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Chronic myeloid leukemia (CML) is often called the “good cancer.” That’s because over the last 20 years, patients and doctors have seen CML become more manageable for many people.

But the CML journey doesn’t turn out to be quite as “good” for some people. Along the way, some people develop resistance to their CML medications or they experience intolerable side effects, which impact their daily life.

How CML affects you

If you’ve had CML for some time, you may be familiar with the disease. If that’s the case, skip ahead and download this Doctor Discussion Guide or take this short quiz. They’re both designed to help you have an open conversation with your doctor about your CML treatment.

What is CML?

CML is a cancer of the blood and bone marrow. Bone marrow is a sponge-like tissue in the center of most bones responsible for creating different types of blood cells.

CML has 3 phases

Instead of being categorized in stages like many cancers, CML is classified into 3 phases. Each phase is based on the percentage of immature white blood cells (also called “blast cells”) in the bone marrow compared to other blood cells. Your doctor may refer to these immature white blood cells as leukemic cells.

The 3 phases of CML include:

  • Chronic phase: The first phase of CML. Most adults are diagnosed in chronic phase and most people respond to treatment. In chronic phase, less than 10% of blood cells in the bone marrow are leukemic cells
  • Accelerated phase: The second phase of CML, in which 10% to 19% of blood cells in the bone marrow are leukemic cells
  • Blast phase: The third phase of CML, in which 20% or more of blood cells in the bone marrow are leukemic cells

Your doctor may discuss with you the importance of keeping CML from progressing from the first phase—the chronic phase—to the more advanced accelerated or blast phases. If CML is left untreated, it is more likely to progress.

What causes CML?

CML occurs when:

  • The blood-forming cells of the bone marrow create too many white blood cells
  • These damaged white blood cells crowd out healthy red blood cells, white blood cells, and platelets
  • This can lead to health problems
More than 95% of people with CML have Philadelphia chromosome-positive chronic myeloid leukemia (Ph+ CML)


  • More than 95% of people with CML have Philadelphia chromosome–positive chronic myeloid leukemia
  • Ph+ CML is caused by an abnormal fusion gene, called BCR-ABL1, which results from a change in chromosomes in the body
  • Each cell in the human body has 23 pairs of chromosomes
  • In CML, pieces of chromosomes 9 and 22 break off and trade places
  • This change can create a new abnormal chromosome—the Philadelphia (Ph+) chromosome
  • It creates the defective BCR-ABL1 gene, which produces an abnormal protein called BCR-ABL


Image showing how a normal chromosome impacted by Ph+ CML break and change in the body

The role of medications in treating CML

Most people with CML are treated with medications called tyrosine kinase inhibitors (TKIs). TKIs are thought to work by blocking the signals that cause cancer cells to grow and spread. Your doctor has several TKIs to choose from. You may find it helpful to use this Doctor Discussion Guide to have a conversation about your treatment options.

Take an active role in helping to choose your medication

While there has been significant progress in CML over the years, there are still patients who don’t do as well as others. If you think you could be doing better with your CML treatment, talk with your doctor. Here is some information you may find helpful in discussing side effects or your treatment goals with your doctor.

When you have CML, it’s important to be your own advocate. That means playing an active role with your doctor in choosing your treatment. If you’re interested in a specific medication, be sure to discuss it with your doctor. This guide may be helpful.

An experienced name in CML

For more than 20 years, Novartis has created medications that have helped many people with CML.

Novartis: leading the way in CML for over 20 years.

Novartis: leading the way in CML for over 20 years.

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