Chronic Myeloid Leukemia (CML): Targeted Therapy  

What is targeted therapy?

Targeted therapy is the use of medicines that target parts of cancer cells that make them unlike normal cells. They do this without affecting most normal, healthy cells. The medicines are different from standard chemotherapy medicines. They may work when chemotherapy medicines don’t. And they often have less severe side effects.

Types of targeted therapy for CML

The types of targeted medicines used to treat chronic myeloid leukemia (CML) are called tyrosine kinase inhibitors (TKIs). These medicines block a kinase protein inside leukemia cells. The protein is made as a result of the cells having the abnormal BCR-ABL gene. This protein helps the leukemia cells grow.

TKIs used to treat CML include:

  • Imatinib

  • Dasatinib

  • Nilotinib

  • Bosutinib

  • Ponatinib

When is targeted therapy used to treat CML?

TKIs are often the first treatment used for CML. These medicines often work well at keeping the CML under control for long periods of time. It’s not clear if they can cure the leukemia. Your doctor will monitor your CML during treatment with blood tests or other tests. If one of these medicines does not work or stops working over time, the dose of the medicine might be increased. Or another TKI may be used.

How targeted therapy is done

Before treatment starts, you will meet with a medical oncologist. This is a doctor who specializes in treating cancer with medicines. The doctor will talk with you about your treatment and explain what to expect.                                                                                                                                                                            

The medicine is taken as pills or capsules, once or twice a day. Make sure to take these medicines exactly as directed by your healthcare team. Taking these medicines every day gives them the best chance to treat your leukemia. It's likely you will need to take these pills ongoing.

Be sure to tell your doctor about all other medicines you take. This includes over-the-counter medicines and supplements such as herbs and vitamins. Some medicines and supplements can change the way targeted therapy medicines work.

During treatment, you’ll have blood tests. These are done to check for a decrease in your levels of white or red blood cells or platelets. These tests will happen more often at the start of treatment. 

Possible side effects of targeted therapy

Side effects of TKIs depend on the medicine, and may include:

  • Bloating or swelling from fluid retention

  • Diarrhea

  • Itchy skin rashes

  • Muscle pain

  • Nausea

  • Tiredness

  • Belly (abdominal) pain 

Side effects from these medicines tend to be mild. But in some cases, they can cause more severe side effects, such as:

  • Fluid buildup around the heart or lungs, which can cause trouble breathing

  • Changes in heart rhythm

  • High blood pressure

  • Liver damage

Ponatinib can also cause serious blood clots. This medicine may be used only if the other TKIs are no longer working, or if the leukemia cells have a certain gene change.

Working with your healthcare provider

It's important to know which medicines you're taking. Write your medicines down, ask your healthcare team how they work, and what side effects they might have.

Talk with your healthcare providers about what side effects to watch out for, and when to call them. Make sure you know what number to call with questions, even on evenings and weekends.

It may be helpful to keep a diary of your side effects. Write down physical, thinking, and emotional changes. A written list will make it easier for you to remember your questions when you go to your appointments. It will also make it easier for you to work with your medical team to make a plan to manage your side effects.