About

TYSABRI® (natalizumab) is a prescription medicine used to treat adults with relapsing forms of multiple sclerosis (MS) to slow the worsening of symptoms common in people with MS and to decrease the number of flare-ups (relapses). TYSABRI increases the risk of progressive multifocal leukoencephalopathy (PML). When starting and continuing treatment with TYSABRI, it is important to discuss with your doctor whether the expected benefit of TYSABRI is enough to outweigh this risk.