Dataset Information

CYP2C19 genetic variation and individualized clopidogrel prescription in a cardiology clinic.

ABSTRACT: Background: Clopidogrel (Plavix) is an antiplatelet medication that is routinely used in patients with cardiovascular disease. Cytochrome P2C19 enzymes play a major role in its metabolism, which determines its varied therapeutic level and its effectiveness. Objectives: To customize clopidogrel therapy and evaluate its efficacy by using CYP2C19 genotypic and phenotypic information to improve clinical outcomes in patients. Methods: A total of 465 patients with underlying cardiovascular disease were selected from our out-patient cardiology clinic. DNA sequences of CYP2C19 were analyzed in 465 patients. Results: Of 465 patients, 183 were wild-type homozygous (*1/*1) and 18.8% gain-of function and 19.8% loss-of-function alleles in our patient population The following changes were made: 1) Switching to prasugrel in patients whose genotype noted them to be "Slow metabolizers. This medication adjustment improved clinical outcomes in this patient group. 2) Discontinuing or lowering clopidogrel doses in patients whose genotypes noted them to be "Fast or ultra-fast metabolizes" to decrease bleeding risk. For those who were not on clopidogrel but carried abnormal allele(s), "clopidogrel caution" was documented. These individuals were followed up for 3 years and there has not been any cardiac clinical symptoms, cardiac death or excessive bleeding reported. Conclusions: Given the varied effectiveness of clopidogrel due to its metabolism by CYP2C19 enzyme, and the relatively high frequency of both gain-of-function (18.8%) and loss-of-function (19.8%) alleles in our patient population, we believe that genotyping CYP2C19 is clinically important in order to improve patient outcomes and minimize patient risk.

SUBMITTER: Mirabbasi SA

PROVIDER: S-EPMC5538219 | biostudies-other | 2017 Jul

REPOSITORIES: biostudies-other

ACCESS DATA

Similar Datasets

Project description:ObjectivesThis study sought to evaluate the influence of the genetic polymorphisms on platelet reactivity and clinical outcomes in acute ischemic stroke patients taking clopidogrel.BackgroundLittle research has been published on relationships between genetic polymorphisms, platelet reactivity, and clinical outcomes in stroke patients treated with clopidogrel.MethodsPatients hospitalized in Changhai Hospital with acute ischemic stroke were randomly enrolled into treatment with a 75-mg daily maintenance dose of clopidogrel. Genotyping was detected by the MassARRAY iPLEX genotyping system (Sequenom Inc, San Diego, CA), and platelet reactivity was evaluated by the VerifyNow P2Y12 test (Accumetrics Inc., San Diego, CA). Sixteen single nucleotide polymorphisms (SNPs) within 9 genes were selected and high on-clopidogrel platelet reactivity (HPR) was defined as P2Y12 reaction units (PRU) value ≥230. The primary endpoint was ischemic events, including major adverse cardiac events (MACE), recurrence of stroke, transient ischemic attack (TIA), and the composite of vascular death, and the secondary endpoint was bleeding.ResultsOf the 345 patients recruited, 275 (79.7%) patients were followed up for 1 year and 122 (35.4%) patients were categorized as HPR. Among the SNPs selected, only the CYP2C19*2 allele and the CYP2C19*3 allele were statistically significantly associated with PRU (P < 0.001 and P = 0.003, respectively). Similarly, the prevalence of HPR was associated with CYP2C19*2 and CYP2C19*3 (P < 0.001 and P = 0.001, respectively). During the 1 year of follow-up, a total of 64 (23.3%) cases of clinical events occurred, including 60 ischemic events and 4 bleeding events. There were no correlation between CYP2C19 variant alleles and clinical outcomes (P > 0.05), but a statistically significant relevance was found between the HPR and the ischemic events in 1 year of follow-up (P = 0.001).ConclusionsCYP2C19*2 and CYP2C19*3 had a significant impact on clopidogrel response, but was not associated with ischemic events during 1 year of follow-up in patients with acute ischemic stroke. HPR was an independent risk factor for ischemic events, and the VerifyNow P2Y12 test may be available to guide individualized antiplatelet therapies in stroke patients in China.

Project description:Cytochrome P450 2C19 (CYP2C19) is the principal enzyme responsible for converting clopidogrel into its active metabolite, and common genetic variants have been identified, most notably CYP2C19*2 and CYP2C19*17, that are believed to alter its activity and expression, respectively.We evaluated whether the consequences of the CYP2C19*2 and CYP2C19*17 variants on clopidogrel response were independent of each other or genetically linked through linkage disequilibrium (LD).We genotyped the CYP2C19*2 and CYP2C19*17 variants in 621 members of the Pharmacogenomics of Anti-Platelet Intervention (PAPI) Study and evaluated the effects of these polymorphisms singly and then jointly, taking into account LD, on clopidogrel prodrug level, clopidogrel active metabolite level, and adenosine 5'-diphosphate (ADP)-stimulated platelet aggregation before and after clopidogrel exposure.The CYP2C19*2 and CYP2C19*17 variants were in LD (|D'| = 1.0; r(2) = 0.07). In association analyses that did and did not account for the effects of CYP2C19*17, CYP2C19*2 was strongly associated with levels of clopidogrel active metabolite (? = -5.24, P = 3.0 × 10(-9) and ? = -5.36, P = 3.3 × 10(-14) , respectively) and posttreatment ADP-stimulated platelet aggregation (? = 7.55, P = 2.9 × 10(-16) and ? = 7.51, P = 7.0 × 10(-15) , respectively). In contrast, CYP2C19*17 was marginally associated with clopidogrel active metabolite levels and ADP-stimulated platelet aggregation before (? = 1.57, P = 0.04 and ? = -1.98, P = 0.01, respectively) but not after (? = 0.40, P = 0.59 and ? = -0.13, P = 0.69, respectively) adjustment for the CYP2C19*2 variant. Stratified analyses of CYP2C19*2/CYP2C19*17 genotype combinations revealed that CYP2C19*2, and not CYP2C19*17, was the primary determinant in altering clopidogrel response.Our results suggest that CYP2C19*17 has a small (if any) effect on clopidogrel-related traits and that the observed effect of this variant is due to LD with the CYP2C19*2 loss-of-function variant.

Dataset Information

CYP2C19 genetic variation and individualized clopidogrel prescription in a cardiology clinic.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets