Natalizumab Reduces Clinical and MRI Activity in Multiple Sclerosis Patients with High Disease Activity: Results from a Multicenter Study in Switzerland

Abstract

Natalizumab has been recommended for the treatment of relapsing-remitting multiple sclerosis (RRMS) in patients with insufficient response to interferon-beta or glatiramer acetate (disease-modifying treatments-DMT) or in aggressive MS. The pivotal trials were not designed to investigate natalizumab monotherapy in these patient populations. To investigate the efficacy of natalizumab after treatment failure of previous DMT and in highly active MS. A retrospective, multicenter study in Switzerland. Three major MS centers reported all RRMS patients who initiated natalizumab>or=12 months prior to study conduction. 85 RRMS patients were included (72% female, mean age 37.3 years, mean Expanded Disability Status Scale 3.1; 88.2% were pretreated with DMT), and mean treatment duration with natalizumab was 18.4+/-2.6 months. 79% of the patients were relapse-free during the observational period. The annualized relapse rate decreased from 2.0+/-0.6 to 0.27+/-0.2, and 92.9% were progression-free after 12 months (p<0.001). The mean number of gadolinium-enhancing lesions decreased from 1.2+/-1.2 to 0.1+/-0.1 at 12 months' follow-up (91.7% reduction).Discontinuation rate was 11.8% (7.1% for antibody positivity). Patients who initiate natalizumab after previous high disease activity experience a marked reduction of clinical and MRI disease activity.