Clopidogrel utilization in patients with coronary artery disease and diabetes mellitus: should we determine CYP2C19*2 genotype?

Analysis of CYP2C19 gene polymorphism and influencing factors of pharmacological response of clopidogrel in patients with cerebral infarction in Zhejiang, China

Background

Certain genetic and non-genetic factors may cause damaged platelet inhibition by clopidogrel. We aimed to determine the effect of cytochrome P4502C19 (CYP2C19) polymorphism, along with other clinical factors, on the platelet response to clopidogrel in patients with acute ischemic stroke (AIS).

Methods

A total of 214 patients with AIS receiving clopidogrel at a maintenance dose of 75 mg daily admitted to the Ningbo First Hospital between 1 January 2020, and 31 December 2021, were enrolled. Platelet aggregation analysis was performed to determine clopidogrel resistance. Quantitative real-time polymerase chain reaction (QRT-PCR) was used to determine CYP2C19 genotype. Other laboratory data on complete blood count and biochemical parameters were taken from patient medical files.

Results

Among the 214 AIS patients treated with clopidogrel in the Ningbo population, the incidence of clopidogrel resistance was approximately 43.9%, and the distribution of CYP2C19 genotypes was highest for CYP2C19(*1/*2) (43.0%), followed by CYP2C19 (*1/*1) (38.8%). The distribution of alleles *1, *2, *3, and *17 was 62.1, 32.5, 4.9, and 0.5%, respectively. A chi-squared test showed that the gene frequencies of alleles *2 and *3 were significantly higher in the clopidogrel-resistant group than in the clopidogrel-sensitive group (p < 0.001), and a Mann-Whitney U-test showed that high HCY levels were significantly correlated with clopidogrel resistance (p < 0.001). Multi-factor logistic regression analysis demonstrated that mutant heterozygous genotype [OR 2.893; 95% confidence interval (CI) 1.456-5.748; p = 0.002], mutant homozygous genotype (OR 4.741; 95% CI 1.828-12.298; p = 0.001), and high HCY levels (OR 1.209; 95% CI 1.072-1.362; p = 0.002) were significantly associated with clopidogrel resistance.

Conclusion

According to our results, carrying the CYP2C19*2/*3 allele and high HCY levels are independent risk factors for clopidogrel resistance after clopidogrel therapy in patients with AIS. These two factors should be considered prior to clopidogrel administration.

Clopidogrel Monotherapy After 1-Month Dual Antiplatelet Therapy in Patients With Diabetes Undergoing Percutaneous Coronary Intervention

BACKGROUND

Diabetes was reported to be associated with an impaired response to clopidogrel.

OBJECTIVES

The aim of this study was to evaluate the safety and efficacy of clopidogrel monotherapy after very short dual antiplatelet therapy (DAPT) in patients with diabetes undergoing percutaneous coronary intervention (PCI).

METHODS

A subgroup analysis was conducted on the basis of diabetes in the STOPDAPT-2 (Short and Optimal Duration of Dual Antiplatelet Therapy After Everolimus-Eluting Cobalt-Chromium Stent-2) Total Cohort (N = 5,997) (STOPDAPT-2, n = 3,009; STOPDAPT-2 ACS [Short and Optimal Duration of Dual Antiplatelet Therapy After Everolimus-Eluting Cobalt-Chromium Stent-2 for the Patients With ACS], n = 2,988), which randomly compared 1-month DAPT followed by clopidogrel monotherapy with 12-month DAPT with aspirin and clopidogrel after cobalt-chromium everolimus-eluting stent implantation. The primary endpoint was a composite of cardiovascular (cardiovascular death, myocardial infarction, definite stent thrombosis, or stroke) or bleeding (TIMI [Thrombolysis In Myocardial Infarction] major or minor) endpoints at 1 year.

RESULTS

There were 2,030 patients with diabetes (33.8%) and 3967 patients without diabetes (66.2%). Regardless of diabetes, the risk of 1-month DAPT relative to 12-month DAPT was not significant for the primary endpoint (diabetes, 3.58% vs 4.12% [HR: 0.87; 95% CI: 0.56-1.37; P = 0.55]; nondiabetes, 2.46% vs 2.49% [HR: 0.99; 95% CI: 0.67-1.48; P = 0.97]; P_interaction = 0.67) and for the cardiovascular endpoint (diabetes, 3.28% vs 3.05% [HR: 1.10; 95% CI: 0.67-1.81; P = 0.70]; nondiabetes, 1.95% vs 1.43% [HR: 1.38; 95% CI: 0.85-2.25; P = 0.20]; P_interaction = 0.52), while it was lower for the bleeding endpoint (diabetes, 0.30% vs 1.50% [HR: 0.20; 95% CI: 0.06-0.68; P = 0.01]; nondiabetes, 0.61% vs 1.21% [HR: 0.51; 95% CI: 0.25-1.01; P = 0.054]; P_interaction = 0.19).

CONCLUSIONS

Clopidogrel monotherapy after 1-month DAPT compared with 12-month DAPT reduced major bleeding events without an increase in cardiovascular events regardless of diabetes, although the findings should be considered as hypothesis generating, especially in patients with acute coronary syndrome, because of the inconclusive result in the STOPDAPT-2 ACS trial. (Short and Optimal Duration of Dual Antiplatelet Therapy After Everolimus-Eluting Cobalt-Chromium Stent-2 [STOPDAPT-2], NCT02619760; Short and Optimal Duration of Dual Antiplatelet Therapy After Everolimus-Eluting Cobalt-Chromium Stent-2 for the Patients With ACS [STOPDAPT-2 ACS], NCT03462498).

Clinical and genetic influencing factors on clozapine pharmacokinetics in Tunisian schizophrenic patients

Clozapine (Clz) is an atypical antipsychotic, which its pharmacokinetics can be influenced by several factors. The CYP1A2 and CYP2C19, major enzymes implicated in Clz metabolism, present an interethnic variation on their activity caused by single nucleotide polymorphisms (SNPs). The present study investigated the influence of genetic and nongenetic factors on Clz pharmacokinetics in a southern Mediterranean population. We included adult Tunisian schizophrenic patients having received Clz and undergone a therapeutic drug monitoring (TDM) of Clz by morning C0 monitoring. The genomic DNA was extracted using a salting-out procedure. CYP1A2*1F (rs762551;-163C>A), CYP1A2*1C (rs2069514;-3860 G>A) and CYP 2C19*2 (rs4244285; 681G>A) was analyzed using PCR-RFLP. Fifty-one patients were enrolled in the study. The mutant allele (CYP1A2*1F) was the most frequently detected (58.8%). For CYP1A2*1F, Clz dose-normalized (C0/D ratio) was as high as 1.28 ± 0.37 in CC versus 0.67 ± 0.32 ng mL^-1 per mg day^-1 in AA group (p < 0.001). The influence of genetic (CYP1A2*1F, CYP1A2*1C and CYP2C19*2) and nongenetic parameters (age, weight, gender, tobacco, coffee, and alcohol consumption) on the variation of the Clz C0/D ratio was investigated. Only the CYP1A2*1 F polymorphism correlates significantly with the Clz C0/D variation and could explain 24% of its variability. Our data support a critical role of the CYP1A2 -163C>A on the variation of Clz exposure in Tunisian schizophrenic patients. Considering its narrow therapeutic range, CYP1A2 genotyping combined with TDM of Clz may improve efficacy and safety of this drug. Further studies are needed to investigate this issue.

Should CYP2C19 Genotyping Be Recommended as a Straight Forward Approach to Optimize Clopidogrel Utilization in Patients with Ischemic Stroke Complicated by Type 2 Diabetes Mellitus?

BACKGROUND

There have been few studies on CYP2C19 genotypes and clopidogrel response associated with ischemic stroke (IS), especially IS complicated by type 2 diabetes mellitus (T2DM). This study aimed to investigate the possible association between CYP2C19 polymorphisms and high on-treatment platelet reactivity (HTPR) in IS patients with T2DM in China.

PATIENTS AND METHODS

A total of 426 consecutive IS patients with T2DM were enrolled in this case-control study and they were divided into HTPR group and non-HTPR group according to the ADP-induced platelet inhibition (PIADP) assessed by thromboelastography (TEG). Genotypes were detected by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. Various clinical and demographic data were also recorded. The association between CYP2C19 genetic variants and platelet function was assessed.

RESULTS

Carriers of CYP2C19*2 heterozygous and mutant homozygous genotypes showed significantly lower PIADP than non-carriers (27.2% vs 38.3%, p < 0.001; 27.41% vs 38.3%, p = 0.012, respectively). Compared with the control group, the CYP2C19*2 A allele was more frequent in the HTPR group (34.51% vs 25.82%, p = 0.002). The carriage of CYP2C19*2 mutant allele was significantly associated with increased risk of HTPR (odds ratio (OR) = 1.94, 95% confidence interval (CI) = 1.32-2.85). There was no significant correlation between CYP2C19*3 or *17 genotypes and HTPR risk.

CONCLUSION

CYP2C19*2 mutant allele was associated with attenuated platelet response to clopidogrel and increased risk of HTPR in IS patients with T2DM, suggesting that CYP2C19*2 polymorphism might be an important predictor of HTPR in this high-risk population.

Effectiveness and safety of high dose clopidogrel plus aspirin in ischemic stroke patients with the single CYP2C19 loss-of-function allele: a randomized trial

Background

Dual antiplatelet aggregation therapy leads to better outcomes in patients with carotid artery stenosis, intracranial artery stenosis, minor strokes, or transient ischaemic attacks. However, carriers of the CYP2C19 loss-of-function allele may not experience the desired effects. We attempted to increase the clopidogrel dose to determine whether it would improve the outcomes of stroke patients who carry a single loss-of-function allele.

Methods

We recruited 131 patients with minor ischaemic stroke, within less than 7 days of stroke onset and a CYP2C19 loss-of-function allele, who had moderate-to-severe cerebral artery stenosis. Patients were divided into the high dose group (clopidogrel 150 mg per day + aspirin 100 mg per day over 21 days.) and a normal dose group (clopidogrel 75 mg per day + aspirin 100 mg per day over 21 days). The reported outcomes included any vascular or major bleeding events as the primary and safety endpoints, respectively.

Results

One and six vascular events occurred in the high dose and normal dose groups during the 3-months follow-up period, respectively. However, no significant difference was found between the two groups when adjusted for history of diabetes (hazard ratio, 5482; 95% confidence interval, 0.660 to 45.543; P = 0.115). No major bleeding events occurred.

Conclusions

In patients with ischaemic stroke who had a single CYP2C19 loss-of-function allele and moderate to severe cerebral stenosis, fewer vascular events occurred within 3 months with high dose of clopidogrel and aspirin than with normal dose of clopidogrel and aspirin. However, the difference between the two groups was not significant.

Trial registration

Clinical study of clopidogrel in the treatment of patients with symptomatic moderate to severe cerebral artery stenosis with intermediate metabolites of CYP2C19, URL: http://www.chictr.org.cn/. Unique identifier: ChiCTR1800017411, 07/28/2018;