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Multiple sclerosis is a progressive disease affecting the central nervous system, causing various forms of sensory and motor disturbances. It is a long term condition, in which symptoms can wax and wane. Relapses are common and progression of the disease may result in various complications. Interferon treatment may help slow the progression of multiple sclerosis and prolong intervals between relapses.
What is Multiple Sclerosis?
Multiple sclerosis (MS) is an autoimmune condition where the body attacks the myelin covering of its nerves and brain tissue. This results in inflammation and damage to these nervous system structures, resulting in disruption in nerve signals. These changes affect motor function, manifested as loss of balance and coordination, spasticity, and uncontrolled muscle movements. Loss of vision (usually in one eye) and fatigue are also common. Most patients have a relapsing remitting type of condition, where there are intervals with mild or no symptoms followed by sudden flare-ups. This can last for years and later deteriorate to a progressive condition. A less common type of disease features a progressive condition with no periods of remission.
Multiple sclerosis affects about 350,000 people in the US and 100,000 in the UK. Caucasians and women are more likely to be affected at an average age of 30, although children and elderly individuals may also get the disease.
The Role of Interferon in the Management of Multiple Sclerosis
There is no cure for MS and management of the disease focuses on relief of symptoms, reducing relapses, delaying progression and treating its complications. This involves the use of steroids, which may reduce inflammation and relieve its symptoms, disease modifying drugs, which can help delay progression of the disease, and specific medications to treat its complications.
Interferons are proteins naturally produced by the immune system, which help protect the body from certain diseases. Their ability to regulate the immune system has led scientists to make synthetic interferons, which may be used as disease-modifying drugs in the management of MS.
The types of interferon-beta approved by the FDA are interferon beta-1a (Avonex, Rebif) and interferon beta-1b (Betaseron, Extavia). All types of interferon beta are given by injection either to the skin or to the muscle.
Research shows that interferon reduces the MS relapse rate by one-third over a two-year period. Magnetic resonance imaging (MRI) has shown that patients treated with high doses of beta-interferon have fewer lesions and less scarring on the brain than patients on lower doses or those given placebo treatment. Studies also show that treatment with interferon beta may reduce severity of symptoms and lower the chance of disability in patients who have relapsing remitting MS.
Other studies show, however, that about 30% of MS patients do not respond to interferon treatment (non-responders), while some studies suggest that combining other disease-modifying drugs such as daclizumab, a monoclonal antibody, with interferon treatment may be more effective in reducing relapse rates than using interferon alone.