[Monoclonal antibodies in multiple sclerosis]

Multiple sclerosis is the main source of significant disability in young adults and is associated with inflammation, demyelinisation and neurodegeneration. Several trials in the past ten years have tested b interfons and other immunomodulators, with some success. Recently, Natalizumab (Tysabri), a monoclonal antibody which targets the a4-integrin expressed by immune effectors, thus preventing their migration from the circulation into the brain tissue, has demonstrated previously unseen efficacy in preventing relapses and disease progression in patients with remitting multiple sclerosis. However, this enthusiasm has been tempered by observed cases of opportunistic infection and especially progressive multifocal leucoencephalopathy, which led to its restricted use to a precise subgroup of patients. This example underlines the difficult evaluation of the benefit/risk ratio experienced by the pratician with these new and often very efficient innovative therapeutics.