Understanding BTK Inhibitors as Treatment Options for Chronic Lymphocytic Leukemia

This article is for people who are living with chronic lymphocytic leukemia (CLL) and their care partners or anyone who wants to learn more about CLL. The goal of this activity is to help you talk to your doctor and healthcare team about Bruton tyrosine kinase (BTK) inhibitors and work with them on your treatment plan.

You will learn about:

• What CLL is

• Types of medicines used to treat CLL

• What BTK inhibitors are and how they work

• Making a treatment plan with your doctor and healthcare team and

• Questions to ask your doctor

Medicines listed in this activity may not be approved by the US Food and Drug Administration (FDA) for CLL but are recommended by the National Comprehensive Cancer Network (NCCN).

CLL is a type of blood cancer that starts in your bone marrow, where blood cells are made. Blood cells begin as stem cells before growing into white blood cells, red blood cells, and platelets. You need the right balance of blood cells to stay healthy.

CLL upsets that balance by causing some stem cells to grow into abnormal B-cell lymphocytes (a white blood cell that helps fight infections). These abnormal lymphocytes, called leukemia cells, aren't fully grown and don't work right.

Leukemia cells grow faster and live longer than normal blood cells. They start to crowd your bone marrow and bloodstream, leaving less room for healthy blood cells. This can lead to other health problems.

Illustration of the inside of a blood vessel showing red blood cells in red, lymphocytes or white blood cells in white, and platelets in yellow.

CLL and SLL are the same kind of cancer. The term SLL is used if leukemia cells are found mostly in your lymph nodes and spleen, instead of in your blood and bone marrow. The lymph nodes and spleen are organs that store lymphocytes and help prevent or fight infections.

How your CLL is managed depends partly on your symptoms and whether you have fast-growing (aggressive) or slow-growing (indolent) CLL. Most people have slow-growing CLL and few or no symptoms at first. They may not need treatment for months, years, or ever.

If you have slow-growing CLL, your doctor may recommend "watching and waiting." This means your doctor watches how your CLL behaves over time and recommends treatment if it gets worse.

Fast-growing CLL tends to cause more symptoms and health problems. If tests show you have fast-growing CLL, your doctor may recommend treatment right away.

CLL is rarely cured. Some treatments are available to try to slow its growth or cause remission (a period when all signs of cancer are gone), and others work to lessen its health effects and symptoms.

More common treatments for CLL include:

• Targeted therapy -- kills leukemia cells by inhibiting (blocking) certain proteins they need to survive and grow

• Chemotherapy ("chemo") -- kills fast-growing leukemia cells

• Stem cell transplant -- replaces damaged stem cells with healthy ones from a donor

• Clinical trial -- a study researching ways to treat CLL

• Supportive care -- treats symptoms but doesn't affect leukemia cells

Your cells use a network of proteins to send messages from one part of the cell to another. The protein network B-cell lymphocytes use is called the B-cell receptor (BCR) pathway. It signals B-cell lymphocytes to stay alive, copy themselves, and travel.

BTK is an important protein in the BCR pathway, and leukemia cells often make too much of it.

BTK inhibitors are targeted therapies that locate BTK proteins and stop them from signaling to other proteins. This causes your leukemia cells to die without making copies or spreading and can slow cancer progression.

Most people treated for CLL will get a BTK inhibitor at some point. There are currently 3 BTK inhibitors for treating CLL:

• Acalabrutinib

• Ibrutinib

• Zanubrutinib

Although each BTK inhibitor targets BTK proteins differently, they all work to kill leukemia cells.

BTK inhibitors come as capsules or tablets that are taken by mouth. They may be given alone or with another type of medicine. A BTK inhibitor is usually taken daily for as long as it works or unless you and your doctor agree you should stop taking it.

All treatments, including BTK inhibitors, can cause side effects. Common side effects of BTK inhibitors include tiredness, body aches, diarrhea, rashes, and low blood counts. BTK inhibitors can also affect your heart and increase your risk of bleeding and infections.

Because each BTK inhibitor works differently, they have some differences in possible side effects. BTK inhibitors also affect everyone differently.

Be sure to tell your doctor about other health issues you have or medicines you take. It can help your doctor decide which BTK inhibitor to recommend or if you need more tests or another type of treatment.

Your doctor and healthcare team will work with you to make a treatment plan. Your options depend on many things, including how your CLL behaves, your health, and what you want most from treatment.

Ask your doctor and healthcare team to explain how each treatment may affect you and your CLL. It's important that you feel comfortable with your treatment plan, so be open about your preferences and concerns.

If your CLL changes over time, you may need to work with your doctor and healthcare team on a new treatment plan.

Questions you can ask about your treatment plan include:

• What treatments are there, and what are their goals?

• What are BTK inhibitors, and how do they work?

• What tests will I need before or during treatment?

• What are possible side effects of my treatment, and how can we manage them?

• How will we know if treatment is working?

• Where can I find more information and resources?

Congratulations!

You have successfully completed the program Understanding BTK Inhibitors as Treatment Options for Chronic Lymphocytic Leukemia.

View Additional Materials on this topic that you may find useful:

Communicating With Your Healthcare Team

Chronic Lymphocytic Leukemia Treatment

Definition of CLL/SLL

Targeted Therapy for Cancer