Chronic myelogenous leukemia

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Treatments for CML in the blast phase

The following are treatment options for chronic myelogenous leukemia (CML) in the blast phase. Your healthcare team will suggest treatments based on your needs and work with you to develop a treatment plan.

In the blast phase, the number of leukemia cells in the bone marrow and the blood rises. The white blood cell (WBC) and platelet counts become very abnormal. Symptoms develop and you may have complications, such as bleeding and infections.

Blast crisis occurs when the accelerated phase changes quickly into the blast phase. Signs and symptoms of blast crisis include fever, tiredness, an enlarged spleen and more than 30% of cells in the blood or bone marrow are blasts.

Most of the time, the leukemia cells change during the blast stage, and the disease acts like acute myelogenous leukemia (AML). When this happens, it is treated in a similar way as AML. Find out more about treatments for AML.

Less often, the leukemia cells change, and the disease acts like acute lymphocytic leukemia (ALL). When this happens, it is treated in a similar way as ALL. Find out more about treatments for ALL.

The goal of treatment during the blast phase is to return the CML to the chronic phase. Your healthcare team will check your blood and bone marrow to closely monitor the response to treatment.

Targeted therapy

Targeted therapy with a tyrosine kinase inhibitor may be offered during the blast phase of CML. If you are already taking targeted therapy, your doctors may increase the dose or try a different drug. The following targeted therapy drugs are used for CML in the blast phase.

Imatinib (Gleevec) is the standard first-line therapy.

Dasatinib (Sprycel) or nilotinib (Tasigna) may be given as a first-line therapy. They may also be given if someone cannot cope with the side effects of imatinib or if CML is resistant to imatinib.

Bosutinib (Bosulif) may be given if someone cannot cope with the side effects of imatinib, dasatinib or nilotinib. Bosutinib is also used if the CML is resistant to these drugs.

Pontatinib (Iclusig) may be given if the CML is resistant to other targeted therapies or if the leukemia cells have a certain gene mutation.


Chemotherapy may be offered for CML in the blast phase. The drugs used depend on if the leukemia cells look like AML or ALL.

The most common drugs used when the leukemia cells look like AML include:

  • cytarabine (Cytosar, Ara-C)
  • high-dose cytarabine (HDAC)
  • daunorubicin (Cerubidine, daunomycin)
  • doxorubicin (Adriamycin)
  • thioguanine (Lanvis, 6-TG)
  • hydroxyurea (Hydrea)

When the leukemia cells look like ALL, the most common drugs used are those listed above, as well as:

  • vincristine (Oncovin)
  • prednisone

During the blast phase, there is a greater risk that leukemia cells will spread to the brain and spinal cord (called the central nervous system, or CNS). The following chemotherapy drugs may be given directly into the spinal fluid (called intrathecal chemotherapy) to prevent or treat CML in the central nervous system:

  • cytarabine (Cytosar, Ara-C)
  • methotrexate

Stem cell transplant

An allogeneic stem cell transplant may be offered for CML in the blast phase. This therapy is usually more effective in the earlier phases. The stem cell transplant is more likely to be successful if the CML can be brought back to the chronic phase before the transplant.

Radiation therapy

External beam radiation therapy may be offered for CML in the blast phase to:

  • shrink the spleen if it is larger than normal
  • relieve bone pain

Radiation may be given to the brain when the leukemia transforms to ALL. This therapy is used less often than intrathecal chemotherapy.


Sometimes surgery is used to remove the spleen (called a splenectomy). This is done when an enlarged spleen causes discomfort.

Supportive therapy

Supportive therapy is important during treatment for every phase of CML. It is used to treat the complications that usually happen with treatments for CML and the disease itself.

Supportive therapies given during the blast phase may include:

  • antibiotics, antivirals or antifungals to prevent or fight infections
  • growth factors to help the bone marrow recover from chemotherapy (chemotherapy can affect the bone marrow so it doesn’t make enough healthy blood cells, which can increase the risk for infection)
  • transfusions of red blood cells, platelets, fresh frozen plasma and cryoprecipitate (a product that replaces clotting factors) as needed
  • drugs to bring down high levels of some chemicals in the blood that increase when many cancer cells die at the beginning of treatment (called tumour lysis syndrome)
  • leukapheresis to remove large numbers of white blood cells from the blood

Clinical trials

You may be asked if you want to join a clinical trial for CML. Find out more about clinical trials.


Referring to DNA, cells, tissues or organs taken (harvested) from a donor to be given to a recipient who is a close, but not identical, genetic match.

For example, an allogeneic stem cell transplant takes blood or bone marrow from a donor (usually a first-degree relative) and gives it to a recipient.


A procedure that uses a special machine (pheresis machine) to separate and collect specific white blood cells from withdrawn blood. The remaining blood is then returned to the body.

Leukapheresis is used to lower a very high white blood cell count in people with cancer (leukemia) or to remove white blood cells for transfusion.