A trial looking at masitinib and imatinib for gastrointestinal stromal tumours

Cancer type:

Soft tissue sarcoma




Phase 3

This trial is comparing masitinib with imatinib as the first drug treatment for gastrointestinal stromal tumours that can’t be removed with surgery, or have spread to other parts of the body.

A gastrointestinal stromal tumour (GIST) is a rare type of soft tissue sarcoma that is found in the digestive system Open a glossary item, most often in the wall of the stomach.

If a GIST can’t be removed with surgery, or has spread to other parts of the body, you may have a drug called imatinib.

Imatinib is a type of biological therapy called a tyrosine kinase inhibitor or TKI. It stops signals that cancer cells use to divide and grow.

Masitinib is another TKI that researchers think might work better as the first drug treatment for gastrointestinal stromal tumours. The aims of this trial are to

  • See if masitinib is better than imatinib for GISTs that can’t be removed with surgery or have spread to another part of the body
  • Learn more about the side effects

Who can enter

You may be able to enter this trial if you

  • Have a gastrointestinal stromal tumour (GIST) that has spread to another part of your body or can’t be removed with surgery or has come back after surgery
  • Have at least 1 area of cancer that can be seen and measured on a scan
  • Have satisfactory blood test results
  • Are well enough to carry out all your normal activities, apart from heavy physical work (performance status of 0 or 1)
  • Are at least 18 years old
  • Are willing to use reliable contraception during the trial and for 3 months afterwards if there is any chance you or your partner could become pregnant

You cannot enter this trial if you

  • Have GIST that has spread to your brain or spinal cord
  • Have already had imatinib unless you had it before or after surgery, you finished taking it more than 4 weeks ago and your GIST has now come back
  • Have had a similar drug
  • Have had another experimental drug in the last month
  • Have high blood pressure that can’t be controlled with medication or have certain heart problems – the trial team can advise you about this
  • Have had any other cancer in the last 5 years, apart from carcinoma in situ of the cervix or basal cell skin cancer
  • Have had problems with drug or alcohol addiction, or you drink large amounts of alcohol and the trial team think this could affect you taking part
  • Have any other medical condition that the trial team think would make it unsafe for you to take part
  • Are pregnant or breastfeeding

Trial design

This phase 3 trial will recruit more than 450 people. It is a randomised trial. The people 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.

  • People in group 1 take masitinib tablets twice a day
  • People in group 2 take imatinib tablets once a day

Masitinib and imatinib for gastrointestinal stromal tumours trial diagram

In earlier trials, some people taking masitinib, had a skin rash or puffiness in their face, eyelids or ankles. To try to prevent these side effects, people in group 1 also take an antihistamine Open a glossary item drug called cetirizine. You start it at the same time as the masitinib tablets and take it for 2 months.

The trial team will give you a diary card to keep at home. In this, you write down when you take your tablets and whether you need to take any other medication.

The trial team will also ask you to fill out a questionnaire before you start treatment, every 3 months during treatment and after you finish treatment. The questionnaire will ask about side effects and how you’ve been feeling.  This is called a quality of life study.

As long as you don’t have bad side effects, you can carry on taking masitinib or imatinib for as long as it is helping you.

If you are taking masitinib and have bad side effects, or a scan shows your tumour has started to get worse, you can start taking imatinib instead.

If you are taking imatinib and your tumour starts to get worse, the trial team will talk to you about switching to a different type of treatment. But you can’t switch from imatinib to masitinib in this trial.

Hospital visits

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

  • Physical examination
  • Blood tests
  • Heart trace (ECG Open a glossary item)
  • Chest X-ray

If you haven’t had one in the last 4 weeks, you also have a CT scan of your tummy (abdomen Open a glossary item) and the area between your hip bones (pelvis Open a glossary item).

You see the trial team every 4 weeks for the first 3 months, and then once every 3 months for the rest of the time you are having treatment. You have a physical examination each time.

You have blood tests

  • Each week during the first 2 months of treatment
  • Every 2 weeks in the 3rd month
  • Each month from the 4th month until 2 years after starting treatment
  • Every 3 months after that

You have a heart trace every 6 months and a CT scan every 3 months during treatment.

When you finish treatment, you see the trial team again and have a physical examination, blood tests, a heart trace and a CT scan. Your doctor may ask to take a biopsy Open a glossary item of your tumour. But you don’t have to agree to this if you don’t want to.

Side effects

As masitinib is a new drug, there may be side effects we don’t know about yet. In earlier trials, the most common side effects were

You take an antihistamine tablet called cetirizine to try to prevent some of these side effects. Cetirizine can make you feel drowsy, so you should take it before you go to bed.

Taking either masitinib or imatinib increases your risk of infection due to a drop in the number of white blood cells.

We have more information about the other side effects of imatinib 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 Michael Leahy

Supported by

AB Science

Questions about cancer? Contact our 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.

Over 60,000 cancer patients enrolled on clinical trials in the UK last year.

Last reviewed:

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