First-in-Human Study to Assess the Safety, Pharmacokinetics, and Pharmacodynamics of an Oral Formulation of DS-1040, an Inhibitor of the Activated Form of Thrombin-Activatable Fibrinolysis Inhibitor, in Healthy Subjects.

DS-1040, a low-molecular-weight imidazole derivative, inhibits the enzymatic activity of thrombin-activatable fibrinolysis inhibitor (TAFIa), enhancing endogenous tissue plasminogen activator-triggered fibrinolysis. This first-in-human, randomized, placebo-controlled, phase 1 study evaluated the safety, pharmacokinetics (PK), and pharmacodynamics (PD) of an oral formulation of DS-1040. Healthy adults (aged 20-45 years; N = 56) were randomized 3:1 to receive DS-1040 orally administered as single ascending doses (50, 100, 200, or 400 mg) or placebo, or DS-1040 multiple ascending doses (100 mg once daily, 200 mg once daily, or 150 mg twice daily) or placebo for 14 days. Safety, PK, and PD parameters were assessed. All doses of DS-1040 were well tolerated; no serious/severe adverse events (AEs) or discontinuations due to AEs occurred. DS-1040 had no effect on coagulation parameters, and no treatment-related trends in the bleeding time were observed. DS-1040 exposure (peak concentration and area under the concentration-time curve) increased in a dose-proportional manner across the single-dose range. With multiple doses, steady state was achieved by day 7 with minimal accumulation (mean accumulation ratio 1.15-1.25), and the PK was time-independent. After 72 hours, approximately 10% of the DS-1040 400-mg single dose was recovered in urine as intact parent drug. The mean terminal half-life ranged from 17.2 to 24.9 hours, which was similar to previous intravenous administration data. Dose-dependent inhibition of total TAFIa activity was observed following single and multiple doses of oral DS-1040. The safety and PK/PD profiles of oral DS-1040 in healthy subjects support further clinical development.