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Background: Prasugrel is an oral antiplatelet agent approved for the reduction of atherothrombotic cardiovascular events in patients presenting with acute coronary syndrome and undergoing percutaneous coronary intervention. Although the approved loading dose is 60 mg, earlier studies of prasugrel suggested that active-metabolite exposure and pharmacodynamic response may be higher in Asian subjects than in white subjects., Objectives: This study compared the pharmacodynamic response to a single 30-mg dose of prasugrel in healthy Chinese and white subjects and the response to a single 30-mg dose of prasugrel and a single 300-mg dose of clopidogrel in healthy Chinese subjects. The pharmacokinetics and tolerability of both drugs were also assessed., Methods: This was an open-label, single-dose study conducted in Singapore. Chinese subjects were randomly allocated to receive prasugrel 30 mg or clopidogrel 300 mg; after a 14-day washout period, they received the alternative drug. White subjects received only prasugrel 30 mg. Blood samples for pharmaco-dynamic assessments were collected before dosing and at 0.5, 1, 2, 4, and 24 hours after dosing. Three methods were used to measure inhibition of platelet aggregation (IPA)-traditional light transmission aggregometry (LTA), the Verify Now P2Y12 (VN-P2Y12) assay, and a vasodilator-stimulated phosphoprotein (VASP) phosphorylation flow cytometry assay-and their results were compared. Blood samples for pharmacokinetic assessments were collected at 0.25, 0.5, 1, 1.5, 2, 4, 8, 12, and 24 hours after dosing. Concentrations of the active metabolite of prasugrel were measured using a validated LC-MS/MS method., Results: The study enrolled 18 Chinese subjects and 14 white subjects. Chinese subjects had a mean (SD) age of 31 (10) years and a mean body weight of 65.2 (8.9) kg; 83% were male. The corresponding values for white subjects were 30 (10) years, 77.2 (12.4) kg, and 86%. Thirty of the 32 enrolled subjects completed the study. Two Chinese men were withdrawn from the study, one due to a low platelet-rich plasma count after receipt of prasugrel 30 mg and the other due to mild, intermittent rectal bleeding after bowel movements that began approximately 2 days after receipt of clopidogrel 300 mg. The mean IPA with prasugrel was significantly higher in Chinese than in white subjects at 0.5, 1, and 2 hours after dosing (P < 0.05), but not at 4 or 24 hours. In Chinese subjects, mean maximal IPA (87%) occurred 1 hour after prasugrel dosing; in white subjects, mean maximal IPA (78%) occurred 2 hours after prasugrel dosing. In Chinese subjects, the mean IPA was significantly higher at all time points after administration of prasugrel 30 mg than after administration of clopidogrel 300 mg (P <0.001). After administration of Clopidogrel 300 mg in Chinese subjects, mean maximal IPA (58%) occurred at 4 hours. The VN-P2Y12 and VASP phosphorylation assays yielded results comparable to those obtained by LTA. Mean exposure to prasugrel's active metabolite was higher in Chinese than in white subjects (geometric least squares mean ratio for AUC(0-t) = 1.47 (90% CI, 1.24-1.73). Both drugs were well tolerated., Conclusions: In this study, platelet inhibition was significantly higher in Chinese than in white subjects up to 2 hours after a single 30-mg dose of prasugrel. Platelet inhibition was significantly higher in Chinese subjects at all time points after a 30-mg dose of prasugrel than after a 300-mg dose of clopidogrel. Both treatments were generally well tolerated., (Copyright 2010. Published by EM Inc USA.)

Objectives: Exenatide is an adjunctive treatment for Type 2 diabetes. This was the first study to evaluate the pharmacokinetics, safety and tolerability of therapeutic doses (5 microg and 10 microg) of exenatide after single and multiple subcutaneous injections in healthy adult Chinese subjects., Methods: 24 healthy volunteers were randomized to receive either 5 microg or 10 microg of exenatide by subcutaneous injection. Subjects received a single injection of exenatide on Day 1, twice daily on Days 2 and 3, and once on Day 4. Serial blood samples were drawn for pharmacokinetic assessment at pre-dose and up to 12 h post dose on Day 1 and Day 4. Adverse events, vital signs, 12-lead ECG, body weight and clinical laboratory evaluations were assessed., Results: Exenatide, 5 microg and 10 microg, was rapidly absorbed with a median tmax of 1 h after single and multiple doses. Exenatide Cmax and AUCtau,ss were (geometric mean (90% CI)) 145 (119 - 176) pg/ml and 370 (297 - 460) pg x h/ml, respectively, after multiple dosing with 5 microg. The Cmax and AUCtau,ss were 311 (271 - 357) pg/ml and 878 (785 - 983) pg x h/ml, respectively, for 10 microg. Mean half-life (t1/2, range 0.99 - 1.25 h), apparent volume of distribution (Vz/F, 19.2 - 22.3 l), and apparent clearance (CL/F, range 11.4 - 13.5 l/h) remained consistent between single and multiple doses and across the two dose levels. Both the accumulation ratios and linearity index approached 1.0. The most common adverse events were gastrointestinal in nature and mild in severity. The frequency of adverse events increased with dose, such that 8% of subjects who received 5 microg and 42% of subjects who received 10 microg experienced adverse events., Conclusions: Exenatide was rapidly absorbed, with similar pharmacokinetic properties following single and multiple doses. Exenatide exposure after multiple doses approximately doubled from 5 microg to 10 microg.