The objective of this study is to evaluate the safety and efficacy of a single intravenous administration of JTR-161 (allogeneic stem cell product derived from the dental pulp of healthy adult humans) to patients with acute ischemic stroke.

This study is comprised of 3 cohorts and conducted in the order of Cohort 1, Cohort 2 and Cohort 3.

Cohort 1 Arm-1: JTR-161, 1 × 10^8 cells/subject, 6 subjects Arm-2: Placebo, 2 subjects

The Data and Safety Monitoring Board (DSMB) and the Sponsor will decide whether Cohort 2 can be initiated or not.

Cohort 2 Arm-1: JTR-161, 3 × 10^8 cells/subject, 6 subjects Arm-2: Placebo, 2 subjects

DSMB and the Sponsor will decide whether Cohort 3 can be initiated or not and the dose of JTR-161 in Cohort 3.

Cohort 3 Arm-1: JTR-161, 1 × 10^8 cells/subject or 3 × 10^8 cells/subject, 30 subjects Arm-2: Placebo, 30 subjects

Inclusion Criteria:

• Patients who have ischemic strokes in the anterior circulation
• Patients whose mRS is 0 or 1 prior to the onset of ischemic stroke
• Patients whose NIHSS score of ≥5 to ≤20 at screening
• Patients who can be administered dosing solutions within 48 h of stroke onset

Exclusion Criteria:

• Patients who have new ischemic lesion in the cerebellum or brainstem

• Patients whose consciousness level drops severely

• Patients whose infarct area is widespread

• Patients who have a clinically significant hemorrhagic transformation

• Patients who had seizures after onset of ischemic stroke

• Patients who have medical history of a neurological event such as stroke or clinically significant head trauma within 180 days prior to giving informed consent

• Patients who have poor blood pressure control

• Patients who have poor glycaemic control

• Patients who have one of the following complications

  1. Severe liver dysfunction
  2. Severe kidney dysfunction
  3. Severe heart failure
  4. Severe pulmonary dysfunction

• Patients who have severe infections

• Patients who have any neurological disorder affecting informed consent or study assessments

• Patients who have the malignant tumor, or medical history of malignant tumor within 2 years prior to the onset of ischemic stroke

• Patients who have a contraindication for MRI

• Patients who have thrombocytopenia

• Patients who have medical history of allergy to products derived from human tissues, bovine or porcine

• Patients who have medical history of allergy to streptomycin

• Patients who have undergone splenectomy in the past

• Patients who have a possibility of transient ischemic attack

• Patients who are scheduled to undergo revascularization (carotid endarterectomy, stent placement etc.)

Some care providers who involved in the preparation or administration of dosing solutions are unblinded.