When you are diagnosed with leukemia, your doctor may recommend various types of treatments. Targeted therapies are a common option. They may be used on their own or in combination with other cancer drugs.
Your doctor can help you understand which targeted therapy drugs may be an option for you based on which type of leukemia you have, which gene changes are found in your leukemia cells, your overall health, and your personal preferences.
Targeted therapies are newer types of medications used to treat cancers like leukemia. They work in a different way than traditional cancer treatments like chemotherapy.
Chemotherapy drugs aren’t very specific — they kill any cell that is rapidly dividing and forming new cells. Chemotherapy destroys cancer cells, but it also harms other quickly growing healthy cells, leading to many side effects. For example, chemotherapy can lead to hair loss because the drugs kill the dividing cells in the roots of your hair.
Targeted therapy drugs can better find and attack cancer cells while leaving your body’s normal cells alone. Cancer cells contain gene mutations, which cause the cells to produce abnormal proteins. The protein changes may cause a cancer cell to grow too quickly or live too long. Targeted cancer therapies block these abnormal proteins, killing the cells or preventing new cancer cells from being made.
After diagnosing your leukemia, your doctor may recommend certain tests to determine which gene or protein changes are found within your leukemia cells. Your doctor can use this information to help determine which targeted therapies may be most likely to work.
Almost all adults and children with chronic myeloid leukemia (CML) have a gene change called the Philadelphia chromosome. About 25 percent of adults and 3 percent to 5 percent of children with acute lymphoblastic leukemia (ALL) also have leukemia cells that contain this gene change.
The Philadelphia chromosome leads to an abnormal protein called BCR-ABL. It can be blocked with tyrosine kinase inhibitors (TKIs), a type of targeted therapy. The U.S. Food and Drug Administration has approved four TKIs that can be used right after being diagnosed with CML:
If these targeted therapies don’t work to control CML, ponatinib (Iclusig) may also be an option. People with a different abnormality in the BCR-ABL protein — the T315I mutation — can also use ponatinib or another TKI, asciminib (Scemblix).
TKIs may also be used along with chemotherapy to treat people with ALL who have the Philadelphia chromosome. They will not work to treat people with ALL or other types of leukemia that do not have the Philadelphia chromosome.
TKIs block proteins called tyrosine kinases, while other types of kinase inhibitors block other abnormal proteins that can lead to leukemia.
Bruton’s tyrosine kinase (BTK) is a protein that causes some cases of chronic lymphocytic leukemia (CLL). BTK inhibitors like ibrutinib (Imbruvica) and acalabrutinib (Calquence) can be used as a first treatment for CLL. They can also be used if other treatments don’t work, or if CLL has returned after being treated.
Changes in a protein called phosphoinositide 3-kinase (PI3K) can also lead to CLL. Idelalisib (Zydelig) and duvelisib (Copiktra) are PI3K inhibitors that may be recommended to treat this type of leukemia.
Some people with acute myeloid leukemia (AML) have mutations in a gene called FLT3. Two types of kinase inhibitors can help treat people with this gene change — midostaurin (Rydapt) and gilteritinib (Xospata).
Monoclonal antibodies are medications that boost the cancer-killing ability of the immune system. (In addition to finding and killing viruses and bacteria, the immune system can also destroy cancer cells.) Typically, the body makes antibodies (immune proteins) to help fight leukemia. Antibodies attach to proteins found on cancer cells, labeling them for destruction by the immune system.
Monoclonal antibodies are laboratory-made versions of the antibodies produced by the body. They are also considered to be types of immunotherapy.
People with AML also have a monoclonal antibody option. Gemtuzumab ozogamicin (Mylotarg) is an antibody combined with a chemotherapy drug. This targeted therapy works by attaching to AML cells, forcing them to come into contact with the chemotherapy. This helps kill the cells.
Two drugs in this category are approved to treat ALL. Inotuzumab ozogamicin (Besponsa) is also an antibody attached to a chemotherapy drug. Blinatumomab (Blincyto) is a drug with two parts — one part attaches to a protein found on leukemia cells, and the other part links to a protein found on immune cells. The immune cells can then more easily kill the cancer cells.
Another targeted therapy option for CLL or AML is venetoclax (Venclexta). This drug targets a protein called BCL-2, which helps prevent leukemia cell death. Taking venetoclax alone or with other treatments such as monoclonal antibodies can make leukemia cells more likely to die.
Some people with AML have mutations in genes called IDH1 and IDH2. Ivosidenib (Tibsovo) can help treat people with IDH1 mutations, while enasidenib (Idhifa) is a treatment option for people with IDH2 mutations.
Certain people with AML may also be able to take glasdegib (Daurismo). This targeted therapy drug can be used along with low doses of chemotherapy for people who are 75 years old or older, or for those who can’t use more aggressive chemotherapy because they have other health conditions.
Targeted therapies are often pills taken once or twice per day. However, some monoclonal antibodies may be given intravenously (into a vein, through an IV). Your doctor will tell you exactly how each medication should be used. Make sure to ask your health care team for help if the instructions aren’t clear.
In some cases, your doctor will recommend taking a targeted therapy for many years. In other cases, you may be able to quit using the drug. For example, if you have CML, have been taking a TKI for three years or more, and have had no signs of cancer for at least two years, you may be able to try stopping the TKI. However, you will need to undergo regular testing to make sure that the leukemia does not return.
Because targeted therapies can recognize specific molecules rather than just killing any fast-growing cells, they are a form of personalized or precision medicine. Targeted therapy drugs are specifically designed to fight your leukemia cells.
Unlike traditional chemotherapy drugs, targeted therapies work in multiple ways to help fight cancer. They may prevent leukemia cells from making copies of themselves, enhance the immune system’s ability to fight off cancer, or kill the cancer cells directly.
Often, targeted therapy drugs attack leukemia cells while leaving your body’s normal cells alone. In some cases, this means a particular targeted therapy drug causes very few side effects. However, it is important to note that these medications can sometimes cause potentially serious side effects as well.
Targeted therapy drugs don’t always work perfectly. In some cases, they may not work as well as expected to slow down or stop the growth of new cancer cells.
In other cases, targeted therapies may work well at first, but then stop working over time. Leukemia cells can sometimes become resistant to the medications after you have been taking them for a while. Using targeted therapies in combination with each other or along with chemotherapy can make this less likely.
Targeted therapies can lead to side effects, which can sometimes be severe. These may include diarrhea, liver problems, high blood pressure, and changes in your skin or nails.
Side effects may be different for children who use targeted therapies. For example, children may be more likely to have immune system problems.
Side effects vary from drug to drug. Ask your doctor which health problems to watch out for while taking your recommended targeted therapy medication.
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