The mRS measures the degree of functional independence following stroke. In this study, 7-category ordinal mRS scale was condensed to the following 5-categories: 0/1, 2, 3, 4, 5/6 where 0 and 1 reflect no disability and near-normal functioning while 5 and 6 represent severe disability and death, respectively.

The modified intent to treat (mITT) population included participants aged 18 to 70 years (inclusive) at the time of randomization, who had received any study drug, and who had at least 1 post-baseline mRS before or at Day 90 visit. Here, 'Overall number of participants analyzed' signifies the number of participants with data available for outcome measure analysis.

Time to all-cause death is defined as the time from randomization to the time of death.

The mITT population included participants aged 18 to 70 years (inclusive) at the time of randomization, who received any study drug, and who had at least 1 post-baseline mRS before or at the Day 90 visit. Here, 'Overall number of participants analyzed' signifies number of participants with data available for outcome measure analysis.

The mRS measures the degree of functional independence following stroke. In this study, the 7-category ordinal mRS scale was condensed to the following 5-categories: 0/1, 2, 3, 4, 5/6 where 0 and 1 reflect no disability and near-normal functioning while 5 and 6 represent severe disability and death, respectively.

The mITT population included participants aged 18 to 70 years (inclusive) at the time of randomization, who received any study drug, and who had at least 1 post-baseline mRS before or at the Day 90 visit. Here, 'Overall number of participants analyzed' signifies number of participants with data available for outcome measure analysis.

Midline shift is the perpendicular distance between the septum pellucidum and the line drawn between the anterior and posterior attachments of the falx to the inner table of the skull.

The mITT population included participants aged 18 to 70 years (inclusive) at the time of randomization, who received any study drug, and who had at least 1 post-baseline mRS before or at the Day 90 visit. Here, 'Overall number of participants analyzed' signifies the number of participants with data available for outcome measure analysis.

An AE is any untoward medical occurrence in a participant or clinical investigation participant administered a pharmaceutical product and that does not necessarily have a causal relationship with this treatment. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease temporally associated with the use of a medicinal (investigational) product, whether or not related to the medicinal (investigational) product. A SAE is any untoward medical occurrence that at any dose results in death, life-threatening event, requires inpatient hospitalization, significant disability/incapacity or congenital anomaly.

The safety population included all participants who were enrolled and had received any portion of the infusion of study treatment (placebo or BIIB093). Here, 'Overall number of participants analyzed' signifies the number of participants with data available for outcome measure analysis.