Aspirin Resistance in Trinidad.

NCT06228820 | Completed Phase 2

• 1 other identifier: CEC1153/06/19
• Study Type: interventional
• Target: 48
• Locations: 1 country
• Sites: 1

Brief Summary

Aspirin's beneficial effect is mediated via the inhibition of arachidonic acid (AA) activation of platelets. It is detected by demonstrating a decrease in platelet function and/or a decrease in prostaglandin metabolites. Besides inhibiting the formation of thromboxane A2 from arachidonic acid, Aspirin has a host of platelet-independent effects that complement its platelet-inhibitory effects. The phenomenon of "Aspirin resistance" is based on the observation of clinical events in some patients taking Aspirin and/or a diminished platelet aggregation inhibitory response to Aspirin therapy. It has been suggested that many individuals taking Aspirin have become resistant to this drug. Unfortunately, laboratory assays used to monitor the efficacy of Aspirin are far from accurate, and the results are not reproducible. Multiple studies demonstrate non-compliance using repeat testing for platelet inhibition in patients with an initial inadequate response to Aspirin. When the test is repeated under the condition that the ingestion of the test Aspirin is assured, the patients' platelets are inhibited. Patients with an inadequate Aspirin response have an increased likelihood of subsequent vascular events.

Conditions

Platelet Dysfunction Due to Drugs

Keywords

Aspirin

Outcome Measures

Primary Outcomes (1)

• Aspirin Resistance Unit

  VerifyNow Aspirin assay is a qualitative test to aid in detecting platelet dysfunction due to Aspirin ingestion in whole blood for the point-of-care or laboratory setting. The assay incorporates the agonist arachidonic acid to activate platelets, and it measures platelet function based on the ability of activated platelets to bind to fibrinogen. Fibrinogen-coated microparticles aggregate in whole blood in proportion to the number of activated platelet GP IIb/IIIa receptors. If Aspirin has produced the expected antiplatelet effect, such aggregation will be reduced. The VerifyNow Aspirin assay reports the extent of platelet aggregation as Aspirin reaction units (ARUs). Given an ARU range of 350-700, ARU values less than 550 are consistent with Aspirin-induced inhibition of platelet function. In contrast, values greater than or equal to 550 ARUs are not compatible with Aspirin-induced inhibition.

  2-weeks

Study Arms (1)

Aspirin Arm

EXPERIMENTAL

Healthy patients will then undergo at least a 2-week course of 81mg of Bayer Aspirin per oral daily, followed by platelet function testing. The patients will then undergo a washout period of 2 weeks, followed by another 2-week course of 81mg Vazalore Aspirin per oral daily, followed by a second round of platelet function testing.

Drug: Aspirin 81Mg Ec Tab

Interventions

Aspirin 81Mg Ec Tab DRUG

Healthy patients will then undergo at least a 2-week course of 81mg of Bayer Aspirin per oral daily, followed by platelet function testing. The patients will then undergo a washout period of 2 weeks, followed by another 2-week course of 81mg Vazalore Aspirin per oral daily, followed by a second round of platelet function testing.

Aspirin Arm

Eligibility Criteria

• Age: 18 Years - 74 Years
• Gender Eligibility Details: All genders are included.
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• between 18 and 74 years of age,
• healthy with no overt medical conditions,
• not on any physician-prescribed medications or complementary/alternative therapies,

You may not qualify if:

• presence of active internal bleeding or history of bleeding diathesis or clinical findings associated with an increased risk of bleeding,
• history of ischemic or hemorrhagic stroke, transient ischemic attack, intracranial neoplasm, arteriovenous malformation, or aneurysm,
• clinical and/or hemodynamic instability,
• within 1 month of placement of a bare metal stent,
• within 30 days of coronary artery bypass graft surgery or PCI without a stent placed,
• planned coronary revascularization,
• treatment with fibrin-specific fibrinolytic therapy \<24 h or non-fibrin-specific fibrinolytic therapy \<48 h,
• use of an oral anticoagulation agent or international normalized ratio \>1.5,
• body weight \<60 kg,
• age \>75 years,
• hemoglobin \<10 g/dL,
• platelet count \<100×106/μL,
• creatinine \>2 mg/dL,
• hepatic enzymes \>2.5 times the upper limit of normal,
• pregnancy and/or lactation,

Sponsors & Collaborators

• The University of The West Indies: lead

Study Sites (1)

The University of the West Indies

Saint Augustine, North, 00000, Trinidad and Tobago

Location

Related Publications (1)

• Seecheran N, McCallum P, Grimaldos K, Ramcharan P, Kawall J, Katwaroo A, Seecheran V, Jagdeo CL, Rafeeq S, Seecheran R, Quert AL, Ali N, Peram L, Khan S, Ali F, Motilal S, Bhagwandass N, Giddings S, Ramlackhansingh A, Sandy S. Pharmacodynamic Comparison of Two Aspirin Formulations in the Caribbean: The ARC Study. Cardiol Ther. 2024 Sep;13(3):593-602. doi: 10.1007/s40119-024-00373-6. Epub 2024 Jul 15.

  PMID: 39008026 DERIVED

MeSH Terms

Interventions

Aspirin

Intervention Hierarchy (Ancestors)

Salicylates; Hydroxybenzoates; Phenols; Benzene Derivatives; Hydrocarbons, Aromatic; Hydrocarbons, Cyclic; Hydrocarbons; Organic Chemicals

Study Design

• Study Type: interventional
• Phase: phase 2
• Allocation: NA
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Principal Investigator

Model Details: Healthy patients will then undergo at least a 2-week course of 81mg of Bayer Aspirin per oral daily, followed by platelet function testing. The patients will then undergo a washout period of 2 weeks, followed by another 2-week course of 81mg Vazalore Aspirin per oral daily, followed by a second round of platelet function testing.

Study Record Dates

• First Submitted: January 18, 2024
• First Posted: January 29, 2024
• Study Start: January 15, 2024
• Primary Completion: December 15, 2024
• Study Completion: December 15, 2024
• Last Updated: September 12, 2025

Record last verified: 2025-09

Data Sharing

• IPD Sharing: Will not share

Locations

TR (1)