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Masitinib 819

Masitinib 819

This leaflet provides information on a course of treatment called masitinib.  The leaflet will explain what this is and when and how it is given.  It will tell you about common side effects that you may experience.  It will also explain why it is an ‘unlicensed’ drug in the UK.

Contact telephone numbers for Velindre Cancer are given at the end of the leaflet.

What is Masitinib?

Masitinib is a new cancer treatment which is given as tablets. It is not chemotherapy.  It works by slowing down or stopping the cancer’s growth.

Masitinib is currently an unlicensed drug.  We will explain this below.

 What is an unlicensed drug?

Before doctors can prescribe a drug it needs a license.  Drugs which are licensed have proven to be safe and effective.  At the moment masitinib is not licensed for use in the UK because it is a new drug.  

Clinical trials have been carried out to test the safety and effectiveness of masitinib.  Your consultant is satisfied that masitinib is safe and effective.  They will take responsibility for monitoring you whilst you are receiving this treatment.  If you have any questions about this, please speak to your consultant.

Why am I having masitinib?

Your doctor has prescribed masitinib because it has been found to be effective in controlling your type of cancer.

How often will I receive my masitinib?

Masitinib will be prescribed twice a day in tablet form.

The treatment will continue for as long as you are coping with masitinib and it is working well.

You will have a clinic appointment every 4-6 weeks to review how you are getting on with your treatment.

How should I take the masitinib tablets?

Masitinib tablets should be taken twice a day with a glass of water.  Try to take the tablets at approximately the same time each day.  Masitinib should be taken with food, after breakfast and your evening meal.  

How many tablets will I need to take?

This will vary for each person. You may have to take a combination of tablets.  The amount you need to take will be clearly marked on the boxes.  Remember to check each box to see how many tablets you need to take.

How should I store the masitinib tablets?

Your tablets should be stored in their original packaging in a safe place away from children.  They should be kept in a cool dry place. 

Any unused tablets should be returned to the hospital pharmacy or your local chemist for safe disposal. 

Can I bring relatives and friends with me? 

You are welcome to bring someone to stay with you during your treatment. Space is limited so there is not usually room for more than one person.  Treatment areas are not suitable for young children.

What are the possible side effects?

There are some of the possible side effects listed below but with all new medicines, there is the possibility of finding other, rare side effects with masitinib. In such a case, your doctor will be immediately informed.   

In the patients treated with masitinib for a cancer, the most frequent side effects were:

Fluid retention (oedema) and skin rash

Among the patients taking masitinib, some experienced puffiness of the eyelids, or face or swelling of the ankles or a skin rash.  To prevent these side effects, patients treated with masitinib will also receive cetirizine, an anti-histamine, 10 mg per day, which will be started at the same time as masitinib, for 60 days.  This drug can make you feel drowsy so it should be taken at bedtime in the evening.

Tiredness and fatigue

Chemotherapy can make you feel more tired than usual.  It is important to listen to your body and rest if you need to, but carry out your normal activities if you feel able.  Some people find it beneficial to take gentle exercise as well as rest.

Skin problems

Some patients will develop dry skin or a rash.  Usually this can be easily treated with some non perfumed cream or lotion.  Very rarely this rash can be severe.  If you have a rash with blisters or is painful you should stop taking your masitinib tablets and telephone Velindre Cancer Centre immediately for advice.  The telephone number is on page 7. 


You may have diarrhoea.  If this occurs it is important that you drink plenty of fluids.  We will give you medication to take if you get diarrhoea.  

You should stop taking your masitinib tablets and contact Velindre Cancer Centre immediately if:

  • you have 4 or more bowel movements in 24 hours above what is normal for you.
  • you are woken up at night with diarrhoea.   

You should also contact us if you have any problems with diarrhoea or an increase in bowel movements which lasts for more than 3 days.


You are at an increased risk of picking up infections because your white blood cells which help fight infections can be reduced by this treatment.  Contact Velindre Cancer Centre immediately if you develop any signs of infection, for example flu like symptoms or a temperature above 37.5°centigrade.  The telephone number is on page 7.


Nausea and vomiting are uncommon these days as we will give you anti-sickness medicines which are usually extremely effective.  If you are sick more than once in 24 hours despite taking regular anti-sickness medicine when you are at home after your chemotherapy treatment, contact Velindre Cancer Centre for advice.  The telephone number is on page 7.

Soreness to your hands and feet

You may experience mild pain, redness, swelling and blistering of your hands or feet.  Moisturising creams can help if this develops. If the soreness does not settle or blistering becomes a problem then your medical team may need to change the dose of your treatment or stop for a while.

Myalgia (pain in the muscles)

Some patients may experience myalgia which is muscle or joint pain.  This can sometimes be severe but will only last for a few days.  If you already have painkillers at home you may find they relieve the pain.  If this does not work please contact Velindre Cancer Centre.  The telephone number is on page 7

Blood clots

A diagnosis of cancer can increase your risk of developing a blood clot (thrombosis), and having cancer treatment may increase this risk further.  It is important to tell your doctor immediately if you have symptoms such as pain, redness and swelling in your leg, or breathlessness and chest pain.  

Blood clots can be very serious.  However, most clots can usually be successfully treated with drugs to thin the blood.  Your doctor or nurse can give you more information.

Other side effects

Watery and sore eyes

Some patients experience sore or watery eyes.  Please tell your doctor or nurse at your next clinic appointment if this occurs.

Sore mouth

Your mouth may become sore or you may notice small ulcers.  Your doctor may prescribe mouthwashes or medication to prevent or clear any infection.

It is important you do not become pregnant or father a child whilst having this treatment as it could damage the unborn baby.  

Contact telephone numbers

Velindre Cancer Centre 029 2061 5888

Ask for the treatment helpline if you are unwell at home and need immediate advice at any time of the day or night.  For example you should phone if you:

  • Are sick more than once in 24 hours
  • Have a temperature of 37.5°C or above or below 35.5°centigrade
  • Have 4 or more bowel movements in 24 hours above what is normal for you
  • Have a very sore mouth 
  • Have very sore hands or feet

Pharmacy department 029 2061 5888 ext 6223

Monday – Friday 9am – 5pm for queries about your medicines

Tenovus freephone 0808 808 1010

cancer helpline 

Macmillan freephone Helpline 0808 808 0000


This leaflet was written by health professionals.  The information contained in this leaflet is evidence based.  It has been approved by a team of doctors, nurses and patients.  It is reviewed and updated every 2 years.