Long-term assessment of No Evidence of Disease Activity with natalizumab in relapsing multiple sclerosis.

In this study we assessed the proportion of patients with relapsing multiple sclerosis (R-MS) who had No Evidence of Disease Activity (NEDA-3), defined as absence of relapses, absence of confirmed disability worsening, and absence of radiological activity (detected by magnetic resonance imaging of the brain and spinal cord) up to 7years after starting natalizumab. Out of 152 patients considered, 58 were still on treatment and 94 discontinued treatment after a median time of 3years. According to an intention-to-treat approach, 52 (34%) patients maintained the NEDA status at the end of follow-up. The proportion of patients with NEDA increases to 41% after excluding from the analysis 64 patients who discontinued natalizumab due to concerns about progressive multifocal leukoencephalopathy. Our findings suggest that natalizumab may ensure higher proportion of patients achieving sustained long-term disease remission than that previously reported with self-injectable treatments (<10%).