Treatment

Acute myeloid leukemia causes changes to blood cell counts. The aim of any treatment for acute myeloid leukemia is to help control the abnormal leukemia cells and restore a balance of healthy blood cells.

Acute myeloid leukemia cannot be defined as a single disease, your symptoms will vary depending on the type of acute myeloid leukemia you have. Therefore, a variety of therapies are used for different types of acute myeloid leukemia and result in different outcomes.

Know AML has put together the animation below summarizing the treatment options available to people with acute myeloid leukemia.

What is chemotherapy?

The standard treatment for most people with acute myeloid leukemia is chemotherapy. Chemotherapy involves using drugs to destroy abnormal leukemia cells, hopefully leading to remission. Chemotherapy is usually given in two main phases: induction and consolidation, which are explained in more detail below.

Induction phase

Induction chemotherapy is used in the first phase of treatment, it aims to kill abnormal leukemia cells and stop them from multiplying in the blood and bone marrow. The most common induction chemotherapies include cytarabine and an anthracycline drug (daunorubicin, idarubicin, or mitoxantrone); these are mostly offered to people under the age of 60, or people aged over 60 years who are considered ‘fit’. Another treatment used for induction chemotherapy is the combination of daunorubicin and cytarabine (CPX-351), which is approved in the United States and Europe to treat people with specific types of acute myeloid leukemia, including therapy-related acute myeloid leukemia and acute myeloid leukemia with myelodysplasia-related changes. Induction chemotherapy can sometimes be administered with other drugs that target specific changes on or in leukemia cells, known as targeted therapies.

Consolidation phase

Consolidation chemotherapy aims to kill and remove abnormal leukemia cells that may remain after induction chemotherapy, but that cannot be detected. This reduces the risk of the leukemia cells multiplying and the subsequent return of acute myeloid leukemia. The consolidation phase involves further treatment with chemotherapy, often with the same drugs that were used in the induction phase.

Stem cell transplant

Allogeneic stem cell transplantation, using a matched sibling or unrelated donor, is increasingly offered to patients with acute myeloid leukemia with disease likely to relapse if they receive only intensive chemotherapy. In patients with no suitable matched sibling or when an unrelated donor cannot be found, transplantation using stem cells from either a family member who is not a complete match, or from umbilical cord blood, may be considered. While transplantation reduces the chances of relapse, it can cause several side effects, such as infections, graft-versus-host disease, and other medical issues that can occur months or years after the transplant (“late effects”). However, recent advances in transplant technology, such as improvements in the prevention of GvHD prophylaxis and the use of reduced-intensity conditioning regimens, are resulting in fewer side effects.

What treatments are available for people who are ineligible for intensive chemotherapy?

Intensive chemotherapy is often not well tolerated by patients over the age of 75 years, or patients with other medical issues (comorbidities), who represent the majority of patients diagnosed with acute myeloid leukemia. The most important treatment advance has been the introduction of venetoclax, a Bcl-2 inhibitor, which alongside either azacitidine or low-dose cytosine arabinoside, has led to more patients achieving remission and prolonged survival.

How is relapsed or refractory acute myeloid leukemia treated?

Currently, treatment approaches for relapsed or refractory acute myeloid leukemia depend on a risk–benefit assessment, which analyzes the likely benefit of further therapy as well as the potential risks associated with it. The treatment decision is based on a number of factors, including age, length of remission, genetics, any previous stem cell transplant, general health status, and the patient’s wishes.

If considered eligible for intensive chemotherapy, treatment options include the following:

• IDAC (intermediate-dose cytarabine) with filgrastim and either cladribine, fludarabine, or clofarabine
• IDAC with etoposide with or without filgrastim
• CLAG-M (cladribine, cytarabine, and mitoxantrone)
• FLAG-IDA (fludarabine, cytarabine, filgrastim, and idarubicin)
• Clofarabine, cytarabine, filgrastim, and idarubicin
• HDAC (high-dose cytarabine) with or without idarubicin, daunorubicin, or mitoxantrone (for people who have not previously received this combination)

If intensive chemotherapy is not considered appropriate, the following treatment options are recommended:

• Venetoclax in combination with an HMA or LDAC
• HMAs (11-azacitidine or decitabine)
• LDAC

Enrollment into a clinical trial may also be an option for people with relapsed or refractory acute myeloid leukemia.

What is maintenance therapy?

Maintenance therapy refers to lower intensity treatments that may be offered to you following an intensive treatment course or if you are unable to complete intensive treatment. The aim of maintenance therapy is to lower the risk of relapse and prolong survival, while minimizing side effects.

What are the advances in formulations of chemotherapy?

When talking about medicines, a formulation refers to how the different components are combined to make a product that can be given easily. Advances in chemotherapy for acute myeloid leukemia include attempts to make the treatment safer, more effective, or more convenient. With this in mind, improvements to traditional chemotherapy have been developed, such as:

• CC-486: An oral formulation of azacitidine that was the first approved oral maintenance treatment for acute myeloid leukemia.
• CPX-351: A formulation of combined daunorubicin and cytarabine that is more easily absorbed by the body.
• ASTX727: A formulation of combined oral decitabine and cedazuridine that is equivalent to intravenous decitabine.

What is targeted therapy?

In recent years, a number of new drugs have been developed to target specific markers found in or on leukemia cells. These advances have resulted in targeted drugs, which work differently to standard chemotherapy and can be useful if particular abnormalities have been identified. Generally, targeted therapies have higher specificity and aim to minimize side effects. Some approved targeted treatments for different types of acute myeloid leukemia are shown below.

FLT3 inhibitors

Approximately 30% of people with acute myeloid leukemia have abnormal changes in a gene called FLT3. These genetic changes give rise to different forms of the FLT3 protein, which can lead to the growth of leukemia cells.

Quizartinib: A drug that blocks the function of the FLT3 protein. Quizartinib can be used in combination with standard induction and consolidation, and alone as a maintenance therapy following consolidation therapy in patients with a specific type of alteration in the FLT3 gene referred to as internal tandem duplication.

Midostaurin: A drug that targets the abnormal FLT3 protein and blocks its function. Midostaurin can be used with standard chemotherapy to treat people who have abnormal changes in the FLT3 gene.

Gilteritinib: A drug that binds to the FLT3 protein and blocks its function. Gilteritinib can be used to treat people who have abnormal changes in the FLT3 gene who have undergone stem cell transplantation.

IDH inhibitors

In some people with acute myeloid leukemia, abnormal changes are detected in the IDH1 or IHD2 genes, which interfere with normal cell processes.

Ivosidenib: A drug that blocks the function of the IDH1 protein in leukemia cells. Ivosidenib can be used to treat people who have abnormal changes in the IDH1 gene.

Olutasidenib: Another drug that blocks the function of the IDH1 protein in leukemia cells, which can be used to treat people who have relapsed/refractory AML with abnormal changes in the IDH1 gene.

Enasidenib: A drug that blocks the function of the IDH2 protein in leukemia cells. Enasidenib can be used to treat people with abnormal changes in the IDH2 gene.

Bcl-2 inhibitor

Bcl‑2 is a protein found inside cells that helps leukemia cells to survive.

Venetoclax: A drug that blocks the Bcl‑2 protein, resulting in increased leukemia cell death. Venetoclax can be used to treat people who are aged 75 years and older or those who have other medical conditions that prevent the use of standard chemotherapy.

Hedgehog pathway inhibitor

In a cell, the ‘hedgehog pathway’ is a finely tuned network of signaling molecules that are important in early-life development. In acute myeloid leukemia, disturbances in this pathway can give rise to cells that are resistant to certain treatments, helping leukemia cells survive.

Glasdegib: A drug that blocks the hedgehog pathway, which can be used to treat people aged 75 years and older or with medical conditions that prevent the use of standard chemotherapy.

Antibody–drug conjugate

Antibody–drug conjugates contain an antibody (a synthetic immune protein that recognizes a specific target on leukemia cells) and an anticancer drug. The antibody is used to guide the drug to the leukemia cells, where it can destroy them.

Gemtuzumab ozogamicin: A drug made up of an antibody that specifically recognizes CD33 (a protein found on leukemia cells) and a chemotherapy drug.

What are clinical trials?

Clinical trials are medical studies involving people, they are a key step towards optimizing treatments for different diseases. A clinical trial may be designed with the aim of improving current therapies or to investigate how safe and effective a new treatment is. There are various ongoing clinical trials investigating treatment options for acute myeloid leukemia.

A patient with acute myeloid leukemia may not respond to the therapies that are currently approved, and for certain types of acute myeloid leukemia, there are very few treatment options available. Therefore, taking part in a clinical trial may be the best option for some people and could provide the opportunity for effective disease treatment/management.

What treatment side effects may be expected?

Treatments for any medical condition can cause side effects. The side effects you may experience can vary depending on the treatment (i.e., chemotherapy/targeted therapy) and your overall health. For most people, side effects are temporary and will go away after treatment has finished or following changes to the treatment regimen, such as altered dosing.

Common side effects of treatment for acute myeloid leukemia include tiredness, increased risk of infection (impaired immune system), nausea, vomiting, hair loss, rashes, and low levels of red blood cells (anemia). Your leukemia specialist should advise you of the common side effects associated with any treatment you may receive.

If you have any questions or concerns regarding treatment options, clinical trials, or side effects, reach out to your leukemia specialist.