Predicting Clinical Response to Clopidogrel — Does Genetic Testing Help?

Because clopidogrel is a prodrug that's activated through cytochrome P₄₅₀-related pathways, genetic variants of the CYP2C19 isoenzyme associated with low metabolism might raise risk for adverse cardiovascular events. In 2010, the FDA — in a boxed warning — advised that testing for these genetic variants is available.

In a new meta-analysis of 15 studies, researchers examined whether variants associated with loss or gain in the function of the CYP2C19 system are associated with differences in adverse cardiovascular events or stent thrombosis. The overall risk for stent thrombosis associated with a loss-of-function variant was 1.77 (95% confidence interval, 1.31–2.40); however, adjustment for bias from small studies and publication year tended…