Impact of Diabetes Mellitus on the Pharmacodynamic Effects of Ticagrelor Versus Clopidogrel in Troponin-Negative Acute Coronary Syndrome Patients Undergoing Ad Hoc Percutaneous Coronary Intervention

Early detection of resistance to dual antiplatelet therapy in patients who have undergone percutaneous coronary intervention using the VerifyNow test and associated factors

Resistance to dual antiplatelet therapy (DAPT), including aspirin and clopidogrel, in patients who have undergone percutaneous coronary intervention (PCI) leads to the inability to prevent thrombotic complications. The present study aimed to evaluate early resistance to aspirin and clopidogrel in patients following PCI using the VerifyNow test and associated factors. A total of 50 patients diagnosed with acute coronary syndromes (ACS) who underwent emergency PCI and received DAPT were recruited in the present study. The detection of resistance to aspirin and clopidogrel was performed using the VerifyNow system. Resistance to aspirin was determined with VerifyNow Aspirin >550 aspirin reaction units (ARU). Resistance to clopidogrel was determined with VerifyNow P2Y12 >208 P2Y12 reaction units (PRU). The resistance rate to aspirin was 14%, while the resistance rate to clopidogrel was higher, at 34%. There were 2 patients with resistance to aspirin and clopidogrel (4%). Univariable logistic regression analysis revealed that diabetes, the use of β-blockers, and low levels of hemoglobin and hematocrit were associated with resistance to clopidogrel. Following multivariable logistic regression analysis, only the use of β-blockers was truly associated with resistance to clopidogrel. On the whole, the results of the present study may also prove to be helpful in the selection of therapeutic drugs for patients undergoing PCI and who are diagnosed with ACS.

CYP2C19 Genetic Testing for Oral P2Y12 Inhibitor Therapy: A Scientific Statement From the American Heart Association

There is significant variability in the efficacy and safety of oral P2Y12 inhibitors, which are used to prevent ischemic outcomes in common diseases such as coronary and peripheral arterial disease and stroke. Clopidogrel, a prodrug, is the most used oral P2Y12 inhibitor and is activated primarily after being metabolized by a highly polymorphic hepatic cytochrome CYP2C219 enzyme. Loss-of-function genetic variants in CYP2C219 are common, can result in decreased active metabolite levels and increased on-treatment platelet aggregation, and are associated with increased ischemic events on clopidogrel therapy. Such patients can be identified by CYP2C19 genetic testing and can be treated with alternative therapy. Conversely, universal use of potent oral P2Y12 inhibitors such as ticagrelor or prasugrel, which are not dependent on CYP2C19 for activation, has been recommended but can result in increased bleeding. Recent clinical trials and meta-analyses have demonstrated that a precision medicine approach in which loss-of-function carriers are prescribed ticagrelor or prasugrel and noncarriers are prescribed clopidogrel results in reducing ischemic events without increasing bleeding risk. The evidence to date supports CYP2C19 genetic testing before oral P2Y12 inhibitors are prescribed in patients with acute coronary syndromes or percutaneous coronary intervention. Clinical implementation of such genetic testing will depend on among multiple factors: rapid availability of results or adoption of the concept of performing preemptive genetic testing, provision of easy-to-understand results with therapeutic recommendations, and seamless integration in the electronic health record.

Prevalence of CYP2C19*2 and CYP2C19*3 Allelic Variants and Clopidogrel Use in Patients with Cardiovascular Disease in Trinidad & Tobago

INTRODUCTION

Trinidad & Tobago has the highest prevalence of cardiovascular disease (CVD) in the Caribbean and clopidogrel is a ubiquitously used treatment. Yet, the extent of genetically mediated clopidogrel resistance is unknown. To determine this, we investigated whether the association between CYP2C19*2 and CYP2C19*3 genetic variants and clopidogrel resistance holds, and calculated the frequencies of these in the Trinidadian CVD population.

METHODS

Demographic data, clinical data, and a saliva sample were collected under informed consent from 22 patients with CVD on dual anti-platelet therapy whose biochemical resistance to clopidogrel is known, and a further 162 patients accessing the main public CVD clinic in Trinidad and who are either currently being treated or are likely to be treated with clopidogrel. A polymerase chain reaction (PCR) and restriction enzyme digestion procedure was used to genotype each patient for the CYP2C19*2 and CYP2C19*3 allelic variants. Genotype was compared to known clopidogrel resistance in the 22 patients, and to disease status and clopidogrel usage in the larger cohort.

RESULTS

CYP2C19*2 genotype was concordant with clopidogrel resistance. CYP2C19*2 was detected in 61.1% (99/162) of patients and CYP2C19*3 was undetected. Clopidogrel was the most prescribed antiplatelet therapy (42%). A total of 120 people presented with coronary artery disease (CAD) and 52.5% of these (n = 63/120) are currently prescribed clopidogrel. 63.5% (40/63) of patients with CAD who are prescribed clopidogrel carry the CYP2C19*2 allele; ten homozygous and 30 heterozygous. Indian patients comprised 65% of the cohort and were four times more likely to carry the CYP2C19*2 allele than African patients.

CONCLUSIONS

A large proportion of Trinidadian patients with CVD who are prescribed or may be prescribed clopidogrel carry genetic variants associated with clopidogrel resistance. These results emphasize the clinical need for further investigation into whether CYP2C19*2 genotype should guide clopidogrel use for the cardiovascular disease population in Trinidad & Tobago. A slide deck is available for this article.

Cardiovascular Outcomes Observed with Ticagrelor versus Clopidogrel in Type 2 Diabetes Mellitus Patients with Acute Coronary Syndrome: A Meta-analysis

INTRODUCTION

Type 2 diabetes mellitus (T2DM) is often associated with macrovascular complications including cardiovascular diseases (CVDs), resulting in acute coronary syndrome (ACS). Newer potent antiplatelet agents have recently been approved for use in clinical practice. In this analysis, we aimed to systematically compare the cardiovascular outcomes observed with ticagrelor versus clopidogrel in T2DM patients with ACS.

METHODS

From August to September 2022, electronic databases were searched for publications that compared cardiovascular outcomes observed with ticagrelor versus clopidogrel in patients with T2DM. The statistical analysis was carried out using RevMan 5.4 software. A random effect statistical model was used to analyze the data. Risk ratios (RR) with 95% confidence intervals (CIs) were used to represent the data post analysis.

RESULTS

A total of 5868 participants with T2DM were included in this analysis, of which 1944 participants were assigned to the ticagrelor group and 3924 participants were assigned to the clopidogrel group. Our analysis showed that ticagrelor was associated with a significantly lower risk of major adverse cardiac events (MACEs) (RR: 0.64, 95% CI: 0.49-0.84; P = 0.001), all-cause mortality (RR: 0.65, 95% CI: 0.51-0.83; P = 0.0004), and cardiac death (RR: 0.60, 95% CI: 0.43-0.84; P = 0.003) in comparison to clopidogrel. However, the risks of repeated revascularization (RR: 1.48, 95% CI: 0.44-4.99; P = 0.53), stent thrombosis (RR: 0.70, 95% CI: 0.18-2.71; P = 0.60), reinfarction (RR: 0.85, 95% CI: 0.58-1.23; P = 0.39), and stroke (RR: 0.56, 95% CI: 0.14-2.21; P = 0.41) were similar. Ticagrelor was associated with a significantly higher risk of minor bleeding (RR: 1.53, 95% CI: 1.07-2.19; P = 0.02), whereas the risk for major bleeding (RR: 1.08, 95% CI: 0.55-2.10; P = 0.82) was not significantly different.

CONCLUSIONS

In these T2DM patients with ACS, a significantly lower risk of major adverse cardiovascular events including all-cause mortality was observed in the ticagrelor group compared with the clopidogrel group. However, T2DM patients who were assigned to ticagrelor showed a significantly higher minor bleeding risk. Larger clinical trials should be able to confirm these hypotheses.

Resistance on the Latest Oral and Intravenous P2Y12 ADP Receptor Blockers in Patients with Acute Coronary Syndromes: Fact or Myth?

Novel P2Y12 ADP receptor blockers (ADPRB) should be preferred in dual-antiplatelet therapy in patients with acute coronary syndrome. Nevertheless, there are still patients who do not respond optimally to novel ADP receptor blocker therapy, and this nonoptimal response (so-called "high on-treatment platelet reactivity" or "resistance") could be connected with increased risk of adverse ischemic events, such as myocardial re-infarction, target lesion failure and stent thrombosis. In addition, several risk factors have been proposed as factors associated with the phenomenon of inadequate response on novel ADPRB. These include obesity, multivessel coronary artery disease, high pre-treatment platelet reactivity and impaired metabolic status for prasugrel, as well as elderly, concomitant therapy with beta-blockers, morphine and platelet count for ticagrelor. There is no literature report describing nonoptimal therapeutic response on cangrelor, and cangrelor therapy seems to be a possible approach for overcoming HTPR on prasugrel and ticagrelor. However, the optimal therapeutic management of "resistance" on novel ADPRB is not clear and this issue requires further research. This narrative review article discusses the phenomenon of high on-treatment platelet reactivity on novel ADPRB, its importance in clinical practice and approaches for its therapeutic overcoming.

The developmental journey of therapies targeting purine receptors: from basic science to clinical trials

Since the discovery of ATP as an extracellular signalling molecule in 1972, purinergic signalling, mediated by extracellular purines and pyrimidines has been identified in virtually all mammalian tissues and is implicated in regulating fundamental cellular processes. In recent years, there has been an increasing focus on the pathophysiology and potential therapeutic interventions based on purinergic signalling. A vast range of compounds targeting purine receptors are in clinical development, and many more are in preclinical studies, which highlights the fast growth in this research field. As a tribute to Professor Geoffrey Burnstock's legacy in purinergic signalling, we present here a brief review of compounds targeting purine receptors that are in different stages of clinical trials. The review highlights the 50-year journey from basic research on purinergic receptors to clinical applications of therapies targeting purine receptors.

Antiplatelet efficacy of ticagrelor versus clopidogrel in Mediterranean patients with diabetes mellitus and chronic coronary syndromes: A crossover pharmacodynamic investigation

Introduction

Patients with diabetes mellitus (DM) have augmented platelet reactivity and diminished responsiveness to clopidogrel. Ticagrelor, a more potent P2Y12 inhibitor, is clinically superior to clopidogrel in acute coronary syndromes, although its role in chronic coronary syndromes (CCS) is still the subject of debate. The aim of this investigation was to compare the pharmacodynamic effectiveness of ticagrelor and clopidogrel in Mediterranean DM patients with CCS.

Materials and methods

In this prospective, randomized, crossover study, patients (n = 20) were randomized (1:1) to receive, on top of aspirin therapy, either ticagrelor 180 mg loading dose (LD)/90 mg maintenance dose (MD) b.i.d. or clopidogrel 600 mg LD/75 mg MD o.d. for 1 week in a crossover fashion with a 2-4 week washout period between regimens. Platelet function measurements were performed at 4 timepoints in each period (baseline, 2 h and 24 h after LD, and 1 week), including light transmission aggregometry (LTA, primary endpoint), VASP assay, Multiplate and VerifyNow P2Y12.

Results

The ticagrelor LD achieved greater platelet inhibitory effect than clopidogrel LD, assessed with LTA (20 μM ADP as agonist), at 2 h (34.9 ± 3.9% vs. 63.6 ± 3.9%; p < 0.001) and 24 h (39.4 ± 3.5% vs. 52.3 ± 3.8%; p = 0.014). After 1 week of therapy, platelet reactivity was again significantly inferior with ticagrelor compared to clopidogrel (30.7 ± 3.0% vs. 54.3 ± 3.0%; p < 0.001). The results were consistent with the other platelet function assays employed.

Conclusion

In Mediterranean patients with DM and CCS, ticagrelor provides a more potent antiplatelet effect than clopidogrel after the LD and during the maintenance phase of therapy.

Clinical trial registration

[ClinicalTrials.gov], identifier [NCT02457130].

Ticagrelor Versus Clopidogrel in East Asian Patients With Acute Coronary Syndrome and Diabetes Mellitus

BACKGROUND

It is still unknown whether diabetes mellitus (DM) affects the relative safety and efficacy of ticagrelor vs clopidogrel in East Asian patients with acute coronary syndrome (ACS).

OBJECTIVES

The authors sought to assess the safety and efficacy of ticagrelor vs clopidogrel according to the diabetic status of East Asian patients with ACS undergoing invasive management.

METHODS

This prespecified analysis of the TICA KOREA (Clinically Significant Bleeding With Ticagrelor Versus Clopidogrel in Korean Patients With Acute Coronary Syndromes Intended for Invasive Management) trial included 800 Korean patients. The primary safety endpoint was clinically significant bleeding (PLATO [Platelet Inhibition and Clinical Outcomes] major or minor bleeding) at 12 months; the efficacy endpoint was major adverse cardiovascular events (cardiovascular death, myocardial infarction, and stroke).

RESULTS

Of 800 patients, 216 (27.0%) had DM. The incidence of clinically significant bleeding within 12 months was significantly higher with ticagrelor than clopidogrel in the nondiabetic group (10.2% vs 4.3%; HR: 2.45; 95% CI: 1.27-4.70; P = 0.007) and tended to be higher in the diabetic group (13.8% vs 8.0%; HR: 1.87; 95% CI: 0.54-4.36; P = 0.15); there was no significant interaction between treatment-arm and DM (P for interaction = 0.64). The incidences of major adverse cardiovascular events were not significantly different after ticagrelor or clopidogrel both in the diabetic group (10.8% vs 6.0%; HR: 1.90; 95% CI: 0.71-5.07; P = 0.20) and in the nondiabetic group (8.5% vs 5.7%; HR: 1.51; 95% CI: 0.81-2.81; P = 0.19) without significant interaction (P-for-interaction = 0.71).

CONCLUSIONS

In Korean ACS patients undergoing early invasive management, diabetes status did not affect the relative safety and efficacy of ticagrelor and clopidogrel. (Safety and Efficacy of Ticagrelor Versus Clopidogrel in Asian/Korean Patients With Acute Coronary Syndromes Intended for Invasive Management [TICA KOREA]; NCT02094963).

Ideal P2Y12 Inhibitor in Acute Coronary Syndrome: A Review and Current Status

Dual antiplatelet therapy (DAPT) has remained the cornerstone for management of acute coronary syndrome (ACS) over the years. Clopidogrel has been the quintessential P2Y12 receptor (platelet receptor for Adenosine 5′ diphosphate) inhibitor for the past two decades. With the demonstration of unequivocal superior efficacy of prasugrel/ticagrelor over clopidogrel, guidelines now recommend these agents in priority over clopidogrel in current management of ACS. Cangrelor has revived the interest in injectable antiplatelet therapy too. Albeit the increased efficacy of these newer agents comes at the cost of increased bleeding and this becomes more of a concern when combined with aspirin. Which P2Y12i is superior over another has been intensely debated over last few years after the ISAR-REACT 5 study with inconclusive data. Three novel antiplatelet agents are already in the pipeline for ACS with all of them succeeding in phase II studies. The search for an ideal antiplatelet remains a need of the hour for optimal reduction of ischemic events in ACS.

A Case of Hypoglycemia With Concomitant Use of a Sulfonylurea and Clopidogrel

Hypoglycemia secondary to sulfonylureas and clopidogrel have been independently described in the literature. However, there has been minimal investigation into the risk of clopidogrel-induced hypoglycemia in the setting of long-term or concomitant sulfonylurea use in patients with Type 2 diabetes mellitus. We present a case of a patient with diabetes well managed on glimepiride (second-generation sulfonylurea) for more than 10 years who presented with an episode of hypoglycemia shortly after initiation of clopidogrel for peripheral vascular disease.

A Review of the Role of the Antiplatelet Drug Ticagrelor in the Management of Acute Coronary Syndrome, Acute Thrombotic Disease, and Other Diseases

P2Y12 inhibitors, including aspirin, are key components of dual-antiplatelet therapy (DAPT), which is the optimal therapeutic strategy for preventing arterial thrombosis in patients with acute coronary syndromes (ACS) who underwent stent implantation. Ticagrelor is a cyclopentyl-triazole pyrimidine antiplatelet drug that was the first reversible oral P2Y12 receptor antagonist. Compared with clopidogrel, ticagrelor exerts a faster onset and offset of function by reversible and selective inhibition of platelet aggregation in ACS patients, including those with coronary artery blood revascularization. Despite improvement in stent materials, stent thrombosis (ST) due to high on-treatment platelet reactivity (HPR) to clopidogrel continues to occur. In addition to antiplatelet aggregation, ticagrelor displays pleiotropic cardioprotective effects, including improving coronary blood flow, reducing myocardial necrosis after an ischemic event, and anti-inflammatory effects. The benefits of ticagrelor over clopidogrel were consistent in the PLATO results, with lower incidence of the primary endpoint. Also, in 2020, the findings from the phase 3 THALES trial (NCT03354429) showed that aspirin combined with 90 mg of ticagrelor significantly reduced the rates of stroke and death compared with aspirin alone in patients with AIS or TIA. Here, we review recent research on the superiority of ticagrelor over clopidogrel, discuss the pharmacological mechanism, and present future perspectives. This review aims to present the roles of ticagrelor in the management of acute coronary syndrome, acute thrombotic disease, and other diseases.

Bimodal Effects of P2Y12 Antagonism on Matrix Metalloproteinase-Associated Contractile Dysfunction in İnsulin-Resistant Mammalian Heart

The matrix metalloproteinases (MMPs) contribute to matrix remodeling in diabetes via tissue degradation; however, their contributions can be different depending on the pathology. For instance, MMPs are elevated in acute stress hyperglycemia, whereas they can be degraded in chronic hyperglycemia. Since studies emphasize the possible cardioprotective effect of ticagrelor (Tica) beyond its antiplatelet action, we aimed to examine whether Tica treatment can reverse the depressed heart function of metabolic syndrome (MetS) rats via affecting the expression levels of MMPs. Tica treatment of high-carbohydrate-induced MetS rats could not affect significantly the depressed contractile activity of Langendorff-perfused heart preparations. On the other hand, the Tica treatment provided a significant recovery in the reduced relaxation activity of the aortic preparations from the same animals. Histological examination of the hearts demonstrated marked damages in Mets rats, such as increases in the number of foamy cells and accumulation of collagen fiber and increases in the elastic lamellar irregularity of tunica media, while Tica treatment provided a slight improvement in the structure of left ventricle tissue. We also could not obtain a significant reverse in the high cytosolic labile Zn²⁺ ([Zn²⁺]_i) with the treatment of cardiomyocytes with Tica. Furthermore, Tica treatment of MetS rats could not significantly reverse the degraded protein levels of MMP-2 and MMP-9 in the heart, as well. Overall, we demonstrated that Tica treatment of MetS rats has no significant benefits on the depressed heart function, although provide a significant beneficial impact on vascular relaxation. This action of Tica may be through its lack of action on both MMP degradation and high [Zn²⁺]_i, which can further precipitate in cleavage of extracellular matrix in the heart.

Cardioprotective effect of extracellular vesicles derived from ticagrelor-pretreated cardiomyocyte on hyperglycemic cardiomyocytes through alleviation of oxidative and endoplasmic reticulum stress

Extracellular vesicles (EVs) play important roles in diabetes mellitus (DM) via connecting the immune cell response to tissue injury, besides stimulation to muscle insulin resistance, while DM is associated with increased risks for major cardiovascular complications. Under DM, chronic hyperglycemia, and subsequent increase in the production of reactive oxygen species (ROS) further lead to cardiac growth remodeling and dysfunction. The purinergic drug ticagrelor is a P₂Y₁₂ receptor antagonist. Although it is widely used in cardioprotection, the underlying molecular mechanism of its inhibitory effect on diabetic cardiomyopathy is poorly elucidated. Here, we aimed to understand how ticagrelor exerts its cardio-regulatory effects. For this purpose, we investigated the anti-oxidative and cardioprotective effect of EVs derived from ticagrelor-pretreated cardiomyocytes under DM conditions. To mimic DM in cardiomyocytes, we used high glucose incubated H9c2-cells (HG). HG cells were treated with EVs, which were derived from either ticagrelor-pretreated or untreated H9c2-cells. Our results demonstrated that ticagrelor-pretreated H9c2-derived EVs significantly decreased the hyperglycemia-induced aberrant ROS production, prevented the development of apoptosis and ER stress, and alleviated oxidative stress associated miRNA-expression profile. Importantly, EVs derived from ticagrelor-pretreated H9c2-cells enhanced endothelial cell migration and tube formation, suggesting a modulation of the EV profile in cardiomyocytes. Our data, for the first time, indicate that ticagrelor can exert an important regulatory effect on diabetic cardiomyopathy through extracellular vesicular modulation behind its receptor-inhibition-related effects.

Illustrative and historic cases of phenoconversion

Intersubject variability in drug response, whether related to efficacy or toxicity, is well recognized clinically. Over the years, drug selection from our pharmacologic armamentarium has moved from providers' preferred choices to more personalized treatments as clinicians' decisions are guided by data from clinical trials. Since the advent of more accessible and affordable pharmacogenomic (PGx) testing, the promise of precise pharmacotherapy has been made. Results have accumulated in the literature with numerous examples demonstrating the value of PGx to improve drug response or prevent drug toxicity. Unfortunately, limited availability of reimbursement policies has dampened the enthusiasm of providers and organizations. The clinical application of PGx knowledge remains difficult for most clinicians under real-world conditions in patients with numerous chronic conditions and polypharmacy. This may be due to phenoconversion, a condition where there is a discrepancy between the genotype-predicted phenotype and the observed phenotype. This condition complicates the interpretation of PGx results and may lead to inappropriate recommendations and clinical decision making. For this reason, regulatory agencies have limited the transfer of information from PGx laboratories directly to consumers, especially recommendations about the use of certain drugs. This mini-review presents cases (mexiletine, propafenone, clopidogrel, warfarin, codeine, procainamide) from historical observations where drug response was modified by phenoconversion. The cases illustrate, from decades ago, that we are still in great need of advanced clinical decision systems that cope with conditions associated with phenoconversion, especially in patients with polypharmacy.

Ticagrelor alleviates high-carbohydrate intake induced altered electrical activity of ventricular cardiomyocytes by regulating sarcoplasmic reticulum-mitochondria miscommunication

Metabolic syndrome (MetS) is associated with additional cardiovascular risk in mammalians while there are relationships between hyperglycemia-associated cardiovascular dysfunction and increased platelet P2Y12 receptor activation. Although P2Y12 receptor antagonist ticagrelor (Tica) plays roles in reduction of cardiovascular events, its beneficial mechanism remains poorly understood. Therefore, we aimed to clarify whether Tica can exert a direct protective effect in ventricular cardiomyocytes from high-carbohydrate diet-induced MetS rats, at least, through affecting sarcoplasmic reticulum (SR)-mitochondria (Mit) miscommunication. Tica treatment of MetS rats (150 mg/kg/day for 15 days) significantly reversed the altered parameters of action potentials by reversing sarcolemmal ionic currents carried by voltage-dependent Na+ and K+ channels, and Na+/Ca2+-exchanger in the cells, expressed P2Y12 receptors. The increased basal-cytosolic Ca2+ level and depressed SR Ca2+ load were also reversed in Tica-treated cells, at most, though recoveries in the phosphorylation levels of ryanodine receptors and phospholamban. Moreover, there were marked recoveries in Mit structure and function (including increases in both autophagosomes and fragmentations) together with recoveries in Mit proteins and the factors associated with Ca2+ transfer between SR-Mit. There were further significant recoveries in markers of both ER stress and oxidative stress. Taken into consideration the Tica-induced prevention of ER stress and mitochondrial dysfunction, our data provided an important document on the pleiotropic effects of Tica in the electrical activity of the cardiomyocytes from MetS rats. This protective effect seems through recoveries in SR-Mit miscommunication besides modulation of different sarcolemmal ion-channel activities, independent of P2Y12 receptor antagonism.

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.

Impact Of Chronic Kidney Disease On The Pharmacodynamic And Pharmacokinetic Effects Of Ticagrelor In Patients With Diabetes Mellitus And Coronary Artery Disease

AIMS

Patients with diabetes mellitus (DM) and chronic kidney disease (CKD) are at increased risk of atherothrombotic events. Ticagrelor reduces ischaemic events compared to clopidogrel, with the greatest risk reduction in patients with both DM and CKD. How CKD status affects the pharmacodynamic (PD) and pharmacokinetic (PK) profiles of different ticagrelor maintenance dose regimens in patients with DM is unknown.

METHODS AND RESULTS

In this randomized, cross-over study, patients with DM on treatment with dual antiplatelet therapy (aspirin and clopidogrel) were stratified according to CKD status and randomized to ticagrelor 90 mg bid or 60 mg bid. PK/PD assessments were performed at baseline, after 7-10 days of ticagrelor (peak and trough), and after 7-10 days of alternative ticagrelor regimen (peak and trough). PK assessments included plasma concentrations of ticagrelor and its major metabolite. PD assessments included VASP-PRI, VerifyNow P2Y12, and LTA.A total of 92 patients with DM (CKD, n = 44; non-CKD, n = 48) were randomized. Levels of platelet reactivity were lower with the 90 mg compared with the 60 mg ticagrelor dose, which was statistically significant in non-CKD but not in CKD patients for most PD measures. There were no significant differences in the primary endpoint (trough levels of VASP-PRI following ticagrelor 90 mg dosing) between cohorts (31 ± 20 vs 25 ± 14; p = 0.105). VerifyNow and LTA provided similar findings. PK assessments tracked PD profiles showing increased plasma concentrations of ticagrelor and its major metabolite in CKD compared to non-CKD patients.

CONCLUSION

In patients with DM, although ticagrelor maintenance dose regimens (60 mg and 90 mg) yield potent P2Y12 inhibition, levels of platelet reactivity tended to be higher and subject to broader variability in non-CKD compared with CKD patients.

CLINICAL TRIAL REGISTRATION

http://www.clinicaltrials.gov Unique Identifier: NCT02539160.

Chronic Inflammatory Status Observed in Patients with Type 2 Diabetes Induces Modulation of Cytochrome P450 Expression and Activity

Diabetes mellitus is a metabolic disease that causes a hyperglycemic status which leads, over time, to serious damage to the heart, blood vessels, eyes, kidneys and nerves. The most frequent form of diabetes is type 2 diabetes mellitus (T2DM) which is often part of a metabolic syndrome (hyperglycaemia, hypertension, hypercholesterolemia, abdominal obesity) that usually requires the use of several medications from different drug classes to bring each of these conditions under control. T2DM is associated with an increase in inflammatory markers such as interleukin-6 (IL-6) and the tumor necrosis factor alpha (TNF-α). Higher levels of IL-6 and TNF-α are associated with a downregulation of several drug metabolizing enzymes, especially the cytochrome P450 (P450) isoforms CYP3As and CYP2C19. A decrease in these P450 isoenzymes may lead to unexpected rise in plasma levels of substrates of these enzymes. It could also give rise to a mismatch between the genotypes determined for these enzymes, the predicted phenotypes based on these genotypes and the phenotypes observed clinically. This phenomenon is described as phenoconversion. Phenoconversion typically results from either a disease (such as T2DM) or concomitant administration of medications inducing or inhibiting (including competitive or non-competitive inhibition) a P450 isoenzyme used by other substrates for their elimination. Phenoconversion could have a significant impact on drug effects and genotypic-focused clinical outcomes. As the aging population is exposed to polypharmacy along with inflammatory comorbidities, consideration of phenoconversion related to drug metabolizing enzymes is of importance when applying pharmacogenomic results and establishing personalized and more precise drug regimens.

Physiologically-Based Pharmacokinetic-Pharmacodynamics Model Characterizing CYP2C19 Polymorphisms to Predict Clopidogrel Pharmacokinetics and Its Anti-Platelet Aggregation Effect Following Oral Administration to Coronary Artery Disease Patients With or Without Diabetes

Background and Objective: Clopidogrel (CLOP) is commonly used in coronary artery disease (CAD) patients with or without diabetes (DM), but these patients often suffer CLOP resistance, especially those with diabetes. This study was aimed to develop a physiologically-based pharmacokinetic-pharmacodynamic (PBPK-PD) model to describe the pharmacokinetics and pharmacodynamics of clopidogrel active metabolite (CLOP-AM) in CAD patients with or without DM.

Methods: The PBPK-PD model was first established and validated in healthy subjects and then in CAD patients with or without DM. The influences of CYP2C19, CYP2C9, CYP3A4, carboxylesterase 1 (CES1), gastrointestinal transit rates (K_t,i) and platelets response to CLOP-AM (k_irre) on predicted pharmacokinetics and pharmacodynamics were investigated, followed with their individual and integrated effects on CLOP-AM pharmacokinetics due to changes in DM status.

Results: Most predictions fell within 0.5–2.0 folds of observations, indicating successful predictions. Sensitivity analysis showed that contributions of interested factors to pharmacodynamics were CES1> k_irre> K_t,i> CYP2C19 > CYP3A4> CYP2C9. Mimicked analysis showed that the decreased exposure of CLOP-AM by DM was mainly attributed to increased CES1 activity, followed by decreased CYP2C19 activity.

Conclusion: The pharmacokinetics and pharmacodynamics of CLOP-AM were successfully predicted using the developed PBPK-PD model. Clopidogrel resistance by DM was the integrated effects of altered K_t,i, CYP2C19, CYP3A4, CES1 and k_irre.

Impact of Diabetes Mellitus and Chronic Kidney Disease on Cardiovascular Outcomes and Platelet P2Y12 Receptor Antagonist Effects in Patients With Acute Coronary Syndromes: Insights From the PLATO Trial

Background

There are limited data on how the combination of diabetes mellitus (DM) and chronic kidney disease (CKD) affects cardiovascular outcomes as well as response to different P2Y₁₂ receptor antagonists, which represented the aim of the present investigation.

Methods and Results

In this post hoc analysis of the PLATO (Platelet Inhibition and Patient Outcomes) trial, which randomized acute coronary syndrome patients to ticagrelor versus clopidogrel, patients (n=15 108) with available DM and CKD status were classified into 4 groups: DM+/CKD+ (n=1058), DM+/CKD− (n=2748), DM−/CKD+ (n=2160), and DM−/CKD− (n=9142). The primary efficacy end point was a composite of cardiovascular death, myocardial infarction, or stroke at 12 months. The primary safety end point was PLATO major bleeding. DM+/CKD+ patients had a higher incidence of the primary end point compared with DM−/CKD− patients (23.3% versus 7.1%; adjusted hazard ratio 2.22; 95% CI 1.88–2.63; P<0.001). Patients with DM+/CKD− and DM−/CKD+ had an intermediate risk profile. The same trend was shown for the individual components of the primary end point and for major bleeding. Compared with clopidogrel, ticagrelor reduced the incidence of the primary end point consistently across subgroups (P‐interaction=0.264), but with an increased absolute risk reduction in DM+/CKD+. The effects on major bleeding were also consistent across subgroups (P‐interaction=0.288).

Conclusions

In acute coronary syndrome patients, a gradient of risk was observed according to the presence or absence of DM and CKD, with patients having both risk factors at the highest risk. Although the ischemic benefit of ticagrelor over clopidogrel was consistent in all subgroups, the absolute risk reduction was greatest in patients with both DM and CKD.

Clinical Trial Registration

URL: http://www.clinicatrials.gov. Unique identifier: NCT00391872.

Comparison between ticagrelor versus clopidogrel in long term outcomes of Taiwanese diabetic subjects with acute coronary syndrome undergoing successful revascularization: From TSOC ACS-DM registry

Although previous clinical trials demonstrated that ticagrelor could reduce cardiovascular events and mortality versus clopidogrel in patients with acute coronary syndrome (ACS), the real-world evidence of its clinical impacts on East Asian Diabetic population has rarely been investigated.Between November 2013 and June 2015, 1534 patients were recruited into the Acute Coronary Syndrome-Diabetes Mellitus Registry of the Taiwan Society of Cardiology (TSOC ACS-DM registry). After propensity score matching, a total of 730 patients undergoing successful revascularization and discharged on ticagrelor (N = 365) or clopidogrel (N = 365) were analyzed. The primary and secondary endpoints were all-cause mortality and re-hospitalization, respectively. The all-cause death associated with ticagrelor vs clopidogrel was 3.6% vs 7.4% (adjusted hazard ratio (HR) 0.34 [0.15-0.80]; P = .0138) at 24 months. The re-hospitalization rate at 24 months was 38.9% vs 39.2% (P = .3258).For diabetic patients with ACS, ticagrelor provided better survival benefit than clopidogrel without an increase of re-hospitalization in 24 months after successful percutaneous coronary intervention. This study in real-world circumstance provided valuable complementary data to externally validate platelet inhibition and patient outcomes (PLATO) finding especially in Asian diabetic population.

Ticagrelor reverses the mitochondrial dysfunction through preventing accumulated autophagosomes-dependent apoptosis and ER stress in insulin-resistant H9c2 myocytes

Ticagrelor, a P₂Y₁₂-receptor inhibitor, and a non-thienopyridine agent are used to treat diabetic patients via its effects on off-target mechanisms. However, the exact sub-cellular mechanisms by which ticagrelor exerts those effects remains to be elucidated. Accordingly, the present study aimed to examine whether ticagrelor influences directly the cardiomyocytes function under insulin resistance through affecting mitochondria-sarco(endo)plasmic reticulum (SER) cross-talk. Therefore, we analyzed the function and ultrastructure of mitochondria and SER in insulin resistance-mimicked (50-μM palmitic acid for 24-h) H9c2 cardiomyocytes in the presence or absence of ticagrelor (1-µM for 24-h). We found that ticagrelor treatment significantly prevented depolarization of mitochondrial membrane potential and increases in reactive oxygen species with a marked increase in the ATP level in insulin-resistant H9c2 cells. Ticagrelor treatment also reversed the increases in the resting level of free Ca²⁺ and mRNA level of P₂Y₁₂ receptors as well as preserved ER stress and apoptosis in insulin-resistant H9c2 cells. Furthermore, we determined marked repression with ticagrelor treatment in the increased number of autophagosomes and degeneration of mitochondrion, including swelling and loss of crista besides recoveries in enlargement and irregularity seen in SER in insulin-resistant H9c2 cells. Moreover, ticagrelor treatment could prevent the altered mRNA levels of Becklin-1 and type 1 equilibrative nucleoside transporter (ENT1), which are parallel to the preservation of ultrastructural ones. Our overall data demonstrated that ticagrelor can directly affect cardiomyocytes and provide marked protection against ER stress and dramatic induction of autophagosomes, and therefore, can alleviate the ER stress-induced oxidative stress increase and cell apoptosis during insulin resistance.

Prognostic Value of Hemoglobin A1c Levels in Postmenopausal Diabetic Patients Undergoing Percutaneous Coronary Intervention (PCI) for Acute Coronary Syndrome

Background

The purpose of our study was to analyze the clinical value of glycosylated hemoglobin Alc (HbA1c) levels in postmenopausal women with acute coronary syndrome (ACS) and diabetes following percutaneous coronary intervention (PCI).

Material/Methods

A total of 173 consecutive postmenopausal patients with comorbid diabetes underwent PCI for primary ACS were enrolled in this study. Serum HbA1c levels were measured prior to PCI, and baseline clinical characteristics of all patients were collected. All patients were followed up at regular intervals for major adverse cardiovascular events (MACEs) during the first year after PCI. MACEs included cardiac death, non-fatal myocardial infarction, and target vessel revascularization (TVR).

Results

At the endpoint of this study, 29 (16.8%) patients out of all 173 patients had MACEs. According to the effect of glycemic control (as indicated by HbA1c levels), all patients were stratified into a well-controlled group (HbA1c ≤7.0%, N=72) and a poorly-controlled group (HbA1c >7.0%, N=101). The incidence rate of MACEs and TVR in poorly-controlled diabetics was prominently higher than that in well-controlled diabetics (10.8% vs. 21.8%, p=0.04). In multivariable COX regression analysis, after adjustment for potential confounders, HbA1c ≥7.0% remained an independent risk predictor of MACE (HR, 2.17; 95%CI, 1.13–5.65; p<0.01).

Conclusions

In postmenopausal ACS patients with comorbid diabetes, a high level of HbA1c is associated with a higher MACE rate after PCI, which is mainly driven by a higher rate of TVR.

Diabetes and antiplatelet therapy: from bench to bedside

Diabetes mellitus (DM) is a metabolic disorder associated with accelerated atherogenesis and an increased risk of atherothrombotic complications. Multiple mechanisms contribute to the pro-thrombotic status which characterizes DM patients underscoring the importance of antiplatelet therapies used for secondary prevention in these patients. For many years, dual antiplatelet therapy (DAPT) with aspirin and the P2Y₁₂ inhibitor clopidogrel has represented the mainstay of treatment following an acute coronary syndrome (ACS) or in patients undergoing percutaneous coronary interventions (PCI). Although DAPT reduces the incidence of atherothrombotic recurrences, these rates remain high in DM patients underscoring the need for more efficacious therapies. Oral platelet P2Y₁₂ receptor inhibitors with enhanced potency, such as prasugrel and ticagrelor, as well as antiplatelet therapies such as vorapaxar inhibiting the thrombin-mediated platelet signaling pathway, constitute treatment opportunities for patients with DM and have shown to be associated with a greater reduction in ischemic recurrences, albeit at the cost of more bleeding. This article reviews currently available antiplatelet agents and delivers an update on the advances and drawbacks of these agents used for secondary prevention in DM patients experiencing an ACS or undergoing PCI.

Differential impact of diabetes mellitus on antiplatelet effects of prasugrel and clopidogrel

Background

Although prasugrel exerts stronger antiplatelet effects compared with clopidogrel, the factors affecting platelet reactivity under prasugrel have not been fully determined. This study aimed to find the novel mechanistic differences between two thienopyridines and identify the factor that influence platelet reactivity to each drug.

Methods

Forty patients with stable angina who underwent elective percutaneous coronary intervention were randomly assigned to receive either prasugrel (20 mg) or clopidogrel (300 mg) as a loading dose. Platelet function (light transmission, laser light scattering, and vasodilator-stimulated phosphoprotein phosphorylation) and plasma active metabolite levels were measured after the loading dose.

Results

Prasugrel consistently inhibited adenosine diphosphate receptor P2Y₁₂ signalling to abolish amplification of platelet aggregation. Prasugrel abolished even small platelet aggregates composed of less than 100 platelets. On the other hand, clopidogrel inhibited large aggregates but increased small and medium platelet aggregates. Diabetes was the only independent variable for determining antiplatelet effects and active metabolite concentration of prasugrel, but not clopidogrel. Sleep-disordered breathing was significantly correlated with platelet reactivity in patients who had clopidogrel.

Conclusions

Prasugrel efficiently abolishes residual P2Y₁₂ signalling that causes small platelet aggregates, but these small aggregates are not inhibited by clopidogrel. Considering the differential effect of diabetes on antiplatelet effects between these two drugs, the pharmacokinetics of prasugrel, other than cytochrome P450 metabolism, might be affected by diabetes.

Trial registration

UMIN-CTR UMIN000017624, retrospectively registered 21 May 2015.

Antithrombotic potency of ticagrelor versus clopidogrel in type-2 diabetic patients with cardiovascular disease

Type-2 Diabetes Mellitus [T2DM] is associated with increased platelet reactivity and hypo-response to antiplatelet drugs. Ticagrelor, with its faster and more potent antiplatelet effects, was shown to reduce adverse events more than clopidogrel in the overall CAD patient population of PLATO trial, but the benefits did not reach statistical significance in the T2DM subgroup. To better understand these findings, we compared the antithrombotic effects of ticagrelor versus with clopidogrel in T2DM patients with cardiovascular disease. In a randomized, 2 treatment-sequence, crossover-design, T2DM patients (n=20, 57±8 years, 60% male) received a loading-dose [LD] plus one week of daily-therapy [DT] of clopidogrel or ticagrelor. Treatment effects were assessed by measuring thrombus formation (Badimon Chamber) and platelet aggregation (Multiple Electrode Aggregometry (MEA) Analyzer and VerifyNow®) at 2- and 6-hour post-LD and on Day-7 of DT, in comparison with pre-treatment baseline. After 2 weeks of washout, patients switched to the second treatment under identical testing conditions. Ticagrelor significantly reduced thrombus formation versus baseline at 2- and 6-hour post-LD and Day-7 of DT (33%, 40% and 31%, respectively, p<0.01 for all) whereas thrombus reductions with clopidogrel were much lower and significant only at 6-hour post-LD (16%, 20% and 17%, respectively). Antithrombotic effect of ticagrelor at 6-hour was significantly stronger than clopidogrel (p<0.05). Platelet aggregation (MEA and VerifyNow®) was inhibited by both treatments but effects of ticagrelor were significantly stronger at each time-point. Ticagrelor exhibits a faster and more potent antithrombotic effect than clopidogrel in T2DM patients with cardiovascular disease, supporting its use in this population.

Clinical Trial Registration: Unique Identifier: NCT01823510.

Supplementary Material to this article is available online at www.thrombosis-online.com.