Last reviewed 2026-04-20 · How we verify

Avonex (INTERFERON BETA-1A)

Avonex works by binding to the interferon alpha/beta receptor, which helps to reduce inflammation and slow disease progression in multiple sclerosis.

Avonex (Interferon Beta-1a) is a medication originally developed by Biogen and currently owned by the same company. It is a recombinant form of interferon beta-1a, a protein that targets the interferon alpha/beta receptor, and is classified as an interferon beta. Avonex is FDA-approved for the treatment of relapsing-remitting multiple sclerosis, and has been commercially available since 1996. As a branded medication, it is not yet available as a generic. Key safety considerations include potential flu-like symptoms, injection site reactions, and liver enzyme elevations.

At a glance

Mechanism of action

The mechanism(s) by which REBIF (interferon beta-1a) exerts its therapeutic effects in patients with multiple sclerosis is unknown.

Approved indications

• Relapsing remitting multiple sclerosis

Common side effects

• Influenza-like symptoms
• Influenza-like symptoms
• Headache
• Headache
• Fatigue
• Fatigue
• Fever
• Fever
• Rigors
• Rigors
• Chest pain
• Chest pain

Key clinical trials

• An Observational Study to Learn About the Interferon-beta Exposure of Pregnant Women During the Second and Third Trimester in Finland and Sweden
• Open Label Randomized Multicenter to Assess Efficacy & Tolerability of Ofatumumab 20mg vs. First Line DMT in RMS (PHASE3)
• Safety and Efficacy of Fingolimod in Pediatric Patients With Multiple Sclerosis (PHASE3)
• A Study to Learn More About The Safety of Diroximel Fumarate (VUMERITY®) in Participants Who Took it During Pregnancy And About the Health of Their Babies
• Traditional Versus Early Aggressive Therapy for Multiple Sclerosis Trial (NA)
• A Study to Evaluate the Safety, Tolerability, and Efficacy of BIIB017 (Peginterferon Beta-1a) in Pediatric Participants for the Treatment of Relapsing-Remitting Multiple Sclerosis (PHASE3)
• Determining the Effectiveness of earLy Intensive Versus Escalation Approaches for RRMS (PHASE4)
• Pregnancy Exposure Registry for Vumerity (Diroximel Fumarate)

Patents

Primary sources

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