• National Institutes of Health Stroke Scale (NIHSS) [ Time Frame: Change from Baseline to day 90 ] [ Designated as safety issue: No ]
  Improvement of greater than or equal to 8 points from baseline, or NIHSS score less than or equal to 1. The NIHSS score ranges from 0 (least severe) to 42 (more severe).
• Modified Rankin Scale (MRS) [ Time Frame: Day 90 ] [ Designated as safety issue: No ]
  Improvement on the Modified Rankin Scale, defined as a score of 0-2. The MRS ranges in severity from 0 (no symptoms) to 6 (Dead).
• Barthel Index (BI) score of 75-100. [ Time Frame: Day 90 ] [ Designated as safety issue: No ]
  The Barthel Index (BI) is a scale used to measure performance in basic Activities of Daily Livingranges from 0 (most disablility) to 100 (no disability)

• (1) Improvement of greater than or equal to 8 points from baseline on the National Institutes of Health Stroke Scale (NIHSS) (or NIHSS score less than or equal to 1)
• (2) Modified Rankin Scale (MRS) score of 0-2
• (3) Barthel Index (BI) score of 75-100.
• Clinical improvement at day 90 defined for each patient as achievement of all three of the following criteria

• Percentage of patients with improvement in NIHSS score [ Time Frame: From Baseline to Day 90 ] [ Designated as safety issue: No ]
  Improvement of greater than or equal to 8 points from baseline on the NIHSS score, or NIHSS score less than or equal to 1.
• Percentage of patients with MRS score of 0-2 [ Time Frame: Day 90 ] [ Designated as safety issue: No ]
• Percentage of patients with BI score of 75-100 [ Time Frame: Day 90 ] [ Designated as safety issue: No ]
• Infarct Volume [ Time Frame: Change from baseline to Day 30 ] [ Designated as safety issue: No ]

• Include the following
• percentage (%) of patients with improvement of greater than or equal to 8 points from baseline on the NIHSS (or NIHSS score less than or equal to 1) at Day 90
• percentage (%) of patients with MRS score of 0-2 at day 90
• percentage (%) of patients with BI score of 75-100 at Day 90
• change from baseline in infarct volume at Day 30.

The purpose of this study is to evaluate desmoteplase (which is a manufactured protein derived from the saliva of the vampire bat) in dissolving clots that are blocking the flow of blood through one (or more) of the blood vessels supplying the brain, thereby reopening the blocked blood vessel and allowing blood to flow again in individuals suffering from ischemic stroke.

• Drug: Desmoteplase
  Desmoteplase 90 mcg/kg, intravenous administration.
• Drug: Desmoteplase
  Desmoteplase 125 mcg/kg, intravenous administration.
• Drug: Placebo
  Dose-Match Placebo, intravenous administration.

• Experimental: Desmoteplase, low dose
  Desmoteplase 90 mcg/kg, intravenous administration.
  Intervention: Drug: Desmoteplase
• Experimental: Desmoteplase, high dose
  Desmoteplase 125 mcg/kg, intravenous administration.
  Intervention: Drug: Desmoteplase
• Placebo Comparator: Placebo
  Dose-Match Placebo, intravenous administration.
  Intervention: Drug: Placebo

Inclusion Criteria:

• Eligible for study treatment within 3-9 hours after onset of stroke symptoms.
• Score of 4-24 on the NIHSS with clinical signs of hemispheric infarction (i.e. hemiparesis) suggestive of ischemic stroke.

Inclusion Criteria from diagnostic imaging screening:

• Distinct penumbra (at least 20%), measured by MRI (PWI/DWI) or perfusion CT, related to middle cerebral artery (MCA), anterior cerebral artery (ACA), or posterior cerebral artery (PCA) territory in a hemispheric distribution.

Exclusion Criteria:

• History or clinical presentation of intracranial hemorrhage (ICH), subarachnoid hemorrhage, arteriovenous malformation, aneurysm, or cerebral neoplasm.
• Rapidly improving neurological symptoms.
• Pre-stroke MRS score of > 1 (including previous disability).
• Suspected acute vertebral or basilar artery occlusion.
• Current use of anticoagulants and a prolonged prothrombin time.
• Uncontrolled hypertension.
• Baseline hematocrit of < 0.25.
• Baseline platelet count < 100,000/mm3.