Ticagrelor vs. clopidogrel in Japanese, Korean and Taiwanese patients with acute coronary syndrome -- randomized, double-blind, phase III PHILO study.

BACKGROUND: Few data on the relative efficacy and safety of new P2Y12inhibitors such as prasugrel and ticagrelor in Japanese, Taiwanese and South Korean patients with acute coronary syndromes (ACS) exist. METHODS AND RESULTS: The multicenter, double-blind, randomized PHILO trial compared the safety and efficacy of ticagrelor vs. clopidogrel in 801 patients with ACS (Japanese, n=721; Taiwanese, n=35; South Korean, n=44; unknown ethnicity, n=1). All were planned to undergo percutaneous coronary intervention and randomized within 24 h of symptom onset. Primary safety and efficacy endpoints were time to first occurrence of any major bleeding event and to any event from the composite of myocardial infarction, stroke or death from vascular causes, respectively.At 12 months, overall major bleeding occurred in 10.3% of ticagrelor-treated patients and in 6.8% of clopidogrel-treated patients (hazard ratio (HR), 1.54; 95% confidence interval (CI): 0.94-2.53); the composite primary efficacy endpoint occurred in 9.0% and in 6.3% of ticagrelor- and clopidogrel-treated patients, respectively (HR, 1.47; 95% CI: 0.88-2.44). For both analyses, the difference between groups was not statistically significant. CONCLUSIONS: In ACS patients from Japan, Taiwan and South Korea, event rates of primary safety and efficacy endpoints were higher, albeit not significantly, in ticagrelor-treated patients compared with clopidogrel-treated patients. This observation could be explained by the small sample size, imbalance in clinical characteristics and low number of events in the PHILO population.

Cardiovascular events in acute coronary syndrome patients with peripheral arterial disease treated with ticagrelor compared with clopidogrel: Data from the PLATO Trial.

AIMS: To determine the effect of ticagrelor compared to clopidogrel in patients with peripheral artery disease (PAD) and acute coronary syndromes (ACS). METHODS AND RESULTS: PLATO (n = 18,624) was a multicentre, double-blind, randomized trial in ACS, that showed a 16% reduction in cardiovascular death (CV-death), myocardial infarction (MI) and stroke with ticagrelor compared with clopidogrel, without significant increase in overall major bleeding. We performed a post-hoc analysis of cardiovascular and bleeding outcomes in PLATO according to reported PAD status at baseline. At one year, CV death, MI or stroke occurred in 19.3% of patients with PAD (n = 1144) compared to 10.2% in patients without PAD (p < 0.001). The Kaplan-Meier one year event rate for the primary endpoint of CV death, MI or stroke in PAD patients treated with ticagrelor as compared with clopidogrel, was 18% vs 20.6% (HR: 0.85 95% CI 0.64-1.11; for PAD status by treatment interaction, p = 0.99) and for death from any cause 8.7% vs 11.9%, (HR: 0.74 95% CI 0.50-1.08; interaction p = 0.73). PLATO-defined major bleeding event rates at one year were 14.8% for ticagrelor compared to 17.9% for clopidogrel, (HR: 0.81 95% CI 0.59-1.10; interaction p = 0.09). CONCLUSION: PAD patients have a high rate of ischaemic and bleeding events post ACS. The reduction of CV death, MI or stroke with ticagrelor compared with clopidogrel in PAD patients was consistent with the overall trial result although it did not reach statistical significance. Overall major bleeding was similar between the therapies.

Stent thrombosis with ticagrelor versus clopidogrel in patients with acute coronary syndromes: an analysis from the prospective, randomized PLATO trial.

BACKGROUND: We aimed to describe the effects of ticagrelor versus clopidogrel on stent thrombosis in the Platelet Inhibition and Patient Outcomes (PLATO) trial. METHODS AND RESULTS: Of 18 624 patients hospitalized for acute coronary syndromes, 11 289 (61%) had at least 1 intracoronary stent. Ticagrelor reduced stent thrombosis compared with clopidogrel across all definitions: definite, 1.37% (n=71) versus 1.93% (n=105; hazard ratio [HR], 0.67; 95% confidence interval [CI], 0.50-0.90; P=0.0091); definite or probable, 2.21% (n=118) versus 2.87% (n=157; HR, 0.75; 95% CI, 0.59-0.95; P=0.017); and definite, probable, and possible, 2.94% (n=154) versus 3.77 (n=201; HR, 0.77; 95% CI, 0.62-0.95). The reduction in definite stent thrombosis was consistent regardless of acute coronary syndrome type, presence of diabetes mellitus, stent type (drug-eluting or bare metal stent), CYP2C19 genetic status, loading dose of aspirin, dose of clopidogrel before randomization, and use of glycoprotein IIb/IIIa inhibitors at randomization. The reduction in stent thrombosis with ticagrelor was numerically greater for late (>30 days; HR, 0.48; 95% CI, 0.24-0.96) and subacute (4 hours-30 days; HR, 0.60; 95% CI, 0.39-0.93) compared with acute (<24 hours; HR, 0.94; 95% CI, 0.43-2.05) stent thrombosis or for patients compliant to therapy (ie, taking blinded study treatment ≥80% of the time) compared with less compliant patients. Randomization to ticagrelor was a strong independent inverse predictor of definite stent thrombosis (HR, 0.65; 95% CI, 0.48-0.88). CONCLUSION: Ticagrelor compared with clopidogrel reduces the incidence of stent thrombosis in patients with acute coronary syndromes, with consistent benefit across a broad range of patient, stent, and treatment characteristics.

Angiographic outcomes in the PLATO Trial (Platelet Inhibition and Patient Outcomes).

OBJECTIVES: The PLATO (Platelet Inhibition and Patient Outcomes) angiographic substudy sought to compare the efficacy of ticagrelor versus clopidogrel with respect to angiographic outcomes before and after PCI in the setting of acute coronary syndrome. BACKGROUND: Greater platelet inhibition has been associated with improved angiographic outcomes before and after percutaneous coronary intervention (PCI). Therefore, it was hypothesized that treatment with ticagrelor, which achieves more rapid, higher, and more consistent platelet inhibition, would be associated with improved angiographic outcomes when compared with those of clopidogrel treatment. METHODS: The angiographic cohort consists of 2,616 patients drawn from the 18,624-patient PLATO trial. Clopidogrel naïve or pre-treated patients were randomized to 180 mg of ticagrelor or 300 mg of clopidogrel (75 mg for clopidogrel pre-treated patients). PCI patients were administered, as per treatment group: 1) an additional 90 mg of ticagrelor if >24 h following the initial loading dose; or 2) an optional further 300 mg of clopidogrel or placebo (total 600 mg) prior to PCI. The substudy primary endpoint was the incidence of post-PCI TIMI (Thrombolysis In Myocardial Infarction) myocardial perfusion grade 3 (TMPG 3) among patients who received a study drug prior to PCI. RESULTS: In total, 21.3% of patients were pretreated with clopidogrel prior to randomization. There was a short time interval between randomization and PCI (median: 0.68 [interquartile range (IQR): 0.30 to 2.21] h) among all patients. Post-PCI TMPG 3 was similar between the ticagrelor and clopidogrel groups (47.1% vs. 46.9%; p = 0.96). Likewise, the following pre-PCI outcomes were similar in the ticagrelor and clopidogrel groups, respectively: TMPG 3 (30.5% vs. 31.2%), TIMI flow grade 3 (37.1% vs. 39.3%), corrected TIMI frame count (median: 100 vs. 71 frames), TIMI thrombus grade 0 (24.1% vs. 27.6%), minimum lumen diameter (median: 0.3 [IQR: 0.0 to 0.6] vs. 0.3 [IQR: 0.0 to 0.6] mm) and percentage of diameter stenosis (median: 89 [IQR: 78 to 100] vs. 89 [IQR: 77 to 100]). CONCLUSIONS: Neither coronary flow nor myocardial perfusion, evaluated on coronary angiograms performed before or following PCI procedures within a few hours after the start of oral antiplatelet treatment in the setting of acute coronary syndromes, demonstrated a difference with ticagrelor versus clopidogrel. (A Comparison of Ticagrelor [AZD6140] and Clopidogrel in Patients With Acute Coronary Syndrome [PLATO]; NCT00391872).

Ticagrelor enhances adenosine-induced coronary vasodilatory responses in humans.

OBJECTIVES: This study was undertaken to determine if ticagrelor augments adenosine-induced coronary blood flow and the sensation of dyspnea in human subjects. BACKGROUND: Ticagrelor is a P2Y(12) receptor antagonist that showed superior clinical benefit versus clopidogrel in a phase III trial (PLATO [Platelet Inhibition and Patient Outcomes]). Ticagrelor has been shown to inhibit cell uptake of adenosine and enhance adenosine-mediated hyperemia responses in a dog model. METHODS: In this double-blind, placebo-controlled study, 40 healthy male subjects were randomized to receive a single dose of ticagrelor (180 mg) or placebo in a crossover fashion. Coronary blood flow velocity (CBFV) was measured by using transthoracic Doppler echocardiography at rest after multiple stepwise adenosine infusions given before and after study drug, and again after the infusion of theophylline. RESULTS: Ticagrelor significantly increased the area under the curve of CBFV versus the adenosine dose compared with placebo (p = 0.008). There was a significant correlation between ticagrelor plasma concentrations and increases in the area under the curve (p < 0.001). In both treatment groups, the adenosine-induced increase in CBFV was significantly attenuated by theophylline, with no significant differences between subjects receiving ticagrelor or placebo (p = 0.39). Furthermore, ticagrelor significantly enhanced the sensation of dyspnea during adenosine infusion, and the effects were diminished by theophylline. CONCLUSIONS: Ticagrelor enhanced adenosine-induced CBFV and the sensation of dyspnea in these healthy male subjects via an adenosine-mediated mechanism. (Study to Assess the Effect of Ticagrelor on Coronary Blood Flow in Healthy Male Subjects; NCT01226602).

Pulmonary function in patients with acute coronary syndrome treated with ticagrelor or clopidogrel (from the Platelet Inhibition and Patient Outcomes [PLATO] pulmonary function substudy).

The Platelet Inhibition and Patient Outcomes (PLATO) trial showed that ticagrelor reduced the risk for cardiovascular events in patients with acute coronary syndromes compared to clopidogrel but was associated with increased incidence of dyspnea. This substudy assessed whether ticagrelor affects pulmonary function in patients with acute coronary syndromes: 199 patients enrolled in the PLATO trial and receiving randomized treatment with ticagrelor 90 mg twice daily (n = 101) or clopidogrel 75 mg/day (n = 98) took part in the pulmonary function substudy. Patients with advanced lung disease, congestive heart failure, or coronary artery bypass graft surgery after the index event were excluded. Pulse oximetry (blood oxygen saturation), spirometry (forced expiratory volume in 1 second, forced vital capacity, and forced expiratory flow between 25% and 75% of forced vital capacity before and 20 minutes after inhalation of a ß(2) agonist), lung volumes (total lung capacity, functional residual capacity, residual volume), and diffusion capacity were performed after patients received study medication for 30 to 40 days. Tests were then repeated <10 days before and approximately 30 days after the discontinuation of study medication. After a mean treatment duration of 31 days, there were no differences between the groups for any of the pulmonary function parameters. At the end of treatment (mean 211 days) and after the discontinuation of study medication (mean 32 days after the last dose), there was also no evidence of a change in pulmonary function in either group. For example, forced expiratory volume in 1 second values before ß(2) agonist inhalation in the ticagrelor and clopidogrel groups were 2.81 ± 0.73 and 2.70 ± 0.84 L, respectively, at the first visit and did not change significantly at subsequent visits. In conclusion, no effect of ticagrelor on pulmonary function was seen in this cohort of patients with acute coronary syndromes compared to clopidogrel.

Characterization of dyspnoea in PLATO study patients treated with ticagrelor or clopidogrel and its association with clinical outcomes.

AIMS To describe the incidence of dyspnoea and its associations with demographic characteristics and clinical outcomes in patients with acute coronary syndromes (ACS) treated with ticagrelor or clopidogrel in the PLATelet inhibition and patient Outcomes (PLATO) study. METHODS AND RESULTS In the PLATO study, 18 624 patients were randomized to receive either clopidogrel [300-600 mg loading dose (LD), 75 mg daily] or ticagrelor (180 mg LD, 90 mg b.i.d.). The occurrence of reported dyspnoea adverse events (AEs) was analysed in the 18 421 patients who received at least one dose of study medication in relation to demographic characteristics, clinical outcomes and other associations of patients with and without dyspnoea. A total of 1339 ticagrelor-treated patients (14.5%) and 798 clopidogrel-treated patients (8.7%) had a dyspnoea AE following randomization, with respectively 39 (0.4%) and 24 (0.3%) classified as severe in intensity. Excluding dyspnoea AEs occurring after the secondary endpoint of myocardial infarction (MI), the yearly rates of the efficacy endpoints in dyspnoea AE patients in the ticagrelor and clopidogrel groups were: for the primary composite of CV death, MI, and stroke, 8.8 and 10.4% (unadjusted P = 0.25; adjusted P = 0.54); for CV death, 3.1 and 4.8% (unadjusted P = 0.024; adjusted P = 0.18); and for total death 3.7 and 6.2% (unadjusted P = 0.004; adjusted P = 0.06), respectively. CONCLUSIONS Ticagrelor-related dyspnoea is usually mild or moderate in intensity and does not appear to be associated with differences concerning any efficacy or safety outcomes with ticagrelor compared with clopidogrel therapy in ACS patients.

The incidence of bradyarrhythmias and clinical bradyarrhythmic events in patients with acute coronary syndromes treated with ticagrelor or clopidogrel in the PLATO (Platelet Inhibition and Patient Outcomes) trial: results of the continuous electrocardiographic assessment substudy.

OBJECTIVES: The aim of this study was to determine whether ticagrelor increased the risk of ventricular pauses compared with clopidogrel and whether these pauses were associated with any clinical bradycardic events in patients presenting with acute coronary syndromes. BACKGROUND: Ticagrelor, an oral reversibly binding P2Y(12) inhibitor, provides more potent and consistent inhibition of platelet aggregation than clopidogrel but in a phase II study was associated with increased risk for ventricular pauses. A prospective continuous electrocardiographic (cECG) assessment was therefore performed within the PLATO (Platelet Inhibition and Patient Outcomes) study comparing ticagrelor and clopidogrel in patients hospitalized with acute coronary syndromes. METHODS: Patients in the cECG assessment had planned 7-day cECG recording initiated at the time of randomization (week 1), which was within 24 h of symptom onset, and then repeated at 1 month after randomization during the convalescent phase. The principal safety endpoint was the incidence of ventricular pauses lasting at least 3 s. Investigators also reported symptomatic bradycardic adverse events during the entire study duration (median 277 days). RESULTS: A total of 2,908 patients were included in the cECG assessment, of whom 2,866 (98.5%) had week 1 recordings, 1,991 (68.4%) had 1-month recordings, and 1,949 (67.0%) had both. During the first week after randomization, ventricular pauses ≥3 s occurred more frequently in patients receiving ticagrelor than clopidogrel (84 [5.8%] vs. 51 [3.6%]; relative risk: 1.61; p = 0.006). At 1 month, pauses ≥3 s occurred overall less frequently and were similar between treatments (2.1% vs. 1.7%). Most were ventricular pauses, and the greatest excess associated with ticagrelor were asymptomatic, sinoatrial nodal in origin (66%), and nocturnal. There were no differences between ticagrelor and clopidogrel in the incidence of clinically reported bradycardic adverse events, including syncope, pacemaker placement, and cardiac arrest. CONCLUSIONS: In the PLATO cECG assessment, more patients treated with ticagrelor compared with clopidogrel had ventricular pauses, which were predominantly asymptomatic, sinoatrial nodal in origin, and nocturnal and occurred most frequently in the acute phase of acute coronary syndromes. There were no apparent clinical consequences related to the excess in ventricular pauses in patients assigned to ticagrelor. (A Comparison of AZD6140 and Clopidogrel in Patients With Acute Coronary Syndrome [PLATO]; NCT00391872).

Ticagrelor versus clopidogrel in patients with ST-elevation acute coronary syndromes intended for reperfusion with primary percutaneous coronary intervention: A Platelet Inhibition and Patient Outcomes (PLATO) trial subgroup analysis.

BACKGROUND: Aspirin and clopidogrel are recommended for patients with acute coronary syndromes (ACS) or undergoing coronary stenting. Ticagrelor, a reversible oral P2Y12-receptor antagonist, provides faster, greater, and more consistent platelet inhibition than clopidogrel and may be useful for patients with acute ST-segment elevation (STE) ACS and planned primary percutaneous coronary intervention. METHODS AND RESULT: Platelet Inhibition and Patient Outcomes (PLATO), a randomized, double-blind trial, compared ticagrelor with clopidogrel for the prevention of vascular events in 18 624 ACS patients. This report concerns the 7544 ACS patients with STE or left bundle-branch block allocated to either ticagrelor 180-mg loading dose followed by 90 mg twice daily or clopidogrel 300-mg loading dose (with provision for 300 mg clopidogrel at percutaneous coronary intervention) followed by 75 mg daily for 6 to 12 months. The reduction of the primary end point (myocardial infarction, stroke, or cardiovascular death) with ticagrelor versus clopidogrel (10.8% versus 9.4%; hazard ratio [HR], 0.87; 95% confidence interval, 0.75 to 1.01; P=0.07) was consistent with the overall PLATO results. There was no interaction between presentation with STE/left bundle-branch block and randomized treatment (interaction P=0.29). Ticagrelor reduced several secondary end points, including myocardial infarction alone (HR, 0.80; P=0.03), total mortality (HR, 0.82; P=0.05), and definite stent thrombosis (HR, 0.66; P=0.03). The risk of stroke, low in both groups, was higher with ticagrelor (1.7% versus 1.0%; HR,1.63; 95% confidence interval, 1.07 to 2.48; P=0.02). Ticagrelor did not affect major bleeding (HR, 0.98; P=0.76). CONCLUSION: In patients with STE-ACS and planned primary percutaneous coronary intervention, the effects of ticagrelor were consistent with those observed in the overall PLATO trial. CLINICAL TRIAL REGISTRATION: URL: http://www.ClinicalTrials.gov. Unique identifier: NCT00391872.

Inhibitory effects of ticagrelor compared with clopidogrel on platelet function in patients with acute coronary syndromes: the PLATO (PLATelet inhibition and patient Outcomes) PLATELET substudy.

OBJECTIVES: The PLATO (PLATelet inhibition and patient Outcomes) PLATELET substudy aimed to compare the antiplatelet effects of clopidogrel and ticagrelor in patients with acute coronary syndromes. BACKGROUND: The PLATO study demonstrated superiority of ticagrelor over clopidogrel in the prevention of ischemic events in patients with acute coronary syndromes. METHODS: Patients were randomized to receive either clopidogrel (300- to 600-mg loading dose [LD], 75 mg/day) or ticagrelor (180-mg LD, 90 mg twice daily). The effects of maintenance therapy were studied in 69 patients pre- and 2 to 4 h post-dose after at least 28 days. The LD effect was studied in 24 clopidogrel-naive patients. Light transmittance aggregometry (adenosine diphosphate 5 to 20 µM), VerifyNow P2Y12, and VASP phosphorylation assays were performed. RESULTS: During maintenance therapy, ticagrelor achieved greater suppression of platelet reactivity compared with clopidogrel. The mean maximum light transmittance aggregometry responses (adenosine diphosphate 20 µM) post-maintenance dose were 44±15% for clopidogrel and 28±10% for ticagrelor (p<0.001). High platelet reactivity was seen more frequently in the clopidogrel group. Proton pump inhibitor use was associated with higher platelet reactivity with clopidogrel but not ticagrelor. The ticagrelor LD also achieved greater inhibition of platelet aggregation compared with the clopidogrel LD. CONCLUSIONS: Ticagrelor achieves greater antiplatelet effect than clopidogrel in patients with acute coronary syndromes, both in the first hours of treatment and during maintenance therapy.

Changes in inflammatory biomarkers in patients treated with ticagrelor or clopidogrel.

BACKGROUND: Inflammation is a key factor in the development of atherosclerotic disease and acute coronary syndromes (ACS). The P2Y(12) receptor antagonists ticagrelor (AZD6140) and clopidogrel may have anti-inflammatory effects. The objective of this analysis from the Dose Confirmation Study Assessing Anti-Platelet Effects of AZD6140 vs Clopidogrel in NSTEMI 2 (DISPERSE 2) trial was to compare ticagrelor and clopidogrel for effects on the inflammatory biomarkers C-reactive protein (CRP), interleukin 6 (IL-6), myeloperoxidase (MPO), and soluble CD40 ligand (sCD40L). HYPOTHESIS: Ticagrelor inhibits the P2Y(12) receptor and inflammation to a greater extent than clopidogrel in nonST-segment elevation ACS (NSTE-ACS) patients. METHODS: In a double-blind, double-dummy, multicenter trial, 990 patients who had been hospitalized within the previous 48 hours with NSTE-ACS were randomized to receive ticagrelor 90 mg twice daily, ticagrelor 180 mg twice daily, or clopidogrel 300 mg initially and then 75 mg once daily. Within the ticagrelor groups, patients were also randomized to receive or not receive a loading dose of ticagrelor 270 mg initially. All patients received standard treatment for ACS, which included 325 mg aspirin initially and 75 to 100 mg aspirin each day subsequently. Inflammatory biomarkers were measured at baseline, upon hospital discharge, and after 4 weeks. RESULTS: Inflammatory biomarker measurements were not significantly different among treatment groups at baseline, discharge, and 4 weeks. CONCLUSIONS: Ticagrelor and clopidogrel appeared not to differ in this study with respect to the inflammatory biomarkers CRP, IL-6, MPO, and sCD40L in patients with NSTE-ACS.

Comparison of ticagrelor with clopidogrel in patients with a planned invasive strategy for acute coronary syndromes (PLATO): a randomised double-blind study.

BACKGROUND: Variation in and irreversibility of platelet inhibition with clopidogrel has led to controversy about its optimum dose and timing of administration in patients with acute coronary syndromes. We compared ticagrelor, a more potent reversible P2Y12 inhibitor with clopidogrel in such patients. METHODS: At randomisation, an invasive strategy was planned for 13 408 (72.0%) of 18 624 patients hospitalised for acute coronary syndromes (with or without ST elevation). In a double-blind, double-dummy study, patients were randomly assigned in a one-to-one ratio to ticagrelor and placebo (180 mg loading dose followed by 90 mg twice a day), or to clopidogrel and placebo (300-600 mg loading dose or continuation with maintenance dose followed by 75 mg per day) for 6-12 months. All patients were given aspirin. The primary composite endpoint was cardiovascular death, myocardial infarction, or stroke. Analyses were by intention to treat. This trial is registered with ClinicalTrials.gov, number NCT00391872. FINDINGS: 6732 patients were assigned to ticagrelor and 6676 to clopidogrel. The primary composite endpoint occurred in fewer patients in the ticagrelor group than in the clopidogrel group (569 [event rate at 360 days 9.0%] vs 668 [10.7%], hazard ratio 0.84, 95% CI 0.75-0.94; p=0.0025). There was no difference between clopidogrel and ticagrelor groups in the rates of total major bleeding (691 [11.6%] vs 689 [11.5%], 0.99 [0.89-1.10]; p=0.8803) or severe bleeding, as defined according to the Global Use of Strategies To Open occluded coronary arteries, (198 [3.2%] vs 185 [2.9%], 0.91 [0.74-1.12]; p=0.3785). INTERPRETATION: Ticagrelor seems to be a better option than clopidogrel for patients with acute coronary syndromes for whom an early invasive strategy is planned.

Ticagrelor versus clopidogrel in patients with acute coronary syndromes.

BACKGROUND: Ticagrelor is an oral, reversible, direct-acting inhibitor of the adenosine diphosphate receptor P2Y12 that has a more rapid onset and more pronounced platelet inhibition than clopidogrel. METHODS: In this multicenter, double-blind, randomized trial, we compared ticagrelor (180-mg loading dose, 90 mg twice daily thereafter) and clopidogrel (300-to-600-mg loading dose, 75 mg daily thereafter) for the prevention of cardiovascular events in 18,624 patients admitted to the hospital with an acute coronary syndrome, with or without ST-segment elevation. RESULTS: At 12 months, the primary end point--a composite of death from vascular causes, myocardial infarction, or stroke--had occurred in 9.8% of patients receiving ticagrelor as compared with 11.7% of those receiving clopidogrel (hazard ratio, 0.84; 95% confidence interval [CI], 0.77 to 0.92; P<0.001). Predefined hierarchical testing of secondary end points showed significant differences in the rates of other composite end points, as well as myocardial infarction alone (5.8% in the ticagrelor group vs. 6.9% in the clopidogrel group, P=0.005) and death from vascular causes (4.0% vs. 5.1%, P=0.001) but not stroke alone (1.5% vs. 1.3%, P=0.22). The rate of death from any cause was also reduced with ticagrelor (4.5%, vs. 5.9% with clopidogrel; P<0.001). No significant difference in the rates of major bleeding was found between the ticagrelor and clopidogrel groups (11.6% and 11.2%, respectively; P=0.43), but ticagrelor was associated with a higher rate of major bleeding not related to coronary-artery bypass grafting (4.5% vs. 3.8%, P=0.03), including more instances of fatal intracranial bleeding and fewer of fatal bleeding of other types. CONCLUSIONS: In patients who have an acute coronary syndrome with or without ST-segment elevation, treatment with ticagrelor as compared with clopidogrel significantly reduced the rate of death from vascular causes, myocardial infarction, or stroke without an increase in the rate of overall major bleeding but with an increase in the rate of non-procedure-related bleeding. (ClinicalTrials.gov number, NCT00391872.)

Ticagrelor yields consistent dose-dependent inhibition of ADP-induced platelet aggregation in patients with atherosclerotic disease regardless of genotypic variations in P2RY12, P2RY1, and ITGB3.

The platelet P2Y(12) receptor is the target of clopidogrel therapy, which has been shown to reduce thromboembolic complications of atherosclerotic disease but has limitations in terms of variability of response and irreversibility of effect. This receptor is also a target for ticagrelor (AZD6140), the first reversibly binding oral P2Y(12) receptor antagonist that does not require metabolic activation and yields more consistent inhibition of platelet aggregation than clopidogrel therapy. Single nucleotide polymorphisms (SNPs) have been described in the gene for this receptor (P2RY12), some of which have been associated with variability in platelet reactivity. SNPs in P2RY1 and ITGB3 have also been reported by some groups to affect platelet reactivity to adenosine diphosphate (ADP). We assessed whether SNPs in these genes influenced the pharmacodynamic response to ticagrelor in patients enrolled in both the DISPERSE study (stable atherosclerotic disease) and the DISPERSE2 study (non-ST-segment elevation acute coronary syndromes). Platelet aggregation data (at baseline and 4 weeks) and DNA samples from clopidogrel-naive Caucasian patients treated with ticagrelor were available for 151 patients. Seventy four SNPs within three genes were genotyped. After adjustment for multiple comparisons, none of these SNPs were found to significantly influence inhibition of ADP-induced platelet aggregation by ticagrelor.

Comparison of ticagrelor, the first reversible oral P2Y(12) receptor antagonist, with clopidogrel in patients with acute coronary syndromes: Rationale, design, and baseline characteristics of the PLATelet inhibition and patient Outcomes (PLATO) trial.

BACKGROUND: Antiplatelet therapy is essential treatment for acute coronary syndromes (ACS). Current therapies, however, have important limitations affecting their clinical success. Ticagrelor, the first reversible oral P2Y(12) receptor antagonist, provides faster, greater, and more consistent adenosine diphosphate-receptor inhibition than clopidogrel. The phase III PLATelet inhibition and patient Outcomes (PLATO) trial is designed to test the hypothesis that ticagrelor compared with clopidogrel will result in a lower risk of recurrent thrombotic events in a broad patient population with ACS. METHODS: PLATO is an international, randomized, double-blind, event-driven trial involving >18,000 patients hospitalized for ST-elevation ACS with scheduled primary percutaneous coronary intervention or for non-ST-elevation ACS. After loading doses of ticagrelor 180 mg or clopidogrel 300 mg in a double-blind, double-dummy fashion (with provision for additional 300 mg clopidogrel at percutaneous coronary intervention), patients will receive ticagrelor 90 mg twice daily or clopidogrel 75 mg once daily for 6 to 12 months on top of acetylsalicylic acid. The primary efficacy end point is time to first occurrence of death from vascular causes, myocardial infarction, or stroke. The primary safety variable is PLATO-defined major bleeding. An extensive substudy program will explore the pathophysiology of ACS, indicators of prognosis and response to treatment, mechanisms of effect and safety of the study medications, health economics, and quality of life. CONCLUSION: The PLATO study will provide a pivotal comparison of the efficacy and safety of ticagrelor with those of clopidogrel in ACS patients, together with extensive information on treatment outcomes in different subsets of ACS in a broad patient population.

Effect of ximelagatran on ischemic events and death in patients with atrial fibrillation after acute myocardial infarction in the efficacy and safety of the oral direct thrombin inhibitor ximelagatran in patients with recent myocardial damage (ESTEEM) trial.

BACKGROUND: New-onset trial fibrillation (AF) occurs commonly after acute myocardial infarction (MI) and is associated with a poor prognosis due to stroke or death. The optimal antithrombotic therapy is unknown. The aim of this study was to investigate whether an oral direct thrombin inhibitor, ximelagatran, added to aspirin, reduced the risk of death, myocardial infarction (MI), and stroke in patients who developed AF after their qualifying MI in the efficacy and safety of the oral direct thrombin inhibitor ximelagatran in patients with recent myocardial damage (ESTEEM) trial. METHODS: The ESTEEM trial evaluated 6 months treatment with ximelagatran together with aspirin, compared to aspirin alone, for prevention of ischemic events in 1883 patients randomized within 14 days after an MI. After their qualifying MI, 174 (9%) patients developed AF in hospital. Multivariate hazard ratios for ximelagatran compared with placebo were calculated by presence AF. RESULTS: Of 101 patients with AF treated with ximelagatran 7 (6.9%) had either death, MI, or stroke, compared with 15 (20.6%) in 73 patients allocated to placebo. Ximelagatran reduced the risk of death, MI, or stroke by 70% (hazard ratio 0.30, 95% CI 0.12-0.74). For the separate outcome events, we found similar, nonsignificant trends. One major bleeding event occurred in each treatment group. CONCLUSIONS: For patients with MI complicated by AF, the combination of aspirin and an oral direct thrombin inhibitor seems beneficial. The high risk for death, MI, and stroke in this population and the increasing use of percutaneous interventions in MI patients may suggest a combination of long-term antiplatelet and anticoagulant therapy. Randomized clinical trials are warranted.