Interferon therapy is a type of immunotherapy. Immunotherapy is a treatment that affects the immune system. It can boost your body's immune system. Or it uses synthetic versions of normal parts of the immune system to help fight cancer. It's also called biologic therapy.

The immune system fights infection by killing germs. And in the same way, it can also destroy cancer cells. Interferon is the immunotherapy medicine most often used to fight CML.

Interferon therapy is rarely the first treatment choice for CML. This is because targeted therapy works so well for CML.

But interferon may be used if your CML is not responding to targeted medicines. It may help kill leukemia cells or help keep them under control. The goal is to destroy as many leukemia cells as possible. Interferon might also be a choice to treat CML during pregnancy.

Interferon is given as a shot (injection) under your skin. You usually get it every day. You can get it as an outpatient at a hospital, clinic, or doctor's office. Or you may be taught how to give it to yourself at home.

If you take interferon, you may need it for a long time. It's common to take it for many years, as long as it's working and the side effects aren't too severe.

Side effects of interferon can include:

• Flu-like symptoms.
• Severe tiredness (fatigue).
• Muscle aches.
• Bone pain.
• Fever.
• Nausea and vomiting.
• Problems with thinking and memory.
• Mood changes.
• Headaches.
• Low levels of blood cells.

Talk with your health care team about ways to ease these side effects. Changing your dose of interferon may help. Some people may need to stop treatment because of side effects. But with the correct management, most people can handle this treatment. Side effects often go away over time after treatment ends.

It's important to know which medicines you're taking. Write down the names of your medicines. Ask your health care team how they work, how they're given, and what side effects they might have.

Talk with your doctor about what signs to watch out for and when you should call your health care team. Make sure you know what number to call with problems or questions, even after office hours, on holidays, and weekends.

It may be helpful to keep a diary of your side effects. Write down any physical, thinking, and emotional changes. A written list will make it easier for you to remember your questions when you go to your appointments. It will also make it easier for you to work with your health care team to make a plan to manage your side effects.