Implementation of CYP2C19 Genotyping to Guide Antiplatelet Therapy

Study Overview
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Brief Summary
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It is well established that clopidogrel-induced antiplatelet effects is suboptimal in many patients who are thus exposed to an increased risk of adverse cardiovascular events. Studies have shown that genotypes of the cytochrome P450 (CYP) 2C19 enzyme, which is a key determinant of clopidogrel metabolism, contribute to these findings. Prasugrel and ticagrelor are alternative agents whose effectiveness is not dependent on CYP2C19 genotype. A boxed warning on the Food and Drug Administration (FDA)-approved clopidogrel labeling warns of reduced effectiveness in patients with the LOF genotype and recommends alternative therapies in these patients. The availability of an assay recently approved by the FDA, SpartanRX, which provides results within one-hour facilitates performing genetic testing as a clinical test in real-world practice. We therefore propose to 1) examine the feasibility of implementing CYP2C19 genotyping using SpartanRX as standard of care for patients undergoing cardiac catheterization at UF Health Jacksonville providing the opportunity for clinicians to embrace genotype-guided antiplatelet therapy in those who proceed to PCI and 2) determine if CYP2C19 genotype-guided antiplatelet therapy reduces the risk for major adverse cardiovascular outcomes after PCI.

Detailed Description
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Dual antiplatelet therapy with aspirin and a P2Y12 receptor inhibitor represents the standard of care treatment for the prevention of major adverse cardiovascular events in patients undergoing percutaneous coronary intervention (PCI). Currently, 3 oral P2Y12 receptor inhibitors (clopidogrel, prasugrel, and ticagrelor) are available for clinical use. Clopidogrel remains the most broadly used P2Y12 receptor inhibitor. However, it is well established that clopidogrel-induced antiplatelet effects is suboptimal in many patients who are thus exposed to an increased risk of adverse cardiovascular events. Studies have shown that genotypes of the cytochrome P450 (CYP) 2C19 enzyme, which is a key determinant of clopidogrel metabolism, contribute to these findings. In fact, clopidogrel is a prodrug that requires bioactivation by the CYP2C19 enzyme. Approximately 30-40% of individuals have the loss-of-function (LOF) CYP2C19 genotype and cannot sufficiently convert clopidogrel to its active form, thereby gaining little to no benefit from the drug. Prasugrel and ticagrelor are alternative agents whose effectiveness is not dependent on CYP2C19 genotype. A boxed warning on the Food and Drug Administration (FDA)-approved clopidogrel labeling warns of reduced effectiveness in patients with the LOF genotype and recommends alternative therapies in these patients. Guidelines from the Clinical Pharmacogenetics Implementation Consortium (CPIC) specifically recommend prasugrel or ticagrelor over clopidogrel for patients with a LOF CYP2C19 genotype who undergo PCI. In turn, these recommendations have led to the use in clinical practice of genetic testing of CYP2C19 genotypes as an aid to clinicians in determining therapeutic strategies for patients undergoing PCI. However, the uptake of genetic testing in real-world clinical practice has been limited by the availability of assays able to provide genetic results in a timely fashion. The availability of an assay recently approved by the FDA, SpartanRX, which provides results within one-hour facilitates performing genetic testing as a clinical test in real-world practice. We therefore propose to 1) examine the feasibility of implementing CYP2C19 genotyping using SpartanRX as standard of care for patients undergoing cardiac catheterization at UF Health Jacksonville providing the opportunity for clinicians to embrace genotype-guided antiplatelet therapy in those who proceed to PCI and 2) determine if CYP2C19 genotype-guided antiplatelet therapy reduces the risk for major adverse cardiovascular outcomes after PCI.

Official Title
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Implementation of CYP2C19 Genotyping to Guide Antiplatelet Therapy for Patients Undergoing Cardiac Catheterization at UF Health Jacksonville

Conditions
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Coronary Artery Disease

Intervention / Treatment
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* Device: SpartanRX


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age ≥18 years Undergoing left heart catheterization for signs and symptoms suggestive for CAD Exclusion Criteria: Inability to provide written informed consent.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Left heart catheterization patients<br>Patients presenting to the UF Health Jacksonville cardiac catheterization laboratory for left heart catheterization for suspected coronary artery disease and intent to undergo percutaneous coronary intervention will be targeted for enrollment and will be genotyped by SpartanRX | Device: SpartanRX<br>* A buccal swap genetic sample will be collected from eligible patients who provide written informed consent for CYP2C19 testing. Genotyping will be performed by the SpartanRX system as a clinical test at the UF Health Pathology Laboratory in Jacksonville.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Percent of patients approached who consent to study participation and are genotyped successfully | Patients undergoing elective procedures will be approached for CYP2C19 genetic testing prior to undergoing left heart catheterization, while patients requiring emergent procedures will be tested prior to hospital discharge. | 48 hours | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Major adverse cardiac events (MACE) | A composite rate of death, myocardial infarction, stroke, stent thrombosis, and ischemia-driven revascularization | 12 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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percutaneous coronary intervention, clopidogrel, loss-of-function allele