Targeted therapy for acute lymphoblastic leukemia

Targeted therapy uses drugs to target specific molecules (such as proteins) on cancer cells or inside them. These molecules help send signals that tell cells to grow or divide. By targeting these molecules, the drugs stop the growth and spread of cancer cells and limit harm to normal cells. Targeted therapy may also be called molecular targeted therapy.

If you have targeted therapy, your healthcare team will use what they know about the cancer and about your health to plan the drugs, doses and schedules.

You may have targeted therapy for the following reasons:

• The leukemia cells have the Philadelphia chromosome (called Ph-positive ALL or Ph+ ALL). This happens when genetic material swaps between chromosomes 9 and 22, resulting in an abnormal chromosome and creating a new gene. The new gene is called BCR-ABL.
• You have B-cell ALL that comes back (relapses or recurs) after treatment or doesn’t respond to treatment (called refractory ALL).

Different types of targeted therapy can be used for ALL.

People with Ph+ ALL will take a targeted therapy drug called a tyrosine kinase inhibitor (TKI). TKIs block chemicals called tyrosine kinases. These chemicals are part of the signalling process within cells. When this process is blocked, the cell stops growing and dividing.

People with Ph+ ALL have targeted therapy in addition to chemotherapy to help the leukemia go into remission. After the induction phase of treatment, continuing targeted therapy can reduce the risk that the cancer will come back (recur).

Imatinib (Gleevec) is the most common TKI used for people with Ph+ ALL. Other TKIs may be offered if imatinib doesn't work or stops working. These include:

• dasatinib (Sprycel)
• nilotinib (Tasigna)
• bosutinib (Bosulif)
• ponatinib (Iclusig)

If you are prescribed a TKI, you will need to take it orally (by mouth) every day.

Monoclonal antibodies have been designed in a lab to recognize and lock onto particular protein markers on the surface of some cancer cells.

The monoclonal antibodies used for B-cell ALL are also used as immunotherapy since they trigger the immune system to attack and destroy leukemia.

Blinatumomab (Blincyto) may be given to people with CD19-positive B-cell ALL. You may receive blinatumomab if there continues to be a low level of minimal residual disease (MRD) in the first complete remission after induction or consolidation treatment. MRD means there are leukemia cells in the bone marrow, but they can only be seen using sensitive tests.

Blinatumomab may also be used to treat relapsed or refractory B-cell ALL. It is recommended to receive chemotherapy to help prevent leukemia cells from spreading to the brain and spinal cord (called CNS prophylaxis) before and during your treatment with blinatumomab. This will prevent ALL from relapsing in the brain and spinal cord (called the central nervous system, or CNS).

This drug is given as a continuous intravenous infusion (through an IV) for 28 days. You will have a 14-day break from treatment, and then may receive more 28-day cycles of treatment.

Inotuzumab ozogamicin (Besponsa) may be given to people with relapsed or refractory CD22-positive B-cell ALL. This drug is given intravenously for an hour. It is given once a week for a cycle of 3 or 4 weeks. The number of cycles you need will depend on the response to treatment.

Find out more about monoclonal antibodies and immunotherapy for ALL.

Side effects of targeted therapy will depend mainly on the type of drug or combination of drugs, the dose, how it's given and your overall health. Tell your healthcare team if you have side effects that you think are from targeted therapy. The sooner you tell them of any problems, the sooner they can suggest ways to help you deal with them. Talk to your doctor or pharmacist about what side effects to expect.

Find out more about targeted therapy. To make the decisions that are right for you, ask your healthcare team questions about targeted therapy.

Details on specific drugs change quite regularly. Find out more about sources of drug information and where to get details on specific drugs.