Large Artery Occlusion Treated in Extended Time With Mechanical Thrombectomy Trial (LATE-MT)

An Investigator Initiated and Conducted, Prospective, Multicenter, Randomized Outcome-blinded Study of Treating Mechanical Thrombectomy Exceeding 24 Hours in Patients With Acute Ischemic Stroke Due to Large Vessel Occlusion

A multi-center, prospective, randomized, open-label, adaptive group sequential designed, blinded endpoint assessment (PROBE) clinical trial of endovascular treatment among selected AIS

Study Overview

• Status: Recruiting
• Conditions: Acute Ischemic Stroke
• Intervention / Treatment: Procedure: Mechanical thrombectomy

Detailed Description

The LATE-MT trial aims to determine that compared with standard medical care without MT, performing MT in a time window that exceeds 24 hours after last seen well, is superior on the functional outcome in AIS patients due to LVO who have been carefully selected by clinical and imaging criteria. The secondary aims include comparing with standard medical care without MT, to determine whether performing MT exceeding 24 hours of last known well is safe on the risks of any ICH, sICH, and any SAE. Other secondary aims include early improvement in neurological recovery as measured by NIHSS scores at 7 days; successful recanalization rate; imaging measurements of infarct size; death or major disability (mRS 3-6); separately on death and disability (mRS 3-5); HRQoL using Euro-QoL EQ-5D questionnaire; utility-weighted modified Rankin scale scores; duration of hospitalization; Barthel Index; and hospital service costs.

• Study Type: Interventional
• Enrollment (Estimated): 336
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Craig Anderson, PhD; Phone Number: +61 2 8052 4521; Email: canderson@georgeinstitute.org.au
• Study Contact Backup: Name: Lili Song, PhD; Phone Number: +86 13916466400; Email: lili_song@fudan.edu.cn

Study Locations

• China
  • Shanghai, China
    • Recruiting
    • Changhai Hospital
    • Contact: Jianmin Liu, MD

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. Age ≥18 years
2. Present 24-72 hours of stroke onset or last seen well
3. Clinical diagnosis of AIS due to anterior circulation LVO (from internal carotid artery (ICA) extracranial segment to middle cerebral artery (MCA) M1 and M2 segment) on brain imaging
4. National Institute of Health stroke scale (NIHSS) ≥6 at randomisation
5. Viable cerebral tissue on computerized tomography perfusion (CTP) assessed: infarct core volume <50 mL, mismatch ratio ≥1.8, and mismatch volume ≥15 mL
6. Written informed consent (by patient or proxy, according to local requirements)

Exclusion Criteria:

Clinical Exclusion Criteria

1. Considered unlikely to benefit from trial (e.g. advanced dementia, major pre-stroke disability (prior modified Rankins scale (mRS) ≥2), high likelihood of early death), as judged by the responsible treating clinician
2. Major co-morbid disease that could interfere with outcome assessments and follow-up (e.g. cancer, severe heart failure, kidney failure)
3. Pregnancy
4. Unable to undergo a CTP
5. Known allergy to iodine, heparin, anaesthesia, or other definite contraindication to receiving endovascular treatment (EVT) procedure
6. Seizures at stroke onset or before randomization and baseline NIHSS scores cannot be accurately determined
7. Baseline blood glucose of <50 mg/dL (2.78 mmol/L) or >400 mg/dL (22.20 mmol/L)
8. Baseline platelet count < 50,000/uL
9. Known hereditary or acquired hemorrhagic diathesis, coagulation factor deficiency; recent oral anticoagulant therapy with International normalized ratio (INR) >3
10. Severe, sustained hypertension that can not be controlled by medication (systolic BP >220 mmHg or diastolic BP >120 mmHg)
11. Presumed septic embolus, suspicion of bacterial endocarditis
12. EVT attempted after stroke onset
13. Unlikely to participate in follow-up assessments
14. Currently participating in another trial that may affect outcomes.
15. Any other condition that, in the opinion of the investigator will pose a significant hazard to the subject if participating in the trial.

Neuroimaging Exclusion Criteria

1. Intracranial hemorrhage (ICH), including parenchymal hemorrhage, ventricular hemorrhage, subarachnoid hemorrhage, and subdural/exsanguination
2. Evidence of intracranial malignant tumor
3. Significant mass effect with midline shift
4. Aortic dissection
5. Intracranial stent implanted in the same vascular territory
6. Any other condition that may affect EVT procedure, like the tortuous vascular path the device is difficult to reach the target position or difficult to recover
7. Occlusions in multiple vascular territories confirmed on Computerized tomography angiography (CTA)/ Magnetic resonance imaging angiography (MRA) (e.g. bilateral MCA occlusions, or an MCA and a basilar artery occlusion)

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Intervention group; Mechanical thrombectomy to be initiated as soon as possible after randomisation.	Procedure: Mechanical thrombectomy; Subjects in intervention group will receive MT as soon as possible. Investigators and clinicians should strive to reduce delays of pre-surgery procedure and follow the local standard guideline of MT during the operation and perioperative period. All CFDA approved devices are allowed in this trial. Angioplasty and stent placement can be performed at the discretion of the physicians. Base on site experience, the randomization-operation start period should be within 60 minutes.
No Intervention: Control group; Patients assigned to the control group will avoid treating MT and only receive the standard medical treatment according to local guidelines.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Functional recovery (level of disability)	A sequence shift (improvement) in scores on the modified Rankin scale (mRS). The value range 0-6: higher scores mean a worse outcome.	at 90 days

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Neurological function	Measured by scores on the National Institute of Health Stroke Scale (NIHSS). The value range 0-42: higher scores mean a worse outcome.	at 24 hours and 7 days
Death or major disability	mRS 3-6	at 90 days
Major disability	mRS 3-5	at 90 days
Death	Death from any cause	within 90 days
Utility-weighted modified Rankin scale scores	Utility-weighted mRS scores calculated by utility weights. A higher score indicates a better outcome	at 90 days
Health-related Quality of Life (HRQoL)	Using the EuroQol 5 Dimension 5 Level (EQ 5D 5L) questionnaire. The EQ 5D 5L comprises five dimensions of health: mobility, self care, usual activities, pain/discomfort, and anxiety/depression. Each dimension has five severity levels (no problems, slight problems, moderate problems, severe problems, and extreme problems)	at 90 days
Barthel Index	The total score ranges from 0 to 100, with higher scores indicating greater independence in self care	at 90 days
Duration of hospitalization	Duration of hospitalization	within 90 days
Hospital service costs	Health economic measurement	within 90 days
Infarct volume	Measured on follow-up CT/MRI	at 7 days
Recanalization	Assessed by CTA/MRA	at 48 hours

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Intracerebral hemorrhage (ICH)	According to the Heidelberg Bleeding Classification	within 7 days
Symptomatic ICH	According to the Heidelberg Bleeding Classification	within 48 hours
Serious adverse events (SAEs)	All SAEs during follow-up	within 90 days
Adverse events of special interest (AESI)	Include procedure complications	within 90 days

Collaborators and Investigators

• Sponsor: Fudan University
• Collaborators: Changhai Hospital
• Investigators: Principal Investigator: Craig Anderson, PhD, The George Institute for Global Health, China; Principal Investigator: Jianmin Liu, Changhai Hospital

Study record dates

Study Major Dates

• Study Start (Actual): November 3, 2022
• Primary Completion (Actual): March 31, 2026
• Study Completion (Estimated): March 31, 2028

Study Registration Dates

• First Submitted: March 29, 2022
• First Submitted That Met QC Criteria: April 6, 2022
• First Posted (Actual): April 14, 2022

Study Record Updates

• Last Update Posted (Actual): August 31, 2026
• Last Update Submitted That Met QC Criteria: August 26, 2026
• Last Verified: August 1, 2026

More Information

Terms related to this study

• Keywords: Acute ischemic stroke; Randomised clinical trial; Large vessel occlusion; Mechanical thrombectomy; Extended time
• Additional Relevant MeSH Terms: Cerebrovascular Disorders; Brain Diseases; Central Nervous System Diseases; Nervous System Diseases; Vascular Diseases; Cardiovascular Diseases; Stroke; Ischemic Stroke
• Other Study ID Numbers: LATE-MT

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: Data can be shared with bona fide researchers after the publication of the main results, based on a submitted protocol to the steering committee of LATE-MT.
• IPD Sharing Time Frame: Data sharing will be available from 12 months after the publication of the main results.
• IPD Sharing Access Criteria: The data sharing will be only for the purposes of health and medical research and within the constraints of the consent under which the data were originally gathered.; The Custodian of the Collection will not consider any Proposals for data sharing that unblind, or potentially unblind, randomised comparisons in active / ongoing trials.; Requesters should be employees of a recognised academic institution, health service organisation, commercial research organisation or from the pharmaceutical industry. Requesters must have experience in medical research.; Requesters must be able to demonstrate through their peer review publications in the area of interest their ability to carry out the proposed use of the requested dataset from a Collection.; The Requesters must not have a conflict of interest that may potentially influence their interpretation of any analyses.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP; ICF; ANALYTIC_CODE; CSR

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No