TYSABRI is approved in more than 40 countries. In the U.S., it is approved for relapsing forms of MS and in the European Union for relapsing-remitting MS. According to data from the Phase III AFFIRM trial published in the New England Journal of Medicine, after two years, TYSABRI treatment led to a 68 percent relative reduction (p<0.001) in the annualized relapse rate, when compared with placebo, and reduced the relative risk of disability progression by 42-54 percent (p<0.001).
TYSABRI is redefining success in the treatment of MS. In post-hoc analyses of the Phase III AFFIRM trial and as published in The Lancet Neurology, 37 percent of TYSBARI-treated patients remained free of their MS activity, compared to seven percent of placebo-treated patients. In addition, data has been presented showing that treatment with TYSABRI significantly increased the probability of sustained improvement in disability in patients with a baseline expanded disability status scale (EDSS) score ≥ 2.0 by 69 percent relative to placebo.
TYSABRI increases the risk of progressive multifocal leukoencephalopathy (PML), an opportunistic viral infection of the brain. Other serious adverse events that have occurred in TYSABRI-treated patients include hypersensitivity reactions (e.g., anaphylaxis) and infections, including opportunistic and other atypical infections. Clinically significant liver injury has been reported in patients treated with TYSABRI in the post-marketing setting. Common adverse events reported in TYSABRI-treated MS patients include headache, fatigue, infusion reactions, urinary tract infections, joint and limb pain and rash.