P.016 Clinical course of relapsing remitting multiple sclerosis post-natalizumab

Abstract

Background: Natalizumab is an efficacious disease modifying therapy (DMT) for relapsing remitting multiple sclerosis (RRMS), however, duration of therapy is often limited by risk of progressive multifocal leukoencephalopathy (PML). We describe the clinical course of RRMS patients switched from natalizumab to another DMT in a Canadian MS clinic. Methods: We conducted a retrospective study of prospectively collected data from the Dalhousie Multiple Sclerosis Research Unit (DMSRU). We identified all RRMS patients treated with natalizumab for >3 months who discontinued therapy with serum JC virus antibody positive status and switched to another DMT. Results: There were 84 individuals who switched to another DMT following natalizumab with 57 (68%) switching to fingolimod. Survival without a relapse on fingolimod was 92% (95% confidence interval 80-97%) at 6 months, 90% (77-96%) at 12 months, 85% (71-93%) at 24 months, 74% (56-86%) at 36 months. Survival without disease progression on fingolimod was 90% (95% CI 78-96%) at 6 months, 86% (72-93%) at 12 months, 78% (63-88%) at 24 months, 78% (63-88%) at 36 months. Conclusions: Although alternative DMTs may be used post-natalizumab, fingolimod remains an effective therapy with a high proportion of patients remaining free of relapses or progression at 3 years.