Medicines for Chronic myeloid leukaemia

What it is

Chronic myeloid leukaemia (CML) is a type of blood cancer that affects the myeloid cells and usually develops slowly over months or years. It is uncommon and mainly affects adults, becoming more common with age. In CML, a specific genetic change in the bone marrow cells (the "Philadelphia chromosome", which produces an abnormal signal that drives the cells to multiply) leads to an overproduction of certain white blood cells. Because it develops slowly, many people have few or no symptoms at first, and CML is often picked up on a blood test done for another reason. When symptoms do occur, they can include: tiredness and weakness; unintentional weight loss; night sweats; a feeling of fullness or discomfort in the tummy (from an enlarged spleen); paleness and breathlessness (anaemia); easy bruising or bleeding; and feeling generally unwell. CML is notable as an example of how targeted treatment has transformed a cancer: the understanding of the specific genetic driver led to the development of targeted medicines (a type called tyrosine kinase inhibitors) that block the abnormal signal driving the leukaemia. These treatments, usually taken as tablets, are often very effective at controlling CML, and for many people CML has become a long-term, manageable condition that is kept under good control, allowing them to live normally. Treatment is usually long-term and monitored, and most people respond well. The key messages are that CML is usually slow-growing, that highly effective targeted tablet treatments are available, and that many people live well with it as a controlled, long-term condition — while, as with other blood cancers, persistent or unexplained symptoms should be checked.

How it is treated

Chronic myeloid leukaemia is managed by specialist haematology teams, and its treatment has been transformed by targeted therapies, so that for many people it is now a well-controlled, long-term condition. Diagnosis involves blood tests and confirmation of the characteristic genetic change (the Philadelphia chromosome / BCR-ABL) through specialised tests, often on a blood or bone marrow sample; this genetic feature is the target of treatment and is also used to monitor the response. The mainstay of treatment is targeted medicines called tyrosine kinase inhibitors (TKIs), usually taken as tablets, which block the abnormal signal that drives the leukaemia. These are often very effective at controlling CML and reducing the abnormal cells to very low levels, and for many people they turn CML into a manageable long-term condition. Treatment is usually taken long-term, and the response is monitored regularly with blood tests (which measure the abnormal genetic marker); if one treatment is not working well or causes problems, others are available. In some situations, other treatments — including a stem cell transplant — may be considered. Taking the medicine reliably as prescribed and attending monitoring are important parts of care, and side effects can usually be managed. Because CML is usually slow-growing and often controlled well with tablets, many people live normally with it, though it is generally a long-term condition needing ongoing treatment and monitoring. The reassuring messages are that CML is usually slow-growing, that highly effective targeted tablet treatments have made it a manageable long-term condition for many people, and that outcomes are generally good with treatment — while persistent or unexplained symptoms (such as tiredness, weight loss, night sweats, or tummy fullness) should be checked, as with other blood cancers.