| Sumario: | Purpose: Ticagrelor (AZD6140) is the first reversibly binding oral P2Y(12) receptor antagonist in development for reduction of clinical thrombotic events in patients with acute coronary syndromes. The purpose of our studies was to determine the effect of single-ascending doses of ticagrelor in healthy subjects. Methods: In two randomised, double-blind, placebo-controlled single ascending dose studies, healthy subjects received oral doses of 0.1-100 mg or placebo (n=25) and 30-400 mg or placebo (n=13). Results: Absorption of ticagrelor was rapid [median time to peak plasma concentration (t(max)) 1.3-2 h], as was the formation of its main (active) metabolite, AR-C124910XX (t(max) 1.5-3 h). For both ticagrelor and AR-C124910XX, the peak plasma concentration (C(max)) and area under the plasma concentration-time curve from time 0 to infinity (AUC0-[infinity]) increased in an apparently dose-proportional manner over the dose range studied, indicating linear pharmacokinetics. The mean terminal-phase half-life (t(½)) was approximately 7-8.5 h for ticagrelor and 8.5-10 h for AR-C124910XX; AR-C124910XX exposure was approximately one third that of ticagrelor. Inhibition of platelet aggregation (IPA) was dose related and was nearly complete at 2 h (mean 88-95%; final extent, with 20 µM adenosine diphosphate ADP) at doses of 100-400 mg. Conclusion: Linear and predictable pharmacokinetics of ticagrelor and AR-C124910XX were observed. A consistent and high IPA was maintained over 2-12 h, gradually decreasing with declining plasma concentration starting around 12 h post-dose, indicating that the IPA is reversible. Ticagrelor was well tolerated, with no serious or doserelated adverse events or notable changes in laboratory values observed.
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