Multiple sclerosis (MS) symptoms vary widely among those with the disease. And that can complicate efforts to prescribe the right treatment for MS patients.

Natalizumab is often used to fight the symptoms and progression of multiple sclerosis, but the drug comes with a significant risk of a rare and potentially fatal viral infection.

Natalizumab (Tysabri) can decrease the disease activity and slow the disabling effects of relapsing-remitting multiple sclerosis, but smoking may change that.

Tysabri , one of the few drugs approved to treat multiple sclerosis, is getting a label makeover courtesy of the FDA. The new look shows off a newly approved safety test for patients.

Multiple sclerosis does its damage in a patient's brain, and that's where most drugs are targeted. But one drug holds the dangerous risk of a severe brain infection for some patients.