A Phase 1 interventional study of Allogeneic Umbilical Cord-Derived Mesenchymal Stromal Cells (UC-MSCs) and Standard Stroke Care Including Mechanical Thrombectomy in Acute Ischemic Stroke, sponsored by Royan Stem Cell Technology Company. Not yet recruiting at 1 site in Iran. Open to participants aged 18 Years to 70 Years. Per ClinicalTrials.gov, last updated 2026-11-03.
Sponsored by Royan Stem Cell Technology Company · Phase 1, Interventional, and Treatment
This study will evaluate the safety and feasibility of administering umbilical cord-derived mesenchymal stromal cells (UC-MSCs) following mechanical thrombectomy in adults with acute ischemic stroke. Acute ischemic stroke occurs when a blood clot blocks blood flow to part of the brain, potentially causing brain tissue damage and neurological impairment.
The study will include 10 adults aged 18 to 70 years. All participants will receive standard stroke care, including mechanical thrombectomy to remove the blood clot. Participants will be randomly assigned to one of two groups.
One group will receive standard care plus a single dose of 20 million UC-MSCs derived from donated umbilical cord tissue. The cells will be delivered through a microcatheter into the artery supplying the affected part of the brain. The other group will receive standard care without the cell treatment. Both groups will receive physical rehabilitation.
Researchers will follow participants for six months. They will monitor health problems and assess recovery, disability, blood markers, and brain scans. The main goal is to determine whether this treatment can be administered safely and feasibly. It is not yet known whether the treatment will improve recovery after stroke.
- Scientific Rationale: Acute ischemic stroke results from an interruption of cerebral blood flow, causing ischemic injury and potentially persistent neurological disability. Mechanical thrombectomy restores blood flow by removing the occluding thrombus; however, successful reperfusion does not necessarily prevent secondary tissue injury or subsequent neurological impairment. Umbilical cord-derived mesenchymal stromal cells (UC-MSCs) possess immunomodulatory and tissue-repair properties that provide a scientific rationale for investigating their therapeutic potential following ischemic stroke. The safety and feasibility of intra-arterial administration after mechanical thrombectomy during the acute phase require further clinical evaluation.
- Study Overview and Procedures:
ARTEMIS (ARterial ThErapy with Mesenchymal stromal cells In Stroke) is a Phase 1 randomized, controlled clinical trial evaluating the safety and feasibility of intra-arterial administration of allogeneic UC-MSCs following mechanical thrombectomy. The study will include ten adults aged 18-70 years with imaging-confirmed acute ischemic stroke, a National Institutes of Health Stroke Scale (NIHSS) score of 6-20, and a prestroke modified Rankin Scale (mRS) score below 2. Participants must be eligible for mechanical thrombectomy within six hours of symptom onset and achieve successful reperfusion, defined as a modified Thrombolysis in Cerebral Infarction (mTICI) grade of 2b-3. Key exclusions include previous stroke, cerebellar or brainstem stroke, intracranial hemorrhage or major structural brain lesions, significant coagulation disorders, severe uncontrolled comorbidities, recent myocardial infarction, seizures, cancer, pregnancy or breastfeeding, contrast-agent allergy, and conditions that prevent informed participation or reliable follow-up. Written informed consent will be obtained from participants or their legally authorized representatives.
Participants will be randomly allocated in a 1:1 ratio to receive standard stroke care alone or standard care supplemented with cell administration. The randomization sequence will be generated using the Sealed Envelope platform, as specified in the study protocol.
In the intervention group, cell administration will take place after angiographic confirmation of successful reperfusion. The cells will be delivered through a microcatheter into the main artery supplying the infarcted territory. Repeat angiography will be performed after administration to assess for vascular occlusion or hemorrhage. Both groups will receive routine post-thrombectomy care and physical rehabilitation.
- Investigational Product:
The allogeneic UC-MSC product, called Whartocell®, is manufactured under Good Manufacturing Practice (GMP) conditions and has approval for cerebral palsy (CP) and osteoarthritis indications.
The investigational product consists of allogeneic mesenchymal stromal cells isolated from Wharton's jelly tissue obtained from donated full-term umbilical cords following the required consent procedures. Umbilical cord tissue will be collected under sterile conditions and processed to isolate the stromal cell population and will undergo product characterization and quality-control testing.
- Safety Monitoring:
Participants will undergo clinical monitoring throughout the study and follow-up period. Adverse events will be documented and evaluated for severity, duration, and potential relationship to the investigational product or study procedures. The protocol specifies the use of the Common Terminology Criteria for Adverse Events, version 5.0 (CTCAE v5.0), for safety monitoring.
Serious adverse events and suspected unexpected serious adverse reactions will be managed and reported according to the study protocol and applicable institutional requirements. Safety information will be reviewed by the clinical team and the Data and Safety Monitoring Board (DSMB), as specified in the protocol.
- Study Objectives:
This early-phase clinical investigation aims to establish preliminary evidence regarding the safety and feasibility of intra-arterial UC-MSC administration following mechanical thrombectomy during the acute phase of stroke. The findings may inform the design of subsequent clinical studies evaluating cell-based interventions for acute ischemic stroke. The study is exploratory and is not intended to establish definitive therapeutic efficacy.
2,612 studies on the registry are indexed under Ischemic Stroke; 971 are open to participants now.
This study's planned enrollment of 10 is below the median of 120 across 1,776 interventional studies indexed under Ischemic Stroke.
Browse Ischemic Stroke studies →This is the only study on the registry with Royan Stem Cell Technology Company as lead sponsor.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Participants in the experimental group will receive standard emergency care for acute ischemic stroke, including mechanical thrombectomy. Following successful thrombectomy and angiographic confirmation of reperfusion, a single dose of 20 × 10⁶ allogeneic umbilical cord-derived mesenchymal stromal cells is administered intra-arterially into the artery supplying the infarcted territory during the same procedure. Thereafter, participants will receive routine post-stroke care and physical rehabilitation.
Biological: Allogeneic Umbilical Cord-Derived Mesenchymal Stromal Cells (UC-MSCs) · Procedure: Standard Stroke Care Including Mechanical Thrombectomy
Participants in the control group will receive standard emergency care for acute ischemic stroke, including mechanical thrombectomy performed using the same procedural approach as in the experimental group. Following thrombectomy, participants will receive routine post-stroke care and physical rehabilitation. No cell infusion will be administered.
Procedure: Standard Stroke Care Including Mechanical Thrombectomy
Allogeneic mesenchymal stromal cells derived from Wharton's jelly of donated full-term umbilical cords. A single dose of 20 × 10⁶ cells suspended in 20 mL of normal saline is administered through a microcatheter into the artery supplying the infarcted area following successful reperfusion after mechanical thrombectomy.
Standard emergency care for acute ischemic stroke, including mechanical thrombectomy to remove the occluding blood clot, followed by routine post-thrombectomy care and physical rehabilitation according to the study protocol.
Incidence of Serious Adverse Events (SAEs)
Number of participants experiencing one or more serious adverse events during follow-up, including events resulting in death, life-threatening conditions, prolonged hospitalization, persistent or significant disability, or requiring medical or surgical intervention to prevent such outcomes. Event severity and relationship to the study intervention will be assessed by the clinical team.
Time frame: During the intervention and 1 hour, 24 hours, 3 days, 7 days, 1 month, 3 months, and 6 months after the intervention
Incidence of Adverse Events (AEs)
The frequency, type, severity, and relatedness of adverse events associated with intra-arterial infusion of allogeneic umbilical cord-derived mesenchymal stromal cells after mechanical thrombectomy based on Common Terminology Criteria for Adverse Events (CTCAE) version 5.
Time frame: During the intervention and 1 hour, 24 hours, 3 days, 7 days, 1 month, 3 months, and 6 months after the intervention.
Feasibility of Intra-Arterial UC-MSC Administration
Feasibility will be assessed by the proportion of participants assigned to the intervention group in whom the planned intra-arterial infusion of 20 × 10⁶ allogeneic UC-MSCs is successfully completed according to the study protocol. The number of successful and unsuccessful administrations will be recorded, together with reasons for any failure to initiate or complete the infusion.
Time frame: During the intervention (Day 0)
Proportion of Participants with mRS 0-2
Number and percentage of participants with a modified Rankin Scale (mRS) score of 0-2 in each study group, comparing the UC-MSC group with the control group. (mRS ranges from 0 (no symptoms) to 6 (death); higher scores mean greater disability)
Time frame: Baseline, 24 hours, 3 days, 7 days, 1, 3, and 6 months
Proportion of Participants with a Reduction in mRS Score Compared with the Initial Pre-Treatment Assessment
Number and percentage of participants achieving a reduction in the modified Rankin Scale (mRS) score, compared between the intervention and control groups. (mRS ranges from 0 (no symptoms) to 6 (death); higher scores mean greater disability.)
Time frame: Baseline, 24 hours, 3 days, 7 days, 1, 3, and 6 months
Change in National Institutes of Health Stroke Scale (NIHSS) from baseline
Change from baseline in National Institutes of Health Stroke Scale score. NIHSS ranges from 0 to 42; higher scores mean more severe neurological deficit.
Time frame: Baseline, 24 hours, 3 days, 7 days, 1, 3, and 6 months
Change in Serum Brain-Derived Neurotrophic Factor (BDNF) Concentration
Change in serum BDNF concentration from baseline, measured using the protocol-specified laboratory assay and compared between the intervention and control groups.
Time frame: Baseline, 3 days, and 6 months after intervention.
Change in Serum Matrix Metalloproteinase-9 (MMP-9) Concentration
Change in serum MMP-9 concentration from baseline, measured using the protocol-specified laboratory assay and compared between the intervention and control groups.
Time frame: Baseline, 3 days, and 6 months after intervention.
Change in Serum S100B Concentration
Change in serum S100B concentration from baseline, measured using the protocol-specified laboratory assay and compared between the intervention and control groups.
Time frame: Baseline, 3 days, and 6 months after intervention.
Changes in Cerebral Infarct Volume on CT/MRI
Cerebral infarct core volume will be assessed using brain imaging according to the study protocol. Imaging findings will be evaluated to characterize changes in the extent of cerebral injury during follow-up.
Time frame: Initial presentation, 24 hours, and 6 months after intervention,
Plan to share: Undecided — The decision to share individual participant data will be made after completion of the study. Data may be made available for non-commercial research purposes, including systematic reviews, meta-analyses, and the design of future clinical trials, upon submission of a written request and approval by the Principal Investigator.
No publications or documents are linked to this record.
Start is estimated for Nov 2026; primary completion for Nov 2027, 12 months later.
Of 42 phase 1 interventional studies under Ischemic Stroke, half reached primary completion within 15 months of starting (the median), counting those still running; a quarter within 7 and three quarters within 29. This study's planned 12 months is below that.
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
This study is not yet recruiting, as verified in Oct 2026. You cannot join it, but the record below documents what was studied.
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