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A Study of Camizestrant and Ribociclib for Patients with Hormone Receptor-Positive Breast Cancer

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What is this trial about?

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

This study involves hormone receptor-positive breast cancer, which is a type of breast cancer where the cancer cells have proteins that allow hormones to attach and help the cancer grow. The study will test two medications given together: camizestrant, also known by its code name AZD9833, and ribociclib. Camizestrant works by breaking down the hormone receptors on cancer cells, while ribociclib blocks certain proteins that help cancer cells divide and grow. The cancer being studied must also be HER2-negative, meaning it does not have high levels of another protein called human epidermal growth factor receptor 2.

The purpose of this study is to find out how long patients can live without their cancer getting worse when treated with this combination of medications, and to compare this with information from previous patients who received different treatments. The study will also look at how safe these medications are when used together and how well they work in shrinking tumors. Patients in this study will take both medications by mouth in the form of tablets and will continue treatment for up to 27 months or until their cancer worsens or side effects become too difficult to manage.

During the study, patients will have regular check-ups where doctors will use scans such as computerized tomography or magnetic resonance imaging to see how the cancer is responding to treatment. The study will also collect tissue samples from tumors to look for specific changes in genes, including ESR1 mutations, which might affect how well the treatment works. Patients will be asked to complete questionnaires about their quality of life and any symptoms they experience. The study is designed for patients whose cancer has spread or come back after previous hormone therapy treatment and who meet specific requirements regarding their overall health and organ function.

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

    Treatment initiation and baseline assessments

    After joining the study, baseline assessments will be completed. These include blood tests to check blood cell counts, liver function, kidney function, and other important health markers.

    Imaging scans such as CT scan (computerized tomography) or MRI (magnetic resonance imaging) will be performed to assess the current state of the disease.

    A tissue sample from a previous biopsy will be reviewed to confirm the characteristics of the breast cancer.

    Quality of life questionnaires will be completed to assess current well-being and symptoms.

  2. Step 2

    Starting study medications

    Treatment will begin with two medications taken by mouth: ribociclib and camizestrant.

    Both medications are taken in the form of film-coated tablets.

    The specific dosage, frequency, and duration of treatment will be determined by the study doctor based on individual assessment.

    If currently taking certain hormone therapy medications such as tamoxifen or toremifene, a waiting period of 35 days after stopping these medications is required before starting the study treatment.

    For pre-menopausal or peri-menopausal women and men, treatment with a hormone therapy called LHRH analogue (luteinizing hormone-releasing hormone analogue) should be started at least 28 days before beginning the study medications.

  3. Step 3

    Regular monitoring visits during treatment

    Regular visits will be scheduled throughout the treatment period to monitor health and how the body is responding to the medications.

    Blood tests will be performed regularly to check blood cell counts, liver function, kidney function, and other safety parameters.

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

    Imaging scans will be performed at scheduled intervals to evaluate whether the cancer is responding to treatment, staying stable, or progressing.

    Quality of life questionnaires will be completed periodically to track symptoms and well-being during treatment.

  4. Step 4

    Assessment of treatment response

    The study doctor will evaluate the imaging scans to determine how the cancer is responding to treatment.

    Response will be classified as complete response (all signs of cancer have disappeared), partial response (cancer has shrunk by at least 30%), stable disease (cancer has neither grown significantly nor shrunk significantly), or progressive disease (cancer has grown).

    The time from starting treatment until the cancer progresses or any other significant change occurs will be carefully tracked.

  5. Step 5

    Ongoing treatment until progression or intolerance

    Treatment with ribociclib and camizestrant will continue as long as the cancer is not progressing and the medications are being tolerated without unacceptable side effects.

    If side effects occur, the study doctor may adjust the dose or temporarily pause treatment to allow recovery.

    Regular monitoring will continue throughout the treatment period to ensure safety.

  6. Step 6

    End of treatment and follow-up

    Treatment will be discontinued if the cancer progresses, if unacceptable side effects occur, or if continuation is no longer appropriate.

    After stopping the study medications, follow-up visits will be scheduled to monitor health status.

    Additional treatments may be considered after the study treatment ends, as determined by the treating doctor.

    For women of childbearing potential, effective birth control must be used until 4 weeks after the last dose of study medications.

    For men, effective birth control must be used until 21 days after the last dose of study medications.

Who can join the trial?

20 criteria

  • You must be able to understand the purpose of the study and sign a written consent form before any study procedures begin.
  • You must have disease that can be measured on scans, or disease that can be evaluated including cancer in the bones with at least one bone area showing signs of cancer damage.
  • If you are taking tamoxifen or toremifene (medicines used to treat breast cancer), you must stop taking them for 35 days before joining the study.
  • You must agree to provide a tissue sample from a biopsy (a small piece of tissue removed for testing) taken when your cancer returned or spread. If this is not available, a stored tissue sample from your original breast cancer may be used.
  • Your blood and organ function must meet certain requirements including adequate levels of white blood cells, neutrophils (a type of white blood cell that fights infection), platelets (cells that help blood clot), and hemoglobin (protein in red blood cells that carries oxygen).
  • Your liver function tests must be within acceptable ranges including albumin (a protein made by the liver), bilirubin (a substance produced when red blood cells break down), and liver enzymes (proteins that help the liver work).
  • Your kidney function must be adequate with creatinine (a waste product filtered by the kidneys) levels within acceptable limits.
  • You must be available and willing to attend all required treatment visits and follow-up appointments.
  • If you are a woman who can become pregnant and are sexually active with a male partner, you must have a negative pregnancy test within 14 days before starting treatment and agree to use highly effective birth control until 4 weeks after your last dose. You must not donate eggs or breastfeed during this time. Your male partner must use a condom during the same period.
  • If you are a man who is sexually active with a woman who can become pregnant, you must be surgically sterilized or use highly effective birth control until 21 days after your last dose. You must not donate sperm during this time. Your female partner must also use highly effective birth control until 4 weeks after your last dose.
  • Your ECOG performance status (a measure of how well you can perform daily activities) must be 0 or 1, meaning you are fully active or have some restrictions but can do light work.
  • Your expected survival must be at least 6 months or longer.
  • You must be 18 years of age or older.
  • If you are a woman who has not gone through menopause or a man, you must be treated with a hormone medicine called LHRH analogue for at least 28 days before starting the study.
  • If you are a woman who has gone through menopause, this means you have not had periods for at least 12 months in a row, or you have had surgery to remove both ovaries.
  • Your breast cancer must be confirmed by tissue testing to be hormone receptor-positive (at least 10% of cancer cells respond to hormones) and HER2-negative (a specific protein is not overexpressed in the cancer cells).
  • Your cancer must have returned locally or spread to other parts of the body and cannot be removed by surgery with the goal of cure.
  • You must have received at least five years of hormone therapy after initial treatment, including at least two years of an aromatase inhibitor (a type of hormone therapy).
  • Your cancer must have grown either while on hormone therapy or within 12 months after finishing it, or more than 12 months after finishing hormone therapy.
  • If you received a CDK4/6 inhibitor (a type of targeted cancer medicine) after initial treatment, you are eligible if your cancer grew more than 12 months after finishing that treatment.

Who cannot join the trial?

3 criteria

  • The source data does not provide specific exclusion criteria, which are reasons why a patient cannot participate in the study
  • Without detailed information about medical conditions, treatments, or situations that would prevent participation, a complete list of reasons for not being able to join this study cannot be provided
  • Generally, clinical trials have exclusion criteria to ensure patient safety and that the study results are reliable, but these specific details are not available in the provided information
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Investigated drugs

  • Camizestrant

    is a medication being tested for the treatment of hormone receptor-positive breast cancer. It works by blocking estrogen receptors, which are proteins that help certain breast cancer cells grow. By blocking these receptors, camizestrant may help slow down or stop the growth of cancer cells that depend on hormones to grow.

  • Ribociclib

    is a cancer medication that belongs to a group of drugs called CDK4/6 inhibitors. It works by blocking certain proteins that cancer cells need to divide and multiply. When used together with hormone-blocking treatments, ribociclib may help prevent breast cancer from growing or spreading in patients with hormone receptor-positive breast cancer.

What is already known about the treatment

  • Camizestrant

    Camizestrant is an investigational medication that is currently being studied in clinical trials and is not yet approved for general medical use. It is being tested as a treatment for hormone receptor-positive breast cancer, specifically targeting cancer cells that depend on hormones to grow. The drug works by blocking estrogen receptors in cancer cells, which prevents estrogen from attaching to these receptors and signaling the cancer cells to multiply. In the CADILLAC study, it is being given in combination with another cancer medication called ribociclib to evaluate if this combination can effectively slow down or stop the progression of advanced breast cancer.

  • Ribociclib

    Ribociclib is an oral medication taken by mouth that is approved and used in the treatment of hormone receptor-positive breast cancer. It belongs to a class of drugs called CDK4/6 inhibitors, which work by blocking specific proteins (cyclin-dependent kinases 4 and 6) that cancer cells need to divide and grow. By stopping these proteins from working, ribociclib helps slow down the growth and spread of cancer cells in patients with advanced or metastatic breast cancer. It is typically used in combination with hormone therapy medications to provide more effective treatment for patients whose cancer depends on hormones to grow.

Investigated diseases

Hormone Receptor-Positive Breast Cancer – This is a type of breast cancer where the cancer cells have proteins called receptors that bind to the hormones estrogen or progesterone. These hormones can fuel the growth and spread of the cancer cells throughout the breast tissue. The disease occurs when abnormal cells in the breast begin to grow and multiply in an uncontrolled manner. In advanced stages, the cancer may spread beyond the breast to other parts of the body through the lymphatic system or bloodstream. The progression of the disease is influenced by the presence of hormone receptors on the cancer cells, which respond to hormonal signals in the body. This type of breast cancer tends to grow more slowly compared to hormone receptor-negative types.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IITrial ID2024-520027-88-00Protocol codeMEDOPP0555Estimated enrolment188 patientsSponsorMedica Scientia Innovation Research S.L.

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