A trial looking at capecitabine and radium 223 for advanced breast cancer (CARBON)

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

Cancer type:

Breast cancer




Phase 1/2

This trial is looking at capecitabine and radium 223 for women with breast cancer that has spread to the bones.

More about this trial

Breast cancer can sometimes spread to the bones. This is advanced or metastatic cancer.

If this happens, you can have treatment with chemotherapy. Often with a drug called capecitabine (Xeloda).

But researchers are looking at new ways of helping women in this situation. In this trial, they are looking at radium 223 (also called Xofigo).          

Radium 223 is a type of internal radiotherapy. Bone cells take up the radium 223 and once it’s in the bones, it releases radiation.          

Radium 223 is already used to treat cancers that have spread to the bones. But doctors want to find out if having it with capecitabine is better. This will be the first time radium 223 and capecitabine have been given together for advanced breast cancer. 

The trial is in 2 parts.

In part 1, researchers are looking at the safest dose of capecitabine and radium 223. This is called the safety phase.

In part 2, they are trying to find out how well capecitabine and radium 223 work as a treatment. This is the extension phase.

Everyone has capecitabine and radium 223 in part 1. In part 2, people have 1 of the following:

  • capecitabine
  • capecitabine with radium 223

The main aims of this trial are to:

  • find out how well capecitabine with radium 223 work as a treatment
  • learn about the side effects of capecitabine with radium 223
  • learn how well people cope with the treatment and side effects  

Who can enter

The following bullet points list 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.

You may be able to join this trial if you are a woman and all of the following apply.

  • You have cancer that has started in the breast (primary breast cancer)  
  • Your cancer has spread to 2 or more areas in the bones. If your cancer has also spread to your brain, you may be able to take part if you have finished treatment for it more than 8 weeks ago and it hasn’t got worse
  • Your doctor thinks you can have capecitabine
  • You have had no more than 2 types of chemotherapy after your cancer has spread to other parts of your body
  • You take drugs to slow down bone damage (such as bisphosphonates) or a biological therapy called denosumab. You must also have started them at least 6 weeks ago
  • You are well enough to be up and about for at least half the day (performance status of 0, 1 or 2)
  • You have satisfactory blood tests results
  • You are at least 18 years old
  • You are willing to use reliable contraception during treatment and for 6 months after treatment if there is any possibility you could become pregnant

You cannot join this trial if any of these apply.

Cancer related

  • You have had chemotherapy in the past 28 days 
  • You have had external radiotherapy in the last 4 weeks
  • You have cancer near the spinal cord Open a glossary item and it’s causing pressure (spinal cord compression), or your doctor thinks you are at risk of it
  • You have had another cancer in the past 5 years apart from basal cell skin cancer Open a glossary item, squamous cell skin cancer or an early cancer (carcinoma in situ) of the bladder or cervix that has been successfully treated
  • Your doctor thinks that you can’t have capecitabine or radium 223 for any reason

Medical conditions

  • You have less amounts of an enzyme called dihydropyrimidine dehydrogenase
  • You have had a blood transfusion Open a glossary item or a drug called erythropoietin Open a glossary item in the past 4 weeks
  • You take drugs to treat viral infections (such as sorivudine or brivudine), to treat a condition called epilepsy (such as phenytoin) or to stop blood clots (such as warfarin)
  • You have an active infection
  • You have heart problems that aren’t controlled such as angina or heart failure
  • You have inflammation of the bowel (ulcerative colitis or Crohn’s disease), problems with your bone marrow Open a glossary item or a condition that affects the way you absorb tablets (active peptic ulcer)
  • You have any other serious medical condition that the trial team think could affect you taking part


  • You have had an experimental drug in the past 4 weeks
  • You are known to be sensitive to drugs that contain fluoropyrimidine (such as capecitabine)
  • You are pregnant or breastfeeding 

Trial design

This is a phase 1/2 trial. The researchers would like up to 48 people from the UK to take part.

This trial has 2 parts:

  • finding the safest dose of capecitabine and radium 223 (safety phase)
  • finding if capecitabine and radium 223 work well as a treatment (extension phase)

Safety phase
Everyone has capecitabine and radium 223. The first few people taking part have a set dose of capecitabine. If they don’t have any serious side effects, the next few people have a lower dose.

Capecitabine are tablets you take every day. You have it for 2 weeks. Then you have a break of 1 week. This is called a treatment cycle.

After 1 treatment cycle of capecitabine, you have radium 223. You have it as an injection into a vein. It takes around 1 minute to have. After 2 days, you start capecitabine again.

You can have up to 12 treatment cycles of capecitabine. You have the radium 223 on every other treatment cycle. So you can have up to 6 radium 223 injections.   

Extension phase
This part of the trial is randomised. The people taking part are put into 1 of the following groups by a computer:

  • capecitabine
  • capecitabine with radium 223

Neither you nor your doctor will be able to decide which group you are in.

You are 2 times more likely to have capecitabine with radium 223 than capecitabine alone. 

CARBON trial diagram

The dose of capecitabine you have depends on the group you join and on the capecitabine dose found on the safety phase.

You have capecitabine as a tablet. You take it every day, for 2 weeks. Then you have a break of 1 week. This is a treatment cycle. You continue having capecitabine for as long as it’s working and the side effects aren’t too bad. You can have up to 12 treatment cycles.

If you have radium 223, you have it as an injection into a vein. It takes around 1 minute to have. You have up to 6 injections as you have it every other treatment cycle of capecitabine.  

Quality of life
Everybody taking part of this trial completes quality of life questionnaires:

  • before starting treatment
  • every 6 weeks
  • after you finish treatment
  • then every 3 months

It asks about how you have been feeling and what side affects you have had.

Blood and urine tests
You have some extra blood and urine tests as part of this trial. You have them every 6 weeks at the time you have treatment.

Researchers want to find out if radium 223 affects the way bones heal and develop.

Hospital visits

You see a doctor and have some tests before taking part. These tests might include:

You see the doctor for blood tests and a physical examination every 3 weeks.

You have a CT or MRI scan after 3 and 6 months of starting treatment.

When you finish treatment, you see the trial team:

  • 4 weeks later
  • then every 3 months  

If your cancer gets worse during the trial, you stop having treatment. And your doctor will discuss other treatments with you. It might be another type of chemotherapy or radiotherapy. 

Side effects

The trial team monitor you during the time you have treatment and you will have a phone number to call them if you are worried about anything. The team will tell you about all the possible side effects before you start the trial.

The most common side effects of radium 223 are:

  • feeling or being sick
  • diarrhoea
  • a drop in the number of cells that help the blood to clot (platelets), causing an increased risk of bleeding
  • a drop in the number of white blood cells and red blood cells (causing an increased risk of infection and anaemia)
  • pain, redness and swelling at the injection site

We have more information on radium 223.   

We also have information on capecitabine

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 Janet Brown

Supported by

Experimental Cancer Medicine Centre (ECMC)
Yorkshire Cancer Research
NIHR Clinical Research Network: Cancer
Sheffield Teaching Hospitals NHS Foundation Trust
University of Leeds

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.

Harriet wanted to try new treatments

A picture of Harriet

“I was keen to go on a clinical trial. I wanted to try new cancer treatments and hopefully help future generations.”

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