Clinical trial NCT00619073: PACT (Platelet Activity After Clopidogrel Termination)
Official title: PACT (Platelet Activity After Clopidogrel Termination)
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Blood Platelets
Clopidogrel
Keywords: blood platelets
platelet aggregation inhibitors
antiplatelet drugs
clopidogrel
Lead sponsor: University of Massachusetts, Worcester
Sponsor class: OTHER
Collaborators: name: Sanofi
name: Bristol-Myers Squibb
First posted: 2008-02-20
Enrollment: 15
Sex: ALL
Minimum age (years): 21
Maximum age (years): 70
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: CROSSOVER
Primary purpose: BASIC_SCIENCE

Brief 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. 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?

Eligibility criteria: 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.

Primary outcomes:
measure: Change From Baseline in Platelet Surface Activated GPIIb-IIIa Complex at 45 Days After Intervention.
timeFrame: Baseline and 45 days after intervention
Secondary outcomes:
Other outcomes:
Locations:
city: Worcester
country: United States
facility: University of Massachusetts Medical School
state: Massachusetts
Study officials:
affiliation: University of Massachusetts, Worcester
name: Alan D. Michelson, M.D.
role: PRINCIPAL_INVESTIGATOR
References:
citation: 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.