Genetic variants of the drug-metabolizing enzyme CYP2C9 lead to high inter-individual dose response variability of certain drugs, in particular coumarin-based anticoagulants. The CYP2C9 mpx RealFast™ Assay allows for the simultaneous detection of CYP2C9*2 and CYP2C9*3 variants exhibiting impaired enzyme function.

CYP2C9

• Both variants of the CYP2C9 enzyme, *2 (c.430C>T) and *3 (c.1075A>C), exhibit impaired function leading to poor metabolism (PM) phenotypes for various drugs.
• Patients with low enzyme activity are at risk of adverse drug reactions or therapeutic failure, particularly for CYP2C9 substrates with a narrow therapeutic window, such as coumarin-based anticoagulants or phenytoin.
• Individuals with PM phenotype (i.e. genotypes with homozygous or compound heterozygous *2 or *3 alleles) are at greater risk of severe bleeding during coumarin-based anticoagulation therapy with warfarin, acenocoumarol and – to a lesser extent – phenprocoumon.