FDA Approves Biogen's Tysabri

Tysabri is a monoclonal antibody that affects the actions of the body's immune system.

Monoclonal antibodies are made to target and destroy only certain cells in the body. This may help to protect healthy cells from damage.

Tysabri is used to treat relapsing forms of multiple sclerosis.

Tysabri is also used to treat moderate to severe Crohn's disease in adults. It is usually given after other Crohn's disease medications have been tried without successful treatment of this condition.

TYSABRI is a prescription medicine approved for adult patients with relapsing forms of MS to slow the worsening of disability that is common in patients with MS and decrease the number of flare-ups (relapses). Because TYSABRI increases the risk of progressive multifocal leukoencephalopathy (PML), a rare brain infection that usually causes death or severe disability, TYSABRI is generally recommended for patients that have not been helped enough by, or cannot tolerate, another treatment for MS. TYSABRI does not cure MS and has not been studied for longer than two years or in patients with chronic progressive MS.

TYSABRI is indicated as monotherapy for the treatment of patients with relapsing forms of multiple sclerosis to delay the accumulation of physical disability and reduce the frequency of clinical exacerbations. The safety and efficacy of TYSABRI beyond two years are unknown.

Because TYSABRI increases the risk of progressive multifocal leukoencephalopathy (PML), an opportunistic viral infection of the brain that usually leads to death or severe disability, TYSABRI is generally recommended for patients who have had an inadequate response to, or are unable to tolerate, an alternate multiple sclerosis therapy

Tysabri can be prescribed to treat patients who have relapsing forms of MS. The drug reduces the frequency of MS attacks. In a study comparing Tysabri with a placebo (sugar pill), Tysabri reduced the average yearly relapse rate by 66%. In addition, patients taking Tysabri had fewer new brain lesions.