Pronunciation guide

Click here to find out how imatinib mesylate works

Imatinib is used to treat chronic myeloid leukaemia (CML).

People who have previously failed on therapy with interferon-alpha (the standard treatment for CML) or whose cancer has spread can be treated with imatinib. It is also used in some countries for the treatment of gastrointestinal stromal tumours (GIST).

Is it effective?

Imatinib is used to treat people with chronic myeloid leukaemia (CML) in various stages of the disease. Patients who have been treated with this drug showed a haematological response , i.e. a reduction in the number of white blood cells to the levels that are normally found in the body of healthy individuals. Patients who were given imatinib also showed a cytogenic response, i.e. a reduction or elimination of the faulty chromosomes that causes CML. Although there may be a link between a cytological response and improved survival, to date there have been no clinical trials that have shown an increase in survival time for patients taking imatinib. ¹ In the treatment of GIST, imatinib has been shown in a clinical trail to produce a partial response in 38% of patients. ²

You should not take imatinib if: ³

• You are hypersensitive to any of the active substances found in imatinib
• You are breastfeeding

In addition, caution should be taken in using this drug to treat the following people:

• People with severe liver impairment ⁴
• Pregnant women – imatinib should only be used in pregnant women where absolutely necessary ⁴

People who are prescribed imatinib should avoid or restrict the use of over the counter or prescription medication that contains paracetamol. ⁴

How is it taken?

• As a capsule, once daily, with a meal and a large glass of water

How does it work?

• People with CML have an over-production of white blood cells, caused by a genetic abnormality
• All cells in the body, including white blood cells, grow because they receive messages from proteins called growth factors
• These growth factors attach themselves onto receptors found on the surfaces of cells
• When the protein attaches to the receptor, it sends signals into the cell, telling the cell to grow and divide
• People with CML have an abnormal receptor, called the tyrosine kinase receptor, on the surface of their white blood cells
• This means that the receptor is activated even when there is no growth factor bound to it, and so the cells are told to grow and divide constantly
• Imatinib binds to the receptor on the surface of the cells
• This stops the signals from being sent, and so stops the cell from growing and dividing

What are the side effects associated with this drug?

As with all types of chemotherapy, there are some side effects associated with imatinib. Generally, these side effects appear to be mild or moderate. However it is important that you report any side effects to your doctor to avoid any problems or more serious side effects developing.

The most common side effects are: ¹

• Nausea and vomiting
• Indigestion
• Diarrhoea
• Cramping or aches in the legs
• Retention of fluid and swelling. This is especially common around the eyes
• Eczema and skin rashes
• Increased susceptibility to infection, due to a reduction in the number of white blood cells, which can cause anaemia, risk of bruising and infection

To ensure that fluid retention does not become serious, if you are given imatinib you will be weighed regularly. If you notice any rapid and unexpected weight gain you should tell you doctor immediately.

To check that you are not at an increased risk of infection, you need to have regular blood tests. When you are first prescribed imatinib, you will need to have blood tests every week for the first month. For the second month you will have blood tests every two weeks; after that your doctor will tell you how often you need to have the tests done.

The information in this section is taken from published literature and the summary of product characteristics for this drug. http://emc.medicines.org.uk/emc/industry/default.asp?page=displaydoc.asp&documentid=15014 . Please contact your healthcare professional for full information on product availability in your country.

References

1. Imatinib Product Monograph.
2. Dagher R, Cohen M, Williams G et al. Approval summary: imatinib mesylate in the treatment of metastatic and/or unresectable malignant gastrointestinal stromal tumours. Clinical Cancer Research 2002; 8(10): 3034-3038.
3. Imatinib Package Leaflet
4. Imatinib Summary of Product Characteristics. http://www.eudra.org/humandocs/Humans/EPAR/glivec/glivec.htm