CYP2C19 Poor Metabolizer Is Associated With Clinical Outcome of Clopidogrel Therapy in Acute Myocardial Infarction But Not Stable Angina

BACKGROUND—More intensive platelet suppression is required in patients with acute myocardial infarction (AMI) than in those with stable angina because of differential platelet activation between AMI and stable angina. In this context, CYP2C19 genotype leading to reduced active metabolite formation may profoundly affect the clinical outcome of clopidogrel therapy in patients with AMI compared with those with stable angina. METHODS AND RESULTS—Effects of CYP2C19 genotypes on the clinical outcome of clopidogrel therapy were evaluated in 2188 patients (532 patients with AMI and 1656 patients with stable angina) undergoing percutaneous coronary intervention. The primary clinical outcome was a composite of major adverse cardiac and cerebrovascular events defined as death from any cause, nonfatal myocardial infarction, or stroke during 1 year of clopidogrel therapy. Compared with extensive metabolizer, the CYP2C19 poor metabolizer was significantly associated with higher risk of major adverse cardiac and cerebrovascular events in patients with AMI (hazard ratio, 2.88; 95% confidence interval, 1.27–6.53; P=0.011). However, this finding was not seen in patients with stable angina. A significant interaction between CYP2C19 genotypes and disease subsets of AMI and stable angina was identified with respect to major adverse cardiac and cerebrovascular events (adjusted interaction P=0.045). The patients with AMI showed lower percent inhibition of P2Y12 compared with patients with stable angina in CYP2C19 poor metabolizer or CYP2C19 intermediate metabolizer genotype groups but not in CYP2C19 extensive metabolizer genotype group. CONCLUSIONS—CYP2C19 poor metabolizer is associated with poor clinical outcome of clopidogrel therapy in Asian patients with AMI but not in those with stable angina possibly because of differential requirement of platelet suppression in patients with AMI and stable angina. CLINICAL TRIAL REGISTRATION INFORMATION—URLclinicaltrials.gov. IdentifierNCTO1239914.