RecruitingPHASE3INTERVENTIONAL

A Study to Investigate Mocertatug Rezetecan Compared With Chemotherapy in Participants With Endometrial Cancer After Platinum-based Chemotherapy and Immunotherapy (BEHOLD-Endometrial01)

This study, called BEHOLD-Endometrial01, is looking into a new treatment called mocertatug rezetecan, or Mo-Rez, for people with a type of cancer that starts in the womb (endometrial cancer). This cancer has already been treated with chemotherapy and immunotherapy but has either come back or not responded well. The main goal is to compare Mo-Rez with standard chemotherapy to see if it works better at controlling the cancer. Researchers also want to understand if Mo-Rez is safe and how people tolerate it, looking out for any side effects. This information will help doctors decide if Mo-Rez could be a good new option for patients in the future.

At a glance

Status

Recruiting

Phase

PHASE3

Sponsor

GlaxoSmithKline

Enrolment target

600

Start

04 Jun 2026

Estimated completion

30 May 2029

Neoplasms, Endometrial

What is this study about?

This research study, known as BEHOLD-Endometrial01, is focused on finding new and better ways to treat womb cancer, specifically when it has already been treated with standard medicines like chemotherapy and immunotherapy. Sometimes, despite these treatments, the cancer can come back or not respond as well as hoped. This study is testing a new drug called mocertatug rezetecan, which we'll call Mo-Rez for short.

The main idea is to see if Mo-Rez can be a more effective treatment compared to the usual chemotherapy options for people in this situation. Researchers will carefully watch how patients respond to Mo-Rez and also keep a close eye on any side effects, comparing these with what happens to patients receiving standard chemotherapy. This will help them understand if Mo-Rez is not only better at fighting the cancer but also safe and tolerable for patients.

Finding new treatments is really important for people living with womb cancer. If Mo-Rez proves to be effective and safe, it could offer a new and valuable option for patients who have already tried other treatments. The study aims to gather clear information so doctors can make informed decisions about future care.

Key takeaways

This study is testing a new drug, Mo-Rez, for womb cancer that has already been treated with chemotherapy and immunotherapy.
It aims to see if Mo-Rez works better and is safer than standard chemotherapy options.
Participants will receive either Mo-Rez or standard chemotherapy, with careful monitoring.
The study involves regular visits for treatment, checks, and scans.
Taking part is voluntary, and you can withdraw at any time.
This research helps find new treatment options for womb cancer patients.

Who may be eligible?

To join this study, you need to be at least 18 years old. You must have a confirmed diagnosis of womb cancer, which doctors have identified under a microscope.

Your cancer should have been treated with at least one, but no more than two, different types of strong medicine (systemic treatment) before. This includes treatments like chemotherapy given after surgery or to shrink the cancer before surgery. You also must have received platinum-based chemotherapy and another type of medicine called immunotherapy (like PD-1/PD-L1 inhibitors), and your cancer must have grown or come back after these treatments. If you couldn't have immunotherapy because of other health reasons, you might still be able to join.

There are also some specific timings about when you received your last platinum-based chemotherapy and when your cancer started to progress again. The study team will check all these details carefully with you to see if you're a good fit.

Could this study suit you?

Answer these quick questions to see if you may be eligible. This is a guide only — the research team makes the final call.

Are you at least 18 years old?
Have you been diagnosed with womb cancer (endometrial carcinoma)?
Has your cancer been treated with at least one, but no more than two, types of strong medicine before?
Did your cancer grow or come back after receiving both platinum-based chemotherapy and immunotherapy?
Are you prepared for regular hospital visits and check-ups?

Answer every question to see your result.

What does participation involve?

If you decide to take part in this study, you would either receive the new drug, Mo-Rez, or one of the standard chemotherapy drugs (paclitaxel or doxorubicin). The study is designed to compare these treatments directly.

You would have regular appointments for check-ups, blood tests, scans, and to get your treatment. These visits are important for the doctors to monitor how you are responding to the treatment and to keep an eye on your general health and any side effects. The frequency and length of visits will vary but will be explained in detail.

The total time you spend in the study will depend on how your cancer responds to the treatment and how you feel. Even after your main treatment period ends, there will be follow-up appointments to check on your long-term health. The study team will explain the full schedule and how long each part is expected to last.

Potential risks and benefits

Taking part in any medical study has potential benefits and risks. You might benefit from receiving a new drug that could work better than current options for your cancer. However, there's no guarantee the new treatment will help you more than standard care, and it might not help at all. Like all medicines, both the study drug and standard chemotherapy can cause side effects. These can range from mild to more serious, and the study team will monitor you closely and explain all known side effects. It's really important to remember that joining this study is completely your choice, and you can decide to leave at any time, for any reason, without it affecting your usual medical care.

Locations (48)

GSK Investigational Site
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Birmingham, United States· Recruiting
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Omaha, United States· Recruiting
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Florida, Argentina· Recruiting
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Mendoza, Argentina· Recruiting
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Buenos Aires, Argentina· Recruiting
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Ciudad Autonoma de Buenos Aire, Argentina· Recruiting
GSK Investigational Site
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Ciudad Autonoma de Buenos Aire, Argentina· Recruiting
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Rosario, Argentina· Recruiting
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Dubbo, Australia· Recruiting
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Auchenflower, Australia· Recruiting
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Herston, Australia· Recruiting
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São Luís, Brazil· Recruiting

Common questions

What is endometrial cancer?

Endometrial cancer is a type of cancer that starts in the lining of the womb (uterus). It's one of the most common cancers that affects women.

What does 'platinum-based chemotherapy' mean?

This is a type of cancer medicine that uses drugs containing platinum to kill cancer cells. It's a common treatment for many cancers, including womb cancer.

What is immunotherapy?

Immunotherapy is a treatment that helps your body's own immune system fight cancer. It works by boosting your natural defences to recognise and attack cancer cells.

What is 'standard of care'?

Standard of care means the best, most accepted treatments currently available for a specific condition. In this study, Mo-Rez is compared against these established treatments.

Why are clinical trials important?

Clinical trials are how doctors find new and better ways to prevent, detect, and treat diseases. They help to make sure new medicines are safe and effective before they can be used more widely.

How to find out more

US GSK Clinical Trials Call Center

gskclinicalsupporthd@gsk.com 877-379-3718 Official trial record

Always speak to your GP or specialist before deciding to take part in a study.