6. National Institute of Health Stroke Scale (NIHSS) score ≥3 but <22 at the time of screening, at least 3 days after the onset of stroke symptoms. Patient should not have shown rapid improvement (≥8 point decrease since the onset of stroke symptoms) or deterioration (≥4 point increase since the beginning of screening) in the NIHSS score from time of initial evaluation to randomization. The time from initial evaluation to initial screening evaluation will be at least 72 hours.