Pereira NL, Farkouh ME, So D, et al. - This open-label randomized clinical trial was conducted to ascertain the impact of a genotype-guided oral P2Y12 inhibitor strategy on ischemic outcomes in CYP2C19 LOF (loss-of-function) carriers following percutaneous coronary intervention (PCI). Participants were 5,302 patients receiving PCI for acute coronary syndromes (ACS) or stable coronary artery disease (CAD). Participants were randomly assigned to genotype-guided group (n = 2,652) or conventional group (n = 2,650). Patients in former group underwent point-of-care genotyping. Ticagrelor was given to CYP2C19 LOF carriers and clopidogrel to noncarriers. Those in the conventional group were treated with clopidogrel and underwent genotyping following 12 months. Findings revealed that genotype-guided selection of an oral P2Y12 inhibitor, vs conventional clopidogrel treatment without point-of-care genotyping, in CYP2C19 LOF carriers with ACS and stable CAD receiving PCI did not afford any statistically significant difference in a composite endpoint of cardiovascular mortality, myocardial infarction, stroke, stent thrombosis, and severe recurrent ischemia on the basis of the prespecified analysis plan and the treatment impact that the study was powered to detect at 12 months.