PACT (Platelet Activity After Clopidogrel Termination)

This study has been completed.
Sponsor:
Collaborators:
Sanofi
Bristol-Myers Squibb
Information provided by (Responsible Party):
Alan Michelson, University of Massachusetts, Worcester
ClinicalTrials.gov Identifier:
NCT00619073
First received: February 6, 2008
Last updated: November 8, 2012
Last verified: November 2012

February 6, 2008
November 8, 2012
April 2008
May 2009   (final data collection date for 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 ] [ Designated as safety issue: No ]
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.
Platelet reactivity will be measured by low-dose ADP-induced platelet surface activated GPIIb-IIIa complex, as reported by monoclonal antibody PAC1 in a whole blood flow cytometric assay. [ Time Frame: The assay will be measured on blood drawn from subjects at 8 timepoints during each arm of the study (clopidogrel and placebo) ] [ Designated as safety issue: No ]
Complete list of historical versions of study NCT00619073 on ClinicalTrials.gov Archive Site
Not Provided
High-dose ADP, TRAP and collagen induced platelet surface activated GPIIb-IIIa complex. Low- and high-dose ADP, TRAP and collagen induced platelet surface P-selectin. Low- and high-dose ADP, TRAP and collagen induced platelet aggregation. [ Time Frame: All assays will be performed on blood drawn from subjects at 8 timepoints during each arm of the study (clopidogrel and placebo) ] [ Designated as safety issue: No ]
Not Provided
Not Provided
 
PACT (Platelet Activity After Clopidogrel Termination)
PACT (Platelet Activity After Clopidogrel Termination)

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.

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?

Interventional
Not Provided
Allocation: Randomized
Endpoint Classification: Pharmacodynamics Study
Intervention Model: Crossover Assignment
Masking: Double Blind (Subject, Caregiver, Investigator, Outcomes Assessor)
Primary Purpose: Basic Science
  • Blood Platelets
  • Clopidogrel
  • Drug: clopidogrel + aspirin
    Clopidogrel 75mg plus aspirin 81mg, tablet by mouth daily for 14 days.
    Other Names:
    • Plavix
    • aspirin
  • Drug: placebo
    Placebo plus aspirin 81 mg, tablet by mouth daily for 14 days.
    Other Name: aspirin
  • Drug: Aspirin
    Aspirin 81mg tablet by mouth continued daily alone for 43 days after day 14.
    Other Name: aspirin
  • 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.
    Interventions:
    • Drug: clopidogrel + aspirin
    • Drug: Aspirin
  • 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.
    Interventions:
    • Drug: placebo
    • Drug: Aspirin
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. Epub 2010 Aug 24.

*   Includes publications given by the data provider as well as publications identified by ClinicalTrials.gov Identifier (NCT Number) in Medline.
 
Completed
15
May 2009
May 2009   (final data collection date for primary outcome measure)

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.
Both
21 Years to 70 Years
Yes
Contact information is only displayed when the study is recruiting subjects
United States
 
NCT00619073
CPFS 2008-1
No
Alan Michelson, University of Massachusetts, Worcester
University of Massachusetts, Worcester
  • Sanofi
  • Bristol-Myers Squibb
Principal Investigator: Alan D. Michelson, M.D. University of Massachusetts, Worcester
University of Massachusetts, Worcester
November 2012

ICMJE     Data element required by the International Committee of Medical Journal Editors and the World Health Organization ICTRP