A trial of BKM120 for advanced hormone receptor positive breast cancer that is HER2 negative and has got worse despite having other treatments (BELLE 3)

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

Cancer type:

Breast cancer




Phase 3

This trial is looking at a drug called BKM120 for breast cancer that has spread into tissue surrounding the breast or to another part of your body. The trial is for women who have breast cancer that has got worse despite having a type of hormone therapy called an aromatase inhibitor Open a glossary item as well as a drug called an mTOR inhibitor.

More about this trial

Breast cancer cells often have receptors for the hormones oestrogen or progesterone, or for a protein called HER2.

If there are a large number of hormone receptors, the cancer is called hormone receptor positive. In post menopausal women, doctors can treat hormone receptor positive breast cancer with hormone therapy drugs called aromatase inhibitors. You may also have biological therapy. But breast cancer may stop responding to these treatments.

If there are only small numbers of receptors for the HER2 protein, the cancer is called HER2 negative. HER2 negative breast cancer is unlikely to respond to drugs such as Herceptin and researchers are looking for new treatments to help women who have this type of breast cancer.

In this trial, they are looking at a drug called BKM120 which is a type of biological therapy.  It is a cancer growth blocker. You have BKM120 alongside a hormone therapy drug called fulvestrant.

The women taking part in this trial have breast cancer that is hormone receptor positive, HER2 negative, has spread into surrounding tissue or to a another part of the body, and has got worse despite having an aromatase inhibitor and a biological therapy drug called an mTOR inhibitor.

The aim of this trial is to see if BKM120 and fulvestrant is better than fulvestrant alone for this group of women.

Who can enter

You may be able to enter this trial if

  • You are a woman with breast cancer that has spread into tissue surrounding your breast (locally advanced) and can’t be removed with surgery, or has spread to another part of your body
  • Your cancer is hormone receptor positive and HER2 negative
  • Your doctors are able to measure your cancer
  • You have already had an aromatase inhibitor Open a glossary item (you may have had more than 1 type of hormone therapy)
  • Your cancer has come back or is getting worse despite having a combination of an  mTOR inhibitor and hormone therapy – if you have stopped having this type of treatment, it must have been the last treatment you had and your cancer must have started to get worse within a month of finishing it
  • You have been through the menopause Open a glossary item
  • You are able to swallow medication
  • You have satisfactory blood test results
  • You are well enough to be up and about for at least half the day (performance status 0, 1 or 2)
  • You are at least 18 years old

You cannot enter this trial if you

  • Have cancer that has spread to your brain or spinal cord and is causing symptoms – you can take part if cancer spread to your brain was treated at least 4 weeks ago and is not causing symptoms
  • Are currently having any other cancer treatment, including experimental drugs
  • Have already had fulvestrant or drugs that target proteins called PI3K or AKT – your doctor can advise you about this
  • Have had surgery in the last 2 weeks, or have not fully recovered from earlier surgery
  • Have had more than 1 type of chemotherapy for breast cancer that has spread
  • Have not recovered from the side effects of earlier treatment (apart from hair loss) unless they are very mild
  • Have had radiotherapy in the last 4 weeks (in the last 2 weeks if it was radiotherapy for symptoms given only to a small area of your body)
  • Haven’t fully recovered from the side effects of earlier radiotherapy treatment, unless they are very mild
  • Have had any other cancer in the last 3 years apart from non melanoma skin cancer or cervical cancer that was successfully treated
  • Take steroids Open a glossary item or any other medication that can damp down your immune system (steroid creams, eye drops and inhalers are allowed)
  • Take medication that can affect body substances called cytochrome P (CYP) enzymes – it is important that you don’t stop any medication without talking to your doctor
  • Take warfarin (or a similar drug) to thin your blood
  • Have had mental health problems in the past, or have moderate to severe depression or severe anxiety– doctors use questionnaires to assess this
  • Have had a heart attack in the last 6 months, have certain other heart problems, or take medication that can affect your heart – the trial doctors can advise you about this
  • Have problems with your digestive system Open a glossary item that could affect how you absorb drugs
  • Are known to be very sensitive to anything in fulvestrant or BKM120
  • Have any other medical condition that the trial team think could affect you taking part
  • Are known to be HIV positive
  • Have acute viral hepatitis or have chronic or active HBV or HCV infection




Trial design

This phase 3 trial will recruit about 420 women around the world. It is a randomised trial. The women taking part are put into treatment groups by a computer. Neither you nor your doctor will be able to decide which group you are in.  And neither of you will know which group you are in. This is called a double blind trial.

Two thirds of the women taking part have fulvestrant and BKM120. The other third have fulvestrant and a dummy drug (placebo Open a glossary item).

BELLE 3 trial diagram

You have fulvestrant as two injections - one into each buttock. BKM120 and the dummy drug are capsules that you swallow.

You have treatment in 4 week periods called cycles of treatment. In the first cycle of treatment, you have fulvestrant injections twice – 2 weeks apart. You take the capsules once every day.

From the 2nd cycle onwards, you have fulvestrant every 4 weeks. You continue to take the BKM120 or dummy drug capsules every day.

You keep a diary at home in which you note down when you take the capsules. You must also note down if you take any medicine for an upset stomach or indigestion.

As long as you don’t have bad side effects, you can carry on having the trial treatment for as long as it helps you.

The researchers will ask you to fill in some questionnaires

  • Before you start treatment
  • Once in the 1st cycle of treatment
  • Twice in the 2nd cycle
  • Once in each cycle after that
  • When you finish treatment

Some of the questionnaires will ask about your mood and whether you feel depressed. Others will ask how anxious you are feeling.




Hospital visits

You see the trial team and have some tests before you start treatment. The tests include

If you have any cancer on your skin, your trial doctor may take a photograph. This will only show the cancer and the surrounding area. Your face will not be in the photograph and it will not be possible to identify you.

The trial team will ask to test a sample of your cancer. They may be able to get a sample of your tumour that was removed and stored when you had surgery or a biopsy Open a glossary item in the past. If there isn't a stored sample available, you can have a new biopsy.

You go to hospital 4 times in each of the first 2 cycles of treatment and once in each cycle after that. You have blood tests at each visit. You also have

  • A heart trace in the 2nd cycle of treatment and then in each cycle after that
  • A heart scan every 4th cycle
  • A CT or MRI scan every 6 weeks

In the first 100 women to join the trial, the researchers will take a number of extra blood samples to learn more about what happens to the drugs in your body. This is called pharmacokinetics Open a glossary item. To have the extra blood tests, they may ask you to stay at hospital for about 9 hours on the first day of treatment. If you live a long way from the hospital, you may stay in overnight.

When you finish treatment, you see the trial team within a week. You have a physical examination, blood tests, a urine test, a heart trace, a heart scan and a CT or MRI scan. They will ask you to have another biopsy, but this is optional. You don't have to agree tot this if you don't want to. The trial team will then contact you once every 3 months to see how you are.

If you stop the trial treatment for any reason other than your cancer getting worse, you have a CT or MRI scan every 6 or 12 weeks. This will continue until your cancer starts to get worse. After that, the trial team will contact you every 3 months to see how you are getting on.




Side effects

BKM120 is a new drug so there may be side effects we don’t know about yet. The most common known side effects include

The most common side effects of fulvestrant include

  • Pain or swelling where you have the injections
  • Changes to the way your liver works
  • Feeling sick
  • Tiredness (fatigue)

We have more information about fulvestrant 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

Professor Stephen Johnston


Supported by

NIHR Clinical Research Network: Cancer


Other information




Questions about cancer? Contact our information nurses

Freephone 0808 800 4040

Last review date

CRUK internal database number:

Oracle 10904

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

Caroline took part in a clinical trial for breast cancer

“I had treatment last year and I want to give something back.”

Last reviewed:

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