Precision medicine in cardiovascular therapeutics: Evaluating the role of pharmacogenetic analysis prior to drug treatment.

Pharmacogenomics is the examination of how genetic variation influences drug metabolism and response, in terms of both efficacy and safety. In cardiovascular disease, patient-specific diplotypes determine phenotypes, thereby influencing the efficacy and safety of drug treatments, including statins, antiarrhythmics, anticoagulants and antiplatelets. Notably, polymorphisms in key genes, such as CYP2C9, CYP2C19, VKORC1 and SLCO1B1, significantly impact the outcomes of treatment with clopidogrel, warfarin and simvastatin. Furthermore, the CYP2C19 polymorphism influences the pharmacokinetics and safety of the novel hypertrophic cardiomyopathy inhibitor, mavacamten. In this review, we critically assess the clinical application of pharmacogenomics in cardiovascular disease and delineate present and future utilization of pharmacogenomics. This includes insights into identifying missing heritability, the integration of whole genome sequencing and the application of polygenic risk scores to enhance the precision of personalized drug therapy. Our discussion encompasses health economic analyses that underscore the cost benefits associated with pre-emptive genotyping for warfarin and clopidogrel treatments, albeit acknowledging the need for further research in this area. In summary, we contend that cardiovascular pharmacogenomic analyses are underpinned by a wealth of evidence, and implementation is already occurring for some of these gene-drug pairs, but as with any area of medicine, we need to continually gather more information to optimize the use of pharmacogenomics in clinical practice.

Pharmacogenomic evaluation of CYP2C19 alleles linking low clopidogrel response and the risk of acute coronary syndrome in Indians.

BACKGROUND: Clopidogrel is an antiplatelet drug widely prescribed to prevent atherothrombotic events in coronary artery disease patients. However, there is evidence to suggest that the effectiveness of clopidogrel varies owing to genetic diversity in CYP2C19. This heterogeneity in South Asians, who are also known to have high risk of cardiac events than other population groups, highlights the importance of investigating CYP2C19 variants to estimate the risk proportion in the groups. METHODS: Given the high prevalence and genetic heterogeneity, the population-based case control was conducted in a cohort of 1191 subjects comprising 645 acute coronary syndrome (ACS) cases (unstable angina, ST-elevation myocardial infarction, and non-ST-elevation myocardial infarction) and 546 healthy controls of South Asian Indian origin. The metabolization status of CYP2C19 was assessed using *2, *3 and *17 variants in the stated cohorts to determine the prevalence of metabolization and its association with phenotypes. RESULTS: The results suggest a possible genetic association between studied CYP2C19 polymorphisms and ACS, since there was a higher proportion of intermediate and poor metabolizers present in the studied cohorts. The association analyses revealed that the *2 allele of CYP2C19 confers a significant risk for ACS, while the *17 allele provides protection. CONCLUSIONS: These findings contribute to the understanding of CYP2C19 genetic variants and their impact on clopidogrel response in South Asian Indians. Additionally, they underline the significance of assessing CYP2C19 variations in patients receiving clopidogrel therapy in order to improve therapeutic outcomes.

Empiric treatment with aspirin and ticagrelor is the most cost-effective strategy in patients with minor stroke or transient ischemic attack.

BACKGROUND: Patients with minor ischemic stroke or transient ischemic attacks (TIAs) are often treated with dual antiplatelet therapy regimens as part of secondary stroke prevention. Clopidogrel, an antiplatelet used in these regimens, is metabolized into its active form by the CYP2C19 enzyme. Patients with loss of function (LOF) mutations in CYP2C19 are at risk for poorer secondary outcomes when prescribed clopidogrel. AIMS: We aimed to determine the cost-effectiveness of three different treatment antiplatelet regimens in ischemic stroke populations with minor strokes or TIAs and how these treatment regimens are influenced by the LOF prevalence in the population. METHODS: Markov models were developed to look at the cost-effectiveness of empiric treatment with aspirin and clopidogrel versus empiric treatment with aspirin and ticagrelor, versus genotype-guided therapy for either 21 or 30 days. Effect ratios were obtained from the literature, and incidence rates and costs were obtained from the national data published by the Singapore Ministry of Health. The primary endpoints were the incremental cost-effectiveness ratios (ICERs). RESULTS: Empiric treatment with aspirin and ticagrelor was the most cost-effective treatment. Genotype-guided therapy was more cost-effective than empiric aspirin and clopidogrel if the LOF was above 48%. Empiric ticagrelor and aspirin was cost saving when compared to genotype-guided therapy. Results in models of dual antiplatelet therapy for 30 days were similar. CONCLUSION: This study suggests that in patients with minor stroke and TIA planned for dual antiplatelet regimens, empiric ticagrelor and aspirin is the most cost-effective treatment regimen. If ticagrelor is not available, genotype-guided therapy is the most cost-effective treatment regimen if the LOF prevalence in the population is more than 48%.

Net clinical benefit of clopidogrel versus ticagrelor in elderly patients carrying CYP2C19 loss-of-function variants with acute coronary syndrome after percutaneous coronary intervention.

BACKGROUND AND AIMS: Elderly patients with acute coronary syndrome (ACS) tend to choose clopidogrel over potent P2Y12 receptor inhibitor such as ticagrelor after percutaneous coronary intervention (PCI) in China considering higher risks of bleeding. CYP2C19 genotype is regarded as a major factor influencing the efficacy of clopidogrel. The present study aims to investigate the efficacy and safety of ticagrelor relative to clopidogrel in elderly ACS patients after PCI in China with reduced CYP2C19 metabolism. METHODS: Between January 2016 and March 2019, 2751 ACS patients over 65 years old with CYP2C19 loss-of-function (LOF) variants after PCI were enrolled. All patients were treated with aspirin and P2Y12 receptor inhibitor, among whom 2056 received clopidogrel and 695 received ticagrelor. Net adverse clinical events (NACE), a composite of cardiac death, myocardial infarction (MI), ischemic stroke, target vessel revascularization and clinically relevant bleeding including Bleeding Academic Research Consortium (BARC) types 2, 3, 5 bleeding, were compared between the two groups at 12 months after PCI. Propensity score matching (PSM) was conducted to balance the baseline characteristics between the two groups. RESULTS: Before and after PSM, NACE was significantly increased in ticagrelor group compared with clopidogrel group at 12 months post PCI (Before PSM, 15.18% vs. 25.61% p<0.001; After PSM, 11.66% vs. 26.01% p<0.001). MACE was comparable between the two groups (Before PSM, 5.45% vs. 5.32% p>0.999; After PSM, 3.59% vs. 5.38% p=0.146). BARC types 2, 3, 5 bleeding events were significantly increased in patients treated with ticagrelor relative to clopidogrel (Before PSM, 10.31% vs. 21.01% p<0.001; After PSM, 8.22% vs. 21.38% p<0.001), which was mainly attributed to a higher incidence of BARC type 2 bleeding events in ticagrelor group (Before PSM, 8.12% vs. 18.56% p<0.001; After PSM, 6.43% vs. 18.83% p<0.001). CONCLUSIONS: In the present real-world study, selection of ticagrelor over clopidogrel showed a significant increase in NACE with a higher incidence of bleeding and similar ischemic events in elderly ACS patients carrying CYP2C19 LOF variants after PCI.

Cytochrome P-450 CYP2C19 genetic polymorphism and its relation with clopidogrel resistance.

Objectives: To find out the prevalence of CYP2C19*2 genetic polymorphism in ischaemic heart disease patients, and to determine its relation with clopidogrel resistance in different genotype groups. METHODS: The cross-sectional study was conducted from August 2015 to December 2019 at the Army Medical College, National University of Medical Sciences, Rawalpindi, Pakistan, and comprised ischaemic heart disease patients of either gender who were on clopidogrel therapy. CYP2C19*2 genotyping of all the patients was carried out through polymerase chain reaction-restriction fragment length polymorphism. Platelet aggregation analysis was done using a light transmission aggregometer. Data was analysed using SPSS 23. RESULTS: Of the 390 patients, 232(59.5%) were males and 158(40.5%) were females. The overall age range was 16-82 years. Clinical indications of clopidogrel were angina 198(50.8%), myocardial infarction 146(37.4%) and acute coronary syndrome 46(11.8%). CYP2C19*2 genotyping showed that 196(50.24%) patients were homozygous wild type carriers (GG or *1/*1), 159(40.8%) were heterozygous carriers (GA or *1/*2), and 35(9%) were homozygous polymorphic allele carriers (AA or *2/*2). Platelet aggregation studies showed that there were 157(80.1%) clopidogrel responders and 39(19.9%) clopidogrel-resistant patients among GG carriers, 118(74.2%) clopidogrel responders and 41(25.8%) clopidogrel-resistant among GA carriers, and 18(51.4%) clopidogrel responders and 17(48.6%) clopidogrel-resistant among AA carriers (p=0.001). Intergroup mean platelet aggregation was significantly different (p=0.025). Allelic frequency of dominant allele *1 and polymorphic variant allele *2 was 0.706(70.6%) and 0.294(29.4), respectively. CONCLUSIONS: Homozygous and heterozygous carriers of CYP2C19 allele *2 was found to have higher prevalence of clopidogrel resistance in the studied population.

Establishment of a mathematical prediction model for voriconazole stable maintenance dose: a prospective study.

Background: In patients with invasive fungal infection (IFI), the steady-state serum trough concentration (C min) of voriconazole (VCZ) is highly variable and can lead to treatment failure (C min < 0.5 mg/L) and toxicity (C min ≥ 5.0 mg/L). However, It remains challenging to determine the ideal maintenance dose to achieve the desired C min level quickly. Aims: This randomized, prospective observational single-center study aimed to identify factors affecting VCZ-C min and maintenance dose and create an algorithmic model to predict the necessary maintenance dose. MeThe study enrolled 306 adult IFI patients, split into two groups: non-gene-directed (A) (where CYP2C19 phenotype is not involved in determining VCZ dose) and gene-directed (B) (where CYP2C19 phenotype is involved in determining VCZ dose). Results: Results indicated that CYP2C19 genetic polymorphisms might significantly impact VCZ loading and maintenance dose selection. CYP2C19 phenotype, C-reaction protein (CRP), and average daily dose/body weight were significant influencers on VCZ-C min, while CYP2C19 phenotype, CRP, and body weight significantly impacted VCZ maintenance dose. A feasible predictive formula for VCZ stable maintenance dose was derived from the regression equation as a maintenance dose (mg) =282.774-0.735×age (year)+2.946×body weight(Kg)-19.402×CYP2C19 phenotype (UM/RM/NM:0, IM:1, PM:2)-0.316×CRP (mg/L) (p < 0.001). Discussion: DiThis formula may serve as a valuable supplement to the Clinical Pharmacogenetics Implementation Consortium (CPIC®) guideline for CYP2C19 and VCZ therapy, especially for IFI patients with highly variable inflammatory cytokines during VCZ therapy.

The Utility of CYP2D6 and CYP2C19 Variants to Guide Pharmacological Treatment in Complex Unipolar Major Depression: A Pilot Longitudinal Study.

Major depression is a frequent condition which variably responds to treatment. In view of its high prevalence, the presence of treatment resistance in major depression significantly impacts on quality of life. Tailoring pharmacological treatment based on genetic polymorphisms is a current trend to personalizing pharmacological treatment in patients with major depressive disorders. Current guidelines for the use of genetic tests in major depression issued by the Clinical Pharmacogenomics Implementation Consortium (CPIC) are based on CYP2D6 and CYP2C19 polymorphisms which constitute the strongest evidence for pharmacogenomic guided treatment. There is evidence of increased clinical response to pharmacological treatment in major depression although largely in non-treatment resistant patients from Western countries. In this study, well characterised participants (N = 15) with complex, largely treatment resistant unipolar major depression were investigated, and clinical improvement was measured at baseline and at week-8 after the pharmacogenomics-guided treatment with the Montgomery Åsberg Depression Rating Scale (MÅDRS). Results suggested a statistically significant improvement (p = 0.01) of 16% at endpoint in the whole group and a larger effect in case of changes in medication regime (28%, p = 0.004). This small but appreciable effect can be understood in the context of the level of treatment resistance in the group. To our knowledge, this is the first study from the Middle East demonstrating the feasibility of this approach in the treatment of complex major depressive disorders.

Rates of 30-Day and 90-Day Readmission Between Genotype-Optimal and Genotype-Suboptimal Antiplatelet Therapy Prescribing After Percutaneous Coronary Intervention.

Current evidence increasingly supports CYP2C19 genotype-guided P2Y12 inhibitor selection. Clopidogrel remains the most prescribed P2Y12 inhibitor despite higher readmission rates than those of more efficacious third-generation P2Y12 inhibitors. It remains unclear whether pharmacogenetically (PGx)-guided antiplatelet therapy directly reduces readmissions after percutaneous coronary intervention (PCI). A single-center retrospective observational cohort study at a tertiary academic medical center was conducted. Patients receiving CYP2C19 genotyping after PCI were included and stratified into 2 groups (PGx-optimal vs PGx-suboptimal P2Y12 inhibitor prescribed) on the basis of CPIC (Clinical Pharmacogenetics Implementation Consortium) recommendations. Primary outcomes included 30-day and 90-day readmissions after index PCI. Most patients (78%) were of non-European ancestry. Among patients receiving PGx-optimal therapy, 50% had acute coronary syndromes whereas 61% receiving PGx-suboptimal therapy had stable coronary artery disease. Comparable 30-day (12% vs 10%, p = 0.481) and 90-day readmission rates (24% vs 28%, p = 0.323) were observed between patients receiving PGx-optimal or PGx-suboptimal therapies. PGx-optimal therapy was associated with fewer emergency department visits (3.4% vs 4.0%, p = 0.021) within 30 days, and patients initially prescribed PGx-suboptimal therapy were switched more often to PGx-optimal therapy during a readmission than were patients prescribed PGx-suboptimal antiplatelet therapy (p <0.001). In conclusion, CYP2C19 genotype-guided P2Y12 inhibitor therapy did not improve 30- and 90-day all-cause readmission rates in a predominantly non-European population. However, P2Y12 inhibitor therapy became concordant with CYP2C19 genotype in approximately half of patients during the first readmission after PCI, which may present further opportunities to revisit and optimize dual antiplatelet therapy in patients who undergo PCI.

A real-life pilot study of the clinical application of pharmacogenomics testing on saliva in epilepsy.

Response to antiseizure medications (ASMs) can be influenced by several gene polymorphisms, causing either lower efficacy or higher occurrence of adverse drug reactions (ADRs). We investigated the clinical utility of salivary pharmacogenomic testing on epilepsy patients. A commercialized pharmacogenomic salivary test was performed in a cohort of epileptic patients. Genetic variants on five genes (i.e., CYP1A2, CYP2C9, CYP2C19, EPHX1, and ABCB1) involved in common ASMs metabolism were selected. Twenty-one individuals (median age [Q1 -Q3 ]: 15 [6.5-28] years) were enrolled. Six patients harboring the homozygous *1F allele in CYP1A2 could have reduced chance of response to stiripentol due to fast metabolism. CYP2C9 had reduced activity in 10 patients (alleles *2 and *3), potentially affecting phenytoin (PHT), phenobarbital (PB), primidone, lacosamide (LCM), and valproic acid metabolism. Seven patients, carrying the *2 allele of CYP2C19, had an increased risk of ADRs with clobazam (CLB), PB, PHT, LCM, brivaracetam; while one individual with the *17 allele in heterozygosity reported a CLB fast metabolism. Six patients showed a CC polymorphism of EPHX1 associated with the impaired efficacy of carbamazepine. ABCB1 polymorphisms related to drug-resistance (3435 CC) or drug-sensitive phenotype (CT or TT) were found in 6 out of 7 patients. Pharmacogenomic testing on saliva proved easy and safe in clinical practice to convey information for the management of epileptic patients, especially those resistant to treatment or sensitive to severe ADRs.

Genotype-Guided Dual Antiplatelet Therapy in Minor Stroke or Transient Ischemic Attack With a Single Small Subcortical Infarction.

BACKGROUND AND OBJECTIVES: Single small subcortical infarction (SSSI) is an important stroke subtype. The optimal antiplatelet medication for patients with ischemic stroke with an SSSI is still unclear. We aimed to test the efficacy and safety of ticagrelor-aspirin in preventing stroke recurrence among patients with SSSI in the Ticagrelor or Clopidogrel with Aspirin in High-Risk Patients with Acute Nondisabling Cerebrovascular Events II (CHANCE-2) trial. METHODS: In the CHANCE-2 trial, patients with a minor stroke or TIA who carried CYP2C19 loss-of-function (LOF) alleles were randomly assigned within 24 hours after symptom onset, to either ticagrelor-aspirin (placebo clopidogrel plus a 180 mg loading dose of ticagrelor on day 1, followed by 90 mg twice daily on days 2-90) or clopidogrel-aspirin (placebo ticagrelor plus a 300 mg loading dose of clopidogrel on day 1, followed by 75 mg daily on days 2-90). Aspirin was applied during the first 21 days. Patients who had an SSSI (diffusion-weighted imaging lesion diameter ≤20 mm) were included in this analysis and further categorized into 2 types according to whether they had the responsible intracranial artery stenosis (ICAS): SSSI + ICAS and SSSI - ICAS. The primary efficacy outcome was a new stroke at 90 days. RESULTS: Among 2,143 eligible patients, 340 had the responsible ICAS, and 1,803 did not. Ticagrelor-aspirin reduced stroke recurrence among all patients with SSSI (hazard ratio [HR]: 0.55; 95% CI 0.38-0.78; p = 0.001) compared with clopidogrel-aspirin. Stroke recurrence occurred in 35/901 (3.9%) patients with SSSI - ICAS on ticagrelor-aspirin and in 72/902 (8.0%) on clopidogrel-aspirin (hazard ratio [HR]: 0.45; 95% CI 0.29-0.68; p < 0.001). In patients with SSSI + ICAS, the corresponding event rates were 14/176 (8.0%) and 13/164 (7.9%), respectively (HR: 1.20; 95% CI 0.45-3.23; p = 0.71; p for interaction = 0.08). The risk of severe or moderate bleeding only occurred in patients with SSSI - ICAS (5/901 [0.6%] vs 5/902 [0.6%]). DISCUSSION: In this prespecified substudy, ticagrelor-aspirin was superior to clopidogrel-aspirin in reducing the risk of stroke at 90 days among patients with SSSI who carried CYP2C19 LOF allele(s). Although there was no treatment-by-heterogeneous etiology interaction, a greater absolute risk reduction of stroke was observed in patients with SSSI - ICAS than in those with SSSI + ICAS. CLASSIFICATION OF EVIDENCE: This study provides Class II evidence that ticagrelor and aspirin reduced the risk of stroke recurrence compared with clopidogrel with aspirin in adult patients with acute minor SSSI.

Pharmacogenetics of P2Y12 receptor inhibitors.

Oral P2Y12 inhibitors are commonly prescribed for cardiovascular disease and include clopidogrel, prasugrel, and ticagrelor. Each of these drugs has its strengths and weaknesses. Prasugrel and ticagrelor are more potent inhibitors of platelet aggregation and were shown to be superior to clopidogrel in preventing major adverse cardiovascular events after an acute coronary syndrome and percutaneous coronary intervention (PCI) in the absence of genotyping. However, both are associated with an increased risk for non-coronary artery bypass-related bleeding. Clopidogrel is a prodrug requiring bioactivation, primarily via the CYP2C19 enzyme. Approximately 30% of individuals have a CYP2C19 no function allele and decreased or no CYP2C19 enzyme activity. Clopidogrel-treated carriers of a CYP2C19 no function allele have decreased exposure to the clopidogrel active metabolite and lesser inhibition of platelet aggregation, which likely contributed to reduced clopidogrel efficacy in clinical trials. The pharmacogenetic data for clopidogrel are most robust in the setting of PCI, but evidence is accumulating for other indications. Guidance is available from expert consensus groups and regulatory agencies to assist with integrating genetic information into P2Y12 inhibitor prescribing decisions, and CYP2C19 genotype-guided antiplatelet therapy after PCI is one of the most common examples of clinical pharmacogenetic implementation. Herein, we review the evidence for pharmacogenetic associations with clopidogrel response and outcomes with genotype-guided P2Y12 inhibitor selection and describe guidance to assist with pharmacogenetic implementation. We also describe processes for applying genotype data for P2Y12 inhibitor therapy selection and remaining gaps in the field. Ultimately, consideration of both clinical and genetic factors may guide selection of P2Y12 inhibitor therapy that optimally balances the atherothrombotic and bleeding risks.

Cost-effectiveness of CYP2C19-guided P2Y12 inhibitors in Veterans undergoing percutaneous coronary intervention for acute coronary syndromes.

AIMS: CYP2C19-guided P2Y12 inhibitor selection can reduce cardiovascular (CV) events and bleeding in patients with acute coronary syndromes (ACSs) post-percutaneous coronary intervention (PCI). The 12-month cost-effectiveness of CYP2C19-guided P2Y12 inhibitor selection for Veterans post-ACS/PCI was evaluated from the Veterans Health Administration's (VHA) perspective. METHODS AND RESULTS: Using average annualized PCI volumes and P2Y12 inhibitor use from VA data, a decision-analytic model simulated CYP2C19 testing vs. no testing outcomes in 2800 hypothetical Veterans receiving PY212 inhibitor for 12 months post-ACS/PCI (74% clopidogrel, 5% prasugrel, and 21% ticagrelor use at baseline without testing). CYP2C19 loss-of-function (LOF) carrier prevalence was 28%. Model inputs were from studies (bleeding/ischaemic events, CYP2C19-guided therapy effect, health state utilities, CYP2C19 LOF carrier prevalence) and VHA administrative data (costs of events, drugs, CYP2C19 testing; PCI volumes, and P2Y12 inhibitor prescriptions). The primary outcome was cost (2020 US${\$}$) per quality-adjusted life year (QALY) gained. Base-case scenarios, probabilistic sensitivity analyses, and scenario analyses were completed. CYP2C19-guided therapy resulted in 496 (24%) escalations (clopidogrel to prasugrel/ticagrelor) and 465 (65%) de-escalations (prasugrel/ticagrelor to clopidogrel). CYP2C19 testing averted 1 stroke, 27 myocardial infarctions, 8 CV-related deaths, and caused 3 bleeds. CYP2C19 testing (vs. no testing) was dominant in the base-case scenario (0.0027 QALYs gained, ${\$}$527 saved/person) and in 97.1% of simulations, making it cost-effective and high-value. In scenario analyses, de-escalation in conjunction with escalation is required for CYP2C19 testing to be cost-effective and high-value. CONCLUSION: In Veterans post-ACS/PCI, CYP2C19-guided P2Y12 inhibitor selection can improve CV outcomes and lower costs for the VHA within 12 months of implementation.

Ticagrelor Aspirin vs Clopidogrel Aspirin in CYP2C19 Loss-of-Function Carriers With Minor Stroke or TIA Stratified by Risk Profile.

BACKGROUND AND OBJECTIVE: Genotype data of the Clopidogrel with Aspirin in Acute Minor Stroke or Transient Ischemic Attack (CHANCE) trial showed that efficacy of clopidogrel aspirin depended on CYP2C19 genotype and risk profile. A stratification of patients who carried CYP2C19 loss-of-function (LOF) alleles according to the risk of recurrent stroke may be important for selecting optimal antiplatelet therapy. We aimed to compare the efficacy and safety of ticagrelor aspirin with clopidogrel aspirin in CYP2C19 LOF carriers with minor stroke or transient ischemic attack (TIA) stratified by risk profile. METHODS: Data were obtained from Ticagrelor or Clopidogrel with Aspirin in High-Risk Patients with Acute Nondisabling Cerebrovascular Events II (CHANCE-2) trial. Low-risk and high-risk profiles were defined by Essen Stroke Risk Score (ESRS) (<3 [low risk] and ≥3 [high risk], respectively). RESULTS: A total of 6,412 CYP2C19 LOF carriers were enrolled; ticagrelor aspirin was associated with a reduced risk of primary outcome (new stroke within 90-day follow-up) in patients at low risk (hazard ratio [HR], 0.65; 95% CI, 0.48-0.82), but not in those at high risk (HR, 0.97; 95% CI, 0.73-1.29), compared with clopidogrel aspirin (p = 0.02 for interaction). Secondary outcomes generally went in the same direction as the primary outcome. The primary safety outcome of severe or moderate bleeding did not differ based on risk profile (p = 0.24 for interaction), although the incidence of total bleeding was greater with ticagrelor aspirin than with clopidogrel aspirin among patients at low risk (p < 0.01 for interaction). Analysis in the per-protocol population yielded similar results. DISCUSSION: This post hoc analysis of CHANCE-2 trial showed that CYP2C19 LOF carriers with minor stroke or TIA at low risk of recurrent stroke received a greater benefit from ticagrelor aspirin than from clopidogrel aspirin. CLASSIFICATION OF EVIDENCE: This study provides Class II evidence that CYP2C19 LOF carriers with minor stroke or TIA at low risk, but not at high risk, of recurrent stroke (by the ESRS) received a greater benefit from ticagrelor aspirin than from clopidogrel aspirin. TRIAL REGISTRATION INFORMATION: URL: www. CLINICALTRIALS: gov. Unique identifier: NCT04078737.

Aminotransferase Level and the Effects of Dual Antiplatelet in Minor Stroke or Transient Ischemic Attack: A post hoc Analysis of a Randomized Control Trial.

INTRODUCTION: This study was intended to evaluate whether the safety and efficacy of dual antiplatelet treatment in patients with minor ischemic stroke (MIS) or transient ischemic attack (TIA) could be modified by the aminotransferase level. Also, we sought to assess the interaction between aminotransferase level and CYP2C19 loss-of-function status on the efficacy of dual antiplatelet therapy. METHODS: This study is a post hoc analysis of the Clopidogrel in High-Risk Patients With Acute Nondisabling Cerebrovascular Events (CHANCE) study, a double-blinded randomized control trial. We included 5,133 patients with a complete workup of baseline alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels. The primary outcome is stroke or TIA recurrence within 90 days. Cox proportional hazard models were used in the evaluation of the efficacy of antiplatelet treatment in patients with different aminotransferase levels and subgroups categorized by the aminotransferase level × CYP2C19 loss-of-function status. RESULTS: The median age of all the included patients was 62 years; 66.3% of the patients were male. More recurrent stroke or TIA occurred in patients with elevated ALT and AST levels within 90 days compared to patients with normal ALT and AST levels (14.5 vs. 11.2%, p = 0.029). Dual antiplatelet treatment with aspirin and clopidogrel reduced recurrence compared with aspirin alone in patients with both normal (adjusted hazard ratio [HR], 95% confidence interval [CI]: 0.72 [0.60-0.86], p < 0.001) and elevated (adjusted HR [95% CI]: 0. 57 [0. 35-0. 92], p = 0. 020) ALT and AST levels (p = 0.64 for interaction). No significant difference in treatment efficacy on 90-day all-cause death or bleeding events was found. CONCLUSIONS: Dual antiplatelet treatment was safe for minor stroke or high-risk TIA patients with mildly elevated aminotransferase. Mild elevation of ALT or AST did not undermine the protective efficacy of the dual antiplatelet regimen in reducing recurrent stroke or TIA within 90 days after MIS or TIA. The interaction between the CYP2C19 loss-of-function allele carrier status and aminotransferase level on the efficacy of dual antiplatelet treatment was not observed.

[Personalized therapy for Helicobacter pylori on initial treatment: the initial treatment is the decisive battle].

As widespread eradication treatment continues, the rate of (Helicobacter pylori, H. pylori) antibiotic resistance is increasing. Together with host CYP2C19 gene polymorphisms, H. pylori coccoid transformation, patient compliance, irregular treatment regimens or empirical repeated eradication therapy by physician, H. pylori eradication rates have gradually decreased. Personalized treatment is an effective measure to achieve successful eradication of H. pylori in the initial treatment. With the first approval of molecular diagnostic kit for H. pylori clarithromycin resistance in China and the updated definition of refractory H. pylori infection by the American Gastroenterological Association (AGA), the personalized treatment of H. pylori guided by antibiotic resistance genotype detection in initial treatment, that follows the latest international consensus and guidelines, conforms to the national situation and surpasses the international standards, has come to the forefront.

[Genotype-guided antithrombotic therapy]. / Genotypegeleide trombocytenaggregatieremming.

Although current literature indicates both a clinical and a cost-effective benefit of routine genotype-guided treatment of patients treated with clopidogrel, this strategy is not recommended in guidelines. In cardiology, but also in neurology and vascular surgery, the current scientific evidence for this is still insufficient. Nevertheless, the role of pharmacogenetics will gain importance in today's medical world, where the demand for personalised medicine is on the rise. The implementation of genotyping in the clinic will nonetheless be a practical challenge due to a lack of clarity about who will bear the associated costs. In patients with coronary artery disease and a higher bleeding risk, it is valuable to determine the CYP2C19 genotype prior to treatment with clopidogrel. Pending further studies, we recommend that specialists prescribing clopidogrel should determine the CYP2C19 genotype in patients at high risk of recurrent ischemic events.

Pitfalls of Physician-Directed Treatment of Helicobacter pylori: Results from Two Phase 3 Clinical Trials and Real-World Prescribing Data.

BACKGROUND: Helicobacter pylori (H. pylori) infects ~ 35% of Americans and can lead to serious sequelae if left untreated. Growing evidence indicates that clarithromycin-based therapies (CBT) are becoming increasingly ineffective for treating H. pylori infection. RHB-105 was approved by the US Food and Drug Administration in 2019 for the treatment of H. pylori infection in adults. AIMS: The primary aim of this study was to assess prescribing patterns and associated cure rates of physician-directed therapy for subjects with persistent H. pylori infection after participation in one of two Phase 3 clinical trials (ERADICATE Hp and ERADICATE Hp2). METHODS: We reviewed study reports to identify specific physician-directed regimens selected for subjects whose H. pylori infection was not eradicated. We also conducted a CYP2C19 genotype analysis of subjects who were prescribed CBT. Finally, we analyzed real-world H. pylori retail prescription data and compared these with to the physician-directed therapies in the clinical trials studies. RESULTS: Following ERADICATE Hp, CBT was prescribed for 27/31 (87%) subjects achieving a 59.3% cure rate. Following ERADICATE Hp2, CBT was prescribed for 48/94 (51%) subjects achieving a 60.4% cure rate. Rapid CYP2C19 metabolizers (2/11) had a cure rate of 18.2% with CBT. Real-world prescription data from IQVIA showed more than 80% of prescriptions for H. pylori infection were for CBT. CONCLUSIONS: Rates of CBT use persist despite sub-optimal eradication rates. Since RHB-105 does not contain clarithromycin, it can be prescribed first-line without concerns about clarithromycin resistance or CYP2C19 status. NCT03198507 & NCT01980095.

CYP2C19 Loss-of-Function Associated with First-Time Ischemic Stroke in Non-surgical Asymptomatic Carotid Artery Stenosis During Clopidogrel Therapy.

This study measures effect of CYP2C19 genotype on ischemic stroke risk during clopidogrel therapy for asymptomatic, extracranial carotid stenosis patients. Using deidentified electronic health records, patients were selected for retrospective cohort using administrative code for carotid stenosis, availability of CYP2C19 genotype result, clopidogrel exposure, and established patient care. Patients with intracranial atherosclerosis, aneurysm, arteriovenous malformation, prior ischemic stroke, or observation time <1 month were excluded. Dual antiplatelet therapy patients were included. Patients with carotid endarterectomy or stenting were analyzed in a separate subgroup. Time-to-event analysis using Cox regression was conducted to model ischemic stroke events based on CYP2C19 loss-of-function allele and adjusted with the most predictive covariates from univariate analysis. Covariates included age, gender, race, length of aspirin, length of concurrent antiplatelet/anticoagulant treatment, diabetes, coagulopathy, hypertension, heart disease, atrial fibrillation, and lipid disorder. A total of 1110 patients met selection criteria for medical therapy cohort (median age 68 [interquartile range (IQR) 60-75] years, 64.9% male, 91.9% Caucasian). Median study period was 2.8 [0.8-5.3] years. A total of 47 patients (4.2%) had an ischemic stroke event during study period. CYP2C19 loss-of-function allele was strongly associated with ischemic stroke events (one allele: HR 2.3, 95% CI 1.1-4.7, p=0.020; two alleles: HR 10.2, 95% CI 2.8-36.8, p<0.001) after adjustment. For asymptomatic carotid stenosis patients receiving clopidogrel to prevent ischemic stroke, CYP2C19 loss-of-function allele is associated with 2- to 10-fold increased risk of ischemic stroke. CYP2C19 genotype may be considered when selecting antiplatelet therapy for stroke prophylaxis in non-procedural, asymptomatic carotid stenosis.

High On-Treatment Platelet Reactivity as Predictor of Long-term Clinical Outcomes in Stroke Patients with Antiplatelet Agents.

The purpose was to explore the value of high on-treatment platelet reactivity (HTPR) in predicting long-term clinical outcomes for stroke patients. The platelet reactivity was assayed after being treated with either 75 mg clopidogrel or 100 mg aspirin daily with VerifyNow System in stroke patients. HTPR for clopidogrel was defined as PRU ≥ 208, and that for aspirin was defined as ARU ≥ 550. CYP2C19 genotyping was performed using the Sequenom MassARRAY iPLEX platform. The primary endpoint was a composite of recurrent ischemic stroke, transient ischemic attack, myocardial infarction, or ischemic vascular death. The safety endpoint was bleeding. In the clopidogrel group, among 345 patients recruited, 174 of them were categorized as HTPR. A total of 270 patients were followed up for 54 months. There was a significant association between HTPR and the primary endpoint (HRadj 2.13 [95% CI, 1.43-3.15], p < 0.001). Among the 314 participants genotyped for CYP2C19, 187 (59.6%) were classified as CYP2C19 loss-of-function allele carriers. Patients with at least 1 loss-of-function allele were more likely to present with HTPR (ORadj 2.61 [95%CI, 1.43-4.77], p = 0.008), and had a higher risk of the primary endpoint (HRadj 2.05 [95% CI, 1.30, 3.25], p = 0.002). In the aspirin group, among 140 patients recruited, 28 of them were categorized as HTPR. A total of 121 patients were followed up for 30 months. Similarly, there was a significant association between HTPR and the primary endpoint (HRadj 3.28 [95% CI, 1.52-7.71], p = 0.002). HTPR is an independent risk factor for ischemic events during long-term follow-up in stroke patients. Platelet function testing is helpful to evaluate the effect of antiplatelet therapy for stroke patients.