Natalizumab induces a rapid improvement of disability status and ambulation after failure of previous therapy in relapsing-remitting multiple sclerosis.
BACKGROUND
Natalizumab (Tysabri) is a monoclonal antibody that was recently approved for the treatment of relapsing-remitting multiple sclerosis (RRMS). Our primary objective was to analyse the efficacy of natalizumab on disability status and ambulation after switching patients with RRMS from other disease-modifying treatments (DMTs).


METHODS
A retrospective, observational study was carried out. All patients (n=45) initiated natalizumab after experiencing at least 1 relapse in the previous year under interferon-beta (IFNB) or glatiramer acetate (GA) treatments. The patients also had at least 1 gadolinium-enhancing (Gd+) lesion on their baseline brain MRI. Expanded Disability Status Scale (EDSS) scores, and performance on the Timed 25-Foot Walk Test and on the Timed 100-Metre Walk Test were prospectively collected every 4 weeks during 44 weeks of natalizumab treatment. Brain MRI scans were performed after 20 and 44 weeks of treatment.


RESULTS
Sixty-two per cent of patients showed no clinical and no radiological signs of disease activity, and 29% showed a rapid and confirmed EDSS improvement over 44 weeks of natalizumab therapy. Patients with improvement on the EDSS showed similar levels of baseline EDSS and active T1 lesions, but had a significantly higher number of relapses, and 92% of them had experienced relapse-mediated sustained EDSS worsening in the previous year. A clinically meaningful improvement in ambulation speed was observed in approximately 30% of patients.


CONCLUSIONS
These results indicate that natalizumab silences disease activity and rapidly improves disability status and walking performance, possibly through delayed relapse recovery in patients with RRMS who had shown a high level of disease activity under other DMTs.
Belachew
S
S
MYelin Disorders REseArch teaM (MYDREAM).|Department of Neurology, C.H.U. Liège University Hospital, Liège.
Phan-Ba
R
R
MYelin Disorders REseArch teaM (MYDREAM).|Department of Neurology, C.H.U. Liège University Hospital, Liège.
Bartholomé
E
E
MYelin Disorders REseArch teaM (MYDREAM).|Department of Neurology, C.H.U. Tivoli, La Louvière.
Delvaux
V
V
MYelin Disorders REseArch teaM (MYDREAM).|Department of Neurology, C.H.U. Liège University Hospital, Liège.
Hansen
I
I
MYelin Disorders REseArch teaM (MYDREAM).|Department of Neurology, C.H.U. Liège University Hospital, Liège.
Calay
P
P
MYelin Disorders REseArch teaM (MYDREAM).|Department of Neurology, C.H.U. Liège University Hospital, Liège.
Hafsi
K E
KE
MYelin Disorders REseArch teaM (MYDREAM).|Department of Neurology, Erasme University Hospital, Brussels.
Moonen
G
G
Department of Neurology, C.H.U. Liège University Hospital, Liège.
Tshibanda
L
L
Department of Neuroradiology, C.H.U. Liège University Hospital, Liège, Belgium.
Vokaer
M
M
MYelin Disorders REseArch teaM (MYDREAM).|Department of Neurology, Erasme University Hospital, Brussels.
D000328:Adult; D000911:Antibodies, Monoclonal / Q000627:therapeutic use*; D061067:Antibodies, Monoclonal, Humanized; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D008297:Male; D009043:Motor Activity / Q000187:drug effects*; D020529:Multiple Sclerosis, Relapsing-Remitting / Q000188:drug therapy*; D000069442:Natalizumab; D020127:Recovery of Function / Q000187:drug effects*; D012189:Retrospective Studies; D016896:Treatment Outcome; D016138:Walking
D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D000069442:Natalizumab