Cytochrome p450 Genotyping - 5/26/2017

The evidence for testing for CYP2C19 metabolizer status by CYP2C19 genotyping in patients with need for antiplatelet therapy who are undergoing or being considered for clopidogrel therapy includes 1 randomized controlled trial (RCT) of CYP2C19 genotype-directed antiplatelet therapy, observational studies, and analyses or RCTs of clopidogrel therapy, and meta-analyses of these studies. Relevant outcomes are morbid events and treatment-related morbidity and mortality. Systematic reviews of observational studies report that genetic variants may be associated with a modest increase in the rate of stent thrombosis and clinical end points. CYP2C19 genotype has been associated with increased risk of thrombosis in patients with coronary disease or cardiac interventions being considered as candidates for clopidogrel treatment. This observation is most pronounced for stent thrombosis in patients undergoing percutaneous coronary intervention. The evidence addressing whether the use of CYP2C19 genotypedirected therapy improves outcomes is limited. One RCT comparing CYP2C19 genotype-directed antiplatelet therapy reported that patients receiving genotype-directed therapy had higher on-treatment platelet reactivity. However, the effect on clinical end points is not well understood. The evidence is insufficient to determine the effects of the technology on health outcomes.