Natalizumab for relapsing-remitting multiple sclerosis

Introduction: Natalizumab is a monoclonal antibody that inhibits leukocyte migration across the blood-brain barrier and has been approved for the treatment of relapsing-remitting multiple sclerosis. Objective: To provide a review and update of the pharmacological and therapeutic characteristics of natalizumab, with special emphasis on the most recently published data on the efficacy, effectiveness and safety of this drug. Development: Several randomized clinical trials in patients with relapsing forms of multiple sclerosis have demonstrated that natalizumab substantially reduces clinical and radiological disease activity. Post hoc analysis of phase III clinical trials and the results of post-approval observational studies indicate that natalizumab significantly increases the proportion of patients with complete clinical and radiological response and is effective in patients with highly active forms of multiple sclerosis and suboptimal response to other treatments. Like other monoclonal antibodies, natalizumab can cause hypersensitivity reactions, which are severe in 1% of patients. Other adverse effects are generally mild or infrequent. Nevertheless, several cases of progressive multifocal leukoencephalopathy have been detected in patients treated with natalizumab monotherapy. The risk of this severe complication seems to increase with the number of doses administered. Conclusion: Natalizumab has a favorable risk-benefit ratio in the treatment of relapsing remitting multiple sclerosis. However, because of the potential risk of progressive multifocal leukoencephalopathy, patients must be carefully selected and specific protocols must be followed during the drug's administration. (C) 2010 Sociedad Espanola de Neurologia. Published by Elsevier Espana, S.L. All rights reserved.