Table 1.

Demographic and clinical characteristics of 20 RRMS patients stratified according to response to therapy before and during treatment with Natalizumab.

	Responders	Nonresponders
Patients (n)	15	5
Sex (male/female)	3/12	0/5
Age at entry, years (mean ± SD)	35.1 ± 10.1	31.6 ± 9.4
EDSS at baseline (mean ± SD)	1.0 ± 1.1	2.3 ± 2.4
EDSS after 21 months of therapy	1.3 ± 1.3	2.8 ± 2.4
Relapses during 21 months of therapy (mean ± SD)	0	1.6 ± 0.9
Patients with new MRI lesions at the end of treatment	4	0

EDSS = Expanded Disability Status Scale; MRI = magnetic resonance imaging; SD = standard deviation.