A trial of BYL719 for advanced solid tumours with a change to the PIK3CA gene

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

Cancer type:

All cancer types




Phase 1

This trial is looking at a new drug called BYL719 for advanced solid tumours Open a glossary item. It is for people whose cancer cells have a change to a gene called PIK3CA .

In many types of cancer, the PIK3CA gene has changed (a mutation Open a glossary item). This gene change affects a protein called P13K which is involved in cell growth.

BYL719 is a new drug that blocks the activity of the PI3K protein. We know from laboratory research that blocking this protein can stop the growth of several types of cancer. But this is the first time BYL719 is being tested in people.

The people taking part have advanced cancer Open a glossary item that has the PIK3CA gene mutation, or has too many copies of the PIK3CA gene (amplification) and has got worse despite having other treatments. The aims of the trial are to

  • Find the best dose of BYL719 to give
  • Learn more about the side effects and what happens to the drug in the body
  • See how well it works for advanced cancer

The trial also aims to find out if it is safe to have BYL719 at the same time as a drug called fulvestrant for breast cancer that is sensitive to the female hormone oestrogen (oestrogen receptor positive Open a glossary item) and has spread outside the breast.

Who can enter

You can enter this trial if you

  • Have a solid tumour Open a glossary item that cannot be removed with surgery and has got worse in the last 3 months despite other treatment
  • Can’t have standard treatment Open a glossary item for some reason, or there is no standard treatment available
  • Have a PIK3CA gene mutation Open a glossary item or too many copies of the PIK3CA gene in your cancer cells (the trial team will test for this by looking at a sample of your cancer if one is available - if not you will need to have a biopsy Open a glossary item)
  • Are well enough to be up and about for at least half the day (performance status 0, 1 or 2)
  • Have satisfactory blood test results
  • Are willing to use a reliable method of contraception throughout the trial if there is any chance you or your partner could become pregnant
  • Are at least 18 years old

You may be able to enter the part of the trial looking at BYL719 alongside fulvestrant if you are a woman who has oestrogen receptor positive breast cancer Open a glossary item with the PIK3CA gene mutation, that has spread outside your breast (metastatic breast cancer) and has come back or got worse despite having hormone therapy.

You cannot enter this trial if you

  • Have cancer that has spread to your brain unless this has been treated, does not cause symptoms and you don’t need to take steroids
  • Have had chemotherapy, biological therapy or hormone therapy in the last 4 weeks (6 weeks if you had a drug called mitomycin C or one of a group of drugs called nitrosoureas Open a glossary item), or you have not recovered from the side effects of earlier treatment
  • Have had radiotherapy in the last 4 weeks or have not recovered from the side effects of earlier treatment
  • Have had radiotherapy to more than about a third of your bone marrow Open a glossary item – your doctor can advise you about this
  • Have had major surgery in the last 2 weeks, or earlier if you have not fully recovered
  • Have had blood cell growth factors called G-CSF in the last 2 weeks
  • Have taken steroids Open a glossary item in the last 2 weeks - it is important that you don’t stop taking steroids without talking to your doctor
  • Have already had treatment with a drug that blocks the PI3K protein
  • Have nerve damage from other treatment (peripheral neuropathy) unless it is mild
  • Have diarrhoea unless it is very mild
  • Have inflammation of the pancreas (pancreatitis)
  • Have had a heart attack in the last 3 months or have any other heart condition that is a cause for concern – the trial doctors can advise you about this
  • Have diabetes or any other medical condition that the trial doctors think could make it unsafe for you to take part
  • Have had any other type of cancer in the last 2 years apart from basal cell skin cancer or carcinoma in situ of the cervix that have been successfully treated
  • Are pregnant or breastfeeding

Trial design

This is a phase 1 trial. Everybody taking part has BYL119 tablets. You take the tablets at about the same time each morning after a light breakfast. You must not eat or drink anything else for an hour afterwards.

The study is in 2 parts. In part 1, the first person has a low dose of BYL719. If they don’t have any bad side effects, the next few people will have a higher dose. And so on, until they find the best dose to give. This is called a dose escalation study.

In part 2, a larger number of people will have the highest safe dose that was found in part 1.

You take BYL719 tablets every day, but each 4 week period is called a treatment cycle. As long as you don’t have bad side effects, you can carry on taking the tablets until your cancer starts to get worse.

Some women taking part who have breast cancer will also have fulvestrant injections. You have the injections 2 weekly for the first 3 doses and then monthly.

The trial team will ask you to have 2 extra biopsies - before you start taking BYL719 and during the 2nd cycle of treatment. They will use these tissue samples, along with an extra blood sample, to look for markers that can show how well BYL719 is working. If you don’t want to have these biopsies, you don’t have to. You can still take part in the main trial.

Hospital visits

You will see the doctors and have some tests before you start treatment. The tests include

  • Physical examination including an eye test
  • Chest X-ray
  • Blood and urine tests
  • Heart trace (ECG Open a glossary item)
  • CT scan or MRI scan
  • PET scan

You go to hospital

  • 8 times in the 1st cycle of treatment
  • 6 times in the 2nd cycle
  • 3 times in each cycle after that

You have regular blood tests and a number of ECGs during the trial. At some hospital visits you have blood tests before taking the tablets and then at regular intervals over the next 24 hours. These blood samples will help the trial team to see how your body absorbs the drug, breaks it down and gets rid of it. This is called pharmacokinetics Open a glossary item.

You have a CT or MRI scan every 8 weeks during treatment. And you have 2 more PET scans at the end of the 1st and 2nd cycles of treatment.

When you finish treatment, you go back to see the trial team about a week later. You have a physical examination including an eye test, blood tests, an ECG and a CT or MRI scan. You have one more follow up appointment with them about 3 weeks later.

Side effects

This is the first time that BYL719 is being tested in people. There may be some side effects we don’t know about yet. The possible side effects include

  • Changes in the way your body processes sugars found in food (you will have regular blood tests to check this)
  • Feeling or being sick
  • Diarrhoea
  • Skin rash (if this happens, you may need to have a skin biopsy Open a glossary item)

You must not eat fruits such as grapefruit or Seville oranges (or drink their juices) during the trial as they may interact with the trial drug.

We have more information about possible side effects of 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 Mark Middleton

Supported by

Experimental Cancer Medicine Centre (ECMC)

Questions about cancer? Contact our information nurses

Freephone 0808 800 4040

Last review date

CRUK internal database number:

Oracle 7816

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

Wendy took part in a new trial studying the possible side effect of hearing loss

A picture of Wendy

"I was delighted to take part in a clinical trial as it has the potential to really help others in the future.”

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