Inclusion Criteria1. Acute ischemic stroke (AIS) for immediate endovascular treatment within 12 hours of symptom onset.
2. Age 19 or greater.
3. Onset (last-seen-well) time to randomization time within 12 hours.
4. Disabling stroke defined as a baseline NIHSS > 5 at the time of randomization.
5. Pre-stroke (24 hours prior to stroke onset) independent functional status in activities of daily living with modified Barthel Index (BI) > 90 (95 or 100). Patient must be living in their own home, apartment or seniors lodge where no nursing care is required.
6. Confirmed symptomatic intracranial occlusion, based on multiphase or dynamic CTA, at one or more of the following locations: Intracranial, carotid T/L, M1 MCA. Anterior temporal artery is not considered an M2. Functionally, when defining the M1 MCA, the bulk of the MCA territory must be ischemic.
7. Non-contrast computed tomography (NCCT)/mCTA for trial eligibility performed or repeated at ESCAPE-NA1 stroke centre with endovascular suite on-site.
8. Endovascular treatment intended to be initiated (groin puncture) within 60 minutes of baseline/qualifying NCCT with target baseline/qualifying NCCT to first recanalization of 90 minutes. Study drug intended to be administered within 60 minutes of the baseline/qualifying NCCT.
9. Signed informed consent from subject or legally authorized representative.
Exclusion Criteria1. Evidence of a large core of established infarction defined as ASPECTS 0-4.
2. Evidence of absence of collateral circulation on CTA or absence of a penumbral pattern on CTP imaging.
3. No femoral pulses, very difficult endovascular access or extreme tortuosity of the great vessels that is predicted to result in an inability to timely deliver endovascular therapy. Direct common carotid or radial/brachial/axillary access is permissible.
4. Estimated or known weight > 120 kg or < 45 kg.
5. Pregnancy; if a woman is of childbearing potential a urine or serum β-hCG test is positive.
6. Severe contrast allergy or absolute contraindication to iodinated contrast preventing endovascular intervention.
7. Clinical history, past imaging or clinical judgment suggests that the intracranial occlusion is chronic or there is suspected intracranial dissection such that there is a predicted lack of success with endovascular intervention.
8. Prior enrolment in the ESCAPE-NA1 trial or prior receipt of NA-1 for any reason.
9. Severe known renal impairment defined as requiring dialysis (hemo- or peritoneal) or if known creatinine clearance < 29 mL/min.
10. Patient has a severe or fatal comorbid illness that will prevent improvement or follow-up.
11. Patient cannot complete follow-up treatment due to co-morbid non-fatal illness or they are a visitor to the city or any other known reason that follow-up would be impossible (e.g. incarcerated in a federal prison).