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A Study of Camizestrant Compared to Standard Hormone Therapy for Patients with ER-Positive HER2-Negative Early Breast Cancer After Initial Treatment

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 study is looking at a type of breast cancer called ER-positive HER2-negative early breast cancer. This means the cancer cells have receptors for the hormone estrogen but do not have high levels of a protein called HER2. The study is specifically for people who have an intermediate-high or high chance of the cancer coming back after they have completed their initial treatment, including surgery and possibly radiation, and who currently show no signs of disease. The main treatment being tested is camizestrant, which is also known by its code name AZD9833. This is a newer type of medicine that works by breaking down estrogen receptors in cancer cells. Camizestrant will be compared to standard hormone treatments, which include medicines called aromatase inhibitors such as anastrozole, letrozole, and exemestane, or a medicine called tamoxifen. Some people in the study may also receive an additional medicine called abemaciclib. For people who have not gone through menopause, treatment with medications called goserelin, triptorelin, or leuprorelin acetate may be given to stop the ovaries from making hormones.

The purpose of this study is to find out if camizestrant, either alone or combined with abemaciclib, works better than standard hormone treatments, either alone or combined with abemaciclib, in preventing breast cancer from coming back. The study will measure how long people remain free from invasive breast cancer returning. People taking part in this study will be assigned by chance to receive either camizestrant or one of the standard hormone treatments. The treatment will continue for a period of time, and people will be monitored regularly to check how well the treatment is working and to watch for any unwanted effects.

During the study, doctors will check for any side effects that occur, perform blood tests, and measure vital signs like blood pressure and heart rate. People in the study will also be asked questions about their quality of life and how the side effects of treatment affect them in their daily lives. Blood samples may be taken to measure the amount of camizestrant in the blood. The study will track whether the cancer comes back, spreads to other parts of the body, or if a new cancer develops, as well as overall survival.

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 assignment

    After joining the study, you will be assigned to one of the treatment groups. The assignment will be done randomly, which means neither you nor your doctor can choose which group you will be in.

    You may receive either camizestrant (a new type of medicine that blocks estrogen receptors) or standard endocrine therapy (which includes medicines called aromatase inhibitors or tamoxifen). Some patients may also receive an additional medicine called abemaciclib.

  2. Step 2

    Treatment with medicines

    The treatment will depend on which group you are assigned to. All medicines in this study are taken by mouth as tablets, except for some hormone-suppressing medicines which may be given as injections into the muscle or under the skin.

    If you receive camizestrant, you will take it orally as a tablet. The exact dosage and frequency will be determined by the study protocol.

    If you receive standard endocrine therapy, you may take one of the following medicines orally: anastrozole (such as Arimidex 1 mg tablet), letrozole, exemestane, or tamoxifen citrate (such as Nolvadex 20 mg tablet). These medicines work by either blocking estrogen production or blocking estrogen from affecting breast cancer cells.

    Some patients may also need to take medicines that suppress hormone production from the ovaries. These include triptorelin, leuprorelin acetate, or goserelin, which are given as injections into the muscle or under the skin.

    If you are assigned to receive abemaciclib in addition to the main treatment, you will take it orally as a tablet.

    The treatment period is expected to last for several years, as this is an adjuvant therapy designed to prevent cancer from returning after your initial treatment.

  3. Step 3

    Regular monitoring visits

    Throughout the study, you will have regular visits to monitor your health and the effects of the treatment.

    During these visits, blood samples will be taken to check your organ function and blood cell counts, and to measure the levels of the study medicine in your blood.

    Your vital signs, such as blood pressure and heart rate, will be measured at each visit.

    You will be asked about any side effects or health problems you have experienced since your last visit.

  4. Step 4

    Quality of life assessments

    At certain times during the study, you will be asked to complete questionnaires about your quality of life and any side effects you are experiencing.

    These questionnaires will ask about your physical well-being, emotional state, and how the treatment is affecting your daily activities.

    The information you provide will help assess how the treatment impacts your overall well-being.

  5. Step 5

    Long-term follow-up

    The study will continue for many years to monitor whether the breast cancer returns and to track your overall health.

    You will continue to have regular follow-up visits even after you complete the active treatment phase.

    The study is expected to continue until 2037, although your individual participation may vary depending on your response to treatment and overall health.

  6. Step 6

    Reporting side effects

    Throughout your participation, it is important to report any new symptoms, health problems, or side effects to your study doctor.

    Any serious health events will be carefully documented and assessed to ensure your safety during the study.

Who can join the trial?

6 criteria

  • You must be a woman or man who is 18 years of age or older at the time of joining the study
  • You must have ER positive and HER2 negative early-stage breast cancer that has been confirmed by tissue examination under a microscope and has been removed by surgery. ER positive means your cancer grows in response to the hormone estrogen. HER2 negative means your cancer does not have too much of a specific protein called HER2. There must be no signs that the cancer has spread to other parts of your body
  • You must have completed appropriate local treatment for your breast cancer, which includes surgery with or without radiation therapy. Radiation therapy uses high-energy rays to destroy cancer cells. You may or may not have received chemotherapy, which is medicine that kills cancer cells, either before or after surgery
  • You must join the study within 12 months after your breast surgery. You may have received up to 12 weeks of hormone therapy, which is treatment that blocks hormones that help cancer grow, either after surgery or before surgery
  • You must have an ECOG performance status of 1 or lower. This is a scale that measures how well you can carry out daily activities, where 0 means you are fully active and 1 means you have some restrictions but can do light work
  • Your body organs and bone marrow, which is the soft tissue inside bones that makes blood cells, must be working well enough based on laboratory test results

Who cannot join the trial?

3 criteria

  • The source data does not provide specific exclusion criteria, which are the reasons why a patient cannot participate in the study
  • Without detailed exclusion criteria listed in the trial information, it is not possible to identify which medical conditions, treatments, or other factors would prevent someone from joining this study
  • Typically, exclusion criteria might include things like other types of cancer, certain medical conditions, previous treatments, or laboratory test results that fall outside acceptable ranges, but these specific details are not available in the provided information
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Investigated drugs

  • Camizestrant

    is an oral medication that works by breaking down estrogen receptors in the body. Estrogen receptors are proteins found on breast cancer cells that help the cancer grow when they attach to estrogen. By removing these receptors, this medication aims to prevent breast cancer from coming back after initial treatment.

  • Abemaciclib

    is an oral medication that blocks certain proteins called CDK4 and CDK6, which help cancer cells divide and grow. By blocking these proteins, this medication helps slow down or stop the growth of cancer cells. In this trial, it may be given in combination with other treatments.

  • Aromatase inhibitor

    is a type of hormone therapy medication that lowers the amount of estrogen in the body. Estrogen can fuel the growth of certain types of breast cancer, so reducing estrogen levels helps prevent the cancer from returning. This is one of the standard treatment options used in this trial.

  • Tamoxifen

    is a hormone therapy medication that blocks estrogen from attaching to estrogen receptors on breast cancer cells. By preventing estrogen from reaching cancer cells, this medication helps reduce the risk of breast cancer coming back. This is another standard treatment option used in this trial.

What is already known about the treatment

  • Camizestrant

    Camizestrant is an oral medication that belongs to a new generation of drugs called selective estrogen receptor degraders, which work by breaking down estrogen receptors in cancer cells to stop them from receiving signals that promote tumor growth. This investigational drug is currently being studied in clinical trials for the treatment of early breast cancer that is estrogen receptor positive and HER2 negative, specifically in patients who have a medium-high to high risk of their cancer returning after completing their initial treatment. It is being compared to standard hormone therapy medications to determine if it is more effective at preventing breast cancer from coming back. The medication is taken by mouth, making it a convenient treatment option for patients requiring long-term therapy.

  • Abemaciclib

    Abemaciclib is an oral medication that belongs to a class of drugs called CDK4/6 inhibitors, which work by blocking specific proteins that cancer cells need to divide and multiply, thereby slowing or stopping tumor growth. This medication is already approved and used in clinical practice for treating certain types of breast cancer, particularly hormone receptor positive and HER2 negative breast cancer. In this clinical trial, it is being used in combination with either the investigational drug camizestrant or standard hormone therapy to help prevent breast cancer from returning in patients who have completed their initial treatment. The medication is taken by mouth in pill form, typically on a daily basis as prescribed by a doctor.

Investigated diseases

Estrogen Receptor-Positive Human Epidermal Growth Factor Receptor 2-Negative Early Breast Cancer – This is a type of breast cancer that is detected in its early stages and has specific characteristics based on laboratory testing of the cancer cells. The cancer cells have receptors for the hormone estrogen on their surface, which means estrogen can promote the growth of these cancer cells. At the same time, these cells do not have an excess of a protein called human epidermal growth factor receptor 2. This particular combination of features affects how the cancer behaves and grows in the body. Early breast cancer means the disease is confined to the breast or nearby lymph nodes and has not spread to distant parts of the body. The cancer may progress over time if not addressed, potentially spreading beyond its original location.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2023-504031-41-00Protocol codeD8535C00001Estimated enrolment5 677 patientsSponsorAstraZeneca AB

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