Natalizumab

FDA informed healthcare professionals of two new cases of progressive multifocal leukoencephalopathy (PML) in European patients receiving natalizumab monotherapy for multiple sclerosis for more than one year. PML, which is usually fatal, is a known risk of natalizumab treatment, but previous cases in patients with multiple sclerosis were seen in combination with other immunomodulatory therapies. Approximately 39,000 patients have received treatment with natalizumab worldwide, with approximately 12,000 patients receiving treatment for a least one year. No new cases have been seen in the US, where about 7,500 patients have received the drug for greater than one year and approximately 3,300 patients have received the drug for at least one and one-half years. In the U.S., natalizumab is available only to patients with relapsing multiple sclerosis or Crohn's disease who are enrolled in the risk minimization plan called the TOUCH Prescribing Program. Under this program, every natalizumab-treated patient is closely monitored and followed for the occurrence of PML and other serious opportunistic infections. While the two patients who developed PML were on monotherapy, the FDA still believes that natalizumab monotherapy may confer a lower risk of PML than when natalizumab is used together with other immunomodulatory medications. Prescribing information for natalizumab will be revised to include information informing prescribers and patients that cases of PML have occurred in patients taking natalizumab as monotherapy. Healthcare professionals should continue to monitor patients for sign and symptoms of PML. Additionally, natalizumab should not be infused if PML is suspected.

Source: http://www.fda.gov/cder/drug/InfoSheets/HCP/natalizumab2008HCP.htm