When Patients with Multiple Sclerosis Discontinue Natalizumab . . .

Disease activity began to return after 3 months but did not exceed pretreatment baseline rates.

Natalizumab is a highly effective therapy for multiple sclerosis (MS), but it carries a risk for progressive multifocal leukoencephalopathy (PML) of about 1 case per 1000 patients. This risk, initially low, rises sharply after 2 to 3 years. Whether a planned dosage suspension can lower PML risk is unknown; nonetheless, this approach has been widely adopted. However, relapses (some severe) have been observed during treatment interruption. Now, investigators have conducted a partially industry-supported, post hoc analysis that was enabled by the manufacturer's decision in 2005 to pull natalizumab from the market for 8 months after the first cases of PML were reported.

Participants were the more than 1800 patients who had received at least one …

Reviewing Author

Jeffrey M. Gelfand, MD