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Study on the Effects and Safety of Camizestrant (AZD9833) Compared to Fulvestrant in Postmenopausal Women with Advanced ER-Positive HER2-Negative Breast Cancer

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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 a type of breast cancer known as Estrogen Receptor Positive HER2 Negative Advanced Breast Cancer. This type of cancer is characterized by the presence of estrogen receptors on the cancer cells and the absence of a protein called HER2. The study is comparing two treatments: camizestrant, also known by its code name AZD9833, and fulvestrant. Camizestrant is taken orally as a film-coated tablet, while fulvestrant is administered as a solution for injection. Both medications belong to a class of drugs called Selective Estrogen Receptor Degraders (SERDs), which work by blocking the effects of estrogen on the cancer cells.

The purpose of the study is to determine how effective and safe camizestrant is compared to fulvestrant in treating women with this type of advanced breast cancer who have gone through menopause. Participants in the study will receive either camizestrant or fulvestrant, and their progress will be monitored over time. The study will look at various outcomes, such as how long patients live without the cancer getting worse, the response of the cancer to the treatment, and any changes in the size of the tumor. Additionally, the study will assess the overall survival of participants and any changes in their quality of life.

Throughout the study, participants will undergo regular check-ups and tests to monitor their health and the effects of the treatment. These tests may include imaging scans and blood tests to measure the levels of the medication in the body. The study aims to provide valuable information on the effectiveness of camizestrant compared to fulvestrant, which could help improve treatment options for women with this type of breast cancer in the future.

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

    Joining the study

    Upon joining the study, the patient provides written consent for participation and for the use of tumor biopsy samples.

    The patient must have a measurable lesion or a specific type of bone lesion that can be accurately assessed.

  2. Step 2

    Initial assessment

    The patient undergoes an initial assessment to confirm eligibility, including a review of medical history and current health status.

    The patient must have a performance status of 0 to 1, indicating they are fully active or restricted in physically strenuous activity but ambulatory.

  3. Step 3

    Treatment phase

    The patient receives either fulvestrant or camizestrant (AZD9833) based on random assignment.

    Fulvestrant is administered via intramuscular injection, while camizestrant is taken orally as a film-coated tablet.

  4. Step 4

    Monitoring and follow-up

    The patient's response to treatment is monitored through regular assessments, including imaging and blood tests.

    Progression-free survival is the primary measure of treatment efficacy, with secondary measures including response rate and overall survival.

  5. Step 5

    End of study participation

    The study is estimated to conclude by March 28, 2025, at which point the patient's participation will end.

    Final assessments will be conducted to evaluate the overall impact of the treatment on the patient's health.

Who can join the trial?

11 criteria

  • Provide signed and dated written consent before any study procedures, including providing past tumor samples.
  • Have at least one tumor that can be measured accurately, or at least one bone lesion if no measurable disease is present.
  • Have a performance status of 0 to 1, which means being fully active or having some symptoms but being able to carry out light work.
  • Have stopped taking tamoxifen, a breast cancer medication, for at least 4 months before the study biopsy.
  • Be a female patient aged 18 years or older.
  • Be post-menopausal, meaning no longer having menstrual periods.
  • Have a confirmed diagnosis of breast cancer through tissue examination.
  • Have a tumor that is **ER-positive**, meaning it grows in response to the hormone estrogen.
  • Have a tumor that is **HER2-negative**, meaning it does not have high levels of the HER2 protein.
  • Have cancer that has spread or returned and can be treated with fulvestrant, a breast cancer medication.
  • Show evidence of cancer progression after the last treatment before starting the study treatment.

Who cannot join the trial?

4 criteria

  • Patients who do not have **Estrogen Receptor Positive HER2 Negative Advanced Breast Cancer** cannot participate. This means the cancer must have certain characteristics related to hormone receptors and a protein called HER2.
  • Only **women** can participate in this study. Men are not eligible.
  • Participants must be within a specific **age range**. If you are outside this range, you cannot join the study.
  • Individuals who are considered part of a **vulnerable population** are not eligible. This typically includes groups who may need special protection in research settings.
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Investigated drugs

  • AZD9833

    is an experimental medication being studied for its effectiveness in treating advanced breast cancer that is positive for estrogen receptors (ER-positive) and negative for human epidermal growth factor receptor 2 (HER2-negative). This medication is taken orally and is being compared to another treatment to see how well it works in slowing down the progression of the cancer.

  • Fulvestrant

    is a medication used in the treatment of advanced breast cancer. It works by blocking the effects of estrogen in the body, which can help slow or stop the growth of certain types of breast cancer cells that need estrogen to grow. In this study, fulvestrant is used as a comparison to evaluate the effectiveness of the new medication, AZD9833.

What is already known about the treatment

  • AZD9833

    AZD9833 is an oral medication currently being studied in clinical trials for its effectiveness in treating advanced estrogen receptor-positive, HER2-negative breast cancer. It is in the investigational stage and is not yet widely available in medical practice. The main therapeutic indication for AZD9833 is to manage this specific type of breast cancer. At the molecular level, AZD9833 works by targeting and inhibiting the estrogen receptor, which is crucial for the growth of certain breast cancer cells. It is classified pharmacologically as a selective estrogen receptor degrader (SERD).

  • Fulvestrant

    Fulvestrant is an injectable medication used in the treatment of advanced estrogen receptor-positive, HER2-negative breast cancer. It is well-established in medical practice and literature as a treatment option for this condition. Fulvestrant is indicated for patients whose cancer has progressed following other hormonal therapies. Its mechanism of action involves binding to estrogen receptors and promoting their degradation, thereby blocking the effects of estrogen on cancer cells. Fulvestrant is classified as an estrogen receptor antagonist.

Investigated diseases

Estrogen Receptor Positive HER2 Negative Advanced Breast Cancer – This type of breast cancer is characterized by the presence of estrogen receptors on the surface of the cancer cells, which means the cancer cells may receive signals from estrogen that could promote their growth. It is classified as HER2 negative, indicating that the cancer cells do not have an excess of the HER2 protein on their surfaces. This form of breast cancer is considered advanced when it has spread beyond the breast to other parts of the body. The progression of this disease can vary, but it often involves the growth and spread of cancer cells to other organs. The disease may lead to symptoms such as lumps in the breast, changes in breast shape, or other systemic symptoms if it spreads. Monitoring the progression often involves assessing tumor size and the presence of cancer in other areas of the body.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IITrial ID2023-504974-40-00Protocol codeD8530C00002Estimated enrolment129 patientsSponsorAstraZeneca AB

sourced from the EU Clinical Trials Register and site verification

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