Blood PlateletsPACTNCT00619073
PACT (Platelet Activity After Clopidogrel Termination)
A study testing clopidogrel + aspirin and Aspirin in people with Blood Platelets and Clopidogrel, run by University of Massachusetts, Worcester at 1 site in United States.
Trial summary
Clopidogrel is a medication that is used to decrease the ability of platelets to form blood clots. The theory has been proposed that, in patients with coronary artery disease or stroke, increased platelet function after discontinuation of clopidogrel therapy is associated with an increased clotting risk. Read more about this study
- Who is it for?
- Ages 21 to 70 yearsHealthy volunteers can take part
- Conditions the study is for
- Blood Platelets, Clopidogrel
- What is being tested?
- clopidogrel + aspirin and Aspirin
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 15 participants
- Where
- 1 siteUnited States
- Study dates
- Apr 2008to May 2009
- Phase
- Interventional
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
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 21 to 70 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Must be a normal healthy subject
- Must be between 21-70 years old
- Must be able to take aspirin and clopidogrel.
- Must be able to have blood drawn 16 times over approximately 3 months.
Who cannot join
- Subject who is currently taking aspirin or another anti-platelet drug such as clopidogrel. Subject must be free of these medications for 10 days before enrolling in this study.
- Subject who is currently taking a non-steroidal anti-inflammatory drug such as ibuprofen or naproxen. Subject must be free of these medications for 3 days before enrolling in this study.
- Subject who is currently taking medications for depression or medications that lower blood pressure or lower blood sugar.
- Subject who are pregnant or may become pregnant during the study or who is breast feeding.
- Subject with a known allergy to aspirin or clopidogrel.
- Cigarette smoking or use of other nicotine product.
Show all 9Show fewer
- Subject with a history of any of the following: coronary artery disease; stroke; bleeding disorder; ongoing bleeding; previous life-threatening hemorrhage; stomach ulcers; gastrointestinal bleeding within the past 1 month; major surgery within the past 1 month; minor surgery within the past 2 weeks; or platelet transfusion within the past 7 days.
- Subject with a blood count, measured on the pre-study drug blood sample, that is not in the normal range.
- Subject who is enrolled in another clinical trial of an investigational drug.
Trial locations and contacts
1 site in 1 country.
United States1 site
University of Massachusetts Medical School
Worcester, Massachusetts, 01655-0002
About this study
Clopidogrel is a medication that is used to decrease the ability of platelets to form blood clots.
The theory has been proposed that, in patients with coronary artery disease or stroke, increased platelet function after discontinuation of clopidogrel therapy is associated with an increased clotting risk. However, this theory has never been rigorously tested.
The goal of this research is to determine whether discontinuation of clopidogrel results in increased platelet function.
Read the detailed description
In this study, we will address the question: does discontinuation of clopidogrel result in platelet hyperreactivity? We will perform a double-blind, placebo-controlled, crossover study in normal subjects, in whom platelet reactivity will be measured before clopidogrel or placebo, during clopidogrel or placebo, and at various time points after discontinuation of clopidogrel or placebo. The dose of clopidogrel will be the standard, FDA-approved dose: 75 mg daily. All subjects will be treated with aspirin 81 mg daily throughout the 57 days of study assessment in both the clopidogrel arm and the placebo arm, because the clinically relevant question is: in patients who remain on aspirin, does discontinuation of clopidogrel result in platelet hyperreactivity?
- Conditions
- Blood Platelets, Clopidogrel
- Being tested
- clopidogrel + aspirin, placebo, Aspirin
- Keywords
- blood platelets, platelet aggregation inhibitors, antiplatelet drugs, clopidogrel
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
clopidogrel + aspirinDrug
Also called Plavix, aspirin
Clopidogrel 75mg plus aspirin 81mg, tablet by mouth daily for 14 days.
placeboDrug
Also called aspirin
Placebo plus aspirin 81 mg, tablet by mouth daily for 14 days.
AspirinDrug
Aspirin 81mg tablet by mouth continued daily alone for 43 days after day 14.
| Study group | Role | What they receive |
|---|---|---|
| Clopidogrel + aspirin | Active comparator | The subjects will be randomized to clopidogrel 75 mg plus aspirin 81 mg orally daily for 14 days. The study drug (i.e., clopidogrel) will then be discontinued and aspirin continued for another 43 days. Receives: Drug: clopidogrel + aspirin; Drug: Aspirin |
| Placebo + aspirin | Placebo comparator | The subjects will be randomized to placebo plus aspirin 81 mg orally daily for 14 days. The study drug (i.e., placebo) will then be discontinued and aspirin continued for another 43 days. Receives: Drug: placebo; Drug: Aspirin |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change From Baseline in Platelet Surface Activated GPIIb-IIIa Complex at 45 Days After Intervention.
Value at 45 days after intervention minus value at baseline in platelet surface activated GPIIb-IIIa complex using flow cytometry.The types and concentrations of agonists used in the flow cytometry assays reported here were: ADP 0.5, 1, and 20 µmol/L; thrombin receptor activating peptide (TRAP) 1 and 20 µmol/L; and a combination of collagen 5 µg/mL and epinephrine 5 µmol/L. Mean Florescence Intensity (MFI) is used as unit of measure. MFI indicates relative degree of shift in fluorescence intensity of a population of platelets in arbitrary units.
Measured: Baseline and 45 days after intervention
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted20 Feb 2008 (estimated)
- Study startApr 2008
- Primary completionMay 2009
- Study completionMay 2009
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Blood PlateletsStudies 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 N/A
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 15 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Massachusetts, Worcester
- Sponsor type
- University, hospital or other
- Collaborators
- Sanofi, Bristol-Myers Squibb
- Responsible party
- Sponsor
- Investigators
- Alan D. Michelson, M.D., Principal investigator, University of Massachusetts, Worcester
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT00619073
- Sponsor's protocol ID
- CPFS 2008-1
- Acronym
- PACT
- Status last verified
- Apr 2018
- First submitted
- 6 Feb 2008
- Last updated
- 31 May 2018
- Results posted
- Yes, on ClinicalTrials.gov
- Data monitoring committee
- No
Publications
Frelinger AL 3rd, Barnard MR, Fox ML, Michelson AD. The Platelet Activity After Clopidogrel Termination (PACT) study. Circ Cardiovasc Interv. 2010 Oct;3(5):442-9. doi: 10.1161/CIRCINTERVENTIONS.110.937961. Epub 2010 Aug 24.
PubMed 20736449
Study at a glance
From the registry record, last updated by the sponsor on 31 May 2018. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- PACT (Platelet Activity After Clopidogrel Termination)
- ClinicalTrials.gov ID
- NCT00619073
- Acronym / sponsor ID
- PACT / CPFS 2008-1
- Conditions
- Blood Platelets, Clopidogrel
- Keywords
- blood platelets, platelet aggregation inhibitors, antiplatelet drugs, clopidogrel
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 15 participants (actual)
- Lead sponsor
- University of Massachusetts, WorcesterUniversity, hospital or other
- Collaborators
- Sanofi, Bristol-Myers Squibb
- Study start
- Apr 2008
- Primary completion
- May 2009 (actual)
- Study completion
- May 2009 (actual)
- First posted
- 20 Feb 2008 (estimated)
- Results
- Posted 6 Nov 2012
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Clopidogrel is a medication that is used to decrease the ability of platelets to form blood clots.
The theory has been proposed that, in patients with coronary artery disease or stroke, increased platelet function after discontinuation of clopidogrel therapy is associated with an increased clotting risk. However, this theory has never been rigorously tested.
The goal of this research is to determine whether discontinuation of clopidogrel results in increased platelet function.
Detailed description
In this study, we will address the question: does discontinuation of clopidogrel result in platelet hyperreactivity? We will perform a double-blind, placebo-controlled, crossover study in normal subjects, in whom platelet reactivity will be measured before clopidogrel or placebo, during clopidogrel or placebo, and at various time points after discontinuation of clopidogrel or placebo. The dose of clopidogrel will be the standard, FDA-approved dose: 75 mg daily. All subjects will be treated with aspirin 81 mg daily throughout the 57 days of study assessment in both the clopidogrel arm and the placebo arm, because the clinically relevant question is: in patients who remain on aspirin, does discontinuation of clopidogrel result in platelet hyperreactivity?
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Clopidogrel + aspirin | Active comparator | Drug: clopidogrel + aspirin, Drug: AspirinThe subjects will be randomized to clopidogrel 75 mg plus aspirin 81 mg orally daily for 14 days. The study drug (i.e., clopidogrel) will then be discontinued and aspirin continued for another 43 days. |
| Placebo + aspirin | Placebo comparator | Drug: placebo, Drug: AspirinThe subjects will be randomized to placebo plus aspirin 81 mg orally daily for 14 days. The study drug (i.e., placebo) will then be discontinued and aspirin continued for another 43 days. |
Who may qualify
- Ages
- 21 to 70 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (4 listed)
- Must be a normal healthy subject
- Must be between 21-70 years old
- Must be able to take aspirin and clopidogrel.
- Must be able to have blood drawn 16 times over approximately 3 months.
Key exclusion criteria (9 listed)
- Subject who is currently taking aspirin or another anti-platelet drug such as clopidogrel. Subject must be free of these medications for 10 days before enrolling in this study.
- Subject who is currently taking a non-steroidal anti-inflammatory drug such as ibuprofen or naproxen. Subject must be free of these medications for 3 days before enrolling in this study.
- Subject who is currently taking medications for depression or medications that lower blood pressure or lower blood sugar.
- Subject who are pregnant or may become pregnant during the study or who is breast feeding.
- Subject with a known allergy to aspirin or clopidogrel.
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 |
|---|---|---|
| clopidogrel + aspirinAlso: Plavix, aspirinClopidogrel 75mg plus aspirin 81mg, tablet by mouth daily for 14 days. | Drug | Clopidogrel + aspirin |
| placeboAlso: aspirinPlacebo plus aspirin 81 mg, tablet by mouth daily for 14 days. | Drug | Placebo + aspirin |
| AspirinAspirin 81mg tablet by mouth continued daily alone for 43 days after day 14. | Drug | Clopidogrel + aspirin, Placebo + aspirin |
Primary outcome
Change From Baseline in Platelet Surface Activated GPIIb-IIIa Complex at 45 Days After Intervention.
Time frame: Baseline and 45 days after intervention
Value at 45 days after intervention minus value at baseline in platelet surface activated GPIIb-IIIa complex using flow cytometry.The types and concentrations of agonists used in the flow cytometry assays reported here were: ADP 0.5, 1, and 20 µmol/L; thrombin receptor activating peptide (TRAP) 1 and 20 µmol/L; and a combination of collagen 5 µg/mL and epinephrine 5 µmol/L. Mean Florescence Intensity (MFI) is used as unit of measure. MFI indicates relative degree of shift in fluorescence intensity of a population of platelets in arbitrary units.
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 31 May 2018.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
- Results publication: PubMed 20736449Frelinger AL 3rd, Barnard MR, Fox ML, Michelson AD. The Platelet Activity After Clopidogrel Termination (PACT) study. Circ Cardiovasc Interv. 2010 Oct;3(5):442-9. doi: 10.1161/CIRCINTERVENTIONS.110.937961. Epub 2010 Aug 24.
- Home page of the study principal investigatorLink provided by the sponsor.
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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.
Alan D. Michelson, M.D. principal investigator
University of Massachusetts, Worcester
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing clopidogrel + aspirin and Aspirin in people with Blood Platelets and Clopidogrel, run by University of Massachusetts, Worcester at 1 site in United States.
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 4 inclusion and 9 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 31 May 2018. 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 United States. 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. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
Yes. Results are posted in the registry (first posted 6 Nov 2012). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
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?
Change From Baseline in Platelet Surface Activated GPIIb-IIIa Complex at 45 Days After Intervention. (time frame: Baseline and 45 days after intervention). 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 NCT00619073, 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 31 May 2018.