Single-dose pharmacokinetics, pharmacodynamics and safety of AZD0837, a novel oral direct thrombin inhibitor, in young healthy male subjects

The novel oral anticoagulant AZD0837 is currently in clinical development for the prevention of stroke and systemic embolic events in patients with atrial fibrillation. AZD0837 is bioconverted to AR-H067637, a selective and reversible direct thrombin inhibitor. This first-time-in-man study (study code D1250C00001) investigated the safety, tolerability, pharmacokinetics (PK) and pharmacodynamics (PD) of AZD0837. Healthy Caucasian male volunteers (n = 44, age 20 - 39 y) were enrolled into this study of single oral escalating doses of AZD0837 given in solution (15 - 750 mg, n = 4 per dose). PD was assessed by ex vivo measurements of activated partial thromboplastin time (APTT), ecarin coagulation time (ECT), thrombin time (TT) and thrombin generation in plasma. AZD0837 was rapidly absorbed, with a mean oral bioavailability of 22 - 52%, and bioconverted to the active form, AR-H067637. In fasting subjects, maximum plasma concentrations (Cmax) for AR-H067637 occurred approximately 1 h post-dosing and declined with a mean half-life of 9.3 h. The Cmax and area under the curve for AR-H067637 showed a low to moderate inter-individual variability of 16% and 28%, respectively, and exhibited a slight deviation from dose-proportionality. AZD0837 produced a dose-dependent prolongation of APTT, ECT and TT, and decreased maximum free thrombin activity. AZD0837 was generally well tolerated. AZD0837 single oral doses (15 - 750 mg) are well tolerated in healthy male subjects and exhibit favorable PK properties and reproducible effects on ex vivo coagulation time variables that support further clinical development.