You may know that your immune system works to protect you from infections, such as the flu and strep throat. However, it can also defend against other diseases, such as cancer.
Immunotherapy is a type of cancer treatment that works by using parts of the immune system to help manage cancer. Several types of cancers can be treated using immunotherapy, including leukemia.
Below, we’ll explore when immunotherapy can be used to treat leukemia. Then, we’ll go on to discuss the different types of immunotherapy treatment options that are available for leukemia, and what we know about their effectiveness.
Leukemia is a term that refers to a group of cancers that impact the blood. In leukemia, abnormal cells begin to grow and divide, displacing healthy cells in the blood and bone marrow.
Leukemias are classified by how fast the cancer grows (acute vs. chronic) and which type of cell is impacted (myeloid vs. lymphoid). There are four main types of leukemia:
- acute myeloid leukemia (AML)
- chronic myeloid leukemia (CML)
- acute lymphocytic leukemia (ALL)
- chronic lymphocytic leukemia (CLL)
Who receives immunotherapy for leukemia?
In many cases, immunotherapy may be used when leukemia has come back, or relapsed, after treatment. It can also be used when other leukemia treatments, such as chemotherapy, haven’t been effective.
For some types of leukemia, immunotherapies are used as a part of initial treatment. An example of this is the monoclonal antibody rituximab in the treatment of CLL. In this situation, immunotherapy is often combined with other cancer treatments like chemotherapy or targeted therapy.
Many immunotherapies directly target certain proteins on the surface of cancer cells. Because the presence of these proteins is important for the treatment to be effective, molecular tests can be used during diagnosis to help detect them.
Can immunotherapy be used for children with leukemia?
Children can also develop leukemia. According to the American Cancer Society, about 3 out of 4 leukemias in children are ALL while most of the remaining instances are AML. Chronic leukemias are quite rare in children.
Some immunotherapies can be used in children that have leukemia. Examples of some that are approved for use in children are:
- blinatumomab (Blincyto), a monoclonal antibody used for ALL
- gemtuzumab ozogamicin (MyloTarg), a conjugated monoclonal antibody used for AML
- tisagenlecleucel (Kymriah), a CAR T-cell therapy used for ALL
Now let’s take a look at the different types of immunotherapies that can be used to treat leukemia.
Antibodies are immune proteins that are produced in response to infections. Monoclonal antibodies (mAbs) are artificial antibodies that mimic the actions of naturally produced antibodies.
mAbs bind to specific proteins on cancer cells, helping the immune system to better detect and kill these cells. Because mAbs target specific proteins on cancer cells, they also fall under the umbrella of targeted therapy.
Some types of mAbs also have a toxic drug attached to them. These are called conjugated mAbs. When the mAb binds to its target on the cancer cell, the drug acts to kill the cell. In this way, the mAb serves as a drug delivery system.
The mAbs that can be used to treat leukemia are:
- alemtuzumab (Campath) (CLL)
- blinatumomab (Blincyto) (ALL)
- obinutuzumab (Gazyva) (CLL)
- ofatumumab (Arzerra) (CLL)
- rituximab (Rituxan) (CLL)
The conjugated mAbs that can be used to treat leukemia include:
- gemtuzumab ozogamicin (MyloTarg) (AML)
- inotuzumab ozogamixin (Besponsa) (ALL)
- moxetumomab pasudotox (Lumoxiti) (hairy cell leukemia)
CAR T-cell therapy
Chimeric antigen receptor (CAR) T-cell therapy is a newer type of immunotherapy. It uses your own T cells to treat leukemia.
In CAR T-cell therapy, a sample of T cells is taken from your blood. This is done through a process called leukapheresis.
These T cells are then modified in a lab so that they have receptors specific for certain proteins on the surface of cancer cells. After the modification process, the T cells are allowed to multiply so that they’re present in larger numbers.
You’ll typically receive chemotherapy for several days before getting a CAR T-cell infusion. When the modified T cells are infused back into your body, they can go on to find and kill cancer cells.
The type of CAR T-cell therapy that’s used for leukemia is called tisagenlecleucel (Kymriah). Tisagenlecleucel is currently approved to treat ALL.
CAR T-cell therapy is also being studied for the treatment of other types of leukemia, such as AML and CLL.
Donor lymphocyte infusion
A donor lymphocyte infusion (DLI) uses white blood cells that have been collected from a healthy matched donor, such as a sibling. It’s typically done when leukemia relapses after a stem cell transplant.
The donor white blood cells are given to you as an infusion. The goal is for these cells to go on to detect and destroy cancer cells.
DLI can be used as a part of CML treatment. It can also be utilized for acute leukemias, but is less effective.
For example, some
Interferon is a human-made version of interferon proteins that are naturally produced by the immune system. You may also see them referred to as an immunomodulatory treatment.
Interferon-alpha is a type of interferon treatment that’s used to treat CML. It can help to slow the growth and division of cancer cells.
Interferon-alpha used to be one of the main treatment options for CML, but it’s now used less often. This is because of the development of newer CML treatments, such as targeted therapies like tyrosine kinase inhibitors.
The effectiveness of immunotherapy for leukemia can depend on many different factors. These include:
- the type of leukemia you have
- the extent (stage) of the leukemia
- the kind of immunotherapy used
- the other types of cancer treatments you’ve had
- your age
- your overall health
Let’s take a look at what the research says about the success rates of some of the commonly used immunotherapies for leukemia.
Overall survival for the individuals that received blinatumomab was significantly higher than those who received chemotherapy. Remission rates within 12 weeks of treatment were also significantly higher in the blinatumomab group.
The results of a clinical trial published in 2016 assessed the efficacy of blinatumomab in pediatric participants with ALL that had relapsed or that was difficult to treat. In total, 93 children were included in the trial.
Researchers found that 27 of 70 participants who received the recommended dosage of blinatumomab, or 39 percent, had complete remission.
Gemtuzumab ozogamicin (MyloTarg)
Clinical trial results published in 2016 detailed the results of a trial investigating the use of gemtuzumab ozogamicin (GO) in older adults with AML who couldn’t undergo chemotherapy. The trial included 237 participants.
Compared to the 119 individuals receiving the best supportive care, the 118 participants who received GO had a significantly higher overall survival. Additionally, complete remission occurred in 30 participants that got GO.
In children and younger adults
Chemotherapy alone was compared to chemotherapy with supplementation of GO. While treatment with chemotherapy and GO together didn’t improve overall survival, it was found to significantly reduce the risk of relapse.
When researchers assessed participants 3 years after the trial began, they found that 65 percent of those receiving chemotherapy and rituximab were free of CLL progression, compared to 45 percent of those receiving chemotherapy alone.
Additionally, chemotherapy with rituximab also slightly improved overall survival. At the 3-year point, 87 percent of participants in this group were alive, compared to 83 percent in the chemotherapy only group.
The results of a
Researchers observed that the overall remission rate within 3 months was 81 percent. The overall survival rate after receiving tisagenlecleucel was 90 percent and 76 percent, 6 and 12 months post-treatment, respectively.
A severe, but typically reversible, side effect called cytokine release syndrome occurred in 77 percent of participants.
Being diagnosed and undergoing treatment for leukemia can be overwhelming. However, there are many things to be hopeful about.
Advances in treatments for leukemia are happening all of the time and researchers continue to investigate potential new treatments. Some examples include:
- additional targets for mAb treatments
- radioimmunotherapy, which is currently used for lymphoma and uses a mAb that’s combined with a radioactive substance
- infusions with modified natural killer (NK) cells, which are another type of immune cell that can kill cancer cells
- cancer vaccines, which are aimed to promote an immune response against cancer cells
Because we’re learning more about leukemia and ways to treat it, outlook has also improved. For example, according to the Leukemia and Lymphoma Society, the 5-year relative survival rate for leukemia has more than quadrupled since the 1960s.
Immunotherapy is a type of leukemia treatment. It uses components derived from the immune system to help treat different types of leukemia.
Most of the time, immunotherapy is used when leukemia has relapsed or hasn’t responded to other treatment options. However, some types of immunotherapies, such as rituximab for CLL, can be used as a part of first-line treatment.
Some examples of immunotherapies include monoclonal antibodies, CAR T-cell therapy, and interferon. The type of immunotherapy that may be recommended will depend on the type of leukemia that you have as well as several other factors.