PACT (Platelet Activity After Clopidogrel Termination) (PACT)

April 30, 2018 updated by: University of Massachusetts, Worcester

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.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

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 Type

Interventional

Enrollment (Actual)

15

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • Massachusetts
      • Worcester, Massachusetts, United States, 01655-0002
        • University of Massachusetts Medical School

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

21 years to 70 years (Adult, Older Adult)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • 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.

Exclusion Criteria:

  • 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.
  • 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.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Quadruple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: Clopidogrel + aspirin
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.
Drug: clopidogrel + aspirin
Clopidogrel 75mg plus aspirin 81mg, tablet by mouth daily for 14 days.
Other Names:
  • Plavix
  • aspirin
Drug: Aspirin
Aspirin 81mg tablet by mouth continued daily alone for 43 days after day 14.
Placebo Comparator: Placebo + aspirin
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.
Drug: Aspirin
Aspirin 81mg tablet by mouth continued daily alone for 43 days after day 14.
Drug: placebo
Placebo plus aspirin 81 mg, tablet by mouth daily for 14 days.
Other Names:
  • aspirin

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
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.
Baseline and 45 days after intervention

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University of Massachusetts, Worcester

Collaborators

Bristol-Myers Squibb
Sanofi

Investigators

  • Principal Investigator: Alan D. Michelson, M.D., University of Massachusetts, Worcester

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

April 1, 2008

Primary Completion (Actual)

May 1, 2009

Study Completion (Actual)

May 1, 2009

Study Registration Dates

First Submitted

February 6, 2008

First Submitted That Met QC Criteria

February 6, 2008

First Posted (Estimate)

February 20, 2008

Study Record Updates

Last Update Posted (Actual)

May 31, 2018

Last Update Submitted That Met QC Criteria

April 30, 2018

Last Verified

April 1, 2018

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • CPFS 2008-1

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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