Ticagrelor: the first reversibly binding oral P2Y12 receptor antagonist

The pleiotropic effects of antithrombotic drugs in the metabolic-cardiovascular-neurodegenerative disease continuum: impact beyond reduced clotting

Antithrombotic drugs are widely used for primary and secondary prevention, as well as treatment of many cardiovascular disorders. Over the past few decades, major advances in the pharmacology of these agents have been made with the introduction of new drug classes as novel therapeutic options. Accumulating evidence indicates that the beneficial outcomes of some of these antithrombotic agents are not solely related to their ability to reduce thrombosis. Here, we review the evidence supporting established and potential pleiotropic effects of four novel classes of antithrombotic drugs, adenosine diphosphate (ADP) P2Y12-receptor antagonists, Glycoprotein IIb/IIIa receptor Inhibitors, and Direct Oral Anticoagulants (DOACs), which include Direct Factor Xa (FXa) and Direct Thrombin Inhibitors. Specifically, we discuss the molecular evidence supporting such pleiotropic effects in the context of cardiovascular disease (CVD) including endothelial dysfunction (ED), atherosclerosis, cardiac injury, stroke, and arrhythmia. Importantly, we highlight the role of DOACs in mitigating metabolic dysfunction-associated cardiovascular derangements. We also postulate that DOACs modulate perivascular adipose tissue inflammation and thus, may reverse cardiovascular dysfunction early in the course of the metabolic syndrome. In this regard, we argue that some antithrombotic agents can reverse the neurovascular damage in Alzheimer's and Parkinson's brain and following traumatic brain injury (TBI). Overall, we attempt to provide an up-to-date comprehensive review of the less-recognized, beneficial molecular aspects of antithrombotic therapy beyond reduced thrombus formation. We also make a solid argument for the need of further mechanistic analysis of the pleiotropic effects of antithrombotic drugs in the future.

Antithrombotic treatment in primary percutaneous coronary intervention

INTRODUCTION

Despite a timely mechanical reperfusion with primary percutaneous coronary intervention (pPCI) patients presenting with ST-elevation myocardial infarction (STEMI) display an increased risk of adverse cardiovascular events. Several studies have demonstrated that guideline-directed antithrombotic therapy is effective to reduce this risk. However, there is still much to be accomplished to improve antithrombotic therapies in this clinical setting.

AREAS COVERED

This paper reviews current data on antithrombotic therapy in STEMI patients undergoing pPCI.

EXPERT OPINION

Antithrombotic therapy for STEMI patients undergoing pPCI should take into account the variability of thrombotic and bleeding risk in the short and long term. Patients with STEMI profit from the administration of early onset antiplatelet agents and anticoagulation to achieve sufficient and predictable antithrombotic effect at the time of pPCI. Thereafter, antithrombotic therapies should be tailored to individual risk of recurrence over the long term, to avoid excess bleeding, while ensuring adequate secondary ischemic prevention.

ADP receptor P2y12 prevents excessive primitive hematopoiesis in zebrafish by inhibiting Gata1

In the past two decades, purinergic signaling has emerged as a key regulator of hematopoiesis in physiological and pathological conditions. ADP receptor P2y12 is a crucial component of this signaling, but whether it is involved in primitive hematopoiesis remains unknown. To elucidate the function of P2y12 and provide new insights for drug development, we established a zebrafish P2y12 mutant by CRISPR/Cas 9-based genetic modification system, and investigated whether P2y12 acted as an important regulator for primitive hematopoiesis. By using mass spectrometry (MS) combined with RNA sequencing, we showed that absence of P2y12 induced excessive erythropoiesis, evidenced by significantly increased expression of mature erythrocytes marker α-globin (Hbae1 and Hbae3), β-globin (Hbbe1 and Hbbe3). Expression pattern analysis showed that P2y12 was mainly expressed in red blood cells and endothelial cells of early zebrafish embryos. Further studies revealed that primitive erythroid progenitor marker Gata1 was markedly up-regulated. Remarkably, inhibition of Gata1 by injection of Gata1 morpholino could rescue the erythroid abnormality in P2y12 mutants. The present study demonstrates the essential role of purinergic signaling in differentiation of proerythrocytes during primitive hematopoiesis, and provides potential targets for treatment of blood-related disease and drug development.

The Total Thrombus Formation (T-TAS) platelet (PL) assay, a novel test that evaluates whole blood platelet thrombus formation under physiological conditions

Dual antiplatelet therapy (DAPT, aspirin, and a P2Y₁₂ inhibitor) reduces thrombotic events in patients with coronary artery disease (CAD). The T-TAS PL assay uses arterial shear flow over collagen surface, better mimicking in vivo conditions compared to conventional agonist-based platelet function assays, to evaluate platelet function. Here, the platelet function in patients taking DAPT is evaluated with the T-TAS PL assay. In 57 patients with CAD, taking DAPT ≥7 days (n = 22 for clopidogrel, n = 15 for prasugrel, n = 20 for ticagrelor), T-TAS PL assessments were performed in duplicate, and expressed as area under the flow pressure curve within a 10-minute period (AUC10). The duplicate measurements were strongly correlated (r = 0.90, p < .001), with an intra-assay coefficient of variation (CV) of 11,5%. For clopidogrel, the median AUC10 was 11.5 (IQR5.9-41.8), for prasugrel 28.8 (IQR10.3-37.6), and for ticagrelor 8.9 (IQR 6.4-10.9). All measurements were below the AUC10 cutoff of 260 measured in healthy volunteers, suggesting excellent discrimination of DAPT-treated and untreated persons. The new T-TAS PL assay demonstrated complete discrimination of platelet function in patients on DAPT based on an established cutoff. Ticagrelor showed lower levels of platelet function and a more uniform response compared to prasugrel and clopidogrel.

Platelet reactivity in response to aspirin and ticagrelor in African-Americans and European-Americans

Platelet gene polymorphisms are associated with variable on-treatment platelet reactivity and vary by race. Whether differences in platelet reactivity and aspirin or ticagrelor exist between African-American and European-Americans remains poorly understood. Biological samples from three prior prospective antiplatelet challenge studies at the Duke Clinical Research Unit were used to compare platelet reactivity between African-American and European-American subjects. Platelet reactivity at baseline, on-aspirin, on-ticagrelor, and the treatment effect of aspirin or ticagrelor were compared between groups using an adjusted mixed effects model. Compared with European-Americans (n = 282; 50% female; mean ± standard deviation age, 50 ± 16), African-Americans (n = 209; 67% female; age 48 ± 12) had lower baseline platelet reactivity with platelet function analyzer-100 (PFA-100) (p < 0.01) and with light transmission aggregometry (LTA) in response to arachidonic acid (AA), adenosine diphosphate (ADP), and epinephrine agonists (p < 0.05). African-Americans had lower platelet reactivity on aspirin in response to ADP, epinephrine, and collagen (p < 0.05) and on ticagrelor in response to AA, ADP, and collagen (p < 0.05). The treatment effect of aspirin was greater in European-Americans with an AA agonist (p = 0.002). Between-race differences with in vitro aspirin mirrored those seen in vivo. The treatment effect of ticagrelor was greater in European-Americans in response to ADP (p < 0.05) but with collagen, the treatment effect was greater for African-Americans (p < 0.05). Platelet reactivity was overall lower in African-Americans off-treatment, on aspirin, and on ticagrelor. European-Americans experienced greater platelet suppression on aspirin and on ticagrelor. The aspirin response difference in vivo and in vitro suggests a mechanism intrinsic to the platelet. Whether the absolute level of platelet reactivity or the degree of platelet suppression after treatment is more important for clinical outcomes is uncertain.

Spontaneous intermuscular hematoma in a patient receiving ticagrelor and aspirin: A case report

Dual antiplatelet therapy is a cornerstone treatment following percutaneous coronary intervention (PCI) for acute coronary syndrome (ACS). Ticagrelor, a direct-acting potent P2Y12 inhibitor, is superior to clopidogrel in the acute setting of ACS: due to its faster onset and potent antiplatelet inhibition. Thus, ticagrelor is becoming widely recommended as the as the initial treatment following PCI in current guidelines. However, due to its potency, the risk of bleeding is higher. Herein, a report of an unusual case of spontaneous intermuscular hematoma is described. Furthermore, single-nucleotide polymorphisms that may be related to bleeding in ticagrelor using population-based genome-wide association studies were also identified and are discussed. As there is a concern that patients of Asian origin may have a higher risk of bleeding, physicians must be made aware of this risk when prescribing ticagrelor to individuals of Asian decent.

Inhibiting P2Y12 in Macrophages Induces Endoplasmic Reticulum Stress and Promotes an Anti-Tumoral Phenotype

The P2Y12 receptor is an adenosine diphosphate responsive G protein-coupled receptor expressed on the surface of platelets and is the pharmacologic target of several anti-thrombotic agents. In this study, we use liver samples from mice with cirrhosis and hepatocellular carcinoma to show that P2Y12 is expressed by macrophages in the liver. Using in vitro methods, we show that inhibition of P2Y12 with ticagrelor enhances tumor cell phagocytosis by macrophages and induces an anti-tumoral phenotype. Treatment with ticagrelor also increases the expression of several actors of the endoplasmic reticulum (ER) stress pathways, suggesting activation of the unfolded protein response (UPR). Inhibiting the UPR with tauroursodeoxycholic acid (Tudca) diminishes the pro-phagocytotic effect of ticagrelor, thereby indicating that P2Y12 mediates macrophage function through activation of ER stress pathways. This could be relevant in the pathogenesis of chronic liver disease and cancer, as macrophages are considered key players in these inflammation-driven pathologies.

Ticagrelor-Related Severe Dyspnoea: Mechanisms, Characteristic Features, Differential Diagnosis and Treatment

With a growing number of patients on ticagrelor therapy after stent implantation, we observe many cases of side effects of the drug, mostly dyspnoea and bradycardia. In our article we present 2 patients, in which the symptoms were particularly severe. Then we describe possible mechanisms of these complications, explain how to carry out differential diagnosis, discuss when to switch ticagrelor to other antiplatelet drug and finally we present the way to deal with the symptoms.

Comparison of Light Transmission Aggregometry With Impedance Aggregometry in Patients on Potent P2Y12 Inhibitors

Since data on the agreement between light transmission aggregometry (LTA) and multiple electrode aggregometry (MEA) in patients on the more potent P2Y₁₂ inhibitors are missing so far, we investigated if the evaluation of the responsiveness to therapy by LTA can be replaced by MEA in 160 acute coronary syndrome (ACS) patients on dual antiplatelet therapy with aspirin and prasugrel or ticagrelor (n = 80 each). Cut-off values for high on-treatment residual platelet reactivity (HRPR) in response to adenosine diphosphate (ADP) or arachidonic acid (AA) were defined according to previous studies showing an association of HRPR with the occurrence of adverse ischemic outcomes. ADP- inducible platelet aggregation was 33% and 37% (P = 0.07) by LTA and 19 AU and 20 AU (P = 0.38) by MEA in prasugrel- and ticagrelor-treated patients, respectively. AA- inducible platelet aggregation was 2% and 3% by LTA and 15 AU and 16 AU by MEA, (all P ≥ 0.3) in patients on prasugrel and ticagrelor, respectively. By LTA, HRPR ADP and HRPR AA were seen in 5%/5% and in 4%/ 13% of patients receiving prasugrel- and ticagrelor, respectively. By MEA, HRPR ADP and HRPR AA were seen in 3%/ 25% and 0%/24% of prasugrel- and ticagrelor-treated patients, respectively. ADP-inducible platelet reactivity by MEA correlated significantly with LTA ADP in prasugrel-treated patients (r = 0.4, P < 0.001), but not in those receiving ticagrelor (r = 0.09, P = 0.45). AA-inducible platelet aggregation by LTA and MEA did not correlate in prasugrel- and ticagrelor-treated patients. Sensitivity/specificity of HRPR by MEA to detect HRPR by LTA were 25%/99% for MEA ADP and 100%/79% for MEA AA in prasugrel-treated patients, and 0%/100% for MEA ADP and 70%/83% for MEA AA in ticagrelor-treated patients. In conclusion, on-treatment residual ADP-inducible platelet reactivity by LTA and MEA shows a significant correlation in prasugrel- but not ticagrelor-treated patients. However, in both groups LTA and MEA revealed heterogeneous results regarding the classification of patients as responders or non-responders to P2Y₁₂ inhibition.

Novel [1,2,3]triazolo[4,5-d]pyrimidine derivatives containing hydrazone fragment as potent and selective anticancer agents

In this paper, based on molecular hybridization, a series of [1,2,3]triazolo[4,5-d]pyrimidine derivatives containing hydrazine was synthesized and their antiproliferative activities against 5 cancer cell lines (MGC-803, PC3, PC9, EC9706 and SMMC-7721) were evaluated. We found that most of them exhibited obvious growth inhibition effects on these tested cancer cells, especially compound 34 on PC3 cells (IC₅₀ = 26.25 ± 0.28 nM). Meanwhile, compound 34 displayed best selectivity on PC3, compared with the other cancer cell lines, as well as excellent selectivity towards normal cell lines (Het-1A, L02 and GES-1). Further investigations demonstrated that 34 could significantly inhibit PC3 cells' colony formation, increase cellular ROS content, suppress EGFR expression and induce apoptosis. Our findings indicate that 34 may serve as a novel lead compound for the discovery of more triazolopyrimidine derivatives with improved anticancer potency and selectivity.

An evaluation of ticagrelor for the treatment of sickle cell anemia

INTRODUCTION

Ticagrelor is an antiplatelet agent approved for the treatment of patients with an acute coronary syndrome or a history of myocardial infarction. Considering the evidence demonstrating that ticagrelor-mediated inhibition of platelet activation and aggregation have beneficial effects in the treatment of thrombotic conditions, clinical studies have been conducted to evaluate the use of this drug for the treatment of sickle cell disease (SCD), demonstrating satisfactory tolerability and safety.

AREAS COVERED

Clinical investigation has characterized the pharmacokinetic and pharmacodynamical profile, as well as the efficacy and safety of ticagrelor to prevent painful vaso-occlusive crisis (painful episodes and acute chest syndrome) in SCD patients.

EXPERT OPINION

While phase 1 and 2 clinical trials demonstrated satisfactory tolerability and safety, the conclusion of phase 3 clinical trials is crucial to prove the efficacy of ticagrelor as a therapeutic option for the treatment of SCD. Thus, it is expected that ticagrelor, especially in combination with other drugs, will improve the clinical profile and quality of life of patients with SCD.

Platelet Protease Activated Receptor 1 Is Involved in the Hemostatic Effect of 20(S)-Protopanaxadiol by Regulating Calcium Signaling

Panax notoginseng (Burk.) F.H. Chen has long been used to stop bleeding for hundreds of years in China. At present, only dencichine, notoginsenoside Ft1, and 20(S)-protopanaxadiol (PPD) showed hemostatic effect. However, the molecular mechanism of PPD on the platelet aggragetion needs to be further investigated. The study aims to evaluate the hemostatic effect of PPD and reveal its interacting targets using a series of experiments. In this study, the bleeding time was measured in mouse tail amputation and liver scratch models to evaluate hemostatic effect of PPD. The routine blood and plasma coagulation parameters in NS, HC, and PPD (2, 4, and 8 mg/kg) groups were measured using a blood analyzer. Platelet aggregation rate and ATP release were analyzed by a platelet aggregometer. Subsequently, the degranulation marker CD62P and PAC-1, and the concentrations of cytosolic Ca²⁺ ([Ca²⁺]_i), cAMP, cGMP, and PAC-1 expressions were also assessed. We found that PPD shorted the bleeding time on the mouse tail amputation and liver scratch models and mainly increased blood platelet count in the rats after subcutaneous injection for 4 h. Meanwhile, PPD decreased APTT, increased FIB content, and directly induced platelet aggregation in vitro. In the absence of Ca²⁺, PPD induced the increase of [Ca²⁺]_i and slightly increased the levels of CD62P and PAC-1. After the addition of 1 mM Ca²⁺, PPD treatment markedly promoted platelet activation by promoting ATP level, releasing CD62P and increasing PAC-1 binding in washed platelets. Excitingly, PPD-induced changes including platelet aggregation, decreased cAMP content, and the increases of CD62P and PAC-1 were significantly reversed by protease-activated receptor 1 (PAR-1) antagonist, vorapaxar, which showed similar function as thrombin. In addition, molecular docking analysis and ELISA assay demonstrated that PPD had a promising docking score with -6.6 kcal/mol and increased PAR-1 expression in human platelets, which indicated that PAR-1 is involved in PPD-induced platelet aggregation by regulating calcium signaling. Collectively, our study could provide the new insights of PPD as an essential hemostatic ingredient in Panax notoginseng for the treatment of hemorrhagic disease.

Pharmacological characterization of the biosynthesis of prostanoids and hydroxyeicosatetraenoic acids in human whole blood and platelets by targeted chiral lipidomics analysis

Platelet 12-lipoxygenase(p-12-LOX) is highly expressed in human platelets, and the development of p-12-LOX inhibitors has the potential to be a novel antithrombotic tool by inhibiting thrombosis without prolonging hemostasis. A chiral liquid chromatography-mass spectrometry(LC-MS/MS) method was used to assess the impact of three commercially available LOX inhibitors[esculetin(6,7-dihydroxycoumarin), ML-355(N-2-benzothiazolyl-4-[[(2-hydroxy-3-methoxyphenyl)methyl]amino]-benzenesulfonamide), CDC(cinnamyl-3,4-dihydroxy-α-cyanocinnamate) and acetylsalicylic acid(ASA; a cyclooxygenase-1 inhibitor) on the generation of prostanoids and HETEs(hydroxyeicosatetraenoic acids) in human whole blood allowed to clot for 1 h at 37 °C(serum), platelet-rich plasma(PRP) stimulated with collagen or TRAP-6(a peptide activating thrombin receptor) and washed platelets. In serum, ML-355 did not affect eicosanoid generation, while CDC caused an incomplete reduction of 12S-HETE levels; esculetin inhibited both 12S-HETE and thromboxane(TX)B₂ production; ASA selectively affected TXB₂ production. In washed platelets stimulated with thrombin, esculetin, and CDC inhibited both 12S-HETE and TXB₂ while ML-355 was almost ineffective. In PRP, ML-355, CDC, and esculetin did not affect platelet aggregation associated with incomplete effects on eicosanoid biosynthesis. ASA alone or in combination with ticagrelor(a P2Y₁₂ blocker) affected platelet aggregation associated with profound inhibition of TXB₂ generation. P2Y₁₂ receptor signaling contributed to platelet 12S-HETE biosynthesis in response to primary agonists. In conclusion, ML-355, esculetin, and CDC were not selective inhibitors of p-12-LOX in different cellular systems. They did not affect platelet aggregation induced in PRP by collagen or TRAP-6. The characterization of 12-LOX inhibitors on eicosanoids generated in human whole blood is useful for information on their enzyme selectivity, off-target effects, and the possible influence of plasma components on their pharmacological effects.

An updated drug profile of ticagrelor with considerations on the treatment of patients with coronary artery disease and diabetes mellitus

INTRODUCTION

Ticagrelor is an antiplatelet agent acting through direct and reversible competitive inhibition of the platelet P2Y₁₂ receptor. While the clinical merits of ticagrelor in patients who experienced an acute coronary syndrome are widely accepted, its role in stable coronary artery disease is less established. Recently, large-scale trials of ticagrelor have been published in this setting, including a trial in patients with diabetes mellitus (DM).

AREAS COVERED

This review aims to inform about recent findings on ticagrelor, by appraising the current body of evidence on its use in different clinical scenarios, particularly in DM, ranging from pharmacology to clinical outcomes and future directions.

EXPERT OPINION

The results of the THEMIS trial, conducted in DM patients with stable coronary artery disease and no prior stroke or myocardial infarction, showed that although ticagrelor in addition to aspirin reduced the risk of ischemic events, this was associated with a parallel increase in bleeding complications. However, patients with history of percutaneous coronary intervention seemed to benefit more from adjunctive ticagrelor therapy. Careful bleeding and ischemic risk stratification remains crucial to define the best antithrombotic strategy for the individual patient.

Predicting the effect of tea polyphenols on ticagrelor by incorporating transporter-enzyme interplay mechanism

This study aimed at exploring the potential mechanism of decreased in vivo exposure of the antiplatelet agent, ticagrelor and its active metabolite, AR-C124910XX, mediated by tea polyphenols, which was first revealed by our previous study, as well as predicting the in vivo drug-drug interaction (DDI) potential utilizing an in vitro to in vivo extrapolation (IVIVE) approach. The bidirectional transport and uptake kinetics of ticagrelor were determined using Caco-2 cells. Inhibition potency of major components of tea polyphenols, epigallocatechin gallate (EGCG) and epigallocatechin (EGC) were obtained from Caco-2 cells, human intestinal and hepatic microsomes (HIMs and HLMs) in vitro. A mean efflux ratio of 2.28 ± 0.38 and active uptake behavior of ticagrelor were observed in Caco-2 cell studies. Further investigation showed that the IC₅₀ values of EGCG and EGC on the uptake of ticagrelor were 42.0 ± 5.1 μM (95% CI 31.9-54.8 μM) and 161 ± 13 μM (95% CI 136-191 μM), respectively. EGCG and EGC also displayed moderate to weak reversible inhibition on the formation of AR-C124910XX and the inactive metabolite, AR-C133913XX in HIMs and HLMs, while no clinically significant time-dependent inhibition was observed for either compound. IVIVE indicated a significant inhibition effect of EGCG on the uptake process of ticagrelor, while no potential DDI risk was found based on microsomal data. A 45% decrease in ticagrelor in vivo exposure was mechanistically predicted by incorporating intestinal and hepatic metabolism as well as intestinal absorption. This dual inhibition of tea polyphenols on ticagrelor revealed the underlying potential of transporter-enzyme interplay, in which the altered uptake process was more critical.

A case report of absolute thrombocytopenia with ticagrelor

BACKGROUND

We report a rare case of absolute thrombocytopenia with ticagrelor after 6 h of single loading dose of ticagrelor.

CASE SUMMARY

A 68-year-old male with ischaemic cardiomyopathy, hypertension, and dyslipidaemia presented with chest pain. He was found to be in new-onset atrial flutter and ruled in for a non-ST-segment elevation myocardial infarction. An echocardiogram showed decreased left ventricular ejection fraction, estimated at 15-20% and serum troponin peaked at 0.2 ng/dL, baseline platelet count was 203 × 10³/µL. He underwent a drug-eluting stent placement to the right coronary artery with excellent angiographic results. He received 3000 units of unfractionated heparin and 180 mg of ticagrelor during the procedure. About 6 h after the procedure, he had coffee ground emesis. A complete blood count revealed a platelet count of 2 × 10³ and 0 × 10³/µL on repeat testing. Peripheral smear did not show any evidence of platelet clumping and schistocytes, serum haptoglobin and lactate dehydrogenase were normal. Ticagrelor and heparin were discontinued, while the aspirin was continued. Five units of platelet were transfused. The platelet count improved to 200 × 10³/µL. Since his CHADS₂VASC score was 3, he was discharged on apixaban and clopidogrel in addition to other medication. No thrombocytopenia was seen on outpatient follow-up.

DISCUSSION

The common side effects of ticagrelor include bleeding, dyspnoea, gynaecomastia, and rarely thrombotic thrombocytopenic purpura. Although extremely rare, absolute or profound thrombocytopenia can occur with ticagrelor, hours after administration and should be considered when other potential causes of thrombocytopenia have been ruled out.

The TICONC (Ticagrelor-Oncology) Study: Implications of P2Y12 Inhibition for Metastasis and Cancer-Associated Thrombosis

Background

In cancer, platelets may facilitate metastatic spread by a number of mechanisms as well as contribute to thrombotic complications. Ticagrelor, a platelet antagonist- that blocks adenosine diphosphate activation of platelet P2Y₁₂ receptors, is widely used in the treatment of cardiovascular disease, but its efficacy in cancer remains unknown.

Objectives

This study sought to evaluate the effect of aspirin and ticagrelor monotherapy, as well as dual antiplatelet therapy, on platelet activation in cancer.

Methods

This study consisted of 2 phases: first, an in vitro study of human platelet−tumor cell interaction; and second, a randomized crossover clinical trial of 22 healthy donors and 16 patients with metastatic breast or colorectal cancer. Platelet activation and inhibition were measured by aggregometry and flow cytometry.

Results

In vitro, tumor cells induced cellular clusters that were predominantly platelet−platelet aggregates. Ticagrelor significantly inhibited formation of large tumor cell-induced platelet−platelet aggregates: 65.4 ± 4.8% to 50.9 ± 5.9% (p = 0.002) and 62.3 ± 3.1% to 48.3 ± 7.3% (p = 0.014) for MCF-7 and HT-29-induced aggregation, respectively. Supporting this finding, cancer patients on ticagrelor had significantly reduced levels of spontaneous platelet aggregation and activation compared with baseline; 14.8 ± 2.7% at baseline to 7.8 ± 2.3% with ticagrelor (p = 0.012).

Conclusions

Our findings suggested that P2Y₁₂ inhibition with ticagrelor might reduce spontaneous platelet aggregation and activation in patients with metastatic cancer and merits further investigation in patients at high risk of cancer-associated thrombosis. (Ticagrelor-Oncology [TICONC] Study; EudraCT: 2014-004049-29)

An Agonist Dependent Allosteric Antagonist of Prostaglandin EP2 Receptors

All reported prostaglandin EP2 receptor antagonists have a purely orthosteric, competitive mode of action. Herein, we report the characterization of compound 1 (pubchem CID 664888) as the first EP2 antagonist that features a reversible, agonist dependent allosteric mode of action. Compound 1 displayed an unsurmountable inhibition of cAMP accumulation stimulated by different EP2 agonists in C6 glioma cells overexpressing human EP2 (C6G-hEP2). The degree of reduction of agonist potency and efficacy depended on the agonist employed. Negative allosteric modulation was not observed in C6G cells overexpressing human EP4, IP, or DP1 receptors. Moreover, in the murine microglial cell line that stably expresses human EP2 receptors (BV2-hEP2), compound 1 reduced the EP2 agonist-induced elevation of interleukin 6 (IL-6), IL-1β, and hEP2 mRNA levels and increased that of tumor necrosis factor (TNF)-α. Compound 1 was docked into a homology model of hEP2. The predicted binding site on the cytoplasmic receptor surface was similar to that of allosteric inhibitors of the β2-adrenergic, CC chemokine receptor 9 (CCR9), and CC chemokine receptor 2 (CCR2) receptors, which supports the notion of a conserved G-protein-coupled receptor (GPCR) binding pocket for allosteric inhibitors. As the first agonist dependent negative allosteric modulator of EP2 receptor, the structure of this compound may provide a basis for developing improved allosteric modulators of EP2 receptors.

Safety and Cumulative Incidence of Major Cardiovascular Events with Ticagrelor in Taiwanese Patients with Non-ST-Segment Elevation Myocardial Infarction: A 12-Month, Prospective, Phase IV, Multicenter, Single-Arm Study

Background

Ticagrelor, an oral, direct-acting, and reversible P2Y₁₂ receptor antagonist, inhibits platelet activation and aggregation. This phase IV, single-arm study analyzed the safety and tolerability of ticagrelor in Taiwanese patients with non-ST-segment elevation myocardial infarction (NSTEMI) during 1 year of follow-up.

Methods

Patients aged ≥ 20 years with an index event of NSTEMI received ticagrelor (180 mg loading and 90 mg doses twice daily thereafter) plus low-dose aspirin (100 mg/day) for up to 1 year. Safety was evaluated according to adverse events (AEs), serious AEs (SAEs), and PLATO-defined bleeding events. The cumulative incidence of major cardiovascular (CV) events including CV death, myocardial infarction, and stroke was also evaluated.

Results

The safety population included 108 patients across 13 centers in Taiwan. During treatment, 32 (29.6%) patients had ≥ one PLATO-defined bleeding event. Major bleeding events occurred in seven (6.5%) patients with a Kaplan-Meier (KM) estimated event risk [95% confidence interval (CI)] of 7.1% (3.4%-14.4%), including life-threatening bleeding [four (3.7%) patients] and other major bleeding [three (2.8%) patients]. No PLATO-defined fatal bleeding was observed. SAEs were reported in 23 (21.3%) patients. Six (5.6%) patients experienced major CV events during the 1-year follow-up period, with a KM-estimated event risk (95% CI) of 5.6% (2.6%-12.0%).

Conclusions

Ticagrelor for up to 1 year was associated with a low rate of major bleeding events and a low incidence of major CV events in Taiwanese patients with NSTEMI. The overall safety of ticagrelor was in accordance with the known safety profile of ticagrelor.

Pharmacokinetic/Pharmacodynamic Modeling To Predict the Antiplatelet Effect of the Ticagrelor-Loaded Self-Microemulsifying Drug Delivery System in Rats

Ticagrelor (TCG) has been used as an antiplatelet agent for acute coronary syndrome patients. The aim of this research was to establish a population pharmacokinetic/pharmacodynamic (PK/PD) model of TCG and to apply the model for predicting the PD response of the TCG-loaded self-microemulsifying drug delivery system (TCG-SME) in rats. Pure TCG and TCG-SME (2, 5, and 10 mg/kg of TCG) were orally administered to male Sprague-Dawley rats. Plasma samples were collected at scheduled time-points and then analyzed for TCG plasma concentrations and antiplatelet effects. The inhibition of platelet aggregation of TCG was measured as a PD response. The PK profiles of pure TCG and TCG-SME could be well-explained with a two-compartment PK model. The accuracy of the PK model was assessed with a goodness-of-fit plot and conditional weight residual error (CWRES). Also, the visual predictive check was investigated based on the predictions. A population PK/PD model for pure TCG was established as an indirect response E_max model linked to the two-compartment PK model of pure TCG. The PK/PD model proposed a suitable fitting to link the plasma concentration of TCG simultaneously with platelet aggregation. Based on the PK data of TCG-SME, as well as the established PK/PD model of pure TCG, the PD profiles of TCG-SME were simulated. TCG-SME was more effective in inducing the antiplatelet effect than pure TCG at equivalent doses of TCG. The accuracy of the simulation was verified by comparing the simulated PD profile with the profile observed in rats. The observations were close to the model simulations. In addition, the values of CWRES were almost within ±2. In conclusion, the PK/PD modeling approach can provide a way for predicting mathematically the PD responses from PK profiles of other TCG formulations and a conceptual prediction for future clinical assessment.

Development and evaluation of TPGS/PVA-based nanosuspension for enhancing dissolution and oral bioavailability of ticagrelor

In this study, we developed ticagrelor-dispersed nanosuspension (TCG-NSP) to enhance the dissolution and oral bioavailability of ticagrelor (TCG) through a statistical design approach. TCG, a reversible P2Y₁₂ receptor antagonist, is classified as a biopharmaceutics classification system (BCS) class IV drug with low solubility and permeability, resulting in low oral bioavailability. Nanosuspension (NSP) is an efficient pharmaceutical technique for overcoming the disadvantages. First, we optimized TCG-NSP consisting of D-α-Tocopherol polyethylene glycol 1000 succinate (TPGS) and polyvinyl alcohol (PVA), which exhibited homogeneously dispersed TCG particle (233 nm) and low precipitation (3%). Characterization studies demonstrated that TCG-NSP provided amorphous TCG particles and supersaturation effect, resulting in higher dissolution than a commercial product. In addition, everted gut sac and pharmacokinetic studies confirmed that TCG-NSP improved the gastrointestinal permeation of TCG by 2.8-fold compared to commercial product, thereby enhancing the oral bioavailability (2.2-fold). These results suggested that TCG-NSP could be successfully used as an efficient pharmaceutical formulation to achieve the enhanced dissolution and oral bioavailability of TCG.

Premature Ticagrelor Discontinuation in Secondary Prevention of Atherosclerotic CVD: JACC Review Topic of the Week

Ticagrelor is a cornerstone of modern antithrombotic therapy alongside aspirin in patients with acute coronary syndrome and after percutaneous coronary intervention. Adverse effects such as bleeding and dyspnea have been associated with premature ticagrelor discontinuation, which may limit any potential advantage of ticagrelor over clopidogrel. The randomized trials of ticagrelor captured adverse events, offering the opportunity to more precisely quantify these effects across studies. Therefore, a meta-analysis of 4 randomized clinical trials of ticagrelor conducted between January 2007 and June 2017 was performed to quantify the incidence and causes of premature ticagrelor discontinuation. Among 66,870 patients followed for a median 18 months, premature ticagrelor discontinuation was seen in 25%; bleeding was the most common cause of discontinuation followed by dyspnea. Versus the comparators, the relative risk of dyspnea-related discontinuation during follow-up was 6.4-fold higher, the relative risk of bleeding was 3.2-fold higher, and the relative risk of discontinuation due to any adverse event was 59% higher for patients receiving ticagrelor. Understanding these potential barriers to adherence to ticagrelor is crucial for informed patient-physician decision making and can inform future efforts to improve ticagrelor adherence. This review discusses the incidence, causes, and biological mechanisms of ticagrelor-related adverse effects and offers strategies to improve adherence to ticagrelor.

One-Month Outcomes of Cases Receiving Ticagrelor after Percutaneous Coronary Intervention; a Case Series

INTRODUCTION

Ticagrelor is the first reversibly binding oral P2Y12 receptor antagonist that can block ADP-induced platelet aggregation. This study aimed to describe one-month follow-up findings of cases undergoing ticagrelor therapy after percutaneous coronary intervention (PCI).

METHODS

This case series was performed on acute coronary syndrome (ACS) patients who were candidates for PCI and received aspirin plus ticagrelor after PCI. Patients were followed for one month and their outcomes were described.

RESULTS

156 cases with the mean age of 59.74 ± 9.24 years were studied (63% male). 45 (28.8%) cases complained of dyspnea (39 cases with mild and 6 cases with severe dyspnea). Bleeding occurred in 4 (2.5%) cases (intra-cranial hemorrhage (ICH) in one, hematuria in two, and skin hemorrhage in one case). There were no cases with bradycardia or thrombosis. One (0.6%) patient developed drug hypersensitivity reaction, which manifested as skin rash. The use of drug was stopped in 10 (6.4%) cases due to severe dyspnea (n= 6), ICH (n=1), skin rash (n=1), and concomitant left ventricular (LV) clot (n=2).

CONCLUSION

The most important finding of one-month ticagrelor consumption were dyspnea, bleeding, and hypersensitivity reaction. No case of bradycardia and stent thrombosis was detected. In our study , iranian population has more susceptibility to dyspnea than PLATO result. The rate of drug discontinuation in this series of cases was 6.4 %.

Simultaneous quantification of ticagrelor and its active metabolite, AR-C124910XX, in human plasma by liquid chromatography-tandem mass spectrometry: Applications in steady-state pharmacokinetics in patients

A sensitive and simple liquid chromatography-tandem mass spectrometry method was developed and validated for the simultaneous quantification of ticagrelor and its active metabolite, AR-C124910XX from 50 µL human plasma using tolbutamide as an internal standard as per regulatory guidelines. Analytes in plasma were extracted by simple protein precipitation using acetonitrile, followed by chromatographic separation with an Acclaim™ RSLC 120 C₁₈ column (2.2 µm, 2.1 × 100 mm) and a gradient acetonitrile-water mobile phase containing 0.1% formic acid within 8 min. Mass spectrometric detection and quantitation were conducted by selected reaction-monitoring on a negative electrospray ionization mode with the following transitions: m/z 521.11 → 361.10, 477.03 → 361.10, and 269.00 → 169.60 for ticagrelor, AR-C124910XX, and tolbutamide, respectively. The lower limit of quantifications was 0.2 ng/mL with linear ranges of 0.2–2,500 ng/mL (r² ≥ 0.9949) for both analytes. All validation data, including selectivity, cross-talk, precision, accuracy, matrix effect, recovery, dilution integrity, stability, and incurred sample reanalysis, were well within acceptable limits. This assay method was validated using K₂-EDTA as the specific anticoagulant. Also, the anticoagulant effect was tested by lithium heparin, sodium heparin, and K₃-EDTA. No relevant anticoagulant effect was observed. This validated method was effectively used in the determination of ticagrelor and its active metabolite, AR-C124910XX, in plasma samples from patients with myocardial infarction.

Therapeutic experience of ticagrelor in Indian patients with acute coronary syndrome: A non-interventional, prospective, and observational study

Objective

This observational study was designed to understand the usage pattern of ticagrelor in real-life clinical practice among a large number of acute coronary syndrome (ACS) patients undergoing percutaneous coronary intervention (PCI), coronary artery bypass graft (CABG), or medical management (MM). The study also recorded clinical events, i.e., bleeding, dyspnea, and cardiovascular (CV) events, reported by the investigator during the follow-up period.

Methods

The ACS patients aged ≥18 years hospitalized for ACS and were prescribed ticagrelor upon discharge or ≤1 month and patients who underwent PCI, CABG, or MM for ACS were enrolled. The subjects were followed up for a period of up to 12 months. The data were collected on a case report form.

Result

The study recruited 2997 subjects from 49 sites in India. Approximately half of the ACS subjects had ST segment elevation myocardial infarction (48.9%), and PCI was used as management in 92.4% subjects. The mean (±SD) duration of use of ticagrelor was 314 (±110.2) days over a period of 12 months. Of 136 subjects (4.5%) who experienced any clinical events, CV deaths were reported in 20 (0.7%), myocardial infraction in 19 (0.6) subjects and ischemic stroke in 23 (0.8%) subjects, and severe dyspnea was reported in 68 (2.2%) subjects. Out of 33 bleeding cases, 25 (0.8%) subjects had thrombolysis in myocardial infarction (TIMI) minimal, seven (0.2%) had TIMI minor, and one TIMI major. Platelet inhibition and patient outcomes (PLATO) major was reported in two subjects and CABG bleed in one subject. The incidence of PLATO defined major and minimal bleeding were lower in subjects undergoing fibrinolysis than overall population.

Conclusion

Ticagrelor has been used across ACS types and in different management strategies in real world settings in India. The incidence of clinical events was lower as compared with data in literature. ClinicalTrials.gov Identifier: NCT02408224

Bleeding frequency of patients taking ticagrelor, aspirin, clopidogrel, and dual antiplatelet therapy after tooth extraction and minor oral surgery

BACKGROUND

Perioperative bleeding complications of ticagrelor, a newer oral antiplatelet, has not been studied in dentistry. Studies about bleeding status after oral surgical procedures in patients receiving continued antiplatelet therapy are also limited. We investigated the effects of continuing aspirin, clopidogrel, ticagrelor, or dual antiplatelet therapy on the frequency of bleeding events in patients undergoing tooth extractions or minor oral surgery.

METHODS

In this retrospective study, patient demographic characteristics, medical history, type of antiplatelet therapy, dental procedures, and perioperative bleeding associated with tooth extraction or other minor oral surgical procedures were obtained from the dental records of 222 patients. Bleeding was classified as normal, mild, moderate, or severe.

RESULTS

One hundred sixty-eight patients (75.7%) had 1 or more teeth extracted, and 54 patients (24.3%) underwent other minor oral surgical procedures. The most common single antiplatelet regimen was aspirin (n = 123; 55.4%), followed by clopidogrel (n = 22; 9.9%) and ticagrelor (n = 17; 7.7%). Sixty patients (27%) received dual antiplatelet therapy. The overall frequency of postoperative bleeding was 4.9% (11 of 222). The frequencies of postoperative bleeding in the aspirin, clopidogrel, ticagrelor, and dual antiplatelet therapy groups were 3.2%, 4.5%, 5.9%, and 8.3%, respectively (P ≥ .5). None of the patients experienced prolonged bleeding.

CONCLUSIONS

Patients taking aspirin, clopidogrel, ticagrelor, and dual antiplatelet therapy experienced acceptable rates of controllable postoperative bleeding after tooth extraction or minor oral surgical procedures.

PRACTICAL IMPLICATIONS

In accordance with recommendations from published studies and guidelines, antiplatelet medications, including dual antiplatelet therapy, should not be interrupted for tooth extractions or minor oral surgery.

Biocatalysis as Useful Tool in Asymmetric Synthesis: An Assessment of Recently Granted Patents (2014–2019)

The broad interdisciplinary nature of biocatalysis fosters innovation, as different technical fields are interconnected and synergized. A way to depict that innovation is by conducting a survey on patent activities. This paper analyses the intellectual property activities of the last five years (2014–2019) with a specific focus on biocatalysis applied to asymmetric synthesis. Furthermore, to reflect the inventive and innovative steps, only patents that were granted during that period are considered. Patent searches using several keywords (e.g., enzyme names) have been conducted by using several patent engine servers (e.g., Espacenet, SciFinder, Google Patents), with focus on granted patents during the period 2014–2019. Around 200 granted patents have been identified, covering all enzyme types. The inventive pattern focuses on the protection of novel protein sequences, as well as on new substrates. In some other cases, combined processes, multi-step enzymatic reactions, as well as process conditions are the innovative basis. Both industries and academic groups are active in patenting. As a conclusion of this survey, we can assert that biocatalysis is increasingly recognized as a useful tool for asymmetric synthesis and being considered as an innovative option to build IP and protect synthetic routes.

P2Y12 inhibitors in acute coronary syndrome patients with renal dysfunction: an analysis from the RENAMI and BleeMACS projects

Aims

The aim of the present study was to establish the safety and efficacy profile of prasugrel and ticagrelor in real-life acute coronary syndrome (ACS) patients with renal dysfunction.

Methods and results

All consecutive patients from RENAMI (REgistry of New Antiplatelets in patients with Myocardial Infarction) and BLEEMACS (Bleeding complications in a Multicenter registry of patients discharged with diagnosis of Acute Coronary Syndrome) registries were stratified according to estimated glomerular filtration rate (eGFR) lower or greater than 60 mL/min/1.73 m2. Death and myocardial infarction (MI) were the primary efficacy endpoints. Major bleedings (MBs), defined as Bleeding Academic Research Consortium bleeding types 3 to 5, constituted the safety endpoint. A total of 19 255 patients were enrolled. Mean age was 63 ± 12; 14 892 (77.3%) were males. A total of 2490 (12.9%) patients had chronic kidney disease (CKD), defined as eGFR &lt;60 mL/min/1.73 m2. Mean follow-up was 13 ± 5 months. Mortality was significantly higher in CKD patients (9.4% vs. 2.6%, P &lt; 0.0001), as well as the incidence of reinfarction (5.8% vs. 2.9%, P &lt; 0.0001) and MB (5.7% vs. 3%, P &lt; 0.0001). At Cox multivariable analysis, potent P2Y12 inhibitors significantly reduced the mortality rate [hazard ratio (HR) 0.82, 95% confidence interval (CI) 0.54–0.96; P = 0.006] and the risk of reinfarction (HR 0.53, 95% CI 0.30–0.95; P = 0.033) in CKD patients as compared to clopidogrel. The reduction of risk of reinfarction was confirmed in patients with preserved renal function. Potent P2Y12 inhibitors did not increase the risk of MB in CKD patients (HR 1.00, 95% CI 0.59–1.68; P = 0.985).

Conclusion

In ACS patients with CKD, prasugrel and ticagrelor are associated with lower risk of death and recurrent MI without increasing the risk of MB.

Targeting Delivery of Platelets Inhibitor to Prevent Tumor Metastasis

Activated platelets have a high affinity for tumor cells, and consequently, they can protect tumor cells from environmental stress and immune attacks. Therefore, preventing platelet-tumor cell interaction can lead to the elimination of circulating tumor cells via natural killer cells and finally metastasis inhibition. It is also shown that CREKA (Cys-Arg-Glu-Lys-Ala), a tumor-homing pentapeptide, targets fibrin-fibronectin complexes that are found on the tumor stroma and the vessel walls. In this study, we linked CREKA to Ticagrelor, a reversible antagonist of the P2Y₁₂ receptor on platelets. In vitro experiments indicated that CREKA-Ticagrelor could not only inhibit the platelet-induced migration of tumor cells with an invasive phenotype but also prevent tumor-platelet interaction. In vivo antitumor and antimetastasis results of this drug showed that CREKA-Ticagrelor could specifically target the tumor tissues within 24 h post intravenous injection and suppress lung metastasis. Meanwhile, by having this antiplatelet drug targeted, its side effects were minimized, and bleeding risk was decreased. Thus, CREKA-Ticagrelor offers an efficient antimetastatic agent.

YINGLONG: A Multicenter, Prospective, Non-Interventional Study Evaluating the Safety and Tolerability of Ticagrelor in Chinese Patients with Acute Coronary Syndrome

INTRODUCTION

Ticagrelor is an oral, reversible, direct-acting P2Y12 receptor inhibitor approved for the prevention of cardiovascular events in acute coronary syndrome (ACS). In China, drug intensive monitoring regulations for new drugs require additional safety data post-approval.

METHODS

YINGLONG, a single-arm, phase-IV, 1-year, non-interventional study, described the safety of ticagrelor 90 mg twice daily in Chinese patients (≥ 18 years) with ACS treated with ≥ 1 dose of ticagrelor. Primary outcomes were the incidence of adverse events (AEs), in particular, PLATelet inhibition and patient Outcomes (PLATO)-defined bleeding AEs, and other serious AEs during the 1-year follow-up. Key secondary outcomes were the incidence of major cardiovascular events.

RESULTS

Patients (n = 1041, median age 61.0 years) had started ticagrelor and had post-dose data. Median duration of ticagrelor treatment was 357 days; 577 patients (55.4%) completed 1-year ticagrelor treatment; 973 patients (93.5%) completed 1-year follow-up. Overall, 38.7% of patients reported an AE during treatment. The most common AEs were dyspnea (n = 37, 3.6%), petechiae (n = 30, 2.9%), and chest discomfort (n = 28, 2.7%). Serious AEs, excluding bleeding, were reported in 9.8% of patients during treatment. Incidence of PLATO-defined major bleeding events was 1.1% (n = 11). Of the 21 deaths that occurred during the study (8 post-treatment), 1 was a fatal bleed. Major cardiovascular events were reported in 37 patients (3.6%).

CONCLUSIONS

Ticagrelor was well tolerated with a low rate of PLATO-defined major bleeding events in Chinese ACS patients. Safety results were consistent with the known ticagrelor profile.

TRIAL REGISTRATION

ClinicalTrials.gov identifier, NCT02430493.

FUNDING

AstraZeneca Investment (China) Co., Ltd.

Development Strategy and Relative Bioavailability of a Pediatric Tablet Formulation of Ticagrelor

BACKGROUND AND OBJECTIVE

Ticagrelor is a P2Y₁₂ receptor inhibitor approved as an antiplatelet drug for patients with acute coronary syndrome or a history of myocardial infarction. Ticagrelor is also being investigated for the reduction of vaso-occlusive crises in pediatric patients with sickle cell disease. A pediatric formulation suitable for this age range was developed; the development strategy is described. Primary objectives were determining the relative bioavailability of ticagrelor pediatric tablets and granules for oral suspension to the adult immediate-release tablet, and the pediatric tablets taken whole and dispersed/suspended in water to the granules for oral suspension. Bioequivalence between the pediatric tablet taken whole or suspended in water was also assessed. Secondary objectives were comparing the formulations' safety and tolerability.

METHODS

We conducted a randomized, four-period, cross-over, single-dose study. Pharmacokinetic parameters were assessed for ticagrelor and its active metabolite AR-C124910XX. Bioequivalence was concluded if the 90% confidence intervals of the maximum plasma concentration and area under the plasma concentration-time curve ratios were contained completely within the 80.00-125.00% limits for ticagrelor/AR-C124910XX.

RESULTS

Forty-four healthy adults (95% white; 57% male) were included. Similar bioavailability of ticagrelor (and AR-C124910XX) was demonstrated for all comparisons tested. Ticagrelor pediatric tablets taken whole were bioequivalent to pediatric tablets suspended in water. The plasma concentration-time profiles for ticagrelor and AR-C124910XX were similar, showing rapid ticagrelor absorption and AR-C124910XX formation. All formulations were well tolerated.

CONCLUSION

Similar bioavailability of a new pediatric dispersible tablet formulation of ticagrelor for use across a wide age range of pediatric patients was demonstrated compared with other oral ticagrelor formulations. CLINICALTRIALS.

GOV IDENTIFIER

NCT03126695.

EUDRACT

2017-000371-93.

Systemic Design and Evaluation of Ticagrelor-Loaded Nanostructured Lipid Carriers for Enhancing Bioavailability and Antiplatelet Activity

Ticagrelor (TGL), a P2Y12 receptor antagonist, is classified as biopharmaceutics classification system (BCS) class IV drug due to its poor solubility and permeability, resulting in low oral bioavailability. Nanostructured lipid carriers (NLC) are an efficient delivery system for the improvement of bioavailability of BCS class IV drugs. Hence, we prepared TGL-loaded NLC (TGL-NLC) to enhance the oral bioavailability and antiplatelet activity of TGL with a systemic design approach. The optimized TGL-NLC with Box-Behnken design showed a small particle size of 87.6 nm and high encapsulation efficiency of 92.1%. Scanning electron microscope (SEM), differential scanning calorimetry (DSC), and powder X-ray diffraction (PXRD) were performed to investigate the characteristics of TGL-NLC. Furthermore, TGL-NLC exhibited biocompatible cytotoxicity against Caco-2 cells. Cellular uptake of TGL-NLC was 1.56-fold higher than that of raw TGL on Caco-2 cells. In pharmacokinetic study, the oral bioavailability of TGL-NLC was 254.99% higher than that of raw TGL. In addition, pharmacodynamic study demonstrated that the antiplatelet activity of TGL-NLC was superior to that of raw TGL, based on enhanced bioavailability of TGL-NLC. These results suggest that TGL-NLC can be applied for efficient oral absorption and antiplatelet activity of TGL.

The introduction of ticagrelor is associated with lower rates of recurrent ischemic stroke after myocardial infarction

BACKGROUND

Previous ischemic stroke is a predictor of recurrent ischemic stroke after an acute myocardial infarction (AMI). Dual antiplatelet therapy, including a P2Y12-inhibitor, is important in secondary prevention after AMI. Ticagrelor, a P2Y12-inhibitor, is more potent than the commonly used clopidogrel. Here, we evaluated the impact of ticagrelor on the risk of ischemic stroke following AMI in patients with previous ischemic stroke.

METHODS

Data for patients with AMI that had a previous ischemic stroke were obtained from the Swedish Registry of Information and Knowledge about Swedish Heart Intensive Care Admissions. Patients were assigned to early and late cohorts, each covering a two-year time period before and after, respectively, the introduction of ticagrelor prescriptions (20 Dec 2011). Patients in the early cohort (n = 1633) were treated with clopidogrel (100%); those in the late cohort (n = 1642) were treated with either clopidogrel (66.3%) or ticagrelor (33.7%). We assessed the risk of ischemic stroke and intracranial bleeding over time with Kaplan-Meier analyses. We identified predictors of ischemic stroke with multivariable Cox regression analyses.

RESULTS

Of 3275 patients, 311 experienced ischemic stroke after AMI. Cumulative Kaplan-Meier incidence estimates of ischemic stroke within one year after AMI were 12.1% versus 8.6% for the early and late cohorts, respectively (p<0.01). Intracranial bleeding incidences (1.2% versus 1.5%) were similar between the two cohorts.

CONCLUSIONS

Ticagrelor introduction was associated with a lower rate of ischemic stroke, with no increase in intracranial bleeding, in an AMI population with a history of ischemic stroke.

De-escalation of anti-platelet therapy in patients with acute coronary syndromes undergoing percutaneous coronary intervention: a narrative review

Objective:

Dual antiplatelet therapy (DAPT) with aspirin and a P2Y₁₂ receptor inhibitor is the cornerstone of treatment in patients with acute coronary syndromes (ACS) and in those undergoing percutaneous coronary intervention (PCI). In current clinical situation, availability of different oral P2Y₁₂ inhibitors (clopidogrel, prasugrel, and ticagrelor) has enabled physicians to switch among therapies owing to specific clinical scenarios. Although optimum time, loading dose and interval of transition between P2Y₁₂ inhibitors is still controversial and needs further evidence, switching between oral inhibitors frequently occurs in clinical practice for several reasons.

Data sources:

This review was based on data in articles published in PubMed up to June 2018, with the following keywords “antiplatelet therapy”, “ACS”, “PCI”, “ticagrelor”, and “clopidogrel”.

Study selection:

Original articles and critical reviews on de-escalation strategy in ACS patients after PCI were selected. References of the retrieved articles were also screened to search for potentially relevant papers.

Results:

Safety concerns associated with switching between antiplatelet agents, has prompted the use of clopidogrel for patients with ACS especially after PCI as a de-escalation strategy. Practical considerations for de-escalating therapies in patients with ACS such as reducing dose of P2Y₁₂ inhibitors or shortening duration of DAPT (followed by aspirin or P2Y₁₂ receptor inhibitor monotherapy) as potential options are yet to be standardized and validated.

Conclusions:

Current review will provide an overview of the pharmacology of common P2Y₁₂ inhibitors, definitions of de-escalation and different de-escalating strategies and its outcomes, along with possible direction to be explored in de-escalation.

Platelet GPIbα is a mediator and potential interventional target for NASH and subsequent liver cancer

Non-alcoholic fatty liver disease ranges from steatosis to non-alcoholic steatohepatitis (NASH), potentially progressing to cirrhosis and hepatocellular carcinoma (HCC). Here, we show that platelet number, platelet activation and platelet aggregation are increased in NASH but not in steatosis or insulin resistance. Antiplatelet therapy (APT; aspirin/clopidogrel, ticagrelor) but not nonsteroidal anti-inflammatory drug (NSAID) treatment with sulindac prevented NASH and subsequent HCC development. Intravital microscopy showed that liver colonization by platelets depended primarily on Kupffer cells at early and late stages of NASH, involving hyaluronan-CD44 binding. APT reduced intrahepatic platelet accumulation and the frequency of platelet-immune cell interaction, thereby limiting hepatic immune cell trafficking. Consequently, intrahepatic cytokine and chemokine release, macrovesicular steatosis and liver damage were attenuated. Platelet cargo, platelet adhesion and platelet activation but not platelet aggregation were identified as pivotal for NASH and subsequent hepatocarcinogenesis. In particular, platelet-derived GPIbα proved critical for development of NASH and subsequent HCC, independent of its reported cognate ligands vWF, P-selectin or Mac-1, offering a potential target against NASH.

Strategic approach to developing a self-microemulsifying drug delivery system to enhance antiplatelet activity and bioavailability of ticagrelor

Background

Ticagrelor (TCG) is used to inhibit platelet aggregation in patients with acute coronary syndrome, but its poor solubility and low bioavailability limit its in vivo efficacy. The purpose of this study was to manufacture an optimized TCG-loaded self-microemulsifying drug delivery system (SMEDDS) to enhance the oral bioavailability and antiplatelet activity of TCG.

Materials and methods

Solubility and emulsification tests were conducted to determine the most suitable oils, surfactants, and cosurfactants. Scheffé's mixture design was applied to optimize the percentage of each component applied in the SMEDDS formulation to achieve optimal physical characteristics, ie, high solubility of TCG in SMEDDS, small droplet size, low precipitation, and high transmittance.

Results

The optimized TCG-loaded SMEDDS (TCG-SM) formulation composed of 10.0% Capmul MCM (oil), 53.8% Cremophor EL (surfactant), and 36.2% Transcutol P (cosurfactant) significantly improving the dissolution of TCG in various media compared with TCG in Brilinta^® (commercial product). TCG-SM exhibited higher cellular uptake and permeability in Caco-2 cells than raw TCG suspension. In pharmacokinetic studies in rats, TCG-SM exhibited higher oral bioavailability with 5.7 and 6.4 times higher area under the concentration-time curve and maximum plasma concentration, respectively, than a raw TCG suspension. Antiplatelet activity studies exhibited that the TCG-SM formulation showed significantly improved inhibition of platelet aggregation compared with raw TCG at the same dose of TCG. And, a 10 mg/kg dose of raw TCG suspension and a 5 mg/kg dose of TCG-SM had a similar area under the inhibitory curve (907.0%±408.8% and 907.8%±200.5%⋅hours, respectively) for antiplatelet activity.

Conclusion

These results suggest that the developed TCG-SM could be successfully used as an efficient method to achieve the enhanced antiplatelet activity and bioavailability of TCG.

The Acute Stroke or Transient Ischemic Attack Treated with Ticagrelor and Aspirin for Prevention of Stroke and Death (THALES) trial: Rationale and design

Rationale

In patients with acute cerebral ischemia, the rate of stroke, myocardial infarction, or death during 90 days was reported to be non-significantly lower with ticagrelor compared with aspirin, with no increase in major hemorrhage. Dual antiplatelet therapy may be more effective in this setting.

Aim

To investigate whether ticagrelor combined with aspirin are superior to aspirin alone in preventing stroke or death in patients with non-severe, non-cardioembolic ischemic stroke or high-risk transient ischemic attack.

Design

The Acute Stroke or Transient Ischemic Attack Treated with Ticagrelor and Aspirin for Prevention of Stroke and Death (THALES) trial is a randomized, placebo-controlled, double-blind, event-driven study. Patients will be randomized within 24 h of onset of acute ischemic symptoms. THALES is expected to randomize 13,000 at ∼450 sites worldwide, to collect 764 primary outcome events. Study treatments are ticagrelor 180 mg loading dose on day 1, then 90 mg twice daily on days 2–30, or matching placebo. All patients will also receive open-label aspirin 300–325 mg on day 1, then 75–100 mg once daily on days 2–30.

Study outcomes

The primary efficacy outcome is time to the composite endpoint of stroke or death through 30-day follow-up. The primary safety outcome is time to first severe bleeding event.

Discussion

The THALES trial will provide important information about the benefits and risks of dual antiplatelet therapy with ticagrelor and aspirin in patients with acute cerebral ischemia in a global setting (funding: AstraZeneca).

Clinical Trial Registration URL

http://www.clinicaltrials.gov. Unique identifier: NCT03354429.

Deciphering biased inverse agonism of cangrelor and ticagrelor at P2Y12 receptor

P2Y12 receptor (P2Y12-R) is one of the major targets for drug inhibiting platelet aggregation in the treatment/prevention of arterial thrombosis. However, the clinical use of P2Y12-R antagonists faces some limitations, such as a delayed onset of action (clopidogrel) or adverse effect profile (ticagrelor, cangrelor), justifying the development of a new generation of P2Y12-R antagonists with a better clinical benefit-risk balance. Although the recent concept of biased agonism offers the possibility to alleviate undesirable adverse effects while preserving therapeutic outcomes, it has never been explored at P2Y12-R. For the first time, using highly sensitive BRET2-based probes, we accurately delineated biased ligand efficacy at P2Y12-R in living HEK293T cells on G protein activation and downstream effectors. We demonstrated that P2Y12-R displayed constitutive Gi/o-dependent signaling that is impaired by the R122C mutation, previously associated with a bleeding disorder. More importantly, we reported the biased inverse agonist efficacy of cangrelor and ticagrelor that could underlie their clinical efficacy. Our study points out that constitutive P2Y12-R signaling is a normal feature of the receptor that might be essential for platelets to respond faster to a vessel injury. From a therapeutic standpoint, our data suggest that the beneficial advantages of antiplatelet drugs might be more related to inverse agonism at P2Y12-R than to antagonism of ADP-mediated signaling. In the future, deciphering P2Y12-R constitutive activity should allow the discovery of more selective biased P2Y12-R blockers demonstrating therapeutic advantages over classical antiplatelet drugs by improving therapeutic outcomes and concomitantly relieving undesirable adverse effects.

Pharmacologically pertinent period of effect (PPPE)

Background

The period of time during which a patient is exposed to a drug does not necessarily correspond to the period during which the drug produces the adverse effect under consideration. We propose the term Pharmacologically pertinent period of effect (PPPE) to address this time window. We explored the PPPE in light of the rofecoxib saga.

Methods

We identified the observational database studies of rofecoxib at doses 25 and 50 mg daily and thromboembolic events. We also obtained the Kaplan‐Meier curves of Vioxx Gastrointestinal Outcomes Research trial (VIGOR) and Adenomatous Polyp Prevention on Vioxx (APPROVE) trials.

Results

We found seven observational studies with nine analyses. All the studies only looked at current exposure. At the dose of 25 mg, only three of nine analyses were barely statistically significant. At the dose of 50 mg, the risk ratios were much higher. The visual inspection of the Kaplan‐Meier curves shows that in the APPROVE trial (25 mg), the placebo and rofecoxib curves start separating to become statistically significantly different only after 36 months. In contrast the VIGOR (50 mg), curves start separating very early and the divergence increases after 8 months.

Discussion

The 50 mg observational studies, looking at current exposure, correctively identified the almost immediate increase in risk evident in the VIGOR Kaplan‐Meier curves. The absence of an immediate increase in risk shown by the APPROVE trial was also correctively identified by most observational 25 mg studies. To our knowledge no observational study was done on the long‐term cardiac toxicity of the 25‐mg dose. It would thus appear that the two doses of rofecoxib have different PPPEs.