Clopidogrel, CYP2C19, and a Black Box

Comparative Bioequivalence Study of 2 Clopidogrel 75-mg Tablet Formulations in Moroccan Volunteers

This study investigates the pharmacokinetic properties and bioequivalence of 2 formulations of clopidogrel tablets administered to a cohort of healthy Moroccan male volunteers. The primary objective was to assess the rate and extent of drug absorption from the test formulation in comparison to a reference formulation, focusing on critical parameters including maximum plasma concentration (Cmax), area under the concentration-time curve from 0 to the last measurable time (AUC0-t), and area under the concentration-time curve extrapolated to infinity (AUC0-∞). The results revealed that the geometric mean ratios of Cmax, AUC0-t, and AUC0-∞ for the test formulation relative to the reference formulation were 105.7%, 105.6%, and 105.6%, respectively. The 90% confidence intervals for these parameters fell within the predefined bioequivalence range of 80%-125%, indicating a statistically and clinically equivalent performance between the 2 formulations. This investigation sheds light on the pharmacokinetic behavior of clopidogrel in the context of the Moroccan male population, offering valuable insights into the comparability of formulations.

Mind the Gap: Model-Based Switching from Selatogrel to Maintenance Therapy with Oral P2Y12 Receptor Antagonists

Background: The P2Y12 receptor antagonist selatogrel is being developed for subcutaneous self-administration with a ready-to-use autoinjector at the onset of acute myocardial infarction (AMI) symptoms. The unique pharmacological profile of selatogrel (fast, potent, and short-acting) can bridge the time gap between the onset of AMI and first medical care. A clinical Phase 1 study showed a time-dependent pharmacodynamic interaction between selatogrel and loading doses of clopidogrel and prasugrel. As treatment switching is a common clinical practice, the assessment of subsequent switching from a clopidogrel loading dose to the first maintenance dose of oral P2Y12 receptor antagonists is highly relevant. Objectives: Model-based predictions of inhibition of platelet aggregation (IPA) for the drugs triggering pharmacodynamic interactions were to be derived to support clinical guidance on the transition from selatogrel to oral P2Y12 receptor antagonists. Methods: Scenarios with selatogrel 16 mg administration or placebo followed by a clopidogrel loading dose and, in turn, prasugrel or ticagrelor maintenance doses at different times of administration were studied. Population pharmacokinetic/pharmacodynamic modeling and simulations of different treatment scenarios were used to derive quantitative estimates for IPA over time. Results: Following selatogrel/placebo and a clopidogrel loading dose, maintenance treatment with ticagrelor or a prasugrel loading dose followed by maintenance treatment quickly achieved sustained IPA levels above 80%. Prior to maintenance treatment, a short time span from 18 to 24 h was identified where IPA levels were predicted to be lower with selatogrel than with placebo if clopidogrel was administered 12 h after selatogrel or placebo. Predicted IPA levels reached with placebo alone and a clopidogrel loading dose at 4 h were consistently lower than with selatogrel administration, followed by a clopidogrel loading dose at 12 h. If a clopidogrel loading dose is administered at 12 h, selatogrel maintains higher IPA levels up to 16 h. IPA levels are subsequently lower than on the placebo until the administration of the first maintenance dose. Conclusions: Model-based predictions informed the transition from selatogrel subcutaneous administration to oral P2Y12 therapy. The application of modeling techniques illustrates the value of employing pharmacokinetic and pharmacodynamic modeling for the simulation of various clinical scenarios of switching therapies.

Pharmacokinetics and Pharmacodynamics of Approved and Investigational P2Y12 Receptor Antagonists

Coronary artery disease remains the major cause of mortality worldwide. Antiplatelet drugs such as acetylsalicylic acid and P2Y12 receptor antagonists are cornerstone treatments for the prevention of thrombotic events in patients with coronary artery disease. Clopidogrel has long been the gold standard but has major pharmacological limitations such as a slow onset and long duration of effect, as well as weak platelet inhibition with high inter-individual pharmacokinetic and pharmacodynamic variability. There has been a strong need to develop potent P2Y12 receptor antagonists with more favorable pharmacological properties. Prasugrel and ticagrelor are more potent and have a faster onset of action; however, they have shown an increased bleeding risk compared with clopidogrel. Cangrelor is highly potent and has a very rapid onset and offset of effect; however, its indication is limited to P2Y12 antagonist-naïve patients undergoing percutaneous coronary intervention. Two novel P2Y12 receptor antagonists are currently in clinical development, namely vicagrel and selatogrel. Vicagrel is an analog of clopidogrel with enhanced and more efficient formation of its active metabolite. Selatogrel is characterized by a rapid onset of action following subcutaneous administration and developed for early treatment of a suspected acute myocardial infarction. This review article describes the clinical pharmacology profile of marketed P2Y12 receptor antagonists and those under development focusing on pharmacokinetic, pharmacodynamic, and drug-drug interaction liability.

Pharmacogenomics in Cardiovascular Diseases

Cardiovascular pharmacogenomics is the study and identification of genomic markers that are associated with variability in cardiovascular drug response, cardiovascular drug-related outcomes, or cardiovascular drug-related adverse events. This overview presents an introduction and historical background to cardiovascular pharmacogenomics, and a protocol for designing a cardiovascular pharmacogenomics study. Important considerations are also included for constructing a cardiovascular pharmacogenomics phenotype, designing the replication or validation strategy, common statistical approaches, and how to put the results in context with the cardiovascular drug or cardiovascular disease under investigation. © 2021 Wiley Periodicals LLC. Basic Protocol: Designing a cardiovascular pharmacogenomics study.

Therapeutic Dilemma in personalized medicine

The practice of medicine depends over a long time on identifying therapies that target an entire population. The increase in scientific knowledge over the years has led to the gradual change towards individualization and personalization of drug therapy. The hope of this change is to achieve a better clinical response to given medications and reduction of their adverse effects. Tailoring of medicine on the road of personalized medicine considers molecular and genetic mapping of the individual. However, many factors still impede the smooth application of personalized medicine and represent challenges or limitations in its achievement. In this article, we put some clinical examples that show dilemmas in the application of personalized medicine such as opioids in pain control, fluoropyrimidines in malignancy, clopidogrel as antiplatelet therapy and oral hypoglycemic drugs in Type2 diabetes in adults. Shaping the future of medicine through the application of personalized medicine for a particular patient needs to put into consideration many factors such as patient's genetic makeup and life style, pathology of the disease and dynamic changes in its course as well as interactions between administered drugs and their effects on metabolizing enzymes. We hope in the coming years, the personalized medicine will foster changes in health care system in the way not only to treat patients but also to prevent diseases.

Anti-Platelet Therapy in Mild Cerebral Infarction Patients on the Basis of CYP2C19 Metabolizer Status

This study aimed to investigate the effects of CYP2C19 metabolizer status on the clinical therapeutic efficacy of cerebral infarction. Patients with cerebral infarction (n = 180; NIHSS score ≤ 5) were recruited and divided into Group A and Group B according to CYP2C19 metabolizer status. In Group A, patients received routine clopidogrel therapy for 1 year; in Group B, the patients with extensive metabolizer (EM) were treated with clopidogrel, and patients with intermediate metabolizer (IM) and poor metabolizer (PM) were treated with aspirin for 1 year. On admission, National Institutes of Health Stroke Scale score was determined, and the therapeutic efficacy was evaluated with Modified Rankin Scale score after 1 year of treatment. The outcomes and adverse effects were recorded during the treatment. After routine clopidogrel treatment, the efficacy in EM patients was significantly better than in PM and IM patients. After adjustment of therapeutic protocol, the therapeutic efficacy in PM and IM patients was markedly improved, which was accompanied by significant reduction in recurrence rate of cerebral infarction. Although the adverse effects increased in patients receiving aspirin treatment, they resolved after symptomatic therapy. CYP2C19 metabolizer status is closely related to the clinical efficacy of clopidogrel. Thus, it is necessary to adjust the anti-platelet treatment according to the CYP2C19 metabolizer status to maximize therapeutic efficacy without increasing recurrence and adverse effects.

Analysis of thrombelastogram-guided medication in patients with coronary heart disease after percutaneous coronary intervention

Effects of thrombelastogram-guided (TEG-guided) clopidogrel and aspirin on major adverse cardiovascular events (MACE) after percutaneous coronary intervention (PCI) were investigated. A retrospective analysis was performed on 203 patients undergoing PCI interventional therapy in the Cardiovascular Medicine of Weihai Central Hospital from February 2015 to September 2016. The patients were treated with clopidogrel and aspirin for anti-thrombus therapy. Among them, 104 patients who had TEG detection of anticoagulant effects for guiding medication were the experimental group, and 99 patients without TEG detection for guiding medication the control group. The coagulation function and the platelet inhibition rate of patients after medication were evaluated and compared between the two groups. The incidence of MACE and bleeding events of patients was counted during three months of follow-up. Patients in the experimental group had higher R (coagulation reaction time) value and K (blood clot formation time) value than those in the control group after treatment (P<0.05), and lower MA (maximum amplitude) value than those in the control group (P<0.05). Patients in the experimental group had higher postoperative platelet inhibition rate than those in the control group (P<0.05). Patients in the experimental group had lower incidence of MACE and bleeding events than those in the control group (P<0.05). Coronary heart disease (CHD) patients after PCI with the TEG-guided dose adjustment of clopidogrel have more satisfactory treatment effects than patients without the TEG guidance. TEG makes the treatment of patients more targeted and is worthy of promotion.

CYP2C19 or CYP3A5 Genotyping Does Not Predict Clinical Response to Clopidogrel

Along with aspirin, clopidogrel has been a widely used antiplatelet therapeutic regimen. Although generally well tolerated, its efficacy varies among individuals, with the main hypothesis that its bioavailability relies on its bioconversion to the active compound, which, in turn, depends on the genetic background and/or interactions with other drugs. To determine which factors influenced response in our patients, 368 patients receiving combined antiaggregation therapy with aspirin and clopidogrel were followed for 1 year to record 30 novel cardiovascular acute events. This clinical relapse was considered a surrogate end point to measure therapeutic response under the influence of the CYP2C19*2, *3, and *17 and CYP3A5*3 alleles, as well as the effects of concomitant medication and the presence of known cardiovascular risk factors and comorbidity. We show that either single CYP2C19 or CYP3A5 genotyping or combined were not useful to predict clinical efficacy in this cohort. Rather than genetic testing, we have found that clinical observations such as suffering type 2 diabetes mellitus requiring insulin, having several vessels affected, and concurrent medication with calcium channel blockers, regardless of CYP3A5 genotype or drug class were, in that order, the strongest independent predictors of disease relapse.

Application of Single-Nucleotide Polymorphism-Related Risk Estimates in Identification of Increased Genetic Susceptibility to Cardiovascular Diseases: A Literature Review

Background

Although largely preventable, cardiovascular diseases (CVDs) are the biggest cause of death worldwide. Common complex cardiovascular disorders (e.g., coronary heart disease, hypertonia, or thrombophilia) result from a combination of genetic alterations and environmental factors. Recent advances in the genomics of CVDs have fostered huge expectations about future use of susceptibility variants for prevention, diagnosis, and treatment. Our aim was to summarize the latest developments in the field from a public health perspective focusing on the applicability of data on single-nucleotide polymorphisms (SNPs), through a systematic review of studies from the last decade on genetic risk estimating for common CVDs.

Methods

Several keywords were used for searching the PubMed, Embase, CINAHL, and Web of Science databases. Recent advances were summarized and structured according to the main public health domains (prevention, early detection, and treatment) using a framework suggested recently for translational research. This framework includes four recommended phases: “T1. From gene discovery to candidate health applications; T2. From health application to evidence-based practice guidelines; T3. From evidence-based practice guidelines to health practice; and T4. From practice to population health impacts.”

Results

The majority of translation research belongs to the T1 phase “translation of basic genetic/genomic research into health application”; there are only a few population-based impacts estimated. The studies suggest that an SNP is a poor estimator of individual risk, whereas an individual’s genetic profile combined with non-genetic risk factors may better predict CVD risk among certain patient subgroups. Further research is needed to validate whether these genomic profiles can prospectively identify individuals at risk to develop CVDs. Several research gaps were identified: little information is available on studies suggesting “Health application to evidence-based practice guidelines”; no study is available on “Guidelines to health practice.” It was not possible to identify studies that incorporate environmental or lifestyle factors in the risk estimation.

Conclusion

Currently, identifying populations having a larger risk of developing common CVDs may result in personalized prevention programs by reducing people’s risk of onset or disease progression. However, limited evidence is available on the application of genomic results in health and public health practice.

Clopidogrel Resistance in Lower Extremity Arterial Endovascular Interventions

Antiplatelet pharmacotherapy for endovascular interventions has been widely adopted, with clopidogrel being one of the most common agents prescribed. A fraction of patients is resistant to clopidogrel resulting in decreased platelet inhibition despite adequate use. This finding is often termed high on-treatment platelet reactivity (HPR) and may lead to decreased patency in lower extremity arterial endovascular interventions. Current literature on HPR with lower extremity arterial endovascular interventions is limited to only a few studies. Resistance to clopidogrel is largely a result of CYP2C19 enzyme loss of function alleles. Several tests are available to measure clopidogrel resistance but light transmittance aggregometry remains the gold standard, yet direct genetic testing may be more reliable. One-year patency rates following lower extremity arterial endovascular interventions in patients with clopidogrel resistance (HPR) range between 35%-83% whereas those with the proper response to clopidogrel range between 73%-100%. Patients with decreased CYP2C19 activity show a significant decrease in one-year patency of endovascular femoropopliteal interventions (35% vs. 73%; p=0.006). Among patients tested for platelet function after in-stent thrombosis, up to 53% are resistant to clopidogrel. Lack of robust data limits our ability to predict patency in lower extremity arterial interventions for patients with HPR, but there is little doubt that longer patency seems to favor non-HPR patients. Large population, prospective trials are needed to guide our practice.

Interactions of omeprazole-based analogues with cytochrome P450 2C19: a computational study

Cytochrome P450 2C19 (CYP2C19) is one of 57 drug metabolizing enzymes in humans and is responsible for the metabolism of ∼7-10% of drugs in clinical use. Recently omeprazole-based analogues were reported to be the potent inhibitors of CYP2C19 and have the potential to be used as the tool compounds for studying the substrate selectivity of CYP2C19. However, the binding modes of these compounds with CYP2C19 remain to be elucidated. In this study, a combination of molecular docking, molecular dynamics (MD), and MM/GBSA calculations was employed to systematically investigate the interactions between these compounds and CYP2C19. The binding modes of these analogues were analyzed in detail. The results indicated that the inclusion of explicit active site water molecules could improve binding energy prediction when the water molecules formed a hydrogen bonding network between the ligand and protein. We also found that the effect of active site water molecules on binding free energy prediction was dependent on the ligand binding modes. Our results unravel the interactions of these omeprazole-based analogues with CYP2C19 and might be helpful for the future design of potent CYP2C19 inhibitors with improved metabolic properties.

Comparative risk of ischemic stroke among users of clopidogrel together with individual proton pump inhibitors

BACKGROUND AND PURPOSE

There is controversy and little information about whether individual proton pump inhibitors (PPIs) differentially alter the effectiveness of clopidogrel in reducing ischemic stroke risk. We, therefore, aimed to elucidate the risk of ischemic stroke among concomitant users of clopidogrel and individual PPIs.

METHODS

We conducted a propensity score-adjusted cohort study of adult new users of clopidogrel, using 1999 to 2009 Medicaid claims from 5 large states. Exposures were defined by prescriptions for esomeprazole, lansoprazole, omeprazole, rabeprazole, and pantoprazole-with pantoprazole serving as the referent. The end point was hospitalization for acute ischemic stroke, defined by International Classification of Diseases Ninth Revision Clinical Modification codes in the principal position on inpatient claims, within 180 days of concomitant therapy initiation.

RESULTS

Among 325 559 concomitant users of clopidogrel and a PPI, we identified 1667 ischemic strokes for an annual incidence of 2.4% (95% confidence interval, 2.3-2.5). Adjusted hazard ratios for ischemic stroke versus pantoprazole were 0.98 (0.82-1.17) for esomeprazole; 1.06 (0.92-1.21) for lansoprazole; 0.98 (0.85-1.15) for omeprazole; and 0.85 (0.63-1.13) for rabeprazole.

CONCLUSIONS

PPIs of interest did not increase the rate of ischemic stroke among clopidogrel users when compared with pantoprazole, a PPI thought to be devoid of the potential to interact with clopidogrel.