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A phase 1 study of prasugrel in patients with sickle cell disease: pharmacokinetics and effects on ex vivo platelet reactivity.

ABSTRACT: Prasugrel is a novel thienopyridine P2Y12 adenosine diphosphate (ADP) receptor antagonist that inhibits ADP-mediated platelet activation and aggregation. Accordingly, it may be useful in reducing platelet-related ischaemia in sickle cell disease (SCD). Exposure to prasugrel's active metabolite (Pras-AM) and its antiplatelet activity in SCD have not been investigated.Thirteen adult patients with SCD and an equal number of matched healthy control subjects were studied before and after 12 days of 5.0 or 7.5 mg?day(-1) prasugrel treatment. Platelet reactivity was assessed by light transmission aggregometry (LTA), impedance aggregometry (MEA), VerifyNow® P2Y12, vasodilator-stimulated phosphoprotein (VASP) phosphorylation and Plateletworks. Exposure to Pras-AM was also assessed.At baseline, patients with SCD showed increased platelet reactivity vs. healthy control subjects with VerifyNow (408 vs. 323 P2Y12 reaction units (PRU), respectively, P = 0.003) and MEA (106 vs. 77 area under the aggregation curve (AU.min), P = 0.002); lower platelet reactivity index with VASP flow cytometry (59 vs. 79% platelet reactivity index (PRI), P = 0.018); and no significant differences with LTA, VASP enzyme-linked immunosorbent assay or Plateletworks. Relative to baseline, prasugrel significantly reduced platelet reactivity by all assays in both populations (all P < 0.05). Prasugrel was well tolerated, with no bleeding-related events in patients with SCD. The mean concentration-time profiles of Pras-AM were comparable between healthy subjects and patients with SCD following a single 10 mg prasugrel dose and following the 12th dose of 7.5 or 5 mg prasugrel.Results demonstrate that in response to prasugrel, patients with SCD and healthy subjects have similar degrees of platelet inhibition and exposure to Pras-AM, and provide a basis for further study of prasugrel in patients with SCD.

SUBMITTER: Jakubowski JA

PROVIDER: S-EPMC3690102 | biostudies-literature | 2013 Jun

REPOSITORIES: biostudies-literature

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A phase 1 study of prasugrel in patients with sickle cell disease: pharmacokinetics and effects on ex vivo platelet reactivity.

Jakubowski Joseph A JA Zhou Chunmei C Small David S DS Winters Kenneth J KJ Lachno D Richard DR Frelinger Andrew L AL Howard Jo J Mant Timothy G TG Jurcevic Stipo S Payne Christopher D CD

British journal of clinical pharmacology 20130601 6

<h4>Aims</h4>Prasugrel is a novel thienopyridine P2Y12 adenosine diphosphate (ADP) receptor antagonist that inhibits ADP-mediated platelet activation and aggregation. Accordingly, it may be useful in reducing platelet-related ischaemia in sickle cell disease (SCD). Exposure to prasugrel's active metabolite (Pras-AM) and its antiplatelet activity in SCD have not been investigated.<h4>Methods</h4>Thirteen adult patients with SCD and an equal number of matched healthy control subjects were studied ...[more]

PMID: 23171128

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Project description:BackgroundMobilization of intra and extracellular calcium is required for platelet activation, aggregation, and degranulation. However, the importance of alterations in the calcium-platelet axis after injury is unknown. We hypothesized that in injured patients, in vivo initial calcium concentrations (pretransfusion) predict ex vivo platelet activation and aggregation, viscoelastic clot strength, and transfusion of blood products. We additionally hypothesized that increasing calcium concentrations ex vivo increases the expression of platelet activation surface receptors and platelet aggregation responses to agonist stimulation in healthy donor blood.MethodsBlood samples were collected from 538 trauma patients on arrival to the emergency department. Standard assays (including calcium), platelet aggregometry (PA) and thromboelastometry (ROTEM) were performed. In PA, platelet activation (prestimulation impedance [Ω]) and aggregation responses to agonist stimulation (area under the aggregation curve [AUC]) with adenosine diphosphate (ADP), thrombin receptor-activating peptide, arachidonic acid (AA), and collagen (COL) were measured. Multivariable regression tested the associations of calcium with PA, ROTEM, and transfusions. To further examine the calcium-platelet axis, calcium was titrated in healthy blood. Platelet aggregometry and ROTEM were performed, and expression of platelet glycoprotein IIb/IIIa and P-selectin was measured by flow cytometry.ResultsThe patients were moderately injured with normal calcium and platelet counts. Higher calcium on arrival (pretransfusion) was independently associated with increased platelet activation (prestimulation, Ω; p < 0.001), aggregation (ADP-stimulated, AUC; p = 0.002; thrombin receptor-activating peptide-stimulated, AUC; p = 0.038), and clot strength (ROTEM max clot firmness; p < 0.001), and inversely associated with 24-hour transfusions of blood, plasma, and platelets (all p < 0.005). Up-titrating calcium in healthy blood increased platelet activation (prestimulation, Ω; p < 0.001), aggregation (ADP, AA, COL-stimulated AUCs; p < 0.050), and expression of P-selectin (p = 0.003).ConclusionInitial calcium concentrations (pretransfusion) are independently associated with platelet activation, aggregation, clot-strength, and transfusions after injury. These changes may be mediated by calcium driven expression of surface receptors necessary for platelet activation and aggregation. However, the therapeutic benefit of early, empiric calcium repletion in trauma patients remains undefined.Level of evidencePrognostic, level V.

Project description:BackgroundThis meta-analysis mainly aimed to compare the impact of prasugrel and ticagrelor on platelet reactivity (PR) in patients with acute coronary syndrome (ACS).MethodsWe searched four electronic databases to identify randomized controlled trials and cohort studies comparing the impact of prasugrel and ticagrelor on PR in patients with ACS. We performed group analyses according to three detection methods, drug dose [loading dose (LD) and maintenance dose (MTD)] and LD effect time, and assessed the robustness of the results through sensitivity analysis.ResultsTwenty-five studies with 5,098 patients were eligible. After LD, the incidence of high on-treatment platelet reactivity (HTPR) of ticagrelor was significantly lower than that of prasugrel within 6-18 h based on vasodilator-stimulated phosphoprotein (VASP) test [RR = 0.25 (0.07, 0.85), P = 0.03], there was no significant difference between ticagrelor and prasugrel in the following results: platelets inhibitory effect within 24-48 h based on VerifyNow P2Y12 (VN) assay (P = 0.11) and VASP test (P = 0.20), and the incidence of HTPR within 2-6 h based on VN assay (P = 0.57) and within 24-48 h based on VN assay (P = 0.46) and VASP test (P = 0.72), the incidence of low on-treatment platelet reactivity (LTPR) within 6-18 h based on VASP test (P = 0.46) and 48 h based on VN assay (P = 0.97) and VASP test (P = 0.73). After MTD, the platelet inhibitory effect of ticagrelor was stronger than that of prasugrel based on VN assay [WMD = -41.64 (-47.16, -36.11), P < 0.00001]and VASP test [WMD = -9.10 (-13.88, -4.32), P = 0.0002], the incidence of HTPR of ticagrelor was significantly lower than that of prasugrel based on VN assay [RR = 0.05 (0.02, 0.16), P < 0.00001], the incidence of LTPR of ticagrelor was significantly higher than prasugrel based on VN assay [RR = 6.54 (4.21, 10.14), P < 0.00001] and VASP test [RR = 2.65 (1.78, 3.96), P < 0.00001], the results of Multiple Electrode Aggregometry (MEA) test was inconsistent with the other two detection methods in platelet inhibitory effect and the incidence of HTPR and LTPR. There was no significant difference between ticagrelor and prasugrel in the following clinical outcomes: all-cause death (P = 0.86), cardiovascular death (P = 0.49), myocardial infarction (P = 0.67), stroke (P = 0.51), target vessel revascularization (P = 0.51), stent thrombosis (P = 0.90), TIMI major bleeding (P = 0.86) and bleeding BARC type ≥ 2 (P = 0.77). The risk of bleeding BARC type 1 of ticagrelor was significantly higher than prasugrel [RR = 1.44 (1.03, 2.02), P = 0.03].ConclusionsCompared with prasugrel, ticagrelor might have a stronger platelet inhibition effect, with a lower incidence of HTPR and a higher incidence of LTPR and bleeding BARC type 1, while there might be no significant difference in the risk of thrombosis/ischemic, bleeding BARC Type ≥ 2 and TIMI major bleeding. A higher incidence of LTPR might indicate a higher risk of bleeding BARC type 1. The results of VN assay were consistent with that of VASP test, and not with the MEA test.Systematic review registrationhttps://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022304205, identifier: CRD42022304205.

Project description:BackgroundPlatelet behavior in trauma-induced coagulopathy is poorly understood. Injured patients have impaired platelet aggregation (dysfunction) in ex vivo agonist-stimulated platelet aggregometry (PA). However, PA assumes that platelets are inactivated before ex vivo stimulated aggregation, which may be altered by injury. We hypothesized that following trauma, platelet aggregation (area under the curve) is decreased regardless of injury burden, but that (1) minor injury is associated with an increased baseline electrical impedance, characteristic of a functional platelet phenotype (platelets that activate in response to injury), and that (2) severe injury is not associated with an increased baseline electrical impedance, characteristic of a dysfunctional phenotype (platelets that do not activate well in response to injury) compared with healthy controls.MethodsBlood from 458 trauma patients and 30 healthy donors was collected for PA. Baseline electrical impedance (Ω); platelet aggregation stimulated by adenosine diphosphate, collagen, thrombin, and arachidonic acid; and rotational thromboelastometry were measured. Multivariate regression was performed to identify associations of PA measures with blood transfusion.ResultsCompared with healthy controls, injured patients had impaired platelet aggregation in response to ex vivo stimulation, regardless of injury burden. However, minorly injured patients had increased endogenous platelet activation (baseline electrical impedance, Ω: with shock, p = 0.012; without shock, p = 0.084), but severely injured patients did not have significant increases in endogenous platelet activation (baseline electrical impedance, Ω: with shock, p = 0.86; without shock, p = 0.37). For every 10 Ω increase in baseline electrical impedance, there was an 8% decrease in units of blood transfused in the first 24 h (-0.08; confidence interval, -0.14 to -0.02; p = 0.015).ConclusionInjury and shock confer differential patterns of platelet aggregation in PA. Minor injury overestimates the presence of platelet dysfunction, while severe injury induces a truly dysfunctional phenotype-platelets that do not activate nor aggregate appropriately after injury. This is consequential in improving accurate phenotyping of postinjury platelet behavior for platelet-based therapeutics.Level of evidencePrognostic, level IV.

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A phase 1 study of prasugrel in patients with sickle cell disease: pharmacokinetics and effects on ex vivo platelet reactivity.

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A phase 1 study of prasugrel in patients with sickle cell disease: pharmacokinetics and effects on ex vivo platelet reactivity.

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