CYP2C19 genotype-guided antithrombotic treatment versus conventional clopidogrel therapy in peripheral arterial disease: study design of a randomized controlled trial (GENPAD)

BACKGROUND

Clopidogrel is recommended in international guidelines to prevent arterial thrombotic events in patients with peripheral arterial disease (PAD). Clopidogrel itself is inactive and metabolism is dependent on the CYP2C19 enzyme. About 30% of Caucasian PAD patients receiving clopidogrel carry 1 or 2 CYP2C19 loss-of-function allele(s) and do not or to a limited extent convert the prodrug into its active metabolite. As a result, platelet inhibition may be inadequate which could lead to an increased risk of adverse clinical events related to arterial thrombosis. A CYP2C19 genotype-guided antithrombotic treatment might be beneficial for PAD patients.

METHODS

GENPAD is a multicenter randomized controlled trial involving 2,276 PAD patients with an indication for clopidogrel monotherapy. Patients with a separate indication for dual antiplatelet therapy or stronger antithrombotic therapy are not eligible for study participation. Patients randomized to the control group will receive clopidogrel 75 mg once daily without pharmacogenetic guidance. Patients randomized to the intervention group will be tested for carriage of CYP2C19 *2 and *3 loss-of-function alleles, followed by a genotype-guided antithrombotic treatment with either clopidogrel 75 mg once daily for normal metabolizers, clopidogrel 150 mg once daily for intermediate metabolizers, or acetylsalicylic acid 80 mg once daily plus rivaroxaban 2.5 mg twice daily for poor metabolizers. The primary outcome is a composite of myocardial infarction, ischemic stroke, cardiovascular death, acute or chronic limb ischemia, peripheral vascular interventions, or death. The secondary outcomes are the individual elements of the primary composite outcome and clinically relevant bleeding complications.

CONCLUSION

The aim of the GENPAD study is to evaluate the efficacy, safety, and cost-effectiveness of a genotype-guided antithrombotic treatment strategy compared to conventional clopidogrel treatment in PAD patients.

Racial and ethnic differences in pharmacotherapy to prevent coronary artery disease and thrombotic events

Awareness of racial/ethnic disparities represents a key challenge for healthcare systems that attempt to provide effective healthcare and to reduce existing inequalities in the use of and adherence to guideline-recommended cardiovascular drugs to improve clinical outcomes for cardiovascular disease (CVD). In this review, we describe important racial/ethnic differences between and within ethnic groups in the prevalence, risk factors, haemostatic factors, anti-inflammatory and endothelial markers, recurrence, and outcomes of CVD.

We discuss important differences in the selection, doses, and response [efficacy and adverse drug reactions (ADRs)] in ethnically diverse patients treated with antithrombotics or lipid-lowering drugs. Differences in drug response are mainly related to racial/ethnic differences in the frequency of polymorphisms in genes encoding drug-metabolizing enzymes (DMEs) and drug transporters. These polymorphisms markedly influence the pharmacokinetics, dose requirements, and safety of warfarin, clopidogrel, and statins. This review aims to support a better understanding of the genetic differences between and among populations to identify patients who may experience an ADR or a lack of drug response, thus optimizing therapy and improving outcomes. The greater the understanding of the differences in the genetic variants of DMEs and transporters that determine the differences in the exposure, efficacy, and safety of cardiovascular drugs between races/ethnicities, the greater the probability that personalized medicine will become a reality.

Utility of a pharmacogenetic-driven algorithm in guiding dual antiplatelet therapy for patients undergoing coronary drug-eluting stent implantation in China

PURPOSES

The POPular Risk Score (PRiS), a pharmacogenetic-driven algorithm consisting of CYP2C19 genotype, platelet reactivity, and clinical risk factors, is developed to evaluate ischemic risk and guide dual antiplatelet therapy (DAPT). This study aimed to evaluate the efficacy and safety of DAPT in accordance with the PRiS in patients undergoing drug-eluting stent (DES) implantation.

METHODS

A total of 1757 patients recruited in this cohort study were divided into four groups according to the PRiS and type of P2Y12 receptor inhibitor treatment at discharge. The primary endpoint was major adverse cardiovascular events (MACE, a composite of cardiovascular death, myocardial infarction, stroke, definite or probable stent thrombosis, and target vessel revascularization) during 1-year follow-up. The safety endpoints were defined by Bleeding Academic Research Consortium (BARC) criteria as major bleeding (BARC 3a, 3b, 3c, and 5) and clinically relevant bleeding (BARC 2, 3a, 3b, 3c, and 5).

RESULTS

Among 1046 patients with PRiS < 2 and 711 patients with PRiS ≥ 2, 34.2% and 38.3% of them were treated with ticagrelor, respectively. The PRiS ≥ 2 was an independent predictor for the 1-year incidence of MACE (HR(95%CI): 2.09 (1.37-3.20), p = 0.001). Multivariable Cox regression indicated that in the PRiS ≥ 2 group, ticagrelor was superior to clopidogrel in reducing the risk of MACE (HR(95%CI): 0.53 (0.29-0.98), p = 0.042), without increasing the bleeding risk. On the other hand, in the PRiS < 2 group, clopidogrel treatment was related to a remarkably lower rate of BARC class ≥ 2 bleeding (HR(95%CI): 0.39 (0.20-0.72), p = 0.003), but comparable incidences of MACE and BARC class ≥ 3 bleeding during 1-year follow-up. Similar associations between P2Y12 receptor inhibitors and 1-year endpoints in the PRiS < 2 and PRiS ≥ 2 group could also be identified in propensity score-weighted analysis and propensity score-matched analysis.

CONCLUSION

Tailored DAPT based on the PRiS could assist in improving the prognosis of patients undergoing DES implantation. Further randomized controlled trials are required to provide more evidence for PRiS-guided DAPT.

Risk of stroke in CYP2C19 LoF polymorphism carrier coronary artery disease patients undergoing clopidogrel therapy: An ethnicity-based updated meta-analysis

BACKGROUND

Antiplatelet agent clopidogrel has been widely used for stroke management for many years, although resistance to clopidogrel may increase the chance of stroke recurrence. CYP2C19 loss-of-function (LoF) polymorphism is assumed to be responsible for the poor metabolism of clopidogrel that ultimately turns to resistance. Previous publications could not provide firm evidence due to highly conflicting and heterogeneous outcomes.

AIM

To get clear evidence from an updated meta-analysis on CYP2C19 LoF polymorphism association with stroke risk in clopidogrel treated patients, this study has been performed.

METHODS

We conducted a meta-analysis with 72 selected studies from authentic databases, including 40,035 coronary artery disease patients treated with clopidogrel.

RESULTS

This analysis showed that the worldwide carrier of one or more CYP2C19 LoF alleles had a significantly higher risk of stroke and composite events than the non-LoF carriers (RR=1.78, 95% CI=1.52-2.07, p<0.00001 and RR=1.39, 95% CI=1.26-1.54, p<0.00001, respectively). Besides, subgroup analysis showed that Asian CYP2C19 LoF carriers had a significantly increased risk of stroke (RR=1.91, 95% CI=1.60-2.28, p<0.00001) while the risk of composite events was significantly higher in all ethnic populations (Asian: RR=1.58, 95% CI=1.32-1.89, p<0.00001; Caucasian: RR=1.27, 95% CI=1.08-1.50, p=0.003; Hispanic and others: RR=1.21, 95% CI=1.09-1.34, p=0.0003).

CONCLUSION

Our meta-analysis confirmed that the presence of CYP2C19 LoF alleles increases the risk of stroke and composite events recurrence in the worldwide population, especially in Asians undergoing clopidogrel treatment. Alternative antiplatelet therapy should be investigated thoroughly for the intermediate and poor metabolizers.

Efficacy and safety of opioid therapy guided by pharmacogenetics: a systematic review

Aim: To perform a systematic review to determine the efficacy/safety of PGx-guided opioid therapy for chronic/postoperative pain. Materials & methods: We searched PubMed and other specialized databases. Articles were considered if they compared the efficacy/safety of PGx-guided opioid therapy versus usual care. The risk of bias assessment was performed using Cochrane tools. Results: A total of 3794 records were retrieved. Only five were included for data extraction. A lower requirement of analgesics during postoperative in the PGx-guided intervention arm was reported in two studies. Also, two studies reported significant pain improvement in favor of the PGx-guided therapy when analyzing the subgroup of patients with a high-risk CYP2D6 phenotype. Conclusion: Despite the findings described, information on the efficacy/safety of this intervention is scarce.

Pharmacogenetic genotype and phenotype frequencies in a large Danish population-based case-cohort sample

Pharmacogenetics aims to improve clinical care by studying the relationship between genetic variation and variable drug response. Large population-based datasets could improve our current understanding of pharmacogenetics from selected study populations. We provide real-world pharmacogenetic frequencies of genotypes and (combined) phenotypes of a large Danish population-based case-cohort sample (iPSYCH2012; data of the Integrative Psychiatric Research consortium). The genotyped sample consists of 77,684 individuals, of which 51,464 individuals had diagnoses of severe mental disorders (SMD case-cohort) and 26,220 were individuals randomly selected from the Danish population (population cohort). Array-based genotype data imputed to 8.4 million genetic variants was searched for a selected pharmacogenetic panel of 42 clinically relevant variants and a CYP2D6 gene deletion and duplication. We identified 19 of 42 variants. Minor allele frequencies (MAFs) were consistent with previously reported MAFs, and did not differ between SMD cases and population cohorts. Almost all individuals carried at least one genetic variant (> 99.9%) and 87% carried three or more genetic variants. When genotypes were translated into phenotypes, also > 99.9% of individuals had at least one divergent phenotype (i.e. divergent from the common phenotypes considered normal, e.g. extensive metabolizer). The high number of identified individuals with at least one pharmacogenetic variant or divergent phenotype indicates the importance of pharmacogenetic panel-based genotyping. Combined CYP2C19-CYP2D6 phenotypes revealed that 72.7% of individuals had divergent phenotypes for one or both enzymes. As CYP2D6 and CYP2C19 have an important role in the metabolism of psychotropic drugs, this indicates the relevance of pharmacogenetic testing specifically in individuals using psychotropic drugs.

A meta-analysis of efficacy and safety of genotype-guided versus standard of care treatment strategies in selecting antiplatelet therapy in patients with acute coronary syndrome

BACKGROUND

Previous studies have shown similar rates of major adverse cardiovascular events (MACE) in acute coronary syndrome (ACS) patients, treated with P2Y₁₂ inhibitors based on genotype guidance compared to standard treatment. However, given lower than expected event rates, these studies were underpowered to assess hard outcomes. We sought to systematically analyze this evidence using pooled data from multiple studies.

METHODS

Electronic databases were searched for studies of ACS patients that underwent genotype-guided treatment (GGT) with P2Y₁₂ inhibitors versus standard of care treatment (SCT). Studies with a minimum follow-up of 12 months were included. Rate of MACE (defined as a composite of cardiovascular [CV] mortality, nonfatal myocardial infarction [MI], and nonfatal stroke) was the primary outcome. Secondary outcomes were individual components of MI, CV mortality, ischemic stroke, stent thrombosis, and major bleeding. Odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were calculated and combined using random effects model meta-analysis.

RESULTS

A total of 4,095 patients (2007 in the GGT and 2088 in the SCT group were analyzed from three studies). Significantly lower odds of MACE (6.0 vs. 9.2%; OR: 0.63, 95% CI: 0.50-0.80, p < .001, I² = 0%) and MI (3.3 vs. 5.45%; OR: 0.63; CI 0.41-0.96; p = .03; I² = 46%) were noted in the GGT group compared to SCT. No significant difference was noted with respect to CV and other secondary outcomes.

CONCLUSION

In patients with ACS, genotype-guided initiation of P2Y₁₂ inhibitors was associated with lower odds of MACE and similar bleeding risk in comparison to SCT.

The Role of Pharmacogenomics in Contemporary Cardiovascular Therapy: A position statement from the European Society of Cardiology Working Group on Cardiovascular Pharmacotherapy

There is a strong and ever-growing body of evidence regarding the use of pharmacogenomics to inform cardiovascular pharmacology. However, there is no common position taken by international cardiovascular societies to unite diverse availability, interpretation and application of such data, nor is there recognition of the challenges of variation in clinical practice between countries within Europe. Aside from the considerable barriers to implementing pharmacogenomic testing and the complexities of clinically actioning results, there are differences in the availability of resources and expertise internationally within Europe. Diverse legal and ethical approaches to genomic testing and clinical therapeutic application also require serious thought. As direct-to-consumer genomic testing becomes more common, it can be anticipated that data may be brought in by patients themselves, which will require critical assessment by the clinical cardiovascular prescriber. In a modern, pluralistic and multi-ethnic Europe, self-identified race/ethnicity may not be concordant with genetically detected ancestry and thus may not accurately convey polymorphism prevalence. Given the broad relevance of pharmacogenomics to areas such as thrombosis and coagulation, interventional cardiology, heart failure, arrhythmias, clinical trials, and policy/regulatory activity within cardiovascular medicine, as well as to genomic and pharmacology subspecialists, this position statement attempts to address these issues at a wide-ranging level.

Genotype-guided antiplatelet treatment versus conventional therapy: A systematic review and meta-analysis

AIM

This meta-analysis was carried out to explore if a personalized antiplatelet strategy based on genotyping is superior to conventional therapy.

METHODS

PubMed, Web of Science, EMBASE and the Cochrane Library were searched from the inception of each database to 5 May 2020. Studies reporting endpoints in genotype-guided treatment group and conventional treatment group were included. The endpoint results were presented as the risk ratio (RR), with 95% confidence interval (CI).

RESULTS

A total of 10 561 patients from 16 studies (eight randomized controlled trials [RCT] and eight cohort studies) were included in the meta-analysis. The rates of major adverse cardiovascular events (MACE), stent thrombosis and myocardial infarction (MI) were significantly lower in the genotype-guided group than in the conventional treatment group (RR 0.56, 95% CI 0.44-0.73, P < .0001; RR 0.40, 95% CI 0.24-0.67, P = .0005; RR 0.45, 95% CI 0.35-0.58, P < .00001, respectively). A significant difference was found between the two groups in major bleeding (RR 0.73, 95% CI 0.55-0.98, P = .04), which was not robust after sensitivity analysis.

CONCLUSION

Genotype-guided antiplatelet treatment could decrease the risk of MACE, stent thrombosis and MI in patients with coronary artery disease or undergoing percutaneous coronary intervention, without increasing the risk of bleeding over a long follow-up period. The decreased risk of efficacy outcomes was more obvious in cohort studies. Well-organized RCTs and clinical trials are required to verify the benefit of genotype-guided therapy.

Risk of major adverse cardiovascular events of CYP2C19 loss-of-function genotype guided prasugrel/ticagrelor vs clopidogrel therapy for acute coronary syndrome patients undergoing percutaneous coronary intervention: a meta-analysis

The most effective antiplatelet treatments for acute coronary syndrome (ACS) patients carrying CYP2C19 loss-of-function (LoF) alleles undergoing percutaneous coronary intervention (PCI) is still debating and conflicting. It was aimed to compare the efficacy and safety endpoints for these patients treated with alternative P2Y12 receptor blockers (e.g. prasugrel or ticagrelor) against clopidogrel. Literature was searched in PubMed, Cochrane library, Synapse and 1000 Genomes databases following PRISMA guidelines for identifying relevant studies. Aggregated risk was estimated by RevMan software using either fixed/random-effects models where P values<0.05 (two-sided) were considered statistically significant. Nine studies comprising 16,132 ACS patients undergoing PCI were included in this analysis in which 2,746 and 2,640 patients were in the CYP2C19 LoF clopidogrel and alternatives treatment group, respectively. It was demonstrated that patients treated with prasugrel or ticagrelor significantly reduced the risk of MACEs (RR 0.58; 95% CI 0.45-0.76; P<0.0001) as compared to patients with clopidogrel where both groups carrying CYP2C19 LoF alleles. Subgroup analysis showed that prasugrel or ticagrelor significantly reduced the risk of cardiovascular death (RR 0.44; 95% CI: 0.25-0.74; P=0.002) and MI (RR 0.60; 95% CI: 0.44-0.81; P=0.0008) while other clinical outcomes were not found statistically significant between these two groups; stroke (RR 0.77; 95% CI: 0.43-1.38; P =0.39), stent thrombosis (RR 0.67; 95% CI: 0.38-1.18; P =0.17), unstable angina (RR 0.55; 95% CI: 0.13-2.33; P =0.42), revascularisation (RR 0.79; 95% CI: 0.28-2.24; P=0.66). Bleeding events were not found significantly different between these groups (RR 1.06; 95% CI: 0.88-1.28; P=0.55). Considering efficacy and safety, alternative antiplatelets (e.g. prasugrel or ticagrelor) may be regarded as better treatment option as compared to clopidogrel for ACS patients undergoing PCI.

The efficacy and safety of CYP2C19 genotype-guided antiplatelet therapy compared with conventional antiplatelet therapy in patients with acute coronary syndrome or undergoing percutaneous coronary intervention: A meta-analysis of randomized controlled trials

Cytochrome P450 (CYP) 2C19 genotype is closely associated with the metabolism and efficacy of clopidogrel, thereby having an important impact on clinical outcomes of patients with acute coronary syndrome (ACS) or undergoing percutaneous coronary intervention (PCI). This study aimed to evaluate the efficacy and safety of CYP2C19 genotype-guided antiplatelet therapy in patients with ACS or undergoing PCI. PubMed, EMBASE, the Cochrane Library and clinicaltrials.gov were searched to identify randomized controlled trials (RCTs) comparing CYP2C19 genotype-guided antiplatelet therapy with conventional therapy in patients with ACS or undergoing PCI. Eight RCTs involving 6708 patients were included in this meta-analysis. CYP2C19 genotype-guided antiplatelet therapy was slightly superior to the conventional antiplatelet therapy in reducing the risk of MACE [RR(95%CI): 0.71(0.51-0.98), p = .04]. Meanwhile, the genotype-guided therapy group had significantly lower incidence of myocardial infarction [RR(95%CI): 0.56(0.40-0.78), p < .01], but similar risk of all-cause mortality, cardiovascular mortality, stent thrombosis, urgent revascularization and stroke compared to the conventional therapy group. Incidences of major/minor bleeding and major bleeding were comparable between the two groups. In patients with ACS or undergoing PCI, CYP2C19 genotype-guided antiplatelet therapy displayed benefit over conventional antiplatelet therapy in reducing the risk of MACE and myocardial infarction, without increasing bleeding risk. Further RCTs are needed to provide more evidences for CYP2C19 genotype-guided antiplatelet therapy.

Genotype-guided antiplatelet therapy compared with standard therapy for patients with acute coronary syndromes or undergoing percutaneous coronary intervention: A systematic review and meta-analysis

OBJECTIVE

To determine, in patients with acute coronary syndromes (ACS) or undergoing percutaneous coronary intervention (PCI), the effectiveness and safety between personalized P2Y12 inhibitors treatment based on genotypes and standard treatment.

METHODS

We systematically searched for articles from PubMed, Cochrane Library, Embase and Web of science from their inception to March 4, 2020, with no language restrictions. The search was performed to identify all randomized clinical trials (RCTs) in which genotype-guided versus standard treatment with P2Y12 inhibitors among patients with ACS or those undergoing PCI. The primary clinical outcomes were major adverse cardiovascular events (MACEs) including death, myocardial infarction (MI), stroke, stent thrombosis (ST), and targeted vessel revascularization (TVR). The secondary outcomes were high on-treatment platelet reactivity (HTPR) and safety outcomes including major bleeding events.

RESULTS

A total of 4859 patients from 7 RCTs were included in the meta-analysis. There were 2430 patients (50.01%) allocated to the genotype-guided group and 2429 (49.99%) allocated to the standard group. Pooled result showed that compared with the standard treatment group, the genotype-guided group had a significantly lower risk of HTPR (Risk Ratio [RR]: 0.35, 95% confidence interval [CI]: 0.14-0.83, P = 0.02, I² = 58%), MI (RR: 0.52, 95% CI: 0.36-0.74, P = 0.0004, I² = 0%) and ST (RR: 0.41, 95% CI: 0.17-0.98, P = 0.05, I² = 0%). No significant difference was found between two groups for the risk of death (RR: 0.78, 95% CI: 0.54-1.12, P = 0.18, I² = 34%), stroke (RR = 0.67, 95% CI: 0.35-1.30, P = 0.24, I² = 0%), TVR (RR: 0.83, 95% CI: 0.46-1.50, P = 0.54, I² = 0%) and major bleeding events (RR: 0.83, 95% CI: 0.60-1.15, P = 0.25, I² = 0%).

CONCLUSIONS

Genotype-guided antiplatelet treatment could reduce the risk of HTPR, MI and ST compared with standard therapy in patients with ACS or undergoing PCI, and no significant difference was found between two groups in the major bleeding events.

[The value of cytochrome P4502C19 gene assay for anti-platelet therapy after PCI in stable angina patients with left main coronary artery lesions]

OBJECTIVE

To evaluate the efficacy and safety of different antiplatelet therapies for stable angina patients with complicated left main coronary artery lesions and intermediate metabolizer Cytochrome P450 2C19 gene (CYP2C19) undergoing PCI.

METHODS

A total of 247 patients diagnosed with stable angina in cardiology department of Fujian union hospital from February 2015 to February 2017 were retrospectively analyzed, among them, the elective PCI were performed on the left main coronary artery and the CYP2C19 gene poly-morphism were intermediate metabolize, they were divided into ticagrelor treatment group(aspirin combined with ticagrelor, n=95)and clopidogrel treatment group(aspirin combined with clopidogrel, n=152) according to the different antiplatelet treatment programs. Both groups were given aspirin 300 mg and clopidogrel 300 mg orally before PCI; the ticagrelor group were given the maintenance dose of ticagrelor (90 mg orally, twice a day) after PCI, while those in clopidogrel group were clopidogrel 75 mg orally (once a day) after PCI; both groups were given the maintenance dose of aspirin (100 mg orally, once a day)after PCI. The major adverse cardiovascular events (MACE) were observed within 12 months after PCI.

RESULTS

At 12 months after PCI, the incidence of MACE in the ticagrelor treatment group was significantly lower than that in the clopidogrel treatment group, the difference was statistically significant (2.1% vs 15.1%, P=0.001).There were no significant differences between the two groups in the restenosis rates of non- revascularized target vessel, recurrent rates of angina pectoris(but not myocardial infarction), recurrent rates of myocardial infarction, and revascularization rates of target vessel (P > 0.05). There were also no significant differences between the two groups in bleeding.

CONCLUSIONS

For stable angina patients with complicated left main coronary artery lesions and intermediate metabolizer CYP2C19 gene, aspirin combined with ticagrelor antiplatelet therapy after PCI is effective, the effect of ticagrelor is better than clopidogrel on MACE, and ticagrelor does not seem to increase the risk of bleeding.

CYP2C19*17 May Increase the Risk of Death Among Patients with an Acute Coronary Syndrome and Non-Valvular Atrial Fibrillation Who Receive Clopidogrel and Rivaroxaban

INTRODUCTION

The aim of this study is to assess the influence of gene CYP2C19, CYP3A4, CYP3A5 and ABCB1 polymorphisms on clopidogrel antiplatelet activity, rivaroxaban concentration equilibrium, and clinical outcomes among patients with acute coronary syndrome and non-valvular atrial fibrillation.

METHODS

In the multicenter prospective registry study of the efficacy and safety of a combined antithrombotic therapy 103 patients with non-valvular atrial fibrillation both undergoing or not a percutaneous coronary intervention were enrolled. The trial assessed the primary outcomes (major bleeding, in-hospital death, cardiovascular death, stroke\transient ischaemic attack, death/renal insufficiency) and secondary outcomes (platelet reactivity units (PRU), rivaroxaban concentration).

RESULTS

For none of the clinical outcomes when combined with other covariates, the carriership of polymorphisms CYP3A5*3 rs776746, CYP2C19*2 rs4244285;*17 rs12248560, ABCB1 3435 C>T, ABCB1 rs4148738 was significant. None of the markers under study (CYP3A5*3 rs776746, CYP2C19*2 rs4244285, *17 rs12248560, ABCB1 3435 C>T, ABCB1 rs4148738) has proven to affect rivaroxaban equilibrium concentration in blood plasma among patients with atrial fibrillation and acute coronary syndrome.

CONCLUSION

In situations of double or triple antithrombotic rivaroxaban and clopidogrel therapy among patients with atrial fibrillation and acute coronary syndrome, the genetic factors associated with bleeding complications risk (CYP2C19*17) may prove to be clinically relevant.

Advances in the Pharmacogenomics of Antiplatelet Therapy

BACKGROUND

Acute coronary syndrome (ACS) is a highly thrombotic state, and a sustained antiplatelet effect is vital to the prevention of thrombotic complications. Clopidogrel, the most widely used oral P2Y12 receptor antagonist in ACS, has attracted considerable attention because of significant variability in antiplatelet effect depending on the presence of CYP2C19 allele. Other P2Y12 receptor antagonists offer sustained and more predictable antiplatelet effects than clopidogrel albeit at an increased cost. Several studies have demonstrated the promising application of pharmacogenetics in choosing personalized antiplatelet therapy using the point-of-care genotype assays.

AREAS OF UNCERTAINTY

Guidelines regarding the genotype-guided approach to the selection of antiplatelet therapy have been conflicting, and studies evaluating the effect of pharmacogenetic-guided selection of antiplatelet therapy on the outcomes have demonstrated mixed results.

DATA SOURCES

A literature search was conducted using MEDLINE and EMBASE for studies reporting the association of pharmacogenetic-guided selection of antiplatelet therapy and the outcomes in patients with ACS until December 2018.

RESULTS

Presence of specific CYP2C19 allele significantly influences clopidogrel metabolism and associated outcomes in patients with ACS. Thrombotic and bleeding complications are more common in patients with loss-of-function (LOF) and gain-of-function (GOF) alleles, respectively. Although the pharmacogenetic-guided approach to the selection of antiplatelet therapy appears promising in ACS, studies have shown conflicting results, and direct randomized evidence linking this approach with the better outcomes is lacking.

CONCLUSIONS

Genotype-guided selection of antiplatelet therapy is expected to be useful in patients undergoing percutaneous coronary intervention (PCI) with a high risk of adverse outcomes. The patient-physician discussion should be an essential part of this decision-making process. Large-scale multicenter randomized controlled trials using the point-of-care genotype assay are needed to investigate this approach further before its use can be recommended in all comers.

Personalized antiplatelet therapy in patients with coronary artery disease undergoing percutaneous coronary intervention: A network meta-analysis of randomized clinical trials

OBJECTIVES

This study aimed to evaluate the efficacy and safety of genotype- and phenotype-guided intensified antiplatelet therapy compared with conventional therapy in patients undergoing stent implantation.

BACKGROUND

Although potent P2Y₁₂ receptor inhibitors are recommended for percutaneous coronary intervention (PCI)-treated acute coronary syndrome, their usage is limited by a high bleeding risk. Therefore, personalized antiplatelet therapy could provide a valuable foundation for selection of antiplatelet therapy in this population.

METHODS

We conducted a Bayesian network meta-analysis for all randomized clinical trials (RCTs) that evaluated genotype- and/or phenotype-guided therapy in PCI-treated coronary artery disease.

RESULTS

Thirteen RCTs were included with a total of 6,845 patients. The results showed no significant differences in major adverse cardiovascular events (MACE) between the treatment options ((genotype guided vs. standard of care; OR 0.64; 95% CI: 0.38-1.05) and (phenotype vs. standard of care; OR 0.93; 95% CI: 0.54-1.37)). In addition, no significant differences were demonstrated in bleeding events ((genotype guided vs. standard of care; OR 0.73; 95% CI: 0.45-1.25) and (phenotype vs. standard of care; OR 0.90; 95% CI: 0.62-1.39)).

CONCLUSIONS

In this mixed treatment meta-analysis of RCTs, neither genotype- nor phenotype-guided antiplatelet therapy in patients with PCI-treated coronary artery disease was superior to conventional therapy.

Cases in Precision Medicine: The Role of Pharmacogenetics in Precision Prescribing

Pharmacogenetics may help physicians deliver individualized treatments based on how a person's genes affect a drug's effects and metabolism. This information can help prevent adverse events or improve drug efficacy by enabling the physician to optimize dosage or to avoid a medication with adverse reactions and to prescribe an alternative therapy. This article discusses the current clinical utility of pharmacogenetic testing in the context of a patient who requires anticoagulation with warfarin.

Pharmacogenetics in the Treatment of Cardiovascular Diseases and Its Current Progress Regarding Implementation in the Clinical Routine

There is a special interest in the implementation of pharmacogenetics in clinical practice, although there are some barriers that are preventing this integration. A large part of these pharmacogenetic tests are focused on drugs used in oncology and psychiatry fields and for antiviral drugs. However, the scientific evidence is also high for other drugs used in other medical areas, for example, in cardiology. In this article, we discuss the evidence and guidelines currently available on pharmacogenetics for clopidogrel, warfarin, acenocoumarol, and simvastatin and its implementation in daily clinical practice.