Phase 3 Study Comparing the Efficacy and Safety of Prasugrel and Clopidogrel in Acute Coronary Syndrome Patients With CYP2C19 Polymorphism Who Undergo Percutaneous Coronary Intervention.

Antiplatelet treatment is recommended worldwide for the secondary prevention and clopidogrel is an essential drug. But clopidogrel has limited value because of its pharmacodynamic interpatient variability and delayed onset time.

It is well known that patients who carry a common reduced-function CYP2C19 allele have a lower level of active metabolite of clopidogrel, diminished platelet inhibition, and furthermore, higher rate of major adverse cardiovascular events than noncarriers.

To achieve maximum plateau more rapidly and reduce the rate of high on-treatment platelet reactivity, higher loading dose of clopidogrel, up to 600 mg, is recommended. Although, however, the higher loading dose of clopidogrel, many patients still remain as non-responder.

Incidence of patients with clopidogrel resistance, especially CYP2C19*2 and *3, which encounter loss function, is higher in Eastern Asian peoples than Western peoples. Some studies report incidence rate of clopidogrel resistance in Eastern Asian peoples up to 99%.

However, the metabolism is not influenced by the presence of CYP2C19 genetic variation and prasugrel shows potent platelet inhibition. Although prasugrel exhibit potent platelet inhibition, recent reports describe the possible over inhibition of platelet especially in the East Asian people.