A trial of datopotamab deruxtecan for breast cancer (TROPION-Breast01)

Please note - this trial is no longer recruiting patients. We hope to add results when they are available.

Cancer type:

Breast cancer
Secondary cancers



This trial is looking at a new drug called datopotamab deruxtecan. It is comparing it with standard chemotherapy for breast cancer. 

It is for people:

  • who can’t have surgery to remove the cancer or it has spread to another part of the body
  • whose cancer has large amounts of hormone receptors (ER positive cancer Open a glossary item)
  • whose cancer has a small number of receptors for HER2 Open a glossary item    

More about this trial

Chemotherapy is a standard treatment for breast cancer. Researchers think that datopotamab deruxtecan might help to treat breast cancer that:

  • has spread to other parts of the body (secondary breast cancer) or 
  • you can’t have surgery to remove it 

Researchers aren’t sure how well it works for these groups of people. So they are running this trial to find out more.

Datopotamab deruxtecan is a combination of 2 drugs. Datopotamab is a monoclonal antibody Open a glossary item. It attaches to a protein called TROP2 on the cancer cells. It then releases deruxtecan into the cancer cell. Deruxtecan or DXd is the chemotherapy part of the drug. It kills or damages the cancer cell. 

In this trial some people have datopotamab deruxtecan. And some have standard chemotherapy Open a glossary item.     

The standard chemotherapy you have is one of the following:

  • capecitabine
  • gemcitabine
  • eribulin
  • vinorelbine

Your doctor decides which is best for you.

The main aims of the trial are to find out:

  • how well datopotamab deruxtecan works for breast cancer 
  • more about the side effects
  • how it affects quality of life Open a glossary item

Who can enter

The following bullet points are a summary of the entry conditions for this trial. Talk to your doctor or the trial team if you are unsure about any of these. They will be able to advise you. 

Who can take part

You may be able to join this trial if all of the following apply. You:

  • have breast cancer that has spread to another part of the body or you can’t have an operation to remove it 
  • have cancer that is hormone receptor positive (hormone receptor positive Open a glossary item)
  • have cancer that has low or very low amounts of HER2. This is HER2 negative breast cancer Open a glossary item
  • have cancer that got worse while you were having hormone therapy Open a glossary item or you can’t have hormone therapy 
  • have had 1 to 2 courses of chemotherapy Open a glossary item for breast cancer that can’t be removed or has spread and your cancer got worse after the most recent course 
  • can have one of the chemotherapy options in the trial. These include epirubicin, capecitabine, vinorelbine, gemcitabine.
  • have at least one area of cancer that your doctor can measure on a scan 
  • are able to look after yourself but might not be able to do heavy physical work (performance status 0 or 1)
  • have satisfactory blood test results
  • there is a sample of tissue available for the trial team to do some tests on 
  • are willing to use reliable contraception during the trial or for a period after if there is any chance you or your partner could become pregnant 
  • are at least 18 years old 

Who can’t take part

Cancer related
You can’t join this trial if any of these apply. 

You have had treatment for breast cancer in the last few weeks that included:

  • radiotherapy 
  • any cancer treatment including hormone therapy Open a glossary item
  • taking part in a trial that looked at datopotamab deruxtecan even if you didn’t have it as part of your treatment 
  • taking part in another trial of an experimental treatment 

As well as the above, the following can’t apply. You:

  • have cancer spread to the brain or spinal cord unless it is stable and doesn’t need treatment
  • have cancer that has spread to the membranes that surround the brain (leptomeningeal carcinomatosis)
  • are having another treatment for cancer apart from bisphosphonates Open a glossary item such denosumab to treat cancer spread to the bone 
  • have had 2 drugs called chloroquine or hydroxychloroquine in the last few weeks
  • have already had treatment with datopotamab deruxtecan or a similar drug
  • have an area of cancer that is pressing on your spinal cord (spinal cord compression Open a glossary item)
  • have or had another cancer unless it has been successfully treated and there have been no signs of it for at least 3 years. This is apart from non melanoma skin cancer, early (insitu) cancers or some other solid tumours  Open a glossary itemYour doctor will know this. 
  • have side effects from past treatments unless they are mild. You might be able to take part if you have hair loss or a side effect that won’t get worse with treatment. Your doctor will know this.

Medical conditions
You can’t join the trial if any of the following apply.

  • have had an organ transplant Open a glossary item or a stem cell transplant Open a glossary item with somebody else’s cells in the past 
  • have an active bleeding problem 
  • have HIV that isn’t well controlled with medication, an active hepatitis B or C infection, an active TB infection or any other infection that needs treatment 
  • have had a heart attack in the last 6 months or any other heart problem Open a glossary item that might affect you taking part. The trial team check if you have a heart condition before you join the trial.
  • had scarring on the lungs or active inflammation of the lungs (pneumonitis Open a glossary item) and you needed to have steroids or you are having this at the moment 
  • have severe lung problems caused by a long term lung conditions. For example you have severe asthma or another serious lung problem. Your doctor will know this.
  • have a serious problem with the outermost lens (cornea) in your eye 
  • are having hormone therapy unless you have it as a patch or cream you rub into the skin 
  • have had major surgery or a very bad injury within 3 weeks of having the first dose of the trial drug or you have major surgery planned 
  • have treatment that damps down the immune system Open a glossary item. This includes steroids unless it was a low dose. 
  • have had another monoclonal antibody that has a chemotherapy drug attached to it. Your doctor will know if you have had one of these.

You can’t join this trial if any of these apply. You:

  • are allergic to datopotamab deruxtecan or anything it contains 
  • are allergic to monoclonal antibodies 
  • are willing not to donate blood during the trial and for a period after 
  • are pregnant or breastfeeding or planning to become pregnant 
  • have had a live vaccine Open a glossary item within 30 days of the start of treatment. Please note that the current approved COVID-19 vaccines are not live. 

Trial design

This phase 3 trial is taking place worldwide. The researchers need 700 people to take part. This includes 26 people from the UK. 

It is a randomised trial. A computer puts you into a treatment group. Neither you nor your doctor can choose which group you go into. There are 2 treatment groups. You have one of the following:

  • datopotamab deruxtecan
  • standard chemotherapy


How you have treatment
Everyone has treatment in cycles. Each 3 week period is 1 cycle of treatment Open a glossary item. You have treatment for as long as it is working and the side effects aren’t too bad. 

You have datopotamab deruxtecan as a drip into a vein. You have it once every 3 weeks. 

In the chemotherapy group you have one of the following:

Your doctor will talk to you about which chemotherapy they think is best. 

Capecitabine is a tablet. You take it twice a day for 2 weeks and then you don’t take it for a week.

You have gemcitabine, eribulin or vinorelbine as a drip into a vein. The first day of each treatment cycle is called day 1. You have gemcitabine, eribulin or vinorelbine on:

  • day 1
  • day 8 and then 
  • you don’t have chemotherapy for a week

Quality of life 
The trial team ask you to fill out some questionnaires:

  • before you start treatment
  • at set times during treatment

The questionnaire asks about side effects and how you’ve been feeling. This is called a quality of life study. You complete these on a tablet, smartphone or on a handheld device that the trial team will provide.

Samples for research 
The trial team ask you to give some extra blood samples. Where possible you have these at the same time as your routine blood tests. 

They will also ask to look at samples of the cancer from when you were diagnosed. They might ask you to give new samples during the trial or if your cancer gets worse.

The researchers plan to use the samples to look at:

  • what happens to datopotamab deruxtecan in the body
  • genes Open a glossary item in your cancer cells to learn more about breast cancer 
  • substances called biomarkers Open a glossary item to help work out why treatment might work for some people and not for others

You need to agree to give most of the samples to take part in the trial. There are a few you can say no to. Your doctor or a member of the trial team will talk to you about the samples. They will tell you which ones you must agree to and which ones don’t have to give. 

Hospital visits

You see the doctor to have tests before taking part. These tests include:

  • a physical examination Open a glossary item
  • blood tests
  • heart trace (ECG)
  • heart scan (MUGA Open a glossary item or Echo Open a glossary item)
  • eye test
  • CT scan or an MRI scan
  • bone scan 
  • breathing tests (lung function tests Open a glossary item)

You see the doctor at regular times during treatment. This is to see how you are and for blood tests.

You have a CT scan or an MRI scan:

  • every 6 weeks for 48 weeks and then
  • every 9 weeks

You stop having the scans as part of the trial if your cancer gets worse.

You see the doctor about a month after you finish treatment for a check up. You then see them every 3 months at a routine hospital appointment. Or they might call you to see how you are. 

Side effects

The trial team monitor you during treatment and afterwards. Contact your advice line or tell your doctor or nurse if any side effects are bad or not getting better. 

Datopotamab deruxtecan is a new drug so there may be side effects we don’t know about yet. The possible side effects we know about so far include:

  • tiredness (fatigue)
  • feeling or being sick 
  • hair loss 
  • sore mouth or inflammation in the lining of the digestive system Open a glossary item
  • an allergic reaction. Symptoms could include swelling, skin rash, a fast heartbeat, difficulty breathing or a tight feeling in the throat or low blood pressure
  • a drop in the number of red blood cells that might cause tiredness and breathlessness (anaemia Open a glossary item)
  • loss of appetite
  • skin rash
  • diarrhoea 
  • dry eyes

Datopotamab deruxtecan might cause a serious lung problem. In some cases this could be life threatening. Symptoms are similar to other heart or lung diseases. Please contact your doctor straight away if you have any new lung symptoms or symptoms that are getting worse. These include:

  • a new or worsening cough
  • trouble breathing
  • new or worsening shortness of breath or other breathing problems
  • high temperatures (fever)

Getting medical treatment right away may keep these problems from becoming more serious.

 We have more information about the chemotherapy drug you may have:

Other medications
The trial team will discuss any medications that you may be taking. Please tell them about all the drugs that you are having. This includes:

Please check with your doctor first before having any of the above. 

Recruitment start:

Recruitment end:

How to join a clinical trial

Please note: In order to join a trial you will need to discuss it with your doctor, unless otherwise specified.

Please note - unless we state otherwise in the summary, you need to talk to your doctor about joining a trial.

Chief Investigator

Professor Peter Schmid 

Supported by


If you have questions about the trial please contact our cancer information nurses

Freephone 0808 800 4040

Last review date

CRUK internal database number:


Please note - unless we state otherwise in the summary, you need to talk to your doctor about joining a trial.

Around 1 in 5 people take part in clinical trials

3 phases of trials

Around 1 in 5 people diagnosed with cancer in the UK take part in a clinical trial.

Last reviewed:

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