Natalizumab De-escalation to Interferon-beta-1b in Patients With Relapsing-remitting Multiple Sclerosis

Multiple Sclerosis (MS) is the most common neurological disorder causing disability in young adults affecting approximately 1 in 1.000 people in western countries. The clinical manifestations usually begin at the age of 20 to 40 years with a median age of 28 years at onset with acute episodes of neurological dysfunction, followed by periods of partial or complete remission and clinical stability in between relapses. This relapsing-remitting phase (RR-MS) of the disease is usually followed by progressive clinical disability (secondary progressive phase, SP-MS). At present, there is no cure for MS. Based on the pathological concept that neuroinflammation is the common element leading or contributing to neurodegenerative changes, immune interventions have been introduced into clinical practice such as Natalizumab (Tysabri), a humanized monoclonal antibody. Natalizumab (Tysabri) is indicated as a disease-modifying monotherapy of highly active relapsing MS. The associated risks, especially progressive multifocal leukoencephalopathy, necessitate active monitoring of patients and a continuous discussion of optimum use of this drug. In clinical practice, the question how to manage patients on natalizumab at a higher risk for progressive multifocal leukoencephalopathy remains unresolved. This prospective, controlled (comparison to the period prior to natalizumab treatment), single-arm, open-label, multi-centre, phase IV study aims to evaluating the concept of natalizumab de-escalation to interferon-beta-1b e.o.d in relapsing-remitting multiple sclerosis patients, who consider stopping natalizumab due to a benefit-risk assessment. In particular, to evaluating if interferon beta-1b treatment may be able to overcome the recurrence of significant clinical and radiological disease activity after natalizumab cessation and may keep disease activity better under control as compared to the time prior to natalizumab. The study population includes patients with relapsing-remitting m