Early Reduction of MRI Activity During 6 Months of Treatment With Cladribine Tablets for Highly Active Relapsing Multiple Sclerosis

Abstract

Background and Objectives The onset of action for high-efficacy immunotherapies in multiple sclerosis (MS) is an important parameter. This study (MAGNIFY-MS) evaluates the onset of action of cladribine tablets by observing changes in combined unique active (CUA) MRI lesion counts during the first 6 months of treatment in patients with highly active relapsing MS. Methods MRI was performed at screening, baseline, and at months 1, 2, 3, and 6 after initiating treatment with cladribine tablets 3.5 mg/kg. CUA lesion counts, defined as the sum of T1 gadolinium-enhancing (Gd+) lesions and new or enlarging active T2 lesions (without T1 Gd+), were compared between postbaseline and the baseline period and standardized to the period length and the number of MRIs performed. Results Included in this analysis were 270 patients who received ≥1 dose of cladribine tablets. After treatment initiation, significant reductions in mean CUA lesion counts were observed from month 1 onward compared with the baseline period (−1.193 between month 1 and month 6, −1.500 between month 2 and month 6, and −1.692 between month 3 and month 6; all p < 0.0001). Mean T1 Gd+ lesion counts were decreased from month 2 onward compared with baseline (−0.857 at month 2, −1.355 at month 3, and −1.449 at month 6; all p < 0.0001), whereas the proportion of patients without any CUA lesions increased from 52.0% between month 1 and month 6 to 80.5% between month 3 and month 6. Discussion Findings suggest an early onset of action for cladribine tablets, with an increasing reduction in active MRI lesions over time. Trial Registration Information NCT03364036; Date registered: December 06, 2017.