How Does AVONEX Treat
Relapsing MS?

As with all relapsing multiple sclerosis (MS) treatments, the way AVONEX works to fight the disease is not known. To understand how AVONEX is thought to work, it helps to know more about how MS affects your brain. Normally, the blood vessels in your brain are protected from substances in your blood by a wall of cells known as the blood-brain barrier. When you have MS, holes appear in your blood-brain barrier. This allows immune cells to cross into your central nervous system (CNS) where they can cause damaging inflammation or lesions.

The diagram below illustrates the two ways AVONEX is thought to fight the damage caused by MS.

1. MS continuously causes holes in your blood-brain barrier. AVONEX is believed to help repair these holes and help prevent new ones from forming. This helps keep harmful cells from crossing into the central nervous system (CNS) and causing damage.
2. AVONEX also appears to modify immune cells outside your CNS. If these modified cells cross the blood-brain barrier, they will work to fight MS inflammation instead of causing it.

The key ingredient in AVONEX is a form of a protein called interferon beta-1a that occurs naturally in your body. AVONEX appears to enhance your body's ability to fight off the inflammation caused by MS. Talk to your doctor to see if AVONEX is right for you.