Table 1 Demographic and baseline disease characteristics of study subjects

CharacteristicPlacebo, n = 219IFNβ-1a, n = 217
p > 0.05 for all comparisons.
IFNβ-1a = interferon β-1a; MSFC = MS Functional Composite; EDSS = Expanded Disability Status Scale; Gd = gadolinium.
Age, y, mean ± SD47.9 ± 7.747.2 ± 8.2
Female sex, n (%)141 (64)138 (64)
Disease duration, y, mean ± SD16.7 ± 9.016.2 ± 9.0
MSFC Z-score, mean ± SD−0.017 ± 0.730.018 ± 0.76
EDSS, mean ± SD5.2 ± 1.15.2 ± 1.1
EDSS distribution, n (%)
    3.5–5.5113 (52)113 (52)
    6.0–6.5106 (48)104 (48)
No. of relapses, mean ± SD
    Prior 3 y1.3 ± 2.11.5 ± 2.1
    Prior 1 y0.5 ± 0.90.6 ± 1.1
Relapse free subjects, n (%)
    Prior 3 y97 (44)80 (37)
    Prior 1 y135 (62)129 (59)
Years since prior relapse, mean ± SD4.0 ± 5.23.4 ± 5.0
Gd-enhancing MRI lesions
    No. per scan, mean ± SD1.2 ± 2.91.9 ± 6.4
    Volume per scan, mm3,  mean ± SD100.4 ± 274.5165.9 ± 696.5
    No. of subjects (%) with
        0136 (66)130 (62)
        135 (17)34 (16)
        211 (5)13 (6)
        35 (2)10 (5)
        ≥420 (10)23 (11)