A trial looking at abiraterone with exemestane for breast cancer that has spread

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

Cancer type:

Breast cancer




Phase 2

This trial is looking at using a new drug called abiraterone with exemestane for breast cancer that has spread to another part of the body. This trial is for women who have oestrogen receptor positive (ER positive) breast cancer.

Doctors often use hormone therapy to treat breast cancer. Two drugs they use are anastrozole and letrozole. But sometimes the cancer starts to grow again and then doctors may use exemestane.  

Abiraterone is a new type of hormone therapy. It stops the body from making certain hormones. The researchers think that using abiraterone with exemestane may be better than exemestane alone.  

The aim of this trial is to compare exemestane alone with abiraterone and exemestane. The researchers want to find out which is best for women whose breast cancer has continued to grow during or after treatment with anastrozole or letrozole.  

Who can enter

You may be able to enter this trial if

You cannot enter this trial if you

  • Have already had exemestane, or drugs called ketoconazole, aminoglutethimide or CYP17 inhibitors – your doctor can tell you this
  • Have had more than 2 courses of treatment for breast cancer that has spread or more than 1 course of treatment if this included chemotherapy
  • Have had immunotherapy Open a glossary item in the past month
  • Have had radiotherapy in the past 2 weeks – you may be able to take part if your radiotherapy was to control symptoms
  • Have had hormone therapy or chemotherapy in the past 2 weeks - 3 weeks if you have had bevacizumab (Avastin)
  • Have cancer that has spread to your brain or spinal cord and is causing symptoms or have cancer cells in your spinal fluid (leptomeningeal disease)
  • Have ongoing moderate to severe side effects from earlier treatment – you may be able to take part if your side effects are hair loss or moderate nerve damage to the feet or hands (peripheral neuropathy Open a glossary item)
  • Have had major chest or tummy (abdominal) surgery in the past month
  • Have had a major injury in the past month
  • Have high blood pressure that is not controlled with medication
  • Have an adrenal gland Open a glossary item that makes too much of the hormone aldosterone (hyperaldostronism)
  • Have an underactive pituitary gland Open a glossary item (hypopituitarism)
  • Have had a heart attack in the last 6 months
  • Have heart pain (angina) that is severe or not controlled with medication
  • Have a problem with your digestive system Open a glossary item that could affect the way you absorb drugs
  • Have an autoimmune disease such as rheumatoid arthritis and are taking steroids
  • Are hepatitis B or hepatitis C positive
  • Are sensitive to abiraterone, exemestane, prednisolone or their ingredients
  • Have had an experimental drug or used an experimental medical device as part of a clinical trial in the last month
  • Have any other medical condition that could affect you taking part in this trial

Trial design

This is a phase 2 trial. It will recruit 300 women from different countries around the world. It is a randomised trial. Women who take part will be put into 1 of 3 treatment groups by a computer. Neither you nor your doctor can choose which group you are in.

In group 1 you have abiraterone, prednisolone and exemestane. In group 2 you have abiraterone and prednisolone. In group 3 you have exemestane alone.

Abiraterone is a tablet. You take 4 tablets daily on an empty stomach. You can’t eat for at least 2 hours before or 1 hour after taking your tablets. You take your tablets about the same time each day.

Prednisolone is a tablet. You take 1 tablet daily at the same time as you take abiraterone. When you stop taking abiraterone you keep taking prednisolone. Your doctor will tell you when and how to stop taking prednisolone.  

Exemestane is a tablet. You take 1 tablet daily after a meal.  

You can continue having treatment as long as the side effects aren’t bad and the treatment is still helping you.

If you are taking exemestane alone and it stops helping, you may be able to switch to abiraterone. Your doctor will talk to you about this.

The researchers will ask you to fill in 3 questionnaires once a month during treatment, at the end of treatment and then every 3 months after that. They will ask about how you are feeling, what you can do and side effects you might have. This is called a quality of life study.  

The researchers will also ask your permission to take a small piece of tissue from when you had your biopsy or surgery. This is to look at the genes in the cancer cells.

Hospital visits

You see the doctor and have some tests before taking part in this trial. These tests include

  • A physical examination
  • Blood tests
  • Heart trace – ECG Open a glossary item
  • Heart scan – ECHO Open a glossary item
  • CT scan or MRI scan
  • Urine test

During the first 3 months of treatment you see the doctor fortnightly for a blood test. You have a physical examination every 4 weeks.

After this you see the doctor every month for a blood test and physical examination. You will not be able to eat before this appointment, so that your doctor can measure the amount of sugar in your blood (a fasting blood test). You have a CT scan or MRI scan and heart trace regularly while having treatment.  

At the end of treatment you see the doctor and have the same tests. After treatment you see the doctor every 3 months.  

Side effects

The most common side effects of abiraterone may include

  • Fluid retention causing swelling of the legs
  • Low levels of potassium in the blood
  • High blood pressure
  • Bladder infection
  • Liver changes
  • High levels of fat in the blood
  • Heart problems

The side effects of exemestane may include

  • Tiredness
  • Hot flushes Open a glossary item
  • Increased sweating
  • Increased appetite
  • Bone thinning, causing an increased risk of broken bones

The most common side effects of prednisolone may include

  • Difficulty getting to sleep (insomnia)
  • Mood changes
  • Depression
  • Changes in blood sugar levels

We have more information on abiraterone, exemestane and prednisolone in our cancer drugs section.

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

Dr Andreas Makris

Supported by

Experimental Cancer Medicine Centre (ECMC)
National Institute for Health Research Cancer Research Network (NCRN)

Questions about cancer? Contact our information nurses

Freephone 0808 800 4040

Last review date

CRUK internal database number:

Oracle 8403

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.”

Last reviewed:

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