急性脑梗死患者CYP2C19基因多态性与纤维蛋白原及D-二聚体相关性研究

目的探讨急性脑梗死患者细胞色素P450酶等位基因(CYP2C19基因)多态性与纤维蛋白原(FIB)及D-二聚体相关性。方法选取常规服用氯吡格雷超过1个月的急性脑梗死患者112例为研究对象,采用RT-PCR法检测脑梗死患者外周全血CYP2C19基因型,运用凝固法(Clauss法)检测FIB,透射比浊法检测血浆中D-二聚体。结果112例急性脑梗死患者中快代谢型(快代谢组,CYP2C19*1/*1)患者较多,为46例,占比41.1%;中代谢型(中代谢组,CYP2C19*1/*2、CYP2C19*1/*3)为41例,占比36.6%;慢代谢型(慢代谢组,CYP2C19*2/*2、CYP2C19*2/*3)最少,为25例,占比22.3%。慢代谢组FIB及D-二聚体水平高于快代谢组及中代谢组,差异有统计学意义(P<0.05)。CYP2C19基因型与FIB及D-二聚体呈正相关(r=0.129、0.158,P<0.05)。结论CYP2C19基因型与FIB和D-二聚体具有一定相关性,使用常规剂量的氯吡格雷治疗CYP2C19基因慢代谢型急性脑梗死患者,可能增加血栓风险,可考虑更换新的药物或增加剂量进行治疗。     

CYP2C8 *3 and *4 define CYP2C8 phenotype: An approach with the substrate cinitapride

Cinitapride is a gastrointestinal prokinetic drug, prescribed for the treatment of functional dyspepsia, and as an adjuvant therapy for gastroesophageal reflux disease. In this study, we aimed to explore the impact of relevant variants in CYP3A4 and CYP2C8 and other pharmacogenes, along with demographic characteristics, on cinitapride pharmacokinetics and safety; and to evaluate the impact of CYP2C8 alleles on the enzyme''s function. Twenty‐five healthy volunteers participating in a bioequivalence clinical trial consented to participate in the study. Participants were genotyped for 56 variants in 19 genes, including cytochrome P450 (CYP) enzymes (e.g., CYP2C8 or CYP3A4) or transporters (e.g., SLC or ABC), among others. CYP2C8*3 carriers showed a reduction in AUC of 42% and C_max of 35% compared to *1/*1 subjects (p = 0.003 and p = 0.011, respectively). *4 allele carriers showed a 45% increase in AUC and 63% in C_max compared to *1/*1 subjects, although these differences did not reach statistical significance. CYP2C8*3 and *4 alleles may be used to infer the following pharmacogenetic phenotypes: ultrarapid (UM) (*3/*3), rapid (RM) (*1/*3), normal (NM) (*1/*1), intermediate (IM) (*1/*4), and poor (PM) metabolizers (*4/*4). In this study, we properly characterized RMs, NMs, and IMs; however, additional studies are required to properly characterize UMs and PMs. These findings should be relevant with respect to cinitapride, but also to numerous CYP2C8 substrates such as imatinib, loperamide, montelukast, ibuprofen, paclitaxel, pioglitazone, repaglinide, or rosiglitazone.     

Personalized Tacrolimus Doses Determined by CYP3A5 Genotype for Induction and Maintenance Phases of Kidney Transplantation

Background

Cytochrome P450 (CYP) 3A4 and 3A5 are major isoforms involved in the metabolism of tacrolimus, with the CYP3A5 gene being more polymorphic. It is hypothesized that individual variation in the metabolism of tacrolimus drug may result from genetic polymorphism of CYP3A5. It has been reported that the clearance of tacrolimus in patients with the CYP3A5*1 allele was ~2.5-fold greater than that in those with the CYP3A5*3/*3 genotype. Recent data have also shown that polymorphism in exon 26 (C3435T) of the multidrug resistance gene (MDR1) was correlated with the expression level and function of P-glycoprotein in the lower duodenum, making the relationship between polymorphism of MDR1 and the effective dose of tacrolimus a source of controversy.

Objectives

This study investigated the influence of genetic polymorphisms of CYP3A5 and MDR1 on the dose requirements for the induction and maintenance phases of tacrolimus therapy in kidney transplant recipients.

Methods

Sixty-eight kidney transplant recipients were enrolled, and their clinical and laboratory data were retrospectively reviewed after 6 months of tacrolimus administration. Genotypes of CYP3A5*1 and CYP3A5*3 and exon 26 of MDR1 (C3435T) were determined by the single-nucleotide polymorphism genotyping method.

Results

The frequencies of CYP3A5*3/*3, CYP3A5*1/*3, and CYP3A5*1/*1 were 44.1%, 35.3%, and 20.6%, respectively. The mean dose of tacrolimus required for the induction phase was significantly greater in the CYP3A5*1/*1 group (0.142 [0.050] mg/kg/d) than that required in the CYP3A5*1/*3 group (0.097 [0.040] mg/kg/d; P = 0.072) and in the CYP3A5*3/*3 group (0.077 [0.020] mg/kg/d; P = 0.005). The maintenance dose of tacrolimus required in the CYP3A5*1/*1 group (0.12 [0.03] mg/kg/d) was 1.3-fold higher than that in the CYP3A5*1/*3 group (0.09 [0.03] mg/kg/d; P = 0.018) and 2.4-fold higher than in the CYP3A5*3/*3 group (0.05 [0.02] mg/kg/d; P < 0.0001). No statistically significant relationship was observed between the doses of tacrolimus required for the induction and maintenance phases and MDR1 polymorphism.

Conclusion

Determination of the CYP3A5 genotype would be helpful in the design of adequate immunosuppressive treatment and in lowering toxicity by predicting the doses of tacrolimus required for the induction and maintenance phases in individual kidney transplant recipients.     

Relationship between cytochrome P450 2C19*2 polymorphism and stent thrombosis following percutaneous coronary intervention in Chinese patients receiving clopidogrel

This study investigated the relationship between the cytochrome P450 2C19 (CYP2C19) *2 polymorphism (681A) and definite stent thrombosis (ST) in patients undergoing percutaneous coronary intervention (PCI) and receiving clopidogrel (75 mg/day, orally). The CYP2C19*2 polymorphism status of 1738 Chinese patients with coronary artery disease was examined. The primary endpoint was the occurrence of definite ST during the 180-day follow-up period. The presence of at least one CYP2C19*2 allele was significantly associated with increased ST risk (19 CYP2C19*2/*2 or *1/*2 patients [2.4%] versus seven homozygous wild-type CYP2C19*1/*1 patients [0.75%]). The risk of definite ST was highest in patients with the CYP2C19*2/*2 genotype. The CYP2C19*2 genotype is associated with an increased risk of definite ST following coronary stent placement among Chinese patients with coronary artery disease receiving clopidogrel.     

CYP2C19 genotype affects diazepam pharmacokinetics and emergence from general anesthesia

OBJECTIVES: Diazepam is widely used to relieve preoperative anxiety in patients. The objective of this study was to investigate the effects of polymorphism in CYP2C19 and the effects of CYP3A4 messenger ribonucleic acid (mRNA) content in blood on recovery from general anesthesia and on diazepam pharmacokinetics. METHODS: Sixty-three Japanese patients were classified into the following 3 genotype (phenotype) groups on the basis of polymerase chain reaction-restriction fragment length polymorphism analysis of CYP2C19 polymorphism: no variants, *1/*1 (extensive metabolizer [EM]); 1 variant, *1/*2 or *1/*3 (intermediate metabolizer [IM]); and 2 variants, *2/*2, *2/*3, or *3/*3 (poor metabolizer [PM]). We assessed the effects of these polymorphisms and of CYP3A4 mRNA content in the lymphocytes on the patients' recovery from general anesthesia. RESULTS: CYP2C19 genotyping analysis in the 63 subjects showed that 32%, 46%, and 22% of subjects were classified into the EM, IM, and PM groups, respectively. The PM subjects showed a larger area under the curve representing the concentration of diazepam over a 24-hour period (AUC(0-24)) (2088 +/- 378 ng/mL.h(-1), P = .0259), lower clearance of diazepam (0.049 +/- 0.009 L.h(-1).kg(-1), P = .0287), and longer emergence time (median, 18 minutes; 25th-75th percentile range, 13-21 minutes; P < .001) in comparison with subjects in the EM group (AUC(0-24), 1412 +/- 312 ng/mL; clearance, 0.074 +/- 0.018 L.h(-1).kg(-1); and emergence time, 10 minutes, 8-12 minutes [median and 25th-75th percentile range]). The IM group also showed a longer emergence time (median, 13 minutes; 25th-75th percentile range, 9-20 minutes; P < .001) and a larger variation in this parameter in comparison with the EM group. The distributions of the CYP2C19 genotype were significantly different between the 2 groups (rapid emergence <20 minutes, slow emergence >20 minutes) (P = .0148). The mean value of the CYP3A4 mRNA level in the slow-emergence group (mean +/- SD, 4.80 +/- 3.99 x10(-10)) was significantly lower than that of the rapid-emergence group (mean +/- SD, 12.50 +/- 11.90 x10(-10)) (P = .0315). However, there was no significant correlation between emergence time and CYP3A4 mRNA levels (r = 0.239, P = .0601). CONCLUSION: We found that the CYP2C19 genotype affects diazepam pharmacokinetics and emergence from general anesthesia and that the slow-emergence group possesses lower levels of CYP3A4 mRNA than are found in the rapid-emergence group.     

ABCB1和CYP2C19基因多态性与动脉粥样硬化性脑梗死患者氯吡格雷疗效的相关性

目的:探讨在急性动脉粥样硬化性脑梗死患者中,不同ABCB1和CYP2C19基因型对氯吡格雷抗血小板疗效的影响。方法:纳入115例发病7 d内住院的急性动脉粥样硬化性脑梗死患者,根据CYP2C19基因型分为3组:快代谢型、中代谢型、慢代谢型;根据ABCB1基因型分为野生型和突变型。再根据ABCB1和CYP2C19两种基因突变的数量,将入组患者分为A组(两个基因均无突变)、B组(其中一个基因发生突变)和C组(两个基因均发生突变)。所有患者均予以卒中单元常规治疗,利用血栓弹力图仪(thromb elasto gram, TEG)检测患者服用氯吡格雷7 d后的血小板功能及血小板药物抑制率,并在患者入院时及服用氯吡格雷治疗7 d后进行神经功能评估,包括美国国立卫生研究院卒中量表(National Institute of Health Stroke Scale, NIHSS)及改良Rankin量表(modified rankin scale, mRS)。结果:CYP2C19基因快代谢型、中代谢型、慢代谢型分别有46例、48例(其中*1/*2 40例,*1/*3 8例)、21例(其中*2/*2 18例,*2/*3 3例);ABCB1野生型49例,突变型66例;A、B、C组患者分别有23例、50例、42例。不同ABCB1、CYP2C19基因型及含不同基因突变数量患者中,血小板药物抑制率、血小板功能及急性期神经功能变化情况差异均无统计学意义。结论:在本研究所纳入的急性动脉粥样硬化性脑梗死人群中,未发现ABCB1、CYP2C19基因多态性对氯吡格雷疗效的影响。     

陕西地区CYP2C19基因多态性在不同性别、年龄、民族冠心病患者中的分布特征以及与国内其他地区的对比分析

目的探讨陕西地区冠心病治疗患者CYP2C19基因多态性分布情况。方法选取该院冠心病治疗患者4248例,检测CYP2C19的基因型,统计等位基因及代谢表型分布特征,并对比不同地区汉族和其他民族等位基因及代谢表型分布差异。结果CYP2C19*1、CYP2C19*2和CYP2C19*33种等位基因的频率分别为64.67%、30.65%、4.68%;快代谢型(*1/*1)1749例,发生率41.17%,中间代谢型(*1/*2、*1/*3)1996例,发生率46.99%,慢代谢型(*2/*2、*2/*3、*3/*3)503例,发生率11.84%;不同性别之间基因型及代谢型分布差异无统计学意义(P>0.05);不同年龄段患者CYP2C19基因型分布差异无统计学意义(P>0.05),等位基因分布差异有统计学意义(P<0.05);我国不同地区汉族人群等位基因分布差异有统计学意义(P<0.05),代谢型分布差异无统计学意义(P>0.05);不同民族等位基因及代谢型分布差异均有统计学意义(P<0.05)。结论陕西地区冠心病患者基因型主要以CYP2C19*1/*2为主,代谢表型主要以中间代谢型为主,可以评估其氯吡格雷抵抗风险,为患者制定个体化的抗血小板治疗方案。     

Pharmacodynamic Effect of Cilostazol Plus Standard Clopidogrel Versus Double-Dose Clopidogrel in Patients With Type 2 Diabetes Undergoing Percutaneous Coronary Intervention

OBJECTIVE

To determine the effect of adding cilostazol (100 mg b.i.d.) to standard-dose clopidogrel (75 mg/d) (TRIPLE) compared with double-dose clopidogrel (150 mg/d) (DOUBLE) and the influence of the cytochrome P450 (CYP2C19*2/*3, CYP3A5*3)and ATP-binding cassette subfamily B1(ABCB1 C3435T) genetic polymorphisms in type 2 diabetes (T2DM) patients.

RESEARCH DESIGN AND METHODS

T2DM patients were treated with TRIPLE (n = 41) or DOUBLE (n = 39) after percutaneous coronary intervention. Conventional aggregometry and VerifyNow were performed at baseline and at 30 days. The primary end point was absolute change in 20-μM ADP-induced maximal platelet aggregation (ΔMPA₂₀) between baseline and switching values.

RESULTS

TRIPLE versus DOUBLE showed greater ΔMPA₂₀ (22.9 ± 11.6 vs.12.7 ± 15.5%; difference, 10.2% [95% CI 4.2–16.3]; P < 0.001). Carriage of one (β coefficient, −5.4%; P = 0.162) and two CYP2C19 loss-of-function allele(s) (−8.3%; P = 0.007) were associated with lower ΔMPA₂₀ in DOUBLE–treated patients, but not in TRIPLE-treated patients.

CONCLUSIONS

Among T2DM patients, adding cilostazol achieves greater platelet inhibition compared with clopidogrel (150 mg/d), which is not influenced by genetic polymorphisms.Patients with type 2 diabetes (T2DM) have greater morbidity and mortality from cardiovascular disease than patients without T2DM. Moreover, increased short- and long-term ischemic event occurrences have been observed in diabetes patients treated with percutaneous coronary intervention (PCI) (1). Dual-antiplatelet therapy with aspirin and a P2Y₁₂ inhibitor has been the mainstay to prevent ischemic events among T2DM patients undergoing PCI. However, the antiplatelet and clinical responses to clopidogrel in PCI-treated patients can be influenced by several single nucleotide polymorphisms of the gene encoding cytochrome P450 (CYP2C19*2/*3, CYP3A5*3) and the ATP-binding cassette gene B1 (ABCB1) (2,3).Cilostazol is a dual-inhibitor of phosphodiesterase type 3 (PDE3) and adenosine reuptake in endothelium, vascular smooth muscle cells, inflammatory cells, and platelets (4). These pleiotropic effects, in addition to platelet inhibition, may affect the occurrence of atherothrombosis in cilostazol-treated patients. The pharmacodynamic and clinical benefit of cilostazol is more prominent in high-risk settings, particularly in diabetes patients (4,5). Cilostazol maintains intraplatelet cyclic AMP levels, which are markedly abnormal in diabetes patients, making them more susceptible to cilostazol effects (5). However, cilostazol metabolism also shows the substantial interindividual variability via CYP3A5 and CYP2C19 polymorphisms (6).The current analysis evaluated the antiplatelet effect of adding cilostazol (TRIPLE) or double-dose clopidogrel (150 mg/d) (DOUBLE) compared with standard-dose clopidogrel in high-risk T2DM patients undergoing PCI. We also assessed the influence of single nucleotide polymorphisms on the effect of these regimens.     

中国福建泉州地区心脑血管患者 CYP2C19，ABCB1基因多态性的检测分析

目的　检测分析泉州地区心脑血管病患者氯吡格雷相关基因细胞色素 P4502C19（ CYP2C19）和三磷酸腺苷黏合 转运体B1 （ ABCB1）的突变情况。方法　收集2018 年5 月~2019 年5 月到泉州第一医院住院接受治疗的2 029 例心脑 血管病患者的全血标本,采用sanger 测序法检测 CYP2C19,ABCB1基因型,应用Hardy-Weinberg 遗传平衡吻合度检验方法, 判断选取的标本是否具有群体代表性。根据性别、年龄因素对患者进行分组,采用四格表资料的χ2 检验,R×C 表资料的 χ2 检验比较各组间氯吡格雷代谢相关基因CYP2C19,ABCB1,氯吡格雷代谢型的分布差异。结果　CYP2C19* 2（G681A）, * 3（G636A）,* 17（C806T）,ABCB1（C3435T）的等位基因频率分别为 57.1 %,10.0%,1.5% 和60.1%,每个等 位基因分布的观察值和预期值差异有统计学意义（χ2=0.000~3.316,均P >0.05）,符合遗传平衡定律, 具有群体代表性。 CYP2C19 * 1 /* 1,CYP2C19 * 1 / * 2,CYP2C19* 1 /* 3,CYP2C19* 1 /* 17,CYP2C19* 2 /* 2,CYP2C19* 2 /* 3, CYP2C19* 2 /* 17,CYP2C19 * 3 /* 17 基因型频率分布分别为 35.5%,42.1%,6.4%,0.9%,11.1%,3.4%,0.4 % 和0.2%, 氯吡格雷超代谢型、快代谢型、中代谢型、慢代谢型的频率分别为0.9%,35.5%,49.1% 和14.5%。CYP2C19 基因型及 氯吡格雷代谢类型在不同性别之间分布差异有统计学意义（χ2=838.9~1361.134,均P <0.05）,氯吡格雷代谢类型在男 性不同年龄段的差异无统计学意义（χ2=11.408,P >0.05）,氯吡格雷代谢类型在女性不同年龄段的差异无统计学意义 （χ2=21.262, P >0.05）。ABCB1（C3435T）基因型CC,CT 和TT 的频率分别为39.9%,44.4% 和15.7%,ABCB1 基 因型在不同性别之间分布差异有统计学意义（χ2=139.445,P <0.05）。结论　泉州地区心脑血管患者 CYP2C19 基因型 主要以CYP2C19 * 1 /* 2 （42.1%）为主,ABCB1 基因型主要以CT（44.4%）为主,氯吡格雷代谢表型以中代谢（49.1%） 为主。CYP2C19 基因型、ABCB1 基因型及氯吡格雷代谢类型在不同性别之间是有差异的。氯吡格雷代谢类型在同性不 同年龄段是没有差异的。     

武汉地区冠心病患者氯吡格雷药物代谢相关基因CYP2C19的多态性分布分析

目的 探讨武汉地区冠心病介入患者氯吡格雷代谢相关基因CYP2C19多态性的分布。方法 选取2014年1月～12月武汉大学人民医院心内科进行介入治疗(PCI)的316例冠心病患者作为研究对象。通过基因芯片法检测氯吡格雷代谢相关的CYP2C19*1,*2,*3基因,并将患者按CYP2C19基因型别分为不同代谢类型:强代谢型(*1/*1),中间代谢型(*1/*2,*1/*3),弱代谢型(*2/*2,*3/*3,*2/*3)。结果 根据CYP2C19基因多态性位点功能代谢分型,携带CYP2C19*1的强代谢型(*1/*1)占43.4%,携带CYP2C19*2或*3的中间代谢型(*1/*2和*1/*3)及弱代谢型(*2/*2,*2/*3和*3/*3)分别占42.4%,14.2%。不同性别在CYP2C19基因分型上差异无统计学意义。结论 武汉地区冠心病介入患者中分布有较多的CYP2C19氯吡格雷代谢功能缺失基因。     

Interindividual variability in ibuprofen pharmacokinetics is related to interaction of cytochrome P450 2C8 and 2C9 amino acid polymorphisms

OBJECTIVE: Our objective was to identify genetic factors related to interindividual variability in the pharmacokinetics of ibuprofen and its enantiomers. METHODS: The time course for ibuprofen plasma concentration was measured by HPLC in 130 healthy individuals who received a single oral dose of 400 mg racemic ibuprofen. Genomic deoxyribonucleic acid was analyzed for common mutations at CYP2C8 and CYP2C9 genes that cause amino acid substitutions. RESULTS: Ibuprofen clearance values were 4.04 L/h (95% confidence interval [CI], 3.61-4.47 L/h), 2.79 L/h (95% CI, 2.07-3.52 L/h), and 0.40 L/h (95% CI, 0.37-0.43 L/h) for carriers of CYP2C8 genotypes *1/*1, *1/*3, and *3/*3, respectively, and 4.43 L/h (95% CI, 3.94-4.92 L/h), 3.26 L/h (95% CI, 2.53-3.99 L/h), 2.91 L/h (95% CI, 1.52-4.30 L/h), 2.05 L/h (95% CI, 0-6.37 L/h), 1.83 L/h (95% CI, 1.24-2.41 L/h), and 1.13 L/h (95% CI, 0.58-1.66 L/h) for carriers of the CYP2C9 genotypes *1/*1, *1/*2, *1/*3, *2/*2, *2/*3, and *3/*3, respectively. The P values for comparison across nonmutated, heterozygous, and homozygous genotypes were as follows: P <.001 for CYP2C8*3, P <.005 for CYP2C9*2, and P <.001 for CYP2C9*3. The main genetic factor for reduced clearance of R-(-)-ibuprofen is the CYP2C8*3 allele, whereas the clearance for S-(+)-ibuprofen is influenced by CYP2C8*3 and CYP2C9*3 alleles to a similar extent. The CYP2C9*2 allele was associated with low clearance only when it was present in combination with the CYP2C8*3 allele. As compared with individuals with no mutations, individuals with the common genotype CYP2C8*1/*3 plus CYP2C9*1/*2 (19% of the population) displayed decreased ibuprofen clearance (mean, 65% [95% CI, 42%-89%]; P <.001). Individuals homozygous or double-heterozygous for CYP2C8*3 and CYP2C9*3 variant alleles (8% of the population) had extremely low ibuprofen clearance rates, with values ranging from 7% to 27% of the mean clearance rates among noncarriers of mutations (P <.001). No enantiospecific reduction of ibuprofen clearance was observed. CONCLUSION: Low ibuprofen clearance occurs in a substantial proportion of healthy subjects, is not enantiospecific, and is strongly linked to CYP2C8 and CYP2C9 polymorphisms.     

DNA微阵列芯片法与直接测序法检测CYP2C19基因型的比较研究

目的 用DNA微阵列芯片法和直接测序法两种方法检测氯吡格雷相关基因CYP2C19的突变情况,并进行比较分析。同时将基因型检测结果与临床资料进行分析,初步探讨CYP2C19基因型检测在氯吡格雷用药治疗中的临床意义。方法收集180例诊断为急性冠脉综合症并首次接受经皮冠状动脉介入治疗术(PCI)的全血标本。其中90例患者术后服用氯吡格雷之前,采用DNA微阵列芯片法和DNA直接测序法检测CYP2C19突变位点,确定其基因型。另外90例对照组患者使用氯吡格雷药物但不检测CYP2C19基因型。分析两组患者随访过程中发生冠脉血栓事件的差异。结果 ①两种检测方法准确度比较:在试验组90例患者中,DNA微阵列芯片法和DNA测序法均检出4种基因型组合:*1/*1(636GG,681GG),*1/*2(636GG,681GA),*2/*2(636GG,681AA)和*1/*3(636GA,681GG),分布频率分别为44例(48.9%),36例(40%),5例(5.6%)和5例(5.6%),而*3/*3(636AA,681GG)和*2/*3(636GA,681GA)未检测到。两种方法的准确度完全一致。②将检测结果与临床资料进行相关性分析:经CYP2C19基因型指导氯吡格雷用药的患者发生支架冠脉血栓事件的比例(0%)明显低于对照组(3.33%,P<0.05)。结论①DNA微阵列芯片法灵敏度和准确度与DNA直接测序法(金标准方法)检测相符率为100%。②DNA微阵列芯片法是一种快速、准确发现CYP2C19突变位点,鉴别CYP2C19基因型的检测方法。③检测结果与临床相关性分析结果显示基因型指导氯吡格雷用药有助于患者用药剂量的调整,或选用其它抗凝血药物,从而可降低冠脉血栓事件的发生率。     

CYP2C19 and ABCB1 genetic polymorphisms correlate with the recurrence of ischemic cardiovascular adverse events after clopidogrel treatment

Background

This study was aimed to investigate the correlation between CYP2C19 and ABCB1 polymorphisms and the recurrence of ischemic cardiovascular adverse events in patients with coronary artery disease treated with clopidogrel.

Methods

A total of 168 patients with coronary heart disease who underwent PCI operation and received clopidogrel treatment were enrolled. Dual antiplatelet therapy was applied to the treatment of patients for 2 years. Thromboelastography was used to test the efficiency of blood coagulation. Polymerase chain reaction (PCR) was used to detect CYP2C19 and ABCB1 3435CT polymorphisms. One‐year follow‐up visit was carried out to record the incidence of cardiovascular adverse events after drug‐eluting stent implantation was inset.

Results

Follow‐up visit results suggested that the patients with high on‐treatment platelet reactivity (HPR) had a higher recurrence rate of cardiovascular adverse events after PCI operation and clopidogrel treatment. Gene polymorphism testing results indicated that patients with CYP2C19*3 had a significantly higher incidence of HPR, whereas CYP2C19*2 and ABCB1 3435CT were not significantly correlated with HPR. Multivariable logistic regression analysis showed that CYP2C19*3 might be an independent predictive factor of post‐PCI HPR. In addition, CYP2C19*3 as well as post‐PCI HPR could function as independent predictive factors of cardiovascular adverse events.

Conclusion

CYP2C19*3 polymorphism could be an important predictive factor of HPR and ischemic cardiovascular adverse events after clopidogrel treatment.

     

Influence of CYP2C9 and CYP2C19 genetic polymorphisms on pharmacokinetics and pharmacodynamics of gliclazide in healthy Chinese Han volunteers

Background and objective: CYP2C9 is the major contributor to gliclazide metabolic clearance in vitro, while the pharmacokinetics of gliclazide modified release are affected mainly by CYP2C19 genetic polymorphisms in vivo. This study aims to investigate the influence of CYP2C9 and CYP2C19 genetic polymorphisms on the pharmacokinetics and pharmacodynamics of gliclazide in healthy Chinese Han volunteers. Methods: Eighteen healthy Han subjects with various combinations of CYP2C9 and CYP2C19 genotypes received 80 mg gliclazide. Plasma gliclazide concentrations were measured by a liquid chromatography–tandem mass spectrometry method for 84 h and plasma glucose and insulin levels were measured up to 15 h post‐dose. Results and discussion: There was no difference in either pharmacokinetic and or pharmacodynamic parameters of gliclazide when group A (CYP2C9*1/*1, CYP2C19 extensive metabolizers) was compared with group B (CYP2C9*1/*3, CYP2C19 *1/*1). When group C (CYP2C9*1/*1 and CYP2C19 poor metabolizers) was compared with group A, the AUC_0–∞ and C_max in group C were significantly higher [83·94 ± 40·41 vs. 16·39 ± 5·10 μg·h/mL (P = 0·000) and 1·50 ± 0·85 vs. 0·45 ± 0·18 μg/mL (P = 0·000)], and the oral clearance was significantly lower [1·17 ± 0·63 vs. 5·38 ± 1·86 L/h (P = 0·000)]. The half‐life of gliclazide was also significantly prolonged in group C subjects when compared with that of group A (33·47 ± 12·39 vs. 19·34 ± 10·45 h), but the difference was not significant (P = 0·052). The increase in serum glucose level at 11 h after dosing (ΔC_glu11) in group C was significantly higher than that of group A (?1·08 ± 0·42 vs. 0·22 ± 1·01 mmol/L, P = 0·022). The corresponding insulin levels showed no difference between the two groups. Conclusion: CYP2C9*3 was not associated with any change in the disposition of gliclazide. CYP2C19 polymorphisms appear to exert the dominant influence on the pharmacokinetics of gliclazide in healthy Chinese Han subjects, and may also affect the observed pharmacodynamics of the drug as a result.     

Phenotyping vs. genotyping for prediction of clopidogrel efficacy and safety: the PEGASUS‐PCI study

Summary. Background: Prognostic values of genotyping and phenotyping for assessment of clopidogrel responsiveness have been shown in independent studies.Objectives: To compare different assays for prediction of events during long‐term follow‐up.Methods: In this prospective cohort study polymorphisms of CYP2C19*2 and CYP2C19*17 alleles, vasodilator‐stimulated phosphoprotein phosphorylation (VASP) assay, multiple electrode aggregometry (MEA), cone and platelet analyser (CPA) and platelet function analyser (PFA‐100) were performed in 416 patients undergoing percutaneous coronary intervention. The rates of events were recorded during a 12‐month follow‐up.Results: Platelet aggregation by MEA predicted stent thrombosis (2.4%) better (c‐index = 0.90; P < 0.001; sensitivity = 90%; specificity = 83%) than the VASP assay, CPA or PFA‐100 (c‐index < 0.70; P > 0.05; sensitivity < 70%; specificity < 70% for all) or even the CYP2C19*2 polymorphism (c‐index < 0.56; P > 0.05; sensitivity = 30%; specificity = 71%). Survival analysis indicated that patients classified as poor responders by MEA had a substantially higher risk of developing stent thrombosis or MACE than clopidogrel responders (12.5% vs. 0.3%, P < 0.001, and 18.5% vs. 11.3%, P = 0.022, respectively), whereas poor metabolizers (CYP2C19*1/*2 or *2/*2 carriers) were not at increased risks (stent thrombosis, 2.7% vs. 2.5%, P > 0.05; MACE, 13.5% vs. 12.1%, P = 0.556). The incidence of major bleedings (2.6%) was numerically higher in patients with an enhanced vs. poor response to clopidogrel assessed by MEA (4% vs. 0%) or in ultra‐metabolizers vs. regular metabolizers (CYP2C19*17/*17 vs. CYP2C19*1/*1; 9.5% vs. 2%). The classification tree analysis demonstrated that acute coronary syndrome at hospitalization and diabetes mellitus were the best discriminators for clopidogrel responder status.Conclusions: Phenotyping of platelet response to clopidogrel was a better predictor of stent thrombosis than genotyping.     

Polymorphism in CYP2C8 is associated with reduced plasma concentrations of repaglinide

OBJECTIVE: Our objective was to investigate the effects of genetic polymorphisms of cytochrome P450 (CYP) 2C8 on the pharmacokinetics and pharmacodynamics of the meglitinide analog antidiabetic drug repaglinide. METHODS: We genotyped 28 healthy volunteers who had participated in our pharmacokinetic studies on repaglinide for variant alleles of the CYP2C8 gene. Each subject ingested a 0.25-mg dose of repaglinide, and plasma drug and blood glucose concentrations were monitored for 7 hours after dosing. RESULTS: There were 19 subjects (68%) with the CYP2C8*1/*1 genotype (wild type), 6 subjects (21%) with the CYP2C8*1/*3 genotype, and 3 subjects (11%) with the CYP2C8*1/*4 genotype. In the 3 genotypic groups, the mean +/- SD area under the plasma repaglinide concentration-time curve from time 0 to infinity [AUC(0- infinity )] was 5.8 +/- 2.5 ng. h/mL for CYP2C8*1/*1, 3.6 +/- 0.9 ng. h/mL for CYP2C8*1/*3, and 5.1 +/- 3.6 ng. h/mL for CYP2C8*1/*4. The mean AUC(0- infinity ) of repaglinide was 45% (P <.005) lower and the peak concentration in plasma was 39% lower (P <.05) in subjects with the CYP2C8*1/*3 genotype compared with those with the CYP2C8*1/*1 genotype. No statistically significant differences were found in the blood glucose response to repaglinide between the genotypes. CONCLUSIONS: Unexpectedly, the CYP2C8*3 variant allele was associated with reduced plasma concentrations of repaglinide. The effects of CYP2C8 polymorphisms on the pharmacokinetics of CYP2C8 substrates warrant further study.     

Potent cytochrome P450 2C19 genotype-related interaction between voriconazole and the cytochrome P450 3A4 inhibitor ritonavir

OBJECTIVES: Cytochrome P450 (CYP) 2C19 and CYP3A4 are the major enzymes responsible for voriconazole elimination. Because the activity of CYP2C19 is under genetic control, the extent of inhibition with a CYP3A4 inhibitor was expected to be modulated by the CYP2C19 metabolizer status. This study thus assessed the effect of the potent CYP3A4 inhibitor ritonavir after short-term administration on voriconazole pharmacokinetics in extensive metabolizers (EMs) and poor metabolizers (PMs) of CYP2C19. METHODS: In a randomized, placebo-controlled crossover study, 20 healthy participants who were stratified according to CYP2C19 genotype received oral ritonavir (300 mg twice daily) or placebo for 2 days. Together with the first ritonavir or placebo dose, a single oral dose of 400 mg voriconazole was administered. Voriconazole was determined in plasma and urine by liquid chromatography-mass spectrometry, and pharmacokinetic parameters were estimated by noncompartmental analysis. RESULTS: When given alone, the apparent oral clearance of voriconazole after single oral dosing was 26%+/-16% (P > .05) lower in CYP2C19*1/*2 individuals and 66%+/-14% (P < .01) lower in CYP2C19 PMs. The addition of ritonavir caused a major reduction in voriconazole apparent oral clearance (354+/-173 mL/min versus 202+/-139 mL/min, P = .0001). This reduction occurred in all CYP2C19 genotypes (463+/-168 mL/min versus 305+/-112 mL/min [P = .023] for *1/*1, 343+/-127 mL/min versus 190+/-93 mL/min [P = .008] for *1/*2, and 158+/-54 mL/min versus 22+/-11 mL/min for *2/*2) and is probably caused by inhibition of CYP3A4-mediated voriconazole metabolism. CONCLUSIONS: Coadministration of a potent CYP3A4 inhibitor leads to a higher and prolonged exposure with voriconazole that might increase the risk of the development of adverse drug reactions on a short-term basis, particularly in CYP2C19 PM patients.     

Pharmacokinetics of the new proton pump inhibitor ilaprazole in Chinese healthy subjects in relation to CYP3A5 and CYP2C19 genotypes

BACKGROUND: PPIs are widely used in peptic diseases, and this paper is to investigate the kinetic characteristics of a new PPI ilaprazole in Chinese healthy subjects and the association with CYP3A5 and CYP2C19 polymorphisms. METHODS: 21 subjects were selected and treated with 10mg ilaprazole according to their CYP3A5*3 genotypes (including 7 of CYP3A5*1/*1, 7 of *1/*3, and 7 of *3/*3). The plasma concentrations of ilaprazole and its metabolites were monitored by LC-MS/MS method. RESULTS: The C(max), AUC((0-6)), AUC((0-48)) and AUC((0-infinity)) of ilaprazole were all significantly different across the 3 CYP3A5 genotypes (including 4 of CYP3A5*1/*1, 4 of *1/*3, 3 of *3/*3; P<0.05) in CYP2C19 wild-type subjects (CYP2C19 wt/wts), similar variety of C(max) and AUC((0-6)) among CYP3A5 genotypes (including 3 of CYP3A5*1/*1, 3 of *1/*3, 4 of *3/*3; P<0.05) were also observed in CYP2C19 heterozygous subjects (CYP2C19 wt/mts). The sulfoxidation metabolic index (measure of collective CYP3A activity) indicates that the CYP3A5*1/*1, (high-expressers), *1/*3, (low-expressers), and *3/*3 (no-expressers) groups have medium, lowest and highest activities on ilaprazole metabolism, inconsistent with genotype-based CYP3A5 enzymatic activity. Further analysis showed no correlation between ilaprazole metabolism and CYP2C19 genotypes, evidenced by that the AUC((0-infinity)) of ilaprazole from either CYP3A5*1/*1 or CYP3A5*1/*3 groups was much higher in CYP2C19 wt/wts (n=4) than that in CYP2C19 wt/mts (n=3) (P<0.001), but the C(max) and AUC((0-6)) of ilaprazole from CYP3A5*3/*3 groups, were significantly lower in CYP2C19 wt/wts (n=3) compared to CYP2C19 wt/mts (n=4) (P<0.01). CONCLUSIONS: There was no demonstrated relationship between ilaprazole metabolism and CYP3A5 polymorphisms.     

Impact of the novel CYP2C:TG haplotype and CYP2B6 variants on sertraline exposure in a large patient population

Sertraline is a commonly used SSRI antidepressant drug, metabolized by CYP2C19 and CYP2B6, that exhibits a substantial interindividual variation in clinical response, of which only a part can be attributed to known genetic variants. In the current study we have examined the role of a newly discovered ultrarapid CYP2C:TG haplotype and CYP2B6 variants in order to identify the possible missing heritability for such variation in sertraline response in a large patient population (n = 840). Compared to the reference group (CYP2C19*1/*1, n = 160), sertraline exposure was increased by 128% in CYP2C19 PMs (n = 29, p < 0.001) but decreased by about 20% in CYP2C19 ultrarapid metabolizers (Ums) (homozygous carriers of CYP2C19*17 and/or CYP2C:TG haplotype) with the diplotypes CYP2C19*17/*17, CYP2C:TG/TG, or CYP2C19*17/CYP2C:TG (n = 135, p < 0.003, p = 0.022, p < 0.003, respectively). Interestingly, in patients carrying the increased function CYP2B6*4 allele, and also carrying the CYP2C19*17 and CYP2C:TG alleles (n = 10), sertraline exposure was 35.4% lower compared to the reference group, whereas in subjects being poor metabolizers (PM) in both the CYP2C19 and CYP2B6 gene, the sertraline concentrations were raised by 189%. In summary, the CYP2C19 variants including the CYP2C:TG haplotype had a significant impact on sertraline metabolism, as well as the CYP2B6*4, *6, and *9 alleles. Knowing the CYP2B6 and CYP2C19 genotype, including the CYP2C:TG haplotype status, can prospectively be useful to clinicians in making more appropriate sertraline dosing decisions

Study highlights

• WHAT IS THE CURRENT KNOWLEDGE ON THE TOPIC?

Sertraline is a commonly used antidepressant subjected to metabolism by multiple enzymes with CYP2C19 playing a key role along with CYP2B6 and CYP3A4. Previous pharmacogenetic studies have reported significant effects of CYP2C19 and CYP2B6 genotypes on sertraline concentration, but with inconsistent findings probably reflecting that the concurrent effects of the genotypes have not been investigated in a large patient population. Furthermore, the studies have not accounted for the recently discovered CYP2C:TG haplotype associated with increased CYP2C19‐mediated metabolism.

• WHAT QUESTION DID THIS STUDY ADDRESS?

Our study investigated the impact of the novel CYP2C:TG haplotype on sertraline serum concentration in a large population genotyped for CYP2C19 (variants *2, *3, *4, and *17) and CYP2B6 (variants *4, *6, and *9).

• WHAT DOES THIS STUDY ADD TO OUR KNOWLEDGE?

This study demonstrates that the novel CYP2C haplotype (CYP2C:TG) is associated with increased rate of CYP2C19 metabolism of sertraline, as previously shown for escitalopram. In addition, patients carrying both the CYP2B6*4 variant and CYP2C19 genotypes encoding ultrarapid CYP2C19 metabolism are at increased risk of underexposure and therapeutic failure when treated with standard recommended doses of sertraline, whereas patients with only inactive or decreased function alleles of both CYP2C19 and CYP2B6 have a lower capacity for sertraline metabolism than CYP2C19 poor metabolizers carrying functional CYP2B6 alleles.

• HOW MIGHT THIS CHANGE CLINICAL PHARMACOLOGY OR TRANSLATIONAL SCIENCE?

Preemptive genotyping of sertraline patients would include CYP2C:TG, CYP2C19, and CYP2B6 variants to increase the dose precision of the drug in patients suffering from depression and/or anxiety.     

Analysis of cytochrome P450 gene polymorphism in a lupus nephritis patient in whom tacrolimus blood concentration was markedly elevated after administration of azole antifungal agents

What is known and Objective: Both itraconazole (ITCZ) and voriconazole (VCZ) are potent inhibitors of cytochrome P450 (CYP) 3A, and their effects have been reported to be equal. However, ITCZ is metabolized by CYP3A, whereas VCZ is mainly metabolized by CYP2C9 and CYP2C19 and only partially by CYP3A. We experienced the case of a patient who showed a 5‐fold increase in trough levels of tacrolimus (FK) level after switching from ITCZ to VCZ. Our objective is to discuss the mechanism of the increase drug–drug interaction in terms of serum concentration of the azole drugs and patient pharmacogenomics. Case summary: A 53‐year‐old woman was treated with FK (1 mg/day) for lupus nephritis. Because fungal infection was suspected, she received ITCZ (100 mg/day). When ITCZ was replaced with VCZ (400 mg/day), the blood concentration of FK increased markedly from 6·1 to 34·2 ng/mL. During coadministration with FK, the levels of ITCZ and VCZ were 135·5 ng/mL and 5·5 μg/mL, respectively, with the VCZ level around 3‐fold higher than the previously reported level (1·4–1·8 μg/mL). Her CYP genotypes were CYP2C19*1/*2, CYP3A4*1/*1 and CYP3A5*3/*3. What is new and Conclusion: The patient was a CYP2C19 intermediate metabolizer (IM) and deficient in CYP3A5. The increase in plasma VCZ level appears to have been at least in part, associated with the CYP2C19 IM phenotype. One possible explanation for the marked increase in blood FK concentration was increased inhibition of CYP3A because of the impaired metabolism and subsequent increased plasma concentration of VCZ. This case shows that the severity of drug interactions may be influenced by metabolic gene polymorphism.