Tyrosine kinase inhibitors (TKIs) are a kind of targeted therapy. They work by blocking tyrosine kinase enzymes. TKI enzymes help manage how cells work, including cell signaling and growth and how often cells divide. Some tyrosine kinase inhibitors are used to treat cancer. TKIs work by blocking enzymes and keeping cancer cells from growing.
Tyrosine kinase inhibitors (TKIs) are targeted therapies that treat many kinds of cancer. They block certain substances in cancerous cells that manage how fast the cells grow and divide. Tyrosine kinase inhibitors can’t cure cancer, but they can put cancer into long-term remission or help people with certain cancers to live longer.
Tyrosine kinase inhibitors disrupt the process that manages how your cells grow and divide. That process involves:
Growth factors flip the switch that activates tyrosine kinases. In turn, tyrosine kinases signal cells so they start to divide. The cells continue dividing until tyrosine kinases turn off. Normal tyrosine kinases turn on and off as needed.
Treatment for chronic myeloid leukemia (CML) is a good example of how TKIs work. CML is a blood cancer that starts in the blood-forming myeloid cells (stem cells) in your bone marrow. When myeloid cells mutate, they make abnormal tyrosine kinase enzymes that turn on when the growth factor flips the switch. They never turn off.
Without an “off” switch, myeloid cells in your bone marrow divide and multiply uncontrollably, making it hard for your bone marrow to make other blood cells and platelets your body needs. Tyrosine kinase inhibitors treat CML by flipping the “on” switch to “off,” blocking abnormal enzyme signals that make cancerous cells divide.
Tyrosine kinase inhibitors treat several kinds of cancer, including:
As of November 2022, the U.S. Food and Drug Administration has approved 50 tyrosine kinase inhibitors to treat tumors including lung, breast and colon cancer, and eight drugs to treat blood cancers like leukemia. Four other medications treat both cancerous tumors and certain blood cancers. Imatinib (Gleevec®), the first FDA-approved tyrosine kinase inhibitor, treats seven types of cancer.
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Tyrosine kinase inhibitors come in pill or liquid form. Depending on the cancer type and stage, people may take one or two pills or liquid medication daily.
That depends on your situation. For example, if you have chronic myeloid leukemia, you may take the medication for the rest of your life.
Tyrosine kinase inhibitors treat a wide range of cancers and cause an equally wide range of side effects. For example, one group of tyrosine kinase inhibitors targets cancers such as non-small lung cancer, breast, colorectal and pancreatic cancer. Those treatment side effects may range from mild skin rashes to life-threatening skin issues like Steven-Johnson syndrome/toxic epidermal necrosis. Another group of TKIs that target non-small lung cancer and colorectal cancer may cause cardiovascular issues like high blood pressure (hypertension) and proteinuria.
Side effects vary based on the specific TKI and may include:
If you’re receiving a tyrosine kinase inhibitor, ask your healthcare provider about specific treatment side effects.
Tyrosine kinase inhibitors are targeted therapies for cancer and other conditions. Like all targeted therapies, its major benefit is killing cancer cells without damaging healthy cells. Tyrosine kinase inhibitors may be an alternative when other cancer treatments aren’t effective.
Tyrosine kinase inhibitors are effective treatments for many kinds of cancer. In general, tyrosine kinase inhibitors slow cancer down and help people live longer. For chronic myeloid leukemia, for example, this treatment turned a life-threatening disease into a chronic illness that medication can manage. They’re also effective treatments for some cancers that come back after treatment (cancer recurrence) or cancer that’s spreading (metastatic cancer).
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Tyrosine kinase inhibitors work well against many kinds of cancer. But over time, some cancers change. When that happens, the treatment that stopped the cancer growth is no longer working.
Most cancer treatment is stressful and challenging, and tyrosine kinase inhibitors are no exception. Side effects may be mild. Rarely, they may be life-threatening. Knowing what to expect is one way you can make this treatment easier. Here are some other suggestions:
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As you go through treatment, your provider will discuss how it may affect you. They’ll also discuss any symptoms that may be signs treatment isn’t working or that the cancer’s spread.
A note from Cleveland Clinic
Tyrosine kinase inhibitors (TKIs) keep cancerous cells from growing and spreading. From a medical standpoint, tyrosine kinase inhibitors launched targeted therapy for cancer — therapy that targets cancerous cells without damaging or destroying healthy cells. For people with cancer, tyrosine kinase inhibitors represent additional ways to treat many kinds of cancer. These medications may not cure all kinds of cancer, but they’re helping many people with cancer to live longer and with good quality of life.
Last reviewed on 05/12/2023.
Learn more about the Health Library and our editorial process.
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Cleveland Clinic is a non-profit academic medical center. Advertising on our site helps support our mission. We do not endorse non-Cleveland Clinic products or services. Policy