Pharmacodynamic Effects of Prasugrel Compared With Ticagrelor in Patients With Coronary Artery Disease

Not Applicable

Completed

Brief Summary: Recently, two P2Y12 receptor inhibitors have been approved for clinical use: prasugrel and ticagrelor. Both prasugrel and ticagrelor have shown to be associated with more potent antiplatelet effects compared with clopidogrel and are associated with an improved net clinical benefit. However, to date there are limited head-to-head comparisons of these two new agents.

Detailed Description: Dual antiplatelet therapy consisting of aspirin and clopidogrel is the cornerstone of treatment for prevention of thrombotic events in patients with coronary artery disease (CAD) undergoing percutaneous coronary intervention (PCI). However, there are a considerable number of patients who continue to have recurrent ischemic events despite this treatment regimen. These observations underscore the need for more potent antiplatelet therapies. Recently, two P2Y12 receptor inhibitors have been approved for clinical use: prasugrel and ticagrelor. Both prasugrel and ticagrelor have shown to be associated with more potent antiplatelet effects compared with clopidogrel. These more favorable pharmacodynamic effects translate into reduced ischemic event rates, at the expense of an increased risk of bleeding in patients with acute coronary syndromes. Overall, these drugs are associated with an improved net clinical benefit. These findings from large-scale clinical investigations have led to approval of prasugrel and ticagrelor. However, to date there are limited head-to-head comparisons of these two new agents.

Recruitment & Eligibility

Inclusion Criteria

Patients with known coronary artery disease
On maintenance treatment with aspirin (81 mg per day) and clopidogrel (75 mg per day) for at least 1-month as per standard of care.
Age between 18 and 74 years old.

Exclusion Criteria

History of stroke, transient ischemic attack or intracranial bleeding.
Known allergies to aspirin, prasugrel, ticagrelor, or clopidogrel.
Weight <60kg
On treatment with oral anticoagulation (coumarin derivate, dabigatran).
Hemoglobin<10 gm/dL
Platelet count <80x106/mL
Active bleeding or hemodynamic instability.
Creatinine Clearance <30 mL/minute.
Baseline ALT >2.5 times the upper limit of normal.
Patients with sick sinus syndrome (SSS) or high degree AV block without pacemaker protection.
Drugs interfering with 2C19 metabolism (to avoid interaction with clopidogrel): , fluconazole (Diflucan), ketoconazole (Nizoral), voriconazole (VFEND), etravirine (Intelence), felbamate (Felbatol), fluoxetine (Prozac, Serafem, Symbyax), fluvoxamine (Luvox), and ticlopidine (Ticlid).
Drugs interfering CYP3A4 metabolism (to avoid interaction with Ticagrelor): Ketoconazole, itraconazole, voriconazole, clarithromycin, nefazodone, ritonavir, saquinavir, nelfinavir, indinavir, atazanavir, and telithromizycin.
Pregnant females*. *Women of childbearing age must use reliable birth control (i.e. oral contraceptives) while participating in the study.

Arm && Interventions

Group	Intervention	Description
Prasugrel	Prasugrel	Prasugrel 60mg loading dose and 10 mg maintenance dose
Ticagrelor	Ticagrelor	Ticagrelor 180mg loading dose and 90mg bid maintenance dose

Primary Outcome Measures

Name	Time	Method
Platelet Reactivity by Vasodilator-stimulated Phosphoprotein (VASP)	1 week	The primary end-point of the study was the comparison in the platelet reactivity index (PRI%) determined by vasodilator-stimulated phosphoprotein (VASP) at 1 week between prasugrel and ticagrelor.

Secondary Outcome Measures

Name	Time	Method
Platelet Reactivity Measured by Vasodilator-stimulated Phosphoprotein (VASP)	24 hours	A secondary outcome was the comparison between groups of platelet reactivity index (PRI) measured by vasodilator-stimulated phosphoprotein (VASP) at 24 hours after loading dose.