Platelet Dysfunction Due to DrugsPhase 2ARTNCT06228820
Aspirin Resistance in Trinidad.
A Phase 2 study testing Aspirin 81Mg Ec Tab in people with Platelet Dysfunction Due to Drugs, run by The University of The West Indies at 1 site in Trinidad and Tobago.
Trial 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. Read more about this study
- Who is it for?
- Ages 18 to 74 yearsHealthy volunteers can take part
- Conditions the study is for
- Platelet Dysfunction Due to Drugs
- What is being tested?
- Aspirin 81Mg Ec Tab
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 48 participants
- Where
- 1 siteTrinidad and Tobago
- Study dates
- 15 Jan 2024to 15 Dec 2024
- Phase
- Phase 2
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 74 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- between 18 and 74 years of age,
- healthy with no overt medical conditions,
- not on any physician-prescribed medications or complementary/alternative therapies,
Who cannot join
- 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,
Show all 16Show fewer
- 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,
- the patient is on any other antithrombotic therapies such as ticagrelor, dabigatran, rivaroxaban and apixaban
Trial locations and contacts
1 site in 1 country.
Trinidad and Tobago1 site
The University of the West Indies
Saint Augustine, North, 00000
About this study
Official title: Aspirin Resistance in Trinidad: The ART Pilot Study.
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.
Read the detailed description
Aspirin is a wonder drug used for over 100 years for its analgesic and antipyretic effects. It is an inexpensive, readily available medication that reduces the risk of subsequent vascular disease by about 25% in patients with known occlusive vascular disease. For the past three decades, it has increasingly been used to prevent primary and secondary cardiovascular events.
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.
The POINT pilot study introduced the preliminary observation that the estimated prevalence of HPR is considerably higher within the heterogeneous population in Trinidad at 50% compared with predominantly Caucasian studies. Furthermore, the HPR is significantly higher in South Asians (Indo-Trinidadians) (>60% of patients), which has severe clinical repercussions considering the cardiovascular disease pandemic. Clopidogrel may not be a satisfactory or optimal antiplatelet agent in this subgroup. Therefore, another more potent antiplatelet, such as ticagrelor, should be used instead.
Patients generally displayed a limited level of cardiovascular medication adherence, which is likely to translate into a higher rate of cardiovascular events with their potentially devastating sequelae.
We postulate that there is a high level of Aspirin resistance in Trinidad and Tobago.
- Conditions
- Platelet Dysfunction Due to Drugs
- Being tested
- Aspirin 81Mg Ec Tab
- Keywords
- Aspirin
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Aspirin 81Mg Ec TabDrug
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 group | Role | What they receive |
|---|---|---|
| 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. Receives: Drug: Aspirin 81Mg Ec Tab |
What is being measured
The primary outcome is the main question the study is designed to answer.
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.
Measured: 2-weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted29 Jan 2024
- Study start15 Jan 2024
- Primary completion15 Dec 2024
- Study completion15 Dec 2024
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Platelet Dysfunction Due to DrugsStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 2
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Model description
- 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.
- Masking
- None (open label)
- Enrolment
- 48 participants (actual)
Sponsor and investigators
- Lead sponsor
- The University of The West Indies
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Naveen Seecheran, The University of The West Indies
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06228820
- Sponsor's protocol ID
- CEC1153/06/19
- Acronym
- ART
- Status last verified
- Sep 2025
- First submitted
- 18 Jan 2024
- Last updated
- 12 Sep 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
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.
PubMed 39008026
Study at a glance
From the registry record, last updated by the sponsor on 12 Sep 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Aspirin Resistance in Trinidad: The ART Pilot Study.
- ClinicalTrials.gov ID
- NCT06228820
- Acronym / sponsor ID
- ART / CEC1153/06/19
- Conditions
- Platelet Dysfunction Due to Drugs
- Keywords
- Aspirin
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 48 participants (actual)
- Lead sponsor
- The University of The West IndiesUniversity, hospital or other
- Study start
- 15 Jan 2024 (actual)
- Primary completion
- 15 Dec 2024 (actual)
- Study completion
- 15 Dec 2024 (actual)
- First posted
- 29 Jan 2024 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Detailed description
Aspirin is a wonder drug used for over 100 years for its analgesic and antipyretic effects. It is an inexpensive, readily available medication that reduces the risk of subsequent vascular disease by about 25% in patients with known occlusive vascular disease. For the past three decades, it has increasingly been used to prevent primary and secondary cardiovascular events.
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.
The POINT pilot study introduced the preliminary observation that the estimated prevalence of HPR is considerably higher within the heterogeneous population in Trinidad at 50% compared with predominantly Caucasian studies. Furthermore, the HPR is significantly higher in South Asians (Indo-Trinidadians) (>60% of patients), which has severe clinical repercussions considering the cardiovascular disease pandemic. Clopidogrel may not be a satisfactory or optimal antiplatelet agent in this subgroup. Therefore, another more potent antiplatelet, such as ticagrelor, should be used instead.
Patients generally displayed a limited level of cardiovascular medication adherence, which is likely to translate into a higher rate of cardiovascular events with their potentially devastating sequelae.
We postulate that there is a high level of Aspirin resistance in Trinidad and Tobago.
Study design
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
- Model description
- 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.
| Arm | Type | Receives |
|---|---|---|
| Aspirin Arm | Experimental | Drug: Aspirin 81Mg Ec TabHealthy 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. |
Who may qualify
- Ages
- 18 to 74 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (3 listed)
- between 18 and 74 years of age,
- healthy with no overt medical conditions,
- not on any physician-prescribed medications or complementary/alternative therapies,
Key exclusion criteria (16 listed)
- 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,
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Aspirin 81Mg Ec TabHealthy 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 Arm |
Primary outcome
Aspirin Resistance Unit
Time frame: 2-weeks
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.
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 12 Sep 2025.
- Derived from this study: PubMed 39008026Seecheran 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.
- Individual participant dataSharing planned: No
Related trials for Platelet Dysfunction Due to Drugs
RecruitingObservational study
Rare Disease Patient Registry & Natural History Study - Coordination of Rare Diseases at Sanford
Rare Disorders, Undiagnosed Disorders
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing Aspirin 81Mg Ec Tab in people with Platelet Dysfunction Due to Drugs, run by The University of The West Indies at 1 site in Trinidad and Tobago.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 16 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 12 Sep 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Trinidad and Tobago. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Aspirin Resistance Unit (time frame: 2-weeks). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT06228820, which also lists 1 linked publication.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 12 Sep 2025.