deCODE Clopidogrel™

Analyzes five SNPs in the CYP2C19 gene that affect response to the anti-platelet drug clopidogrel. This test identifies those who may need adjustment of their clopidogrel dose or who should be put on an alternative medication to prevent recurrent adverse cardiovascular events.

Login to order test

Personalizing therapy

How deCODE Clopidogrel™ can help.

Detecting carriers of reduced function alleles in the CYP2C19 gene identifies those who have decreased bioconversion of clopidogrel to its active metabolite and a decreased anti-platelet response. As a result, they may be at increased risk of recurrent adverse cardiovascular events despite their anti-platelet drug treatment.

The U.S. Food and Drug Administration (FDA) has added a Boxed Warning to the label for clopidogrel, informing health care providers of the availability of the CYP2C19 genetic test for the identification “poor metabolizers”, for whom other anti-platelet medications or alternative dosing strategies should be considered.

Clopidogrel is effective for prevention of adverse cardiovascular events in majority of patients.

The clinical evidence for the efficacy of clopidrogel is derived from three double-blind trials involving 77,599 patients. The CAPRIE study (clopidogrel vs. Aspirin in Patients at Risk of Ischemic Events) was a comparison of clopidogrel to aspirin. The CURE (clopidogrel in Unstable Angina to Prevent Recurrent Ischemic Events) and the COMMIT/CCS-2 (clopidogrel and metoprolol in Myocardial Infarction Trial/Second Chinese Cardiac Study) studies were comparisons of clopidogrel to placebo, given in combination with aspirin and other standard therapy. The CHARISMA (clopidogrel for High Atherothrombotic Risk Ischemic Stabilization, Management, and Avoidance) study (n=l 5,603) also compared clopidogrel to placebo, given in combination with aspirin and other standard therapy.

The lower plasma exposure to the active clopidogrel metabolite in carriers of CYP2C19 loss-of-function alleles is well established, as is the decreased anti-platelet effect by platelet aggregation measurements(1-4).

Although a higher dose regimen in poor metabolizers increases anti-platelet response, the FDA advises healthcare professionals to consider alternative dosing strategies. An appropriate dose regimen for poor metabolizers has not been established by clinical studies.

Recent studies have investigated the association between CYP2C19 genotypes and clinical outcomes in patients. Several studies(1,2,4-9,14) have shown 1.5- to 4-fold more frequent adverse cardiovascular event rates in CYP2C19 loss-of-function allele carriers and poor metabolizers than in non-carriers. Two other studies found that the presence of reduced function CYP2C19 alleles made no or limited difference in primary efficacy outcome compared to that of non-carriers(10,11).

This content was last reviewed on May 12, 2011.