Updated 14 Mar 2019

The aim of treatment for CML is to reduce the number of leukaemia cells in your body to low enough levels for you to have a normal life expectancy. The most common treatment for CML is a targeted therapy drug called a tyrosine kinase inhibitor (TKI), which is taken daily in tablet form (orally).

Chemotherapy

If your white blood cell count is high and/or you have a lot of symptoms and feel unwell when doctors first suspect you have CML, your doctor may give you a mild chemotherapy tablet, known as hydroxycarbamide. This will lower the number of blood cells in your bloodstream and control your symptoms until your diagnosis is confirmed.

If you’re given hydroxycarbamide, you’ll usually also be given another tablet called allopurinol. This is to prevent gout (which happens when uric acid builds up in the blood), which can be a side effect of hydroxycarbamide.

Leukapheresis

If your white blood cell count is very high, and particularly if you have certain symptoms such as blurred vision, your doctors might advise removing some white blood cells from your bloodstream in a process called leukapheresis.

In this procedure, a plastic tube will be inserted into each arm. Your blood will drain from one tube into a machine (centrifuge) which will be spinning at high speed. The spinning separates the blood into white blood cells, red blood cells and plasma. The white blood cells are removed and either thrown away or, with your agreement, could be used for research. The red blood cells and plasma are then returned to your body through the tube in your other arm.

At any one time no more than a cupful of blood will be in the centrifuge and the procedure is very safe. As the procedure can take two to three hours to lower your white blood cell count in this way, you may want to bring something to keep you entertained, like a book or tablet. The leukapheresis will be done by a specially trained nurse, who will talk you through the procedure.

Watch Professor Jane Apperley, Consultant Haematologist at Hammersmith Hospital, talk about initial treatment for CML.

Tyrosine kinase inhibitors (TKIs)

Once your diagnosis is confirmed, your doctors will usually prescribe a targeted therapy drug called a tyrosine kinase inhibitor (TKI). The TKI that you’re prescribed when you’re first diagnosed will depend on your disease phase, the potential risk of side effects, your risk score and any other conditions you have.

First-line treatment

If you’re diagnosed in the chronic phase, your first treatment will usually be a regular standard dose of one of three types of TKI: imatinib, dasatinib or nilotinib. In general, people cope well with these drugs, and can return to a relatively normal lifestyle, such as continuing to work and study. Most people start on imatinib, which is taken once a day, after food.

Second- and third-line treatment

If the first TKI that you try stops working for you or you struggle to cope with its side effects, your doctor may suggest you try another TKI. This is known as second-line treatment. This will be either imatinib, nilotinib, dasatinib, bosutinib or ponatinib, depending on which TKI you tried first. Nilotinib is taken twice a day with a ‘fasting regimen’, meaning no food two hours before or one hour after taking the tablet. Dasatinib and ponatinib are taken once a day (with or without food). Bosutinib is taken once a day after food.

If you don’t respond to second-line treatment, you may be able to try a third TKI. Some people may also be able to have a stem cell transplant if TKIs don’t work for them.

For more information about stem cell transplants, order or download our booklet, The seven steps: blood stem cell and bone marrow transplants.

Taking your TKI

It’s important that you take your TKI exactly as directed by your doctor. Evidence shows that if you do, you’ll have a better response to the treatment. Your healthcare team can help you with this.

At the moment, most people with chronic-phase CML are advised to take their TKI for life. However, growing research suggests that it’s safe for some people who are doing well on TKIs (and who have been taking them for five years or more with a deep molecular response for at least two years) to reduce their dose or potentially stop taking them altogether, as long as they continue to be closely monitored by their doctor.

This won’t be suitable for everyone, so it’s very important that you don’t stop taking your TKI unless your doctor tells you to. Otherwise, the number of leukaemia cells in your blood could increase and you’ll be at greater risk of progressing to the accelerated or blast phases. If you have any questions about your treatment plan, your healthcare team will be able to talk you through it.

Watch Kris talk about his treatment for CML.

If you’re diagnosed in the blast phase

If you’re diagnosed in the blast phase, your CML will be treated with stronger treatments, in a similar way to an acute (fast-growing) leukaemia. This usually includes chemotherapy, and sometimes TKIs.

If treatment for blast phase CML is successful and you return to the chronic phase, your doctor may recommend a stem cell transplant.

Watch Professor Jane Apperley, Consultant Haematologist at Hammersmith Hospital, talk about stem cell transplants for CML.

Side effects of TKIs

For most people on TKIs, side effects are not severe. However, you may notice some changes to your body that could be linked to the drugs you’re taking. If you do, it’s important to let your healthcare team know, as there are lots of things they can do to help you manage these side effects.

The following side effects are common to all TKIs:

  • extreme tiredness (fatigue)
  • fluid build-up
  • problems with your liver
  • skin rash
  • muscle cramps
  • joint pains
  • headaches
  • feeling sick (nausea) – if you’re taking imatinib, this can happen if you don’t take the drug on a full stomach
  • diarrhoea (frequent watery poos) – if you’re taking bosutinib, this can be particularly severe in the first few days
  • low blood counts – a low red blood cell count can cause tiredness (fatigue), a low white blood cell count can cause frequent infections, a low platelet count can cause bruising or bleeding.

To find out more about ways to reduce your risk of infection, download our fact sheet, Understanding infection.

Imatinib

Some other side effects of imatinib include:

  • fluid build-up that causes puffiness around the eyes
  • dry, gritty eyes
  • haemorrhages into the white of the eye - these are not dangerous or harmful to your sight but can look unpleasant.

Dasatinib

Some other side effects of dasatinib include:

  • fluid build-up between the lining of the lungs – it’s important to tell your doctor if you get a fever, a cough, or pain in the chest when you take a deep breath
  • tummy (abdominal) pain
  • shortness of breath
  • sickness (vomiting)
  • very rarely, blood in your stool (poo).

If you experience sickness and/or vomiting as a side effect of treatment, download our fact sheet, Managing sickness and vomiting.

Nilotinib

Some other side effects of nilotinib include:

  • an itchy rash (more common than with other TKIs)
  • high blood pressure
  • higher blood glucose (sugar) levels
  • higher cholesterol levels
  • rarely, clots in the arteries of the heart, brain or lower legs. This might happen if you already have a higher risk of cardiovascular problems, for example if you smoke, have high blood pressure or a previous history of clots. You’ll be monitored closely for these side effects if you’re at greater risk.

Ponatinib

Some other side effects of nilotinib include:

  • dry skin
  • high blood pressure
  • inflammation of the pancreas, an organ in the abdomen (stomach area) – if this happens you’d notice severe pain
  • clots in the arteries of the heart, brain or lower legs. This might happen if you already have a higher risk of cardiovascular problems, for example if you smoke, have high blood pressure or a previous history of clots. You’ll be monitored closely for these side effects if you’re at greater risk.

Watch Professor Jane Apperley, Consultant Haematologist at Hammersmith Hospital, talk about the side effects of treatment for CML.

Fertility

Impact on fertility for women

While there’s no evidence that TKIs affect fertility (your ability to have a baby), doctors strongly recommend that you avoid becoming pregnant while you’re taking TKIs and use reliable contraception. This is because there’s evidence to suggest TKIs might be harmful to a baby in the womb (uterus).

If you think you might like to have children in the future, your doctor can refer you to a specialist who’ll explain all the options available to you. For example, you may want to think about storing your eggs or embryos (eggs that have been fertilised with your partner’s or a donor’s sperm), or coming off treatment for a period of time to become pregnant. Your doctor can make recommendations based on how you’re responding to treatment.

If you’re diagnosed with CML while you’re pregnant, or if you become pregnant after being diagnosed, your doctors will discuss your options with you. This might – if appropriate for you – include delaying or adapting your treatment until the baby is born. This is something you’ll need to think very carefully about and discuss with your healthcare team. There’s also evidence to suggest that TKIs are present in the breast milk of women taking them, so doctors recommend that you don’t breastfeed while taking them.

If you have a stem cell transplant, it’s likely that the drugs used for the transplant will cause an early menopause (when the ovaries stop releasing an egg each month and you no longer have periods). This would mean you could no longer become pregnant naturally. You may want to discuss with your doctor ways to keep your fertility after the transplant. Some people can start hormone replacement therapy (a treatment that takes away some of the symptoms of menopause) soon after their transplant.

Watch Professor Jane Apperley, Consultant Haematologist at Hammersmith Hospital, talk about being diagnosed with CML while pregnant.

Impact on fertility for men

For men, there’s currently no convincing evidence to suggest taking TKIs at the time of conception could have a harmful impact on an unborn child. However, there is less information about the newer TKIs (bosutinib and ponatinib) so your doctor may suggest coming off treatment – if appropriate for you – if you decide to try for a baby. This is something you’d need to think very carefully about and discuss with your healthcare team.

Most hospitals and treatment centres will also recommend storing some of your sperm at the time when you’re diagnosed, but if this isn’t discussed with you, you can ask your healthcare team about it. If you are considering a stem cell transplant, it’s important to have this conversation with your healthcare team.

Watch Professor Jane Apperley, Consultant Haematologist at Hammersmith Hospital, talk about the impact of TKIs on fertility for men and women.

Late effects of TKIs

Because TKIs were only first introduced in the UK in 2003, we don’t fully understand the effects of taking them for life. During your treatment, your healthcare team may run tests to monitor you for long-term side effects. If you experience any new side effects while you’re taking TKIs, it’s important to let your nurse or doctor know.

Taking TKIs with other drugs

There’s some evidence to suggest that taking TKIs in combination with other treatments may cause more side effects than if you take them on their own. Your healthcare team can explain how this might affect any other medication you’re taking.

Response to treatment and follow-up

There are several levels of response to treatment for CML, which you normally achieve one by one. Your doctor will measure your response at your follow-up appointments.

Haematological response

When your blood counts return to normal, you’re said to have achieved a complete haematological response (CHR). This normally happens around three months after you start treatment.

A haematological response is measured using a full blood count. Although your blood counts will be within the normal range at this stage, there may still be leukaemia cells in your body that a full blood count can’t pick up, so you will need to continue having treatment to keep these levels under control.

Cytogenetic response

To measure your cytogenetic response, your doctor will either take a bone marrow biopsy or run a polymerase chain reaction (PCR) test on a sample of your blood. These tests are more sensitive than a full blood count, so give doctors a better idea of the levels of leukaemia in your body.

Molecular response

A PCR test (done using a blood sample) is also used to measure your molecular response. If you’re responding to treatment, your doctor will usually take a blood sample and run a PCR test every three months. It’s a very reliable test that can detect one leukaemia cell in up to 100,000 normal blood cells.

PCR results are expressed as percentages. The results tell you what proportion of your blood cells are leukaemia cells. The table below shows the different PCR results you can get, and what they mean. The symbol ‘<’ means ‘less than’.

PCR RESULT KNOWN AS WHAT IT MEANS
< 1% Complete cytogenetic response (CCyR) Less than 1 leukaemia cell in every 100 blood cells
< 0.1% Major molecular response (MMR) Less than 1 leukaemia cell in every 1,000 blood cells
< 0.01% Deep molecular response (MR4) Less than 1 leukaemia cell in every 10,000 blood cells
< 0.0032% MR4.5 Less than 1 leukaemia cell in every 32,500 blood cells
< 0.001% MR5 Less than 1 leukaemia cell in every 100,000 blood cells

Once you’ve achieved MMR, you’ll still have regular PCR tests – usually every three to six months – to make sure you’re continuing to respond to treatment. If no leukaemia cells can be detected you might hear your result referred to as ‘undetectable transcripts’. This means there may be an incredibly small number of leukaemia cells present somewhere in your body, but the test can’t pick these up. This is also called a complete molecular response (CMR) – where your tests can’t detect any signs of CML and you no longer have disease symptoms.

Watch Professor Jane Apperley, Consultant Haematologist at Hammersmith Hospital, talk about responses to treatment for CML.

Clinical trials

If you’d like to find out more about clinical trials for CML, speak to your healthcare team. You can also visit the UK Clinical Trials Gateway.

For more information about what it’s like to be part of a clinical trial, order or download our booklet, Your guide to clinical trials.

The outlook

Thanks to TKIs, survival rates for people with CML have improved dramatically over the last 20 years. Most people with CML will have a very good outlook – particularly those diagnosed in the chronic phase. Recent evidence suggests that if you respond well to treatment, you could have a similar life expectancy to someone who doesn’t have cancer.

Unfortunately, it’s harder to control blast-phase CML, as it doesn’t always respond to TKIs. If this is the case for you, your healthcare team will talk you through other treatment options and explain the impact they might have on your outlook.

If you want to find out more

Cancer Research UK has more information on the general outlook for CML. Remember that statistics can only give an overall picture. Your own outlook is individual to you and will depend on your age, level of fitness and the stage of your disease. The Cancer Research UK information nurses can help you with any questions you may have about these statistics on 0800 800 4040.

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