Interferon (IFN) therapy is a type of immunotherapy that helps the body’s immune system fight cancer cells. It can help kill leukemia cells or cause leukemia cells to grow more slowly.

IFN therapy was used more frequently in the past and can cause many side effects. Doctors are now more likely to recommend other treatments that are more effective and not as hard on the body. However, IFN therapy may still be a good option for some people with leukemia.

What Are Interferons?

The body naturally makes many different types of IFNs. These proteins play many important roles within the immune system. They help fight off infections, strengthen the immune system’s reactions, and help the immune system kill cancer cells.

Researchers have learned how to make these molecules in the lab. Laboratory-made IFNs act the same as the IFNs made by the body. IFN drugs such as IFN alfa-2a (Roferon-A) and IFN alfa-2b (Intron A) mimic the protein IFN-alpha that is part of the body’s natural immune system.

IFNs may be used as a treatment for leukemia, a type of cancer in which immature blood cells grow and divide too quickly. IFN therapy slows down this process, which leads to fewer cancer cells. These drugs also encourage different types of immune system cells, such as T cells, to attack and destroy the cancer cells.

IFN medications frequently cause side effects, causing some people to stop using them. However, newer versions of IFNs may be easier to tolerate. These new formulations are pegylated — they contain chemical changes that help them stay in the blood longer. This means that people can often take lower doses of IFN drugs and experience fewer side effects. Pegylated IFN alfa-2a is sold under the brand name Pegasys.

When Do Doctors Recommend Interferon Therapy?

IFN therapy is approved to treat certain types of leukemia, including chronic myeloid leukemia (CML) and hairy cell leukemia (HCL). Researchers are also studying whether IFN can be used to treat other kinds of leukemia.

Chronic Myeloid Leukemia

Chronic myeloid leukemia is a slower-growing type of leukemia that most often affects older adults. IFN therapy used to be the main treatment option for this type of leukemia. However, newer drugs called tyrosine kinase inhibitors (TKIs) are now used more frequently in the treatment of CML because they tend to work better and lead to fewer side effects. TKIs include drugs like imatinib (sold as Gleevec) or dasatinib (sold as Sprycel).

TKIs target a specific gene change called BCR-ABL, which is almost always found in CML cells. These drugs are often very effective at keeping leukemia under control. However, sometimes, they may be ineffective. In this case, doctors may recommend trying other treatments, including IFN therapy.

IFN drugs may help leukemia cells become more sensitive to TKIs. Using these two medications together may produce better results when TKIs alone are ineffective.

Hairy Cell Leukemia

HCL is a rare form of chronic leukemia similar to chronic lymphocytic leukemia. This kind of cancer affects B cells, a type of immune cell.

Roferon-A is approved by the U.S. Food and Drug Administration (FDA) to treat people who have been diagnosed with HCL within the past year. Typically, HCL is treated with chemotherapy. However, IFN therapy may be an option if you can’t undergo chemotherapy, or if you’ve tried chemotherapy and it didn’t work.

Other Types of Leukemia

Although IFN therapy is not yet approved for use in other types of leukemia, some studies have found that these medications may be useful.

Acute myeloid leukemia is a more aggressive type of leukemia that is typically treated with chemotherapy and sometimes with targeted therapy drugs. Some researchers have found that when IFN drugs are added to chemotherapy regimens, people with acute myeloid leukemia may have a better chance of a positive outcome. Using both types of drugs together caused more leukemia cells to be destroyed and led to lower relapse rates in some studies. However, more research is needed before IFNs become standard therapy for people with acute leukemias.

IFN treatments have been studied as possible treatments for lymphoid leukemias. However, these drugs did not always seem to be effective. In recent years, some researchers have continued to study IFN therapy in these conditions. For example, studies have shown that the drugs could help improve outcomes for people with acute lymphoblastic leukemia who underwent stem cell transplants.

Researchers use clinical trials to test whether new treatment approaches are safe and effective. People with leukemia may be able to access IFN therapy or other new treatment options by participating in a trial.

Myeloproliferative Neoplasms

Myeloproliferative neoplasms (MPNs) are blood cancers that lead to high levels of different types of blood cells. In 2021, the FDA approved an IFN formulation of ropeginterferon alfa-2b-njft called Besremi to treat one of the most common types of MPNs, polycythemia vera.

Researchers are also studying whether IFN therapy may be effective in treating the other two main types of MPNs, essential thrombocythemia and myelofibrosis.

IFNs may be a treatment option for people with certain rare types of MPNs, including chronic neutrophilic leukemia and chronic eosinophilic leukemia. These conditions cause the body to produce high levels of certain types of immune cells.

IFN therapy has been able to help a few people with chronic neutrophilic leukemia temporarily go into remission (have signs and symptoms of cancer go away). IFN alfa-2a may also be given to those with chronic eosinophilic leukemia when other treatments such as steroids and hydroxycarbamide stop working.

What To Expect When Using Interferon Therapy

IFN medications are usually injected under the skin, into the abdomen, thigh, or upper arm. These drugs may come in:

• A syringe that contains the exact drug dose you need
• A vial containing several doses of liquid, which you will need to draw up into a syringe and then inject
• An injection pen that automatically delivers the needed dose

Your health care team can teach you or a caregiver how to inject the drug, so it can be done at home. The injections usually don’t cause a lot of pain, but they may lead to a little aching, stinging, redness, or itchiness in the skin in the surrounding area.

IFN drugs need to be taken on a consistent schedule. Depending on your leukemia type and the IFN you’re prescribed, you may need to have injections every day, or three times per week. Pegylated IFN drugs may only need to be injected once a week or less. Make sure to follow the schedule that your doctor gives you.

As you undergo IFN treatments or other types of leukemia therapies, your doctor will keep an eye on your condition. Your doctor may recommend follow-up visits or blood tests to see if the cancer cells are responding to the treatment.

Side Effects of Interferon Therapy

Like other cancer treatments, IFN therapy often leads to painful or uncomfortable side effects:

• Feeling like you have the flu
• Fever
• Tiredness
• Muscle aches
• Bone pain
• Headaches
• Abdominal pain
• Nausea or vomiting
• Diarrhea
• Dry mouth
• Blurry vision
• Hair loss
• Problems with focusing or thinking
• Mood changes
• Sleeping problems
• Anemia (low levels of red blood cells), which can cause fatigue, dizziness, shortness of breath, or irregular heartbeats
• Low white blood cell counts, leading to frequent infections
• Low levels of platelets can cause breathing problems

In rare cases, IFN therapy can lead to more severe side effects:

• Sepsis (infection throughout your body)
• Diabetes
• Heart attack
• Kidney damage
• Brain bleeds
• Hallucinations
• Suicidal thoughts

Less than 1 percent of people who use IFN therapy experience any of these rare effects.

Make sure to tell your health care team if your side effects are severe or if they are getting worse.

IFN side effects often become milder over time. However, sometimes they are very hard to tolerate and decrease a person’s quality of life. In this case, palliative care may help. The goal of palliative care is to relieve cancer symptoms and treatment side effects. A palliative care team may be able to help find solutions that make IFN therapy easier to deal with.

Talk With Others Who Understand

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