Avonex® (interferon beta-1a)
FDA-Approved Medications: Administered by Self-Injection
- Taken via weekly intramuscular injections; dosage is 30 mcg (micrograms)
- The FDA approved Avonex in 1996 for relapsing MS and more recently for individuals with clinically isolated syndrome (CIS)
Avonex has been shown to reduce the number of relapses and lesions on an MRI, as well as slow the progression of physical disability. This drug has been shown to be both safe and effective.
Interferons appear to reduce inflammation by modulating a favorable balance between cells that increase inflammation and cells that decrease inflammation. They also reduce the transport of damaging lymphocytes into the brain. Lymphocytes are immune-system cells produced to fight infection and disease.
In 2012, Avonex became available with a single-use, prefilled autoinjector called the Avonex Pen. The Avonex Pen incorporates the current Avonex Prefilled Syringe. Its needle is 25 gauge (width) and 5/8ths of an inch in length. Rather than a manual injection, the Avonex Pen injects with a click, using a covered needle that’s half the length of the standard needle used with the Avonex Prefilled Syringe. In a Phase IIIb study, 94 percent of patients preferred the Avonex Pen over the Avonex Prefilled Syringe. This new option has the potential to make the weekly intramuscular self-injection process less stressful for people using this medication.
Long-term studies of Avonex include the ASSURANCE study, which evaluated 15-year data and showed that early suppression of clinical disease activity by Avonex is a marker of treatment response. This is associated with significant long-term benefits for quality of life as compared to patients who had received placebo. These results support other accumulating evidence that short-term responders to Avonex are also inclined to experience beneficial long-term outcomes.
A 10-year analysis of data from the CHAMPS trial – which treated patients with CIS and MRI findings consistent with MS – showed that although some had characteristics of disease progression, there was evidence of improved disease course with early treatment. These results again emphasize the value of early treatment. This effect remained evident in both the CHAMPIONS five- and 10-year extension studies.