Effect of Natalizumab on Infarct Volume in Acute Ischemic Stroke
Effect of Natalizumab on Infarct Volume in Acute Ischemic Stroke
The primary objective of the study is to determine whether one 300 mg dose of intravenous
 (IV) natalizumab reduces change in infarct volume from Baseline to Day 5 on magnetic
 resonance imaging (MRI) in participants with acute ischemic stroke when given at ≤6 hours or
 at >6 to ≤9 hours from when they were last known normal (LKN).

 The secondary objectives of this study in this study population are as follows: to assess the
 efficacy of natalizumab on change in infarct volume from Baseline to Day 30; to assess
 efficacy of natalizumab on change in infarct volume from 24 hours to Day 5 and Day 30; to
 assess the efficacy of natalizumab on clinical measures of stroke outcome; to assess the
 safety of natalizumab in participants with acute ischemic stroke.
Key Inclusion Criteria:

 -  Diagnosis of acute ischemic stroke.

 -  Score of ≥6 points on the National Institute of Health Stroke Scale (NIHSS) at
 Screening.

 -  At least 1 acute infarct with largest diameter of more than 2 cm on Baseline brain
 diffusion-weighted imaging (DWI).

 -  Participants who have received reperfusion therapy may be eligible to participate but
 must meet all eligibility criteria and perform the Baseline study magnetic resonance
 imaging (MRI) after reperfusion therapy has been completed.

 -  Subjects of childbearing potential must practice effective contraception during the
 study and be willing and able to continue contraception for at least 3 months after
 their dose of study treatment.

 Key Exclusion Criteria:

 -  Presence of any intracranial hemorrhage (ICH) on head computed tomography (CT) or
 non-petechial ICH on screening MRI.

 -  Stroke isolated to the brainstem.

 -  Presence of coma

 -  Expected to die OR unable to be evaluated within 5 days.

 -  Hypotension requiring the use of intravenous (IV) vasopressor support or systolic
 blood pressure <90 mmHg at the time of randomization.

 -  Known prior treatment with natalizumab.

 -  Immunocompromised subjects, as determined by the Investigator.

 -  History of progressive multifocal leukoencephalopathy (PML).

 -  Contraindications to MRI, e.g., implanted pacemaker or other contraindicated implanted
 metal devices, history of or risk for side effects from gadolinium, or claustrophobia
 that cannot be medically managed.

 NOTE: Other protocol-defined inclusion/exclusion criteria may apply.