http://www.fda.gov/cder/drug/infopage/natalizumab/default.htm
Center for Drug Evaluation and Research, U.S. Food and Drug Administration
On June 5, 2006, the Food and Drug Administration (FDA) approved an application for resumed marketing of Tysabri (natalizumab), a monoclonal antibody, for the treatment of patients with relapsing forms of multiple sclerosis (MS).