Role of genetic polymorphisms in clopidogrel response variability: a systematic review

Introduction Clopidogrel is a P2Y 12 inhibitor that has become a mainstay treatment following percutaneous intervention with drug-eluting stent placement to decrease restenosis and its potential complications, including sudden cardiac death and ischaemic strokes in patients with significant vascular disease. Areas covered As a prodrug, the metabolism and efficacy of clopidogrel are contingent on the presence of wild-type CYP450 (CYP2C19) alleles. Genetic polymorphisms and variants are well known to impair its ability to prevent major adverse cardiovascular events in these patients, with inadequate response rates as high as 30% in previous publications. Patterns of allelic frequencies are expected to exhibit similarities between individuals of the same ancestry, ethnic group or geographic region. Accordingly, we seek to further elucidate worldwide prevalence rates for genetic polymorphisms in the CYP2C19-dependent metabolism of clopidogrel and review the potential of personalised CYP2C19 genotyping in clinical practice to mitigate this high treatment resistance and its associated burden on patients. Experts' commentary Our findings support the consideration of genotyping before initiation of therapy to guide adequate dosage or substitutions of other P2Y 12 inhibitors to promote personalised, precision medicine and to prevent adverse events when these therapies may inevitably fail in patients with variants of the CYP450 (CYP2C19) system.