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A study comparing BNT323 with chemotherapy in patients with HER2-expressing recurrent endometrial cancer who received previous treatment

Fast replyRegistered 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 involves patients with endometrial cancer, which is cancer of the lining of the uterus, that has come back after previous treatment. The study is looking at patients whose cancer shows a protein called HER2 on the surface of the cancer cells. Patients in this study will receive either an investigational treatment called BNT323, which is given through a vein, or a chemotherapy medicine chosen by their doctor. The chemotherapy options include paclitaxel, which is a medicine that stops cancer cells from dividing, or doxorubicin hydrochloride, which is a medicine that damages the genetic material inside cancer cells to stop them from growing.

The purpose of the study is to compare how well BNT323 works against the doctor's choice of chemotherapy in stopping the cancer from getting worse or spreading. The study will measure how long patients live without their cancer growing or spreading, and how long patients survive overall. The study will also look at how many patients have their tumors shrink or disappear, how long these responses last, and what side effects occur with each treatment. Patients will be assigned to one treatment or the other by chance, similar to flipping a coin, and both the patients and their doctors will know which treatment is being given.

During the study, patients will receive their assigned treatment for up to six months, and they will be monitored regularly with scans and tests to see how their cancer is responding and to check for any side effects. The study will track whether the cancer grows or spreads, and doctors will use specific measurement criteria to evaluate the size and extent of the tumors throughout the treatment period. The information gathered will help determine whether BNT323 is more effective than standard chemotherapy for treating this type of recurring uterine cancer.

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

    Random assignment to treatment group

    Upon joining the study, you will be randomly assigned to one of two treatment groups. This process is similar to flipping a coin and determines which treatment you will receive.

    One group will receive BNT323 (also known as DB-1303), which is an investigational therapy being tested in this study.

    The other group will receive chemotherapy chosen by your doctor, which may include paclitaxel or doxorubicin hydrochloride.

  2. Step 2

    Treatment administration

    If you are assigned to receive BNT323, the medication will be given through intravenous infusion, which means it will be delivered directly into your vein over a period of time.

    If you are assigned to receive chemotherapy, the medication will be administered either through intravenous infusion or as a solution for injection, depending on which chemotherapy your doctor selects.

    The specific dosage, frequency, and duration of treatment will be determined by the study protocol and your doctor's assessment.

  3. Step 3

    Regular monitoring and imaging assessments

    Throughout the study, your cancer will be monitored using imaging scans to assess how the treatment is affecting the tumor.

    These assessments will follow specific criteria called RECIST 1.1, which is a standardized method for measuring tumor size and response to treatment.

    The images will be reviewed by independent experts who are not directly involved in your care to ensure objective evaluation.

  4. Step 4

    Safety monitoring

    Your health will be closely monitored throughout the study for any side effects or adverse reactions to the treatment.

    Any new symptoms or medical issues that occur during treatment will be documented and evaluated.

    Your doctor may adjust your treatment, including pausing, reducing the dose, or stopping the medication, depending on how you respond and any side effects you experience.

  5. Step 5

    Continuation of treatment

    You will continue receiving the assigned treatment until your cancer progresses, you experience unacceptable side effects, or you and your doctor decide to stop treatment.

    The study will track how long your cancer remains stable or responds to treatment.

  6. Step 6

    Long-term follow-up

    After completing or stopping treatment, you will continue to be followed to monitor your overall health and survival.

    This follow-up period will continue until the study ends, which is estimated to be in November 2029.

Who can join the trial?

10 criteria

  • You must be a female adult
  • You must have endometrial cancer, which is cancer of the lining of the uterus, that has been confirmed by examining tissue under a microscope
  • Your cancer must have come back after previous treatment, which is called recurrent cancer
  • Your cancer must have a specific protein called HER2 with a score of 1+, 2+, or 3+, which will be tested by a central laboratory
  • Your cancer must not be a type called true sarcoma, which is a different kind of cancer
  • You must have cancer that can be measured using imaging scans, according to specific guidelines called RECIST 1.1, which are standards used to measure tumors
  • You must have an ECOG Performance Status of 0, 1, or 2, which is a score that measures how well you can perform daily activities, with 0 meaning you are fully active and 2 meaning you are able to care for yourself but cannot work
  • You must have received at least one previous treatment with platinum-based therapy, which is a type of chemotherapy containing platinum drugs, at any point during your cancer care
  • You may have had up to three previous lines of treatment for your cancer
  • Your doctor must expect that you will live for at least 12 weeks or longer at the time of screening

Who cannot join the trial?

6 criteria

  • You cannot participate if you are male, as this study is only for female patients
  • You cannot participate if you are under 18 years of age
  • You cannot participate if your endometrial cancer (cancer of the lining of the womb) does not express HER2, which is a specific protein found on the surface of some cancer cells
  • You cannot participate if you have not received previous ICI treatment, which stands for immune checkpoint inhibitor therapy - a type of cancer treatment that helps your immune system fight cancer
  • You cannot participate if your cancer has not come back or is not recurrent, meaning the cancer has not returned after previous treatment
  • You cannot participate if you have not previously received chemotherapy, as this study compares a new treatment to standard chemotherapy options
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Investigated drugs

  • BNT323

    (also known as DB-1303) is an investigational medication being studied for the treatment of endometrial cancer that has come back and expresses a protein called HER2. This medication is being tested to see if it works better than standard chemotherapy treatments in patients who have already received previous treatment.

  • Investigator's choice of chemotherapy

    refers to standard chemotherapy medications that the doctor will select based on what is considered appropriate for treating recurrent endometrial cancer. These are established cancer treatments that are already in use, and the specific chemotherapy chosen will depend on the individual patient's situation and the doctor's medical judgment.

What is already known about the treatment

BNT323/DB-1303 – This is an investigational medication currently being studied in clinical trials for the treatment of endometrial cancer that has returned after previous treatment. It is specifically designed for patients whose tumors express a protein called HER2 and who have already received immune checkpoint inhibitor therapy. The medication works by targeting the HER2 protein on cancer cells, which is a molecule that can promote tumor growth when overexpressed. In this phase III trial, researchers are comparing BNT323/DB-1303 to standard chemotherapy treatments to determine if it can better slow or stop cancer progression in this specific group of patients.

Investigated diseases

Endometrial Cancer – Endometrial cancer is a type of cancer that begins in the lining of the uterus, called the endometrium. It occurs when cells in this tissue start to grow abnormally and out of control. The cancer typically develops slowly over time, starting from abnormal changes in the endometrial cells. As the disease progresses, the cancerous cells can form a tumor that may invade deeper layers of the uterine wall. In more advanced stages, the cancer can spread beyond the uterus to nearby organs or distant parts of the body. This condition most commonly affects women after menopause, though it can occur at any age.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2023-507525-42-00Protocol codeBNT323-01Estimated enrolment480 patientsSponsorBioNTech SE

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