FDA-approved Avonex, a formulation of interferon beta-1a, is an injectable medication from Biogen approved for patients with relapsing forms of multiple sclerosis (MS) who have had a first attack and show lesions on an MRI. Avonex injections help reduce the number of flare-ups and MS disease progression.

How Avonex Works

Interferon beta-1a, the active ingredient in Avonex, is a protein found naturally in the body. It is a signaling molecule produced by cells and is used for communication. When interferon beta-1a is injected for MS treatment, the molecule balances pro- and anti-inflammatory signals, reduces the number of inflammatory cells that traverse the blood-brain barrier, and contributes to neuron survival.

Avonex is injected once a week using one of three methods. In one method, the Avonex Pen allows patients to self-administer their medication using a prefilled syringe with a small covered needle provides patients with the exact dose they need.

The Avonex Prefilled Syringe also allows self-administration, but the injection device is larger than the Avonex Pen. In the third method, Avonex Powder is administered by a doctor. The doctor mixes the powder into an injectable form and injects the patient with the correct dosage. A titration period may be necessary before the correct dosage is decided.

History of Avonex

The U.S. Food and Drug Administration (FDA) approved Avonex in 1996, and the Avonex Pen was approved in February 2012. Since 1996, more than 455,000 RRMS patients have been prescribed treatment with Avonex.

Two clinical trials formed the basis of the FDA approvals. A two-year study initiated in 1990 treated 158 RRMS patients with Avonex and 143 patients with a placebo. A four-year study initiated in 1996 treated another 193 RRMS patients with Avonex and 190 patients with a placebo.

In these studies, Avonex was found to reduce the number of relapses by 32 percent with two years of treatment and by 18 percent with fewer than two years of treatment. For patients with only one flare-up before the studies, there was a 44 percent reduction in relapses at the three-year mark following treatment. The patients were 37 percent less likely to see an increase in physical disability, and 78 percent of patients had no increase in physical disability. Finally, patients treated with Avonex had 91 percent smaller lesions detectable by MRI than the placebo group at 18 months.

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