Objectives: There is a clinical need for safe new oral anticoagulants. The safety, tolerability, pharmacodynamics, and pharmacokinetics of BAY 59-7939--a novel, oral, direct Factor Xa (FXa) inhibitor--were investigated in this single-center, placebo-controlled, single-blind, parallel-group, multiple-dose escalation study.
Methods: Healthy male subjects (aged 20-45 years, body mass index 18.6-31.4 kg/m(2)) received oral BAY 59-7939 (n=8 per dose regimen) or placebo (n=4 per dose regimen) on days 0 and 3-7. Dosing regimens were 5 mg once, twice (bid), or three times daily, and 10 mg, 20 mg, or 30 mg bid.
Results: There were no clinically relevant changes in bleeding time or other safety variables across all doses and regimens. There was no dose-related increase in the frequency or severity of adverse events with BAY 59-7939. Maximum inhibition of FXa activity occurred after approximately 3 h, and inhibition was maintained for at least 12 h for all doses. Prothrombin time, activated partial thromboplastin time, and HepTest were prolonged to a similar extent to inhibition of FXa activity for all doses. Dose-proportional pharmacokinetics (AUC(tau, norm) and C(max, norm)) were observed at steady state (day 7). Maximum plasma concentrations were achieved after 3-4 h. The terminal half-life of BAY 59-7939 was 5.7-9.2 h at steady state. There was no relevant accumulation at any dose.
Conclusions: BAY 59-7939 was safe and well tolerated across the wide dose range studied, with predictable, dose-proportional pharmacokinetics and pharmacodynamics and no relevant accumulation beyond steady state. These results support further investigation of BAY 59-7939 in phase II clinical trials.