Given the number of drugs available to treat chronic myeloid leukemia (CML)—several new drugs have been approved since 2001—it is important to get treatment at a specialized center with CML expertise, like Seattle Cancer Care Alliance (SCCA). Our doctors have detailed knowledge about the efficacy and side effects of each treatment option. Your doctor will consider this information, along with your age, health, and therapeutic goals, when recommending the best treatment course for you.
Treatment options, prognosis, and goals of therapy for CML depend on the phase of the disease and other factors. The main types of treatment are:
- Targeted therapy
- Bone marrow transplant
The majority of people with CML are diagnosed in the chronic phase. Most people with chronic-phase CML are treated with targeted therapy. Those who have a good response on targeted therapy may stay on their treatment indefinitely.
Those who are diagnosed in the accelerated or blast phase or who progress to the accelerated or blast phase may be treated with targeted therapy, chemotherapy, or bone marrow transplant.
Since the introduction of effective targeted therapies, doctors very rarely use interferon, once the standard of care, to treat CML. Interferon-alpha (IFN-α) is a protein that interacts with receptors on the surface of cells. It stops cancer cells from dividing, stimulates the patient’s own immune system to fight the cancer, and may be an option for some people with CML.
Monitoring Treatment Results
It is important to monitor how well your treatment is working, especially early in treatment. If you are not responding well to treatment, if your CML progresses, or if you can’t tolerate the side effects, you may need to switch to a different drug or different type of treatment.
To monitor your response, your doctor will periodically check your blood and bone marrow, and you may need some of the same tests used to diagnose CML. Typically, these tests are done every three months for the first two years of treatment and then every six months thereafter.
There are three types of response your doctor will be looking for: hematologic, cytogenetic, and molecular.
A hematologic response means your blood cell counts and spleen size have returned to normal. Most people have a hematologic response within three months of starting therapy.
A cytogenetic response means your marrow, in addition to your blood, is responding to treatment. Doctors measure your cytogenetic response using tests that examine your chromosomes.
- If the Philadelphia chromosome (common in CML cells) is present in less than 35 percent of the cells tested, you have a major cytogenetic response.
- If the tests cannot detect any Philadelphia chromosomes, you have a complete cytogenetic response.
Doctors often use a test called quantitative polymerase chain reaction (qPCR) as a surrogate for cytogenetic response in the bone marrow. This extremely sensitive test can detect very low levels of BCR-ABL transcripts in your blood. (BCR-ABL is the abnormal gene present in the Philadelphia chromosome.) A qPCR result of less than 1 percent typically means you have a complete cytogenetic response.
Complete cytogenetic response typically occurs within six to 12 months of starting therapy.
Doctors also use qPCR to assess molecular response. If the amount of BCR-ABL in your blood is 0.1 percent or less, you are considered to have a major molecular response. This typically occurs within 12 to 18 months of starting therapy.
Access to clinical studies conducted by researchers at SCCA founding organizations—Fred Hutch and UW Medicine—is one reason why many patients come to SCCA for treatment. The goal of clinical studies, also known as clinical trials, is to develop more effective lifesaving treatments in the fight against leukemia. Areas of research include testing new drugs and cancer vaccines, determining which targeted therapy drug to use first, testing whether treatment can be discontinued in people who have a good response to therapy, and testing new combinations of treatments.
For some people, taking part in a clinical study may be the best treatment choice. At any time, SCCA has studies ongoing that are evaluating treatments for CML. Be sure to ask your doctor if a clinical study is right for you. For more information about participating, see our patient guide to clinical studies.
If you or someone you know has recently been diagnosed with chronic myeloid leukemia, you’re probably thinking hard about what to do next. Your most important decision is selecting where to get treatment.
Targeted therapies focus on a specific gene or protein responsible for allowing cancer to grow and survive. For CML, targeted drugs that inhibit the ABL tyrosine kinase protein are the standard treatment.
Chemotherapy was once a primary treatment for CML. But since the introduction of targeted therapies, chemotherapy is mainly used when targeted therapies no longer work or as part of a bone marrow transplant.
Bone marrow transplant (also called stem cell or hematopoietic cell transplant) isn’t often used to treat CML. Typically it’s used only if the disease has progressed or is not responding to standard treatments.
People with accelerated- or blast-phase CML or relapsed disease will most likely have a different course of treatment than people with chronic-phase disease.