Randomized Trial of Natalizumab with 4-Week or 6-Week Dosing

Extended-interval dosing of natalizumab has been observed to mitigate the risk for progressive multifocal leukoencephalopathy (PML) without worsening of multiple sclerosis (MS) disease severity. In this open-label trial, participants with relapsing-remitting MS who were treated with natalizumab for at least 12 months were randomized 1:1 to receive natalizumab every 4 or 6 weeks. Examining neurologists and the central MRI rater were blinded.

Among the 499 patients enrolled, relapses were low between the treatment groups (unadjusted annualized relapse rate, 0.02). The adjusted mean number of new or enlarging T2 lesions at week 72 was 0.20 (95% confidence interval, 0.07–0.63) in the 6-week group and 0.05 (95% CI, 0.01–0.22) 4-week group. Advers…