to a class of drugs called CDK4/6 inhibitors, which work by blocking specific proteins that help cancer cells grow and divide. It is an approved treatment used in combination with hormone therapy for certain types of breast cancer, particularly hormone receptor-positive, HER2-negative breast cancer. In this clinical trial, researchers are studying whether ribociclib combined with hormone therapy can be as effective as chemotherapy followed by ribociclib and hormone therapy in patients with early-stage breast cancer at intermediate risk of the cancer returning. The medication targets the cell cycle machinery inside cancer cells, essentially putting the brakes on their ability to multiply and spread throughout the body.

Investigated diseases

Breast Cancer – Breast cancer is a disease where abnormal cells in the breast tissue grow uncontrollably and form a tumor. In this study, the focus is on a specific type called hormone receptor-positive and HER2-negative early breast cancer, which means the cancer cells have receptors for hormones like estrogen or progesterone but do not have excess HER2 protein. Early breast cancer refers to cancer that has not spread beyond the breast or nearby lymph nodes. The disease can progress by spreading to other parts of the breast, nearby tissues, lymph nodes, or distant organs in the body. Patients in this study have an intermediate risk of the cancer returning after initial treatment. The cancer may recur in the same breast, the opposite breast, nearby areas, or in distant parts of the body.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2025-520979-13-00Protocol codeUC-BCG-2501Estimated enrolment3 746 patientsSponsorUnicancer

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On this site, “treatment” means an investigational medicine being studied in a clinical trial. Its safety and efficacy for the use being studied have not yet been confirmed, some participants may receive a placebo or a comparator medicine, and taking part does not guarantee any health benefit. The decision to take part is made by the doctor at the research site. This site is for information only and does not replace medical advice.

This service is not affiliated with the European Commission, the EMA, or the official CTIS system. Most information comes from publicly available international clinical-trial registries, supplemented by data from academic sites, national regulators and commercial sponsors. On this site, “treatment” and “therapy” mean a medicine being tested in a clinical trial. Its safety and effectiveness in the use being studied are not yet confirmed, some participants may receive a placebo or a comparator, and taking part does not guarantee a health benefit. The doctor at the research site decides who can take part. This site provides information, not medical advice. Certain content and visual elements on this website have been generated or enhanced using artificial intelligence (AI).