Jane S. Ricciuti, RPh, MS


March 19, 2003

In This Article

Neurologic Agents

(interferon beta-1a)

Manufacturer: Biogen, Inc.

Drug Approval Classification: Biologics License Application Supplement (Approval Date: 1/31/03)

New Indication: Avonex (interferon beta-1a) has received FDA approval to include a new indication in patients who have experienced a first clinical episode of multiple sclerosis (MS) and have magnetic resonance imaging (MRI) features consistent with MS.

Dosing: The recommended dosage of Avonex is 30 mcg injected intramuscularly (IM) once a week.

Clinical Summary: The supplemental indication for the treatment of a first clinical episode with interferon beta-1a was based on a single randomized, double-blind trial of 383 patients who had a first acute clinical demyelinating event (optic neuritis, incomplete transverse myelitis, or brain-stem or cerebellar syndrome) and evidence of prior subclinical demyelination on MRI of the brain.[1] Patients enrolled in the CHAMPS study received 30 mcg interferon beta-1a or placebo by IM injection once weekly for 2 years and followed up to 3 years or until a second clinical exacerbation.

The primary end point was time from the first to a second MS attack. Within 24 months, 38.6% of patients treated with interferon beta-1a developed an exacerbation of MS.

Avonex-treated subjects experienced a 44% decrease in the rate of developing a second attack when compared with placebo.

Jacobs LD, Beck RW, Simon JH, et al. Intramuscular interferon beta-1a therapy initiated during a first demyelinating event in multiple sclerosis. CHAMPS Study Group. N Engl J Med. 2000;343:898-904.

Adverse Effects: The FDA approval letter for this supplemental indication for Avonex included the request for a patient Medication Guide. Due to serious adverse events based on postmarketing experience, the following Avonex safety information has been revised:

  • Avonex should be used with caution in patients with depression or other mood disorders and in patients with seizure disorders. Avonex should not be used by pregnant women. Patients with cardiac disease should be closely monitored. Patients should also be monitored for signs of hepatic injury. Routine periodic blood chemistry and hematology tests are recommended during treatment with Avonex. Rare cases of anaphylaxis have been reported.

Additionally, Biogen is to conduct a pregnancy registry study to prospectively record and analyze pregnancy outcomes in 300 pregnant women with multiple sclerosis exposed to interferon beta-1a at the time of conception or during the first trimester of pregnancy. This information will be used to assess the potential risk to the mother, fetus, and/or live-born infant. The Avonex supplemental approval letter indicates a final study report is to be submitted to the FDA by July 31, 2009.

Avonex (interferon beta-1a) Labeling

Avonex (interferon beta-1a)


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