Multiple Sclerosis Centers of Excellence
Natalizumab (Tysabri®) is a humanized monoclonal antibody directed at alpha 4 beta 1 integrin, a lymphocyte cell surface receptor involved in cell adhesion. It is thought to act in MS by limiting the migration of lymphocytes across the blood brain barrier, thereby reducing demyelination and inflammation in the brain or spinal cord. It was found to have a dramatic effect on MS disease activity to reduce the frequency of exacerbations. The recommended dose of natalizumab for relapsing forms of MS is 300 mg by IV infusion over one hour every four weeks. Side effects include urticaria and flushing.
Patients must have a JC virus test prior to initiation of natalizumab, due to the risk of developing progressive multifocal leukoencephalopathy (PML) caused by the JC polyomavirus. Patients on natalizumab should be evaluated at 3 months and 6 months after the first infusion and at least every 6 months after that for clinical response, side effects, and any symptoms suggesting PML as well as a decision to continue natalizumab therapy.
The medication must be prescribed through the Tysabri Outreach: Unified Commitment to Health (TOUCH™) program. Individuals who have questions about natalizumab should contact their healthcare provider.