Avonex (interferon beta-1a)


Avonex (interferon beta-1a) is an injectable disease-modifying treatment for people diagnosed with MS, made by Biogen Idec. Avonex is indicated (approved for use) for the treatment of relapsing forms of MS to reduce frequency of exacerbations or relapses and to slow the progression of disability. Avonex is also approved for delaying a second exacerbation in people who have been diagnosed with clinically isolated syndrome (CIS).

How does Avonex work?

Avonex is an interferon, a family of glycoproteins produced naturally in the body in response to viral infection or invasion of the body by another biologic agent. Avonex, produced through a biotechnological process using mammalian cells containing naturally occurring interferon, contains all of the same basic components as the interferon beta occurring naturally in the human body.

The exact process by which Avonex and other interferon beta drugs work to reduce the frequency of exacerbations and slow the progression of disability in MS is unknown. However, as interferons play an important role in controlling immune system activities, Avonex may use its ability (as an interferon) to control the abnormal immune response that appears to be involved in MS. When Avonex is given to a person, levels of an immune system protein called interleukin-10 (IL-10) are increased. IL-10 is an anti-inflammatory cytokine that helps to stop or inhibit inflammation.

How is Avonex taken?

Avonex is given as an intramuscular injection once a week, preferably on the same day every week. For instance, you might take Avonex every week on Monday night before going to bed. Avonex is available in three forms, each containing the recommended dose of 30 micrograms (μg or mcg):

  • A powder contained in a vial to be reconstituted with sterile water
  • A pre-mixed sterile liquid in a single-use prefilled syringe
  • A pre-mixed sterile liquid in a single-use prefilled autoinjector

To reduce flu-like symptoms that can happen with Avonex, the drug may be titrated using a lower starting dose, 7.5 micrograms for the first week and increased by 7.5 micrograms at each administration over the next 3 weeks until the recommended 30 microgram dose is reached. The first time Avonex is injected, you should be supervised by a qualified healthcare professional.

What should I do if I miss a dose of Avonex?

If you miss a dose of Avonex, take your next dose as soon as you remember and continue taking Avonex on your regular schedule the next week. DO NOT take Avonex on 2 consecutive (back to back) days.

How should Avonex be stored and prepared?

All three forms of Avonex (powder, pre-filled syringe, and pre-filled autoinjector) should be stored under refrigeration (36ºF to 46ºF). However, each form may be left unrefrigerated (at 77ºF) for a limited period of time, 30 days for the powdered unreconstituted product and 7 days for the liquid product. The product should be allowed to reach room temperature before injection.

When you start Avonex, you’ll get specific instructions for mixing or reconstituting the powdered product and preparing and administering both powder reconstituted and liquid pre-filled syringes. These instructions should be followed carefully.

Are there people who should not take Avonex?

Avonex should not be taken by persons who have had a previous allergic reaction to an interferon beta medication, such as itching, hives, difficulty breathing (dyspnea), and flushing, or a history of hypersensitivity to albumin.

If you have had problems with depression, thyroid gland problems, blood problems (such as bleeding, easy bruising, anemia, or low white blood cell counts), seizures, heart problems, liver disease, or are planning to become pregnant, talk to your doctor before starting Avonex. Avonex can cause serious side effects related to each of the conditions previously mentioned. You should tell your doctor about all medications and supplements you are taking, including vitamins and herbal preparations, before starting Avonex.

You should avoid becoming pregnant while taking Avonex, as it may cause miscarriage. If you should become pregnant while taking Avonex, stop taking the drug immediately and talk to your doctor. Talk to your doctor about whether you should breast feed while taking Avonex, as it is not known whether Avonex is passed through breast milk or if it can harm your baby.

Learn More about Avonex Safety

What evidence do we have that Avonex works?

Avonex was compared with placebo in clinical trials to determine its effectiveness. People with relapsing forms of MS who received Avonex were less likely to experience progression of disability, had fewer exacerbations, and had fewer active brain lesions and a smaller volume of lesions as shown on MRI than people who received placebo.

In a separate study, people diagnosed with clinically isolated syndrome (CIS) and MS-like brain lesions who took Avonex experienced a delay in the time it took to have a second exacerbation, leading to diagnosis of MS.

Is there a generic alternative to Avonex?

There is no generic alternative to Avonex. However, the drug Rebif (interferon beta-1a), a subcutaneous injectable medication given three days each week made by EMD Serono, contains the same active ingredient as Avonex.