This is a single-center, randomized, open-label, placebo-controlled, dose-escalation trial. The objective of this research is to evaluate the safety, tolerability, and preliminary efficacy of intravenous administration of human-induced neural stem cell-derived extracellular vesicles (NouvSoma001) in the treatment of ischemic stroke.

This is a single-center, randomized, open-label, placebo-controlled, dose-escalation trial. This study will consist of 2 parts, with Part 1 being a dose-escalation study and Part 2 being a dose-extension study based on the results of Part 1. Part 1 will follow a traditional 3+3 dose-escalation design, enrolling a total of 9 subjects. Cohort 1: receive 4×10^9 particles/kg, Cohort 2: receive 8×10^9 particles/kg, and Cohort 3: receive 1.6×10^10 particles/kg. If no dose-limiting toxicities (DLT) are observed within 2 weeks after the initial administration, a new cohort will be enrolled at the next higher dose level. If DLTs are observed in 1 participant, another 2 participants will be treated at the same dose level. Dose escalation will cease if DLTs are observed in more than 33% of the participants. In Part 2, the remaining 60 participants will be randomized in a 2:1 ratio to the treatment and placebo groups, with the dose level determined by the Data Safety Monitoring Board based on the results of Part 1.

Inclusion Criteria:

1. The age of the recruiters ranged from 18 to 75 years.
2. Clinical diagnosis of ischemic stroke, the time of stroke onset is known, and the onset occurred no more than 7 days before enrollment.
3. Magnetic resonance imaging (MRI) or computed tomography (CT) findings consistent with ischemic stroke.
4. At the time of enrollment, the NIHSS score is between 6 and 20; additionally, there is at least one limb with muscle strength ≤ Grade 3.
5. Patients who have the mental capacity to understand and participate in the study.
6. Informed consent was obtained from patients or their legal representatives.

Exclusion Criteria:

1. CT indicates intracranial hemorrhage, including hemorrhagic stroke, epidural hematoma, subdural hematoma, intraventricular hemorrhage, subarachnoid hemorrhage, or hemorrhagic transformation.
2. Patients with Alzheimer's disease, Parkinson's syndrome, or other neurodegenerative disorders.
3. Evidence of brain tumors, epilepsy, or a history of traumatic brain injury.
4. Presence of non-vascular diseases causing white matter lesions, such as carbon monoxide poisoning, multiple sclerosis, or adrenoleukodystrophy.
5. Rapid spontaneous neurological improvement during the screening period, defined as a reduction of NIHSS score by ≥ 8 points from symptom onset to the first administration.
6. Persistent systemic infection, severe local infection, or ongoing use of immunosuppressants.
7. Patients with malignant diseases or an expected survival of less than 5 years.
8. Significant hearing or vision impairments, language disorders, or claustrophobia that would hinder cooperation with neuropsychological assessments and MRI examinations.
9. Contraindications to MRI.
10. Patients unable to comply with follow-up requirements during the study.
11. Severe liver, renal, cardiac, or pulmonary insufficiency, hematologic disorders, or malignant tumors (Liver insufficiency is defined as ALT or AST levels greater than 1.5 times the upper normal limit; renal insufficiency is defined as serum creatinine levels greater than 1.5 times the upper normal limit).
12. Patients with alcohol addiction or those testing positive for drug abuse.
13. Patients with a history of severe allergies or known allergy to human biological products.
14. Pregnant or breastfeeding women, and those planning to conceive during the trial period.
15. Participation in other clinical trials within the past 3 months.
16. Patients considered unsuitable for participation by the investigator.