About CML

What is chronic myelogenous leukemia (CML)?

CML is a cancer of white blood cells (WBCs), which are part of the immune system responsible for fighting infections.

Under normal circumstances, the body carefully regulates the number of white blood cells circulating in the blood, increasing them when needed to fight an infection and bringing them back to normal when the infection is controlled.

In CML, this regulation is lost due to over production of abnormal WBCs in the bone marrow. The abnormal WBCs fill up the bone marrow and spill into the blood, resulting in symptoms of CML.


What causes CML?

  • In most cases of CML, there is a rearrangement in 2 specific chromosomes (9 and 22) which leads to 2 genes (called BCR and ABL1) being fused together.
  • The abnormal chromosome can be seen under a microscope and is called the Philadelphia chromosome (Ph).

How is the diagnosis for CML made?

  • The diagnosis of CML is made by laboratory tests like blood and bone marrow examination.
  • Presence of the Philadephia chromosome in the microscopic examination of the bone marrow, or testing of blood for the fused gene product can confirm the diagnosis.

Signs and symptoms of CML

  • In CML, the growth of white blood cells is no longer carefully regulated so they can increase to large numbers.
  • This leads to all of the symptoms and health effects suffered by CML patients, including fever, night sweats, and tiredness.
  • Red blood cells, which are responsible for carrying oxygen, and platelets, which help the blood clot, can be affected as well.
Night Sweats

What are the Three Phases of CML?

This form of leukemia is called chronic because it frequently follows an indolent course, slowly building up over months or years. This is different from acute myelogenous leukemia, which is caused by different mutations, and typically following a rapid, aggressive course. There are 3 phases of CML. The first one is called the chronic phase, and follow an indolent course. However, some patients with CML move on to progressively more aggressive phases, called the accelerated phase and blast phase, which are associated with more symptoms, are harder to treat and are a greater threat to life.


How is it treated?

Fortunately, the chronic phase of CML can now be successfully treated with target agents known as tyrosine kinase inhibitors (TKIs) of BCR-ABL1, and many patients can expect to live many years to a normal life expectancy.

  • The TKIs for BCR-ABL1 specifically inactivate the BCR-ABL1 gene, turning it off and allowing the body to control white blood cell levels normally.
  • TKIs also delay or prevent the progression of CML to the accelerated or blast phases.
  • In number of patients, the disease progresses despite initially responding to the TKI, usually because there are other mutations in the cell besides the BCR-ABL1 gene which are making the CML cells resist the drugs.
  • SPARC is developing vodobatinib to help patients with CML who no longer respond to their medication, or can’t take them because of side effects.
  • Vodobatinib is an investigational medication (experimental), it is not approved for sale in any country and can only be obtained by participating in a clinical trial.