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Treatment and the treatment process

Treatment of CML

Treatment for chronic myeloid leukemia (CML) has changed perhaps more than any other in the last 25 years: most people now control the disease for many years with a daily tablet.

Last updated: ~2 min read
A glowing tablet on a dark navy surface with a calm line of light stretching to the horizon.
Figure 1.CML treatment is usually a daily tablet.

01Short answer

CML is caused by the BCR::ABL1 gene on the Philadelphia chromosome; it makes a protein that constantly tells cells to divide. The main treatment is tyrosine kinase inhibitors (TKIs): imatinib, dasatinib, nilotinib, bosutinib, and in later lines ponatinib and asciminib. They are usually taken by mouth every day. Response is tracked with regular PCR tests measuring BCR::ABL1 levels. In some people with a long-lasting deep molecular response, stopping the drug under medical supervision ("treatment-free remission") may be possible. In the accelerated or blast phase, treatment is more intensive and a transplant may be considered.

02Simple explanation

The cause. A "broken" gene orders cells to keep dividing.

The medicine. A TKI "switches off" this gene’s protein.

Monitoring. A blood test measures BCR::ABL1; it should fall.

A long road. Treatment usually lasts years, sometimes for life.

03Scientific explanation

Molecular response: BCR::ABL1 is measured on the International Scale (IS). A level of ≤0.1% by 12 months (major molecular response, MMR) is the optimal goal according to ELN; deeper responses are called MR4 and MR4.5.

Choosing a drug: the first-line TKI is chosen by risk group, other illnesses (heart, lungs, diabetes, pancreas) and side-effect profile. With resistance, ABL1 kinase domain mutations (such as T315I) are tested for.

Treatment-free remission (TFR): considered in selected people after at least 3–5 years of TKI and at least 2 years of stable deep response; frequent PCR monitoring is needed after stopping, because about half may lose MMR, in which case the drug is restarted.

04What happens in the body?

The phases of CML

Most people are diagnosed in the chronic phase — the most treatable stage. Without treatment, the disease can progress to the accelerated and blast phases; the blast phase resembles acute leukemia.

Under a dark navy sky, a calm valley, rolling hills and distant stormy peaks.
Figure 3.The three phases of CML: chronic, accelerated and blast.

How is treatment monitored?

Blood tests are frequent at first, then a PCR test every 3 months. With a good, stable response, tests may become less frequent. If targets are not met on time, the doctor may switch the drug.

A staircase of light, each step a little fainter, descending into calm darkness.
Figure 2.Falling BCR::ABL1 levels show the treatment is working.

Everyday life

Many people work, travel and live normal lives. Some TKIs interact with food and other medicines (for example grapefruit), so tell your doctor or pharmacist about new medicines and supplements. If you are planning a pregnancy, it is important to discuss it with your doctor beforehand.

05The CML treatment path

A simplified general outline.

Diagnosis — BCR::ABL1 confirmed.1DiagnosisBCR::ABL1 confirmed.
TKI — A daily tablet.2TKIA daily tablet.
PCR monitoring — Every 3 months.3PCR monitoringEvery 3 months.
Review — Continue, switch or TFR.4ReviewContinue, switch or TFR.
ControlDisease stable.
Deep responseVery low BCR::ABL1.
Shared decisionA plan with your doctor.

06Treatment options in CML

OptionWhen?Note
ImatinibFirst lineLongest experience
Dasatinib, nilotinib, bosutinibFirst or second lineResponse may be faster
PonatinibResistance, T315ICardiovascular risk monitored
AsciminibAfter earlier TKIsA different binding site
Allogeneic transplantBlast phase, multiple resistanceRarely
Treatment-free remissionLong deep responseOnly under medical supervision

* Simplified table; your doctor chooses the drug.

07Key terms

CML
Chronic myeloid leukemia.
BCR::ABL1
The fusion gene that causes CML.
TKI
Tyrosine kinase inhibitor.
MMR
Major molecular response, BCR::ABL1 ≤0.1%.
Treatment-free remission
Response that lasts after stopping the drug.
Blast phase
A phase of CML resembling acute leukemia.

08Key points

  • CML is usually controlled with tablets.
  • Taking the drug every day matters.
  • A PCR test measures response.
  • If there is no response, the drug can be changed.
  • Some people can stop treatment.
  • Do not stop the drug on your own.

09Frequently asked questions

Will I take tablets for life?

Often for many years; some people can stop under supervision after a long deep response.

What if I miss a dose?

Do not double the next dose; check your medicine’s leaflet or ask your doctor.

Will side effects go away?

Many ease in the first months; if not, the doctor can change the dose or drug.

Can CML turn into acute leukemia?

Without treatment, yes; with TKIs this risk has fallen greatly.

10Questions for your doctor

Take these questions to your appointment. The ones you save are collected on the “My questions” page and stay on this device only.

  1. Will I take tablets for life?

  2. What if I miss a dose?

  3. Will side effects go away?

  4. Can CML turn into acute leukemia?

My questions

12Sources

  1. National Cancer Institute (NCI). Chronic Myeloid Leukemia Treatment (PDQ) – Patient Version
  2. American Cancer Society. Treating Chronic Myeloid Leukemia
  3. Cancer Research UK. Treatment for chronic myeloid leukaemia (CML)
  4. NHS. Chronic myeloid leukaemia: Treatment
  5. Leukemia & Lymphoma Society. CML treatment
  6. European LeukemiaNet. 2020 ELN recommendations for treating chronic myeloid leukemia (Leukemia, 2020)
  7. New England Journal of Medicine, 2003. Imatinib compared with interferon and low-dose cytarabine for newly diagnosed chronic-phase chronic myeloid leukemia
  8. New England Journal of Medicine, 2013. Retinoic acid and arsenic trioxide for acute promyelocytic leukemia
  9. New England Journal of Medicine, 2017. Midostaurin plus Chemotherapy for Acute Myeloid Leukemia with a FLT3 Mutation
  10. New England Journal of Medicine, 2020. Azacitidine and Venetoclax in Previously Untreated Acute Myeloid Leukemia
Medical disclaimerThis information is for educational purposes only and does not replace medical advice.
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