AuthorisedTherapeutic confirmatory (Phase III)Interventional

A randomized, open-label, multicenter, Phase 3 study to investigate mocertatug rezetecan compared with chemotherapy in participants with endometrial cancer after platinum-based chemotherapy and immunotherapy

Endometrial cancer starts in the lining of the womb. When it comes back or spreads after standard treatments, doctors need new and more effective options. This clinical trial is testing an experimental medicine called mocertatug rezetecan to see if it works better than standard chemotherapy drugs (paclitaxel or doxorubicin). The trial is open to adults who have already received platinum chemotherapy and immunotherapy. Participants will be randomly placed into one of two groups: one receives the study drug, and the other receives standard chemotherapy. Doctors will measure whether the new medicine shrinks tumours, delays cancer growth, and helps patients live longer. Taking part involves regular hospital visits for medicine given through a drip, routine scans, and health checks. The goal is to find out if this treatment can improve survival and quality of life for people facing advanced womb cancer.

At a glance

Status

Authorised

Phase

Therapeutic confirmatory (Phase III)

Sponsor

Glaxosmithkline Research & Development Limited

Enrolment target

287

Start

21 Sep 2026

Neoplasms, Endometrial

What is this study about?

Endometrial cancer is a type of cancer that begins in the lining of the womb (uterus). For many people, initial treatments such as surgery, chemotherapy, and immunotherapy work well. However, if the cancer returns or continues to grow, doctors often have fewer standard treatments to offer. This clinical trial is designed to find out whether a new medicine can offer better control of the disease.

The study compares an investigational medicine called mocertatug rezetecan against standard chemotherapy drugs (either paclitaxel or doxorubicin). Because this is a Phase 3 study, researchers have already tested the drug in smaller groups of patients and are now comparing it directly against current standard treatments to see which works best and causes fewer side effects.

Throughout the study, doctors will closely monitor whether tumours shrink or disappear, how long the cancer remains stable, and overall survival. They will also look carefully at safety and how each treatment affects daily life, including fatigue, pain, and common symptoms related to the bladder and bowel.

Studies like this are vital for improving cancer care on the NHS and around the world. If the study drug proves more effective than current chemotherapy, it could become a valuable new treatment option for people living with advanced womb cancer.

Key takeaways

A Phase 3 study comparing a new medicine against standard chemotherapy for advanced womb cancer.
Open to adults aged 18 and older whose cancer has progressed after platinum chemotherapy and immunotherapy.
Treatments are given by drip in the hospital, and participants are randomly assigned to a treatment group.
The main goals are to check if the new drug shrinks tumours, extends survival, and protects quality of life.
Taking part is voluntary, and you are free to leave the trial at any time.

Who may be eligible?

This trial is designed for adults aged 18 and older who have been diagnosed with advanced or recurrent endometrial cancer (cancer of the womb lining). It is aimed at people whose cancer has come back or worsened after receiving standard treatments.

To be considered, you must have already had both platinum-based chemotherapy and immunotherapy in the past. These prior treatments are standard first-line therapies for this type of cancer, and this study looks specifically at what to do when those treatments are no longer working.

You will also need to be well enough to carry out everyday activities and attend frequent hospital appointments. The study team will run blood tests, heart checks, and scans to ensure it is safe for you to take part.

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 18 years of age or older?
Have you been diagnosed with advanced or recurrent endometrial (womb) cancer?
Have you previously received platinum-based chemotherapy?
Have you previously received an immunotherapy treatment?
Are you able to travel regularly to the hospital for infusions, blood tests, and scans?

Answer every question to see your result.

What does participation involve?

If you take part, you will be randomly assigned by a computer to receive either the study drug (mocertatug rezetecan) or standard chemotherapy (paclitaxel or doxorubicin). Both you and your doctor will know which treatment you are receiving. The medicines are given directly into a vein through a drip (an intravenous infusion) at the hospital on set days.

You will need to attend regular clinic visits for physical exams, blood tests, heart checks (ECGs), and quality-of-life questionnaires. You will also have regular CT or MRI scans to see how your tumour is responding to the treatment. Treatment typically continues for as long as your cancer remains stable and the side effects are manageable. After you finish treatment, the medical team will keep in touch to check on your long-term health.

Potential risks and benefits

The possible benefit of joining this study is that the new treatment may help shrink or slow down the growth of your cancer, and your care will be very closely monitored by a specialist team. However, there is no guarantee the study drug will work better than standard chemotherapy. Like all cancer treatments, both the new drug and standard chemotherapy can cause side effects such as tiredness, sickness, changes in blood counts, and other health issues. Your study doctor will explain all known risks before you decide. Taking part is completely voluntary, and you can leave the study at any time without giving a reason and without your normal medical care being affected.

Locations (12)

Some site locations are approximate. We're improving this — please verify with the trial team before travelling.

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Unverified
Denmark
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Unverified
Netherlands
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Unverified
Italy
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Unverified
Spain
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Unverified
France
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Unverified
Portugal
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Unverified
Greece
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Unverified
Poland
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Unverified
Germany
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Unverified
Belgium
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Unverified
Norway
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Unverified
Czechia

Common questions

Can I choose which treatment I receive?

No. A computer randomly decides whether you receive the new study drug or standard chemotherapy. This ensures the results of the trial are completely fair and unbiased.

Will I have to pay for the study treatment?

No. The trial medicine, extra tests, and scans required for the study are provided free of charge. Some studies also help cover travel expenses to hospital appointments.

What happens if my cancer gets worse during the trial?

Your team will do regular scans. If tests show the cancer is growing or if side effects become too difficult, the study treatment will stop, and your doctor will discuss other treatment options with you.

Can I stop taking part if I change my mind?

Yes. You have the right to leave the study at any point. Your decision will not change the standard of care or support you receive from your healthcare team.

How does this study measure my quality of life?

You will be asked to fill in short surveys asking how you feel, how well you can perform everyday tasks, and whether you have symptoms like pain, swelling, or digestive upset.