Table 4 Magnetic resonance imaging as outcome measure

Necessary but not sufficient evidence of protective effect

Protective effect may be attenuation of expected lesion growth or

partial DWI lesion reversal

Clinical benefit unlikely if no protective effect on lesion volume (go/no

go decision at phase II)

Smaller sample size requirements than for typical clinical endpoints

(∼ 50-100 per arm)

May be confirmatory evidence supporting positive clinical endpoint trial

for regulatory approval