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Treatment and the treatment process

Resistant leukemia

Sometimes leukemia doesn’t respond to first treatment as expected. This is called refractory, or resistant, leukemia, and the team then looks for other paths.

Last updated: ~2 min read
On a dark navy background, a small cluster of red cells behind a faint crystalline barrier, with teal treatment light around it.
Figure 1.Some leukemia cells resist treatment.

01Short answer

Refractory (resistant) leukemia means remission has not been reached after standard treatment. In acute leukemias it is usually defined by blasts remaining in the bone marrow after one or two induction courses. In chronic leukemias, resistance shows as no response or a lost response to a medicine: for example, BCR::ABL1 not falling as expected in CML, or the disease progressing during treatment in CLL. Causes vary: particular genetic changes in the leukemia cells (such as TP53), new mutations in the drug’s target, problems with taking the medicine, or drug interactions. In these cases genetic tests are repeated and treatment is changed — other chemotherapy, targeted drugs, immunotherapy, transplant or a clinical trial may be considered.

02Simple explanation

No response. Leukemia remains after first treatment.

Looking for the cause. Genetics and how medicines are taken are checked.

A different key. A treatment that works differently is chosen.

An expert centre. An experienced team and trials can help.

03Scientific explanation

Definition: in AML, primary refractory disease is usually defined as no CR after one or two intensive induction courses (ELN); in ALL, high MRD at a protocol checkpoint is also considered high risk.

Mechanisms: TP53 mutation and complex karyotype, drug efflux pumps (such as P-glycoprotein), BCR-ABL1 kinase domain mutations (such as T315I), BTK C481 or BCL2 mutations, and CD19-negative escape. A mutation panel or sequencing guides targeted choices.

Approach: salvage regimens with a different mechanism, FLT3/IDH inhibitors, menin inhibitors (in certain genetic subtypes), bispecific antibodies and CAR-T (B-ALL), later-generation TKIs (CML), sequencing BTK and BCL2 inhibitors (CLL), and allogeneic transplant after remission. In CML, adherence and interactions are checked before concluding resistance.

04What happens in the body?

Why are some cells resistant?

Leukemia cells are not all the same. Some have "pumps" that push the drug out, or mutations that change its target, and survive treatment.

Looking for another key

When one medicine doesn’t work, a treatment with a different mechanism can often help. The choice is based on genetics and previous treatment.

On a dark background, a glowing gold key before several different locks.
Figure 2.In resistant leukemia, a treatment that works is sought.

Genetics shows the way

Repeat genetic tests uncover new changes. Sometimes this allows a specific targeted drug to be chosen.

A double helix of light with one small segment glowing a different colour.
Figure 3.A new genetic change can cause resistance.

05Steps in resistant leukemia

A simplified outline.

Confirmation — Bone marrow or marker.1ConfirmationBone marrow or marker.
The cause — Genetics, medicine-taking.2The causeGenetics, medicine-taking.
Expert opinion — An experienced centre.3Expert opinionAn experienced centre.
New treatment — A different mechanism or a trial.4New treatmentA different mechanism or a trial.
A chance of remissionWith other treatment.
Targeted choiceBased on genetics.
SupportSymptom control alongside.

06Possible paths by type of resistance

LeukemiaExample of resistancePossible approach
AMLNo remission after inductionSalvage regimen, targeted drugs, transplant
ALLMRD stays highBispecific antibody, CAR-T, transplant
CMLBCR::ABL1 not fallingAnother TKI, mutation test, adherence check
CLLProgression on treatmentA different class of drug, a trial

* Only your treating team decides which path fits.

07Key terms

Refractory
Not responding to treatment.
Primary refractory
No remission after first treatment.
Salvage treatment
The next treatment for resistant or relapsed leukemia.
Mutation panel
A test that checks many genes.
TP53
A gene linked to resistance.
T315I
A CML mutation causing resistance to some TKIs.

08Key points

  • Resistance doesn’t mean there are no options.
  • The cause is looked for with genetic tests.
  • A treatment with a different mechanism can help.
  • Ask about clinical trials.
  • Take medicines exactly as prescribed.
  • A second opinion is normal and helpful.

09Frequently asked questions

Is resistance caused by something I did?

Usually not; it comes from the biology of the leukemia cells. With tablet medicines, how they are taken is also checked.

Is a transplant still possible?

It is often considered once remission is reached; the team will assess whether it suits you.

Is a clinical trial dangerous?

Trials run under strict oversight; the benefits and risks should be explained to you in detail.

What is done about my symptoms?

Symptom control and support run alongside treatment at every stage.

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. Is resistance caused by something I did?

  2. Is a transplant still possible?

  3. Is a clinical trial dangerous?

  4. What is done about my symptoms?

My questions

12Sources

  1. National Cancer Institute (NCI). Adult Acute Myeloid Leukemia Treatment (PDQ) – Patient Version
  2. National Cancer Institute (NCI). Adult Acute Lymphoblastic Leukemia Treatment (PDQ) – Patient Version
  3. National Cancer Institute (NCI). Chronic Myeloid Leukemia Treatment (PDQ) – Patient Version
  4. National Cancer Institute (NCI). Definition of refractory – NCI Dictionary of Cancer Terms
  5. National Cancer Institute (NCI). Cancer Clinical Trials Information
  6. MedlinePlus. Acute lymphocytic leukemia (ALL)
  7. Cancer Research UK. Treatment for chronic myeloid leukaemia (CML)
  8. Leukemia & Lymphoma Society. CML treatment
  9. American Cancer Society. Treating Chronic Lymphocytic Leukemia
  10. Cancer Research UK. Treatment for chronic lymphocytic leukaemia (CLL)
Medical disclaimerThis information is for educational purposes only and does not replace medical advice.
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