Skip to navigation Skip to content



About this Medication
  • Brand Name: Avonex® (U.S. and Canada)
  • Chemical Name: interferon (in-ter-feer-on) beta-1a
  • Usage in MS: Disease-Modifying Agent
  • Generic Available: No

This medication is taken by injection.

Biogen, the manufacturer of  AVONEX® (interferon beta-1a), will be discontinuing the AVONEX Lyophilized powder (LYO) in a single-use vial on or around October 31, 2018. AVONEX will continue to be available in the Prefilled syringe and AVONEX PEN® formulations. If you are using the lyophilized version of AVONEX please speak with your healthcare provider about switching to the AVONEX PEN or AVONEX Prefilled Syringe. If you have questions, please contact Biogen at 1-800-456-2255, 8:30 AM to 8 PM ET, Monday through Friday.


Avonex® is a medication manufactured by a biotechnological process from one of the naturally-occurring interferons (a type of protein). It is made up of exactly the same amino acids (major components of proteins) as the interferon beta found in the human body. In controlled clinical trials in relapsing MS, those taking the medication had a reduced risk of disability progression, experienced fewer exacerbations, and showed a reduction in number and size of active lesions in the brain (as shown on MRI) when compared with the group taking a placebo. In a subsequent study of patients who had experienced a single demyelinating event in the optic nerve, spinal cord, or brainstem, and had lesions typical of MS on brain MRI, Avonex significantly delayed the time to a second exacerbation, and thus to a clinically definite diagnosis of MS.

Avonex is approved by the U.S. Food and Drug Administration (FDA) for the treatment of patients with relapsing forms of MS to slow the accumulation of physical disability and decrease the frequency of clinical exacerbations. Patients with MS in whom efficacy has been demonstrated include those who have experienced a first clinical episode and have MRI features consistent with MS.

Click here to read the FDA prescribing information for healthcare professionals.

Click here to read the FDA Medication Guide for patients.



Financial Assistance Program

Above MS