Comparison of Clopidogrel-based Antiplatelet Therapy Versus Warfarin as Secondary Prevention Strategy for AntiPhospholipid Syndrome-related STROKE

Study Overview
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Brief Summary
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Antiphospholipid syndrome (APS) has a close association with ischemic stroke; however, the optimal treatment strategy for APS-related stroke has yet to be established. The clinical guidelines suggest using warfarin for APS-related stroke, but these suggestions are largely based on retrospective studies from the 1990s and expert opinion, rather than high-quality clinical trials. Moreover, the evidence on the role of antiplatelet drugs other than aspirin (e.g., clopidogrel) in APS-related stroke is particularly limited. Considering the relatively young age of patients with APS and the high clinical burden of using warfarin, it is necessary to verify whether warfarin is essential. Thus, the investigators aim to compare clopidogrel-based antiplatelet therapy and warfarin as a secondary preventive medication for patients with APS-related stroke. APS-STROKE is an exploratory, multicenter, prospective, randomized, open, blinded-endpoint clinical trial. Adult patients with definite APS who have a history of ischemic stroke will be included. Patients with high-risk APS (triple positivity or persistently high titers of anti-cardiolipin or anti-β2-glycoprotein I antibodies), systemic lupus erythematous, or indications for continued antiplatelet or anticoagulant therapy will be excluded. Eligible patients will be 1:1 randomized to receive clopidogrel-based antiplatelet therapy or warfarin. Patients assigned to the clopidogrel-based antiplatelet therapy group will be permitted to use additional antiplatelet drugs other than clopidogrel at the investigator's discretion. The primary outcome is a composite of any death, major adverse cardiovascular events, systemic thromboembolic events, and major bleeding during a follow-up period of at least 2 years. This study would provide valuable information for determining the optimal secondary prevention strategy for APS-related stroke.

Official Title
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Comparison of Clopidogrel-based Antiplatelet Therapy Versus Warfarin as Secondary Prevention Strategy for AntiPhospholipid Syndrome-related STROKE (APS-STROKE)

Conditions
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Antiphospholipid Syndrome, Ischemic Stroke, Transient Ischemic Attack, Cerebrovascular Disease, Cardiovascular Diseases, Major Bleed

Intervention / Treatment
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* Drug: Antiplatelet Drug
* Drug: Warfarin


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age 19 years or older History of ischemic stroke (cerebral infarction, transient ischemic attack, or retinal arterial ischemic event) Patients who meet the laboratory diagnostic criteria for antiphospholipid syndrome (APS) Patients or guardians who agree to the study protocol and sign with informed consent Exclusion Criteria: Patients with high-risk antiphospholipid antibody profile (triple positivity; persistent high-titers exceeding 80 U/mL of anti-cardiolipin or anti-β2 glycoprotein I antibodies) Systemic lupus erythematous Patients unable to discontinue previously taken anticoagulants or antiplatelet agents (e.g., atrial fibrillation, valvular heart disease, or a history of percutaneous coronary intervention) Women who are pregnant, breastfeeding, or intending to become pregnant during the study period Deemed unsuitable for participation in the study for more than two years, as per the investigators' discretion

Ages Eligible for Study
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Minimum Age: 19 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Clopidogrel-based antiplatelet therapy group<br>Clopidogrel 75 mg daily Patients assigned to this group will be permitted to use additional antiplatelet drugs other than clopidogrel at the investigator's discretion. | Drug: Antiplatelet Drug<br>* Clopidogrel ± other antiplatelet drug<br>|
| Active Comparator: Warfarin group<br>Warfarin (target prothrombin time-international normalized ratio 2.0-3.0) | Drug: Warfarin<br>* Warfarin (target prothrombin time-international normalized ratio 2.0-3.0)<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Composite endpoint | Composite endpoint of any death, major adverse cardiovascular events (MACEs), systemic thromboembolic events, and major bleeding. MACE includes any stroke, transient ischemic attack, and acute coronary syndrome (i.e., ST-elevation myocardial infarction, non-ST elevation myocardial infarction, and hospitalization with unstable angina) in this study. Major bleeding refers to bleeding events meeting the criteria for Bleeding Academic Research Consortium (BARC) type 3 or 5. | 2 years | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| MACE | MACE includes any stroke, transient ischemic attack, and acute coronary syndrome (i.e., ST-elevation myocardial infarction, non-ST elevation myocardial infarction, and hospitalization with unstable angina) in this study. | 2 years | 
| Ischemic stroke | Ischemic stroke or transient ischemic attack | 2 years | 
| Any bleeding | Major or minor bleeding according to definitions from BARC | 2 years | 
| Major bleeding | BARC bleeding type 3 or 5 | 2 years | 
| Intracranial bleeding | Intracranial bleeding that is objectively confirmed by brain imaging | 2 years | 
| Clinically relevant non-major bleeding | Any bleeding that does not fit the criteria for major bleeding but does meet at least one of the following criteria: requiring nonsurgical, medical intervention by a healthcare professional leading to hospitalization or increased level of care prompting evaluation. | 2 years | 
| Any death | Death from any cause | 2 years | 
| Thrombosis-related death | Death from arterial, venous, or capillary thrombotic events | 2 years | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Antiphospholipid syndrome, Ischemic stroke, Secondary prevention, Thrombosis