Treatments for chronic myeloid leukemia in the blast phase

In the blast phase of chronic myeloid leukemia (CML), blast cells begin to collect in the blood and bone marrow in much higher numbers. The white blood cell (WBC) and platelet counts become very high or very low. Symptoms get worse and you may have complications, such as bleeding and infections.

A blast crisis occurs when the chronic or accelerated phase progresses quickly to the blast phase. Signs and symptoms of a blast crisis include fever, tiredness, an enlarged spleen and more than 30% of cells in the blood or bone marrow are blasts. Blast phase CML is very rare, because of the advances of treatment using TKIs.

The following are treatment options for CML in the blast phase. The goal of treatment is to return CML to the chronic phase. Your healthcare team will suggest treatments based on your needs and work with you to develop a treatment plan. They will check your blood and bone marrow to closely monitor the response to treatment.

Targeted therapy is the main treatment for CML in the blast phase. Targeted therapy uses drugs to target specific molecules (such as proteins) on cancer cells or inside them to stop the growth and spread of cancer.

The targeted therapy drugs used to treat CML are called tyrosine kinase inhibitors (TKIs).

The TKI given in the blast phase will depend on if CML is newly diagnosed or if it has progressed from the chronic or accelerated phase while being treated with TKIs. If you are already taking a TKI, your healthcare team may increase the dose or try a different one.

Imatinib (Gleevec) is the first TKI used when CML is newly diagnosed in the blast phase. It may also be offered if it wasn't used to treat CML in an earlier phase.

Dasatinib (Sprycel), nilotinib (Tasigna) or bosutinib (Bosulif) may be used if CML is newly diagnosed in the blast phase. These drugs may also be offered if CML stops responding to imatinib or another TKI, or if they cause severe side effects.

Ponatinib (Iclusig) is given if there are other gene mutations in addition to the BCR-ABL gene, such as the T315I gene mutation.

Find out more about targeted therapy for CML.

In the blast phase, the blast cells in the blood and bone marrow may have other changes in addition to the BCR-ABL gene. These are called additional chromosomal abnormalities (ACA). They can make the blast cells look more like the immature cells found in acute leukemia. Your healthcare team may order blood or bone marrow tests to see what type of cells and ACAs are present.

If CML changes to look like acute leukemia, your healthcare team may offer you chemotherapy along with a TKI. The drugs offered will depend on the changes to the blast cells.

Myeloid blast phase means that the blast cells have changed so CML starts to act more like acute myeloid leukemia (AML). The most common combination of drugs offered is FLAG-IDA with either dasatinib (Sprycel) or ponatinib (Iclusig). FLAG-IDA is fludarabine (Fludara), cytarabine (Cytosar), filgrastim and idarubicin. Your healthcare team may offer other combinations of drugs. Find out more about chemotherapy for AML.

Lymphoid blast phase means that CML starts to act more like acute lymphoid leukemia (ALL). The most common combination of drugs offered is hyperfractionated CVAD (cyclophosphamide, vincristine, doxorubicin and dexamethasome) with either imatinib or dasatinib. Your healthcare team may offer other combinations of drugs. Find out more about chemotherapy for ALL.

A stem cell transplant replaces stem cells. The type that may be offered for CML in the blast phase is an allogeneic stem cell transplant using a matched donor.

A stem cell transplant may be offered if treatment with TKIs moves the disease back to the chronic phase or improves blood cell counts. This is because there is a better chance that the transplant will be successful. It will not be done if CML is still in the blast phase.

Find out more about a stem cell transplant for CML.

Talk to your doctor about clinical trials open to people with CML in Canada. Clinical trials look at new ways to prevent, find and treat cancer. Find out more about clinical trials.