Interferons: Uses, common brands, and safety info

Our immune system is complex, consisting of organs like the bone marrow where immune cells are produced, cells like white blood cells that fight against germ pathogens and cancers, and proteins called cytokines that flow through our bloodstream and tissues to signal our immune cells.

Interferons are a group of cytokines that play a multifaceted role in our immune response to infection and cancer, a role that is still not fully understood. Using recombinant genetic technology, interferons are able to be synthesized and have been put to use in the treatment of viral illnesses and cancers. In this review, we will examine the interferon products that are available by covering their use, mechanism, cost, and potential for side effects.

Other interferons

• Alferon N (interferon alfa-n3)

• Plegridy (pegylated interferon beta-1a)

What are interferons?

Interferons are a group of naturally occurring proteins in our bodies that modify the action of our immune system and regulate tissue growth. More specifically, they assist in fighting viruses and alter how our body’s cells develop (cell differentiation) and how our tissues get their blood supply (angiogenesis). The genetic types of interferon include alpha, beta, and gamma forms. Synthetic versions exist for each of these forms of interferon and are used for either antiviral, anticancer, or immune altering activity. 

How do interferons work?

The cells of our immune system have different functions. For example, some immune cells, e.g. natural killer cells and macrophages, kill germs or cancer cells. Other immune cells, such as B lymphocytes produce antibodies to assist the killer cells. To orchestrate these efforts, our bodies have cytokines, substances that are made by one cell and tell another cell what to do. This process is called a signaling pathway. Interferons are a type of cytokine that functions with our immune system’s signaling pathway.

Therapeutic use of interferons relies on some of their different functions. For instance, interferons can direct our immune system to fight off hepatitis viruses or chronic myeloid leukemia. Conversely, they can quiet the immune-mediated inflammation in multiple sclerosis. 

What are interferons used for?

• Multiple Sclerosis

• Chronic Hepatitis C

• Chronic Hepatitis B

• Chronic myeloid leukemia (CML)

• Melanoma

• Renal cell carcinoma

• Chronic granulomatous disease

• Malignant osteopetrosis

Types of interferons

Interferon alpha (IFN-α)

The alpha type of interferon was one of the first to be put to use medicinally, but better options are now available for most conditions. Hepatitis C treatment was a major indication for interferon alpha usage in the past, but newer antiviral drugs have taken their place. Interferon alpha-2b was used prominently for CML until the tyrosine kinase inhibitor Gleevec became a treatment of choice. High-dose interferon alpha was used for advanced cases of melanoma skin cancer in the past, but it has largely been replaced by newer immunotherapy drugs, like Opdivo, based on better effectiveness with fewer side effects.

Some IFN-α products continue to be used. Alferon (interferon alpha-n3) is a therapy still available for genital warts, which are actually caused by a virus. Alferon is used by injecting it under the wart. Pegasys (pegylated interferon alpha-2a) is a weekly injection for chronic hepatitis B treatment. By being pegylated, or bound to a polyethylene glycol molecule, Pegasys is slowly absorbed so it is able to be injected once a week instead of daily. 

Our natural IFN-α is directly activated by virus infections and provides antiviral activity. Therefore, it makes sense that synthetic interferon alpha products are used to direct the immune system to fight chronic viral infections, like hepatitis B and genital warts. 

Interferon beta (IFN-β)

Interferon beta is very similar to interferon alpha, and in fact, they can utilize the same cell receptor and are classified together as type 1 interferons. The interferon beta-1a products, Rebif and Avonex, are used for relapsing forms of multiple sclerosis (MS), with Rebif injected three times a week and having the option of an automatic injector called Rebidose and with Avonex injected once a week. Plegridy consists of pegylated IFN-β1a, so it only needs to be injected every 14 days. Also used for relapsing MS, Betaseron and Extavia are interferon beta-1b drugs that are injected every other day. These drugs all reduce the immune system’s attack on the nervous system in patients with MS.

Interferon gamma (IFN-γ)

Interferon gamma has substantial differences from the alpha and beta types, and it is called type 2 interferon accordingly. Actimmune (interferon gamma-1b) can be injected three times a week for chronic granulomatous disease (CGD), an immune system deficiency, and malignant osteopetrosis, a genetic condition causing excess bone formation in childhood. Our bodies make IFN-γ when T cells and NK cells are activated. The pharmacologic version seems to alter the function of immune cells in CGD.

Who can take interferons?

Can adult men and women take interferons?

Interferon products can be used by both men and women.

Can children take interferons?

Although study data is often limited, children are prescribed different interferon products when their potential benefits are judged to outweigh the possible risk.

Can seniors take interferons?

The risk of toxicity is often higher for seniors taking interferons, but if other options are not available or effective, interferons can be used.

Are interferons safe?

Interferon alpha products have the FDA’s strongest black box warning regarding the potential for fatal reactions involving neurologic, psychiatric, immune, circulatory, or infectious complications.

Recalls

No active recalls are currently in place for interferon products, but the FDA’s database can be searched for the most up-to-date listings.

Restrictions

If you have had a hypersensitivity reaction to interferons in the past, you should not take interferon again. Likewise, anyone with a history of autoimmune disease or severe psychiatric, liver, or thyroid disease should typically avoid interferon alpha. Caution with any of the interferon products should be taken in the setting of liver, kidney, circulatory, heart, neurologic, psychiatric, bone marrow, or immune diseases. In addition to these cautionary notes, interferon alpha use is also a particular concern for those with diabetes, eye problems, and lung disease.

Can you take interferons while pregnant or breastfeeding?

Study data is lacking, so an informed decision on whether to take interferons during pregnancy is difficult. Interferon gamma has shown harm in pregnancy in animal studies at high doses. Usage during breastfeeding is possible but is done with the understanding that safety has not been proven.

Are interferons controlled substances?

The DEA does not categorize interferons as controlled substances.

Common interferon side effects

• Kidney damage

• Liver damage

• Heart failure or heart rhythm disturbance

• Bone marrow disorders and reduced blood cell counts

• Severe skin reactions, rash, or hair loss

• Autoimmune disease

• Infections

• Thyroid problems

• Diabetes mellitus

• Depression, anxiety, suicidal thoughts, or irritability

• Altered mental status or sleep disturbance

• Seizure, stroke, or headache

• Fever, chills, fatigue, or achiness

• Vomiting, diarrhea, or stomach bleeding

• Eye problems

• High blood pressure

How much do interferons cost?

Interferon therapy can be extremely expensive. For example, a patient with MS could be charged over $8000 for a one-month supply of Betaseron or Rebif. A SingleCare discount card can provide significant cost savings for these and other medications.