[Disease modifying therapies in multiple sclerosis]

The purpose of this section is to introduce the clinical utility of several disease-modifying agents including natalizumab and immunosuppressive treatments that are currently available in Japan, and glatiramer acetate that will be probably available in Japan within a few years. Immunosuppressive therapy has been used to treat multiple sclerosis(MS) for over 30 years based on the hypothesis that MS is a T cell-mediated autoimmune disease. The most commonly used immunosuppressive agents in MS are azathioprine, cyclophosphamide, methotrexate, and mitoxantrone. Like the interferons and glatiramer acetate, immunosuppressive drugs are most efficacious in stages of MS that have an inflammatory component as evidenced by relapses and/or gadolinium-enhancing lesions on MRI or in patients in earlier stages of disease where inflammation predominates over degenerative processes in the CNS. There is no evidence of efficacy in primary progressive MS or later stages of secondary progressive MS. It is appropriate to consider glatiramer acetate for treatment in any patient who has relapsing remitting MS (RRMS), and glatiramer acetate may be helpful in patients with progressive disease. Because of the possibility that natalizumab therapy may be responsible for the increased risk of primary progressive leukoencephalopathy (PML), it is recommended that natalizumab be reserved for use in selected patients with relapsing remitting disease who have failed other therapies either through continued disease activity or medication intolerance, or who have a particularly aggressive initial disease course.