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Study on the Impact of Fluoroestradiol F-18 PET on Treatment for Patients with ER+ HER2- Metastatic Breast Cancer After First-Line Hormone Therapy Relapse

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 is focused on studying the impact of a special imaging technique on the treatment of patients with a specific type of breast cancer. The disease being studied is metastatic breast cancer, which means the cancer has spread to other parts of the body. The patients involved in this study have breast cancer that is estrogen receptor-positive (ER+) and HER2-negative. This means their cancer cells grow in response to the hormone estrogen but do not have an excess of the HER2 protein. The patients have experienced a return of cancer after their initial treatment, which included hormone therapy.

The treatment being tested in this study is called FLUOROESTRADIOL F-18, also known by the code name EstroTep. This is a solution that is injected into the body and used in a type of imaging called Positron Emission Tomography (PET). The purpose of the study is to see how this imaging technique can help doctors make better treatment decisions for patients whose cancer has returned after the first line of treatment. The study will involve patients undergoing a PET scan with FLUOROESTRADIOL F-18 to help guide their future treatment options.

Throughout the study, patients will receive the PET scan and their doctors will use the results to decide on the best course of treatment. This may involve changes to their current treatment plan, such as adjusting hormone therapy or adding other treatments like chemotherapy or radiotherapy. The study aims to understand how this imaging technique can improve the management of metastatic breast cancer and help doctors make more informed decisions about patient care.

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

    Initial assessment

    Upon joining the clinical trial, an initial assessment is conducted to confirm eligibility. This includes reviewing medical history and current health status.

    Eligibility criteria include being a woman aged at least 18 years with metastatic breast cancer that is estrogen receptor positive and HER2 negative, and having relapsed after a first line of treatment combining hormone therapy.

  2. Step 2

    Baseline PET/CT scan

    A baseline PET/CT scan is performed using a substance called 18F-fluoroestradiol (FES). This scan helps in assessing the current state of the cancer.

    The scan involves an injection of the FES tracer, which helps in visualizing estrogen receptor activity in the body.

  3. Step 3

    Treatment planning

    Based on the results of the PET/CT scan, a treatment plan is developed. This may involve changes to the current treatment regimen.

    The treatment plan could include modifications such as changing hormone therapy, adding or withdrawing medications, or adjusting chemotherapy.

  4. Step 4

    Follow-up PET/CT scan

    A follow-up PET/CT scan is scheduled within 2 to 28 days after the baseline scan to monitor the response to the treatment plan.

    This scan also uses the FES tracer to provide updated information on the cancer's status.

  5. Step 5

    Evaluation of treatment impact

    The impact of the treatment is evaluated by comparing the initial and follow-up scan results.

    A standardized questionnaire is used to assess any substantial therapeutic measures implemented following the PET/CT scan analysis.

  6. Step 6

    Ongoing monitoring

    Regular monitoring continues throughout the trial to assess progression-free survival and the effectiveness of the treatment.

    The relevance of therapeutic measures is reviewed at 3 months, based on all available medical data.

Who can join the trial?

8 criteria

  • Must be a woman aged at least 18 years old.
  • Must have primary breast cancer that shows overexpression of hormonal estrogen receptors (ER ≥ 10%). This means the cancer cells have a lot of estrogen receptors.
  • The primary breast tumor must be HER2 negative. HER2 is a protein that can affect the growth of cancer cells. Negative means the protein is not overexpressed.
  • Must be at a metastatic stage, which means the cancer has spread to other parts of the body, with at least one identifiable lesion (area of cancer) other than in the liver.
  • Must be experiencing a recurrence (return) of cancer after the first line of treatment that included a CDK4/6 inhibitor and hormone therapy.
  • Must have had a PET/CT scan with FDG (a type of imaging test) during the follow-up of the first metastatic line that shows the relapse, or be planning to have one during the assessment of the second line of treatment. There should be a period of 2 to 28 days between the two PET/CT scans (FDG/FES).
  • Must have an ECOG performance status of 0, 1, or 2. This is a scale that measures how well a person can perform ordinary tasks. 0 means fully active, 1 means restricted in physically strenuous activity, and 2 means capable of all self-care but unable to carry out any work activities.
  • Must have a life expectancy of at least 12 months.

Who cannot join the trial?

5 criteria

  • Patients who do not have metastatic breast cancer with overexpression of estrogen receptors (ERs) and absence of overexpression of HER2.
  • Patients who have not relapsed after a first treatment that combines hormone therapy.
  • Patients who are not female.
  • Patients who are not within the specified age range for the study.
  • Patients who are considered part of a vulnerable population that is not eligible for this study.
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Investigated drugs

18F-fluoroestradiol (FES) is a special type of imaging agent used in a PET scan. It helps doctors see how much estrogen is present in certain breast cancer cells. This is important because some breast cancers grow in response to estrogen. By using FES, doctors can get a clearer picture of the cancer and decide the best way to treat it. This imaging agent is particularly useful for patients whose breast cancer has come back after initial treatment.

What is already known about the treatment

18F-fluoroestradiol (FES) – This medication is administered through an injection and is used in a PET scan, a type of imaging test. It is currently being studied for its role in managing metastatic breast cancer that has specific characteristics, such as high levels of estrogen receptors and low levels of HER2, especially after initial hormone therapy has failed. The main purpose of FES is to help doctors see how much estrogen is being used by cancer cells, which can guide treatment decisions. It works by attaching to estrogen receptors in the body, allowing doctors to visualize these areas during a PET scan. FES is classified as a radiopharmaceutical, which means it is a radioactive compound used for diagnosis or treatment.

Investigated diseases

Metastatic Breast Cancer – This disease occurs when breast cancer cells spread beyond the breast to other parts of the body, such as bones, liver, lungs, or brain. Initially, the cancer may present with an overexpression of estrogen receptors (ERs) and lack of HER2 overexpression. The progression involves the cancer cells growing and forming new tumors in other organs. Over time, the cancer may become resistant to initial treatments, such as hormone therapy. As the disease advances, it can lead to more significant symptoms and complications due to the involvement of multiple organs. The spread and growth of cancer cells can vary greatly among individuals, affecting the disease's progression rate.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2024-517400-11-00Protocol code2021-FES-ESTROTIMP-4Estimated enrolment165 patientsSponsorGE Healthcare Limited

sourced from the EU Clinical Trials Register and site verification

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