Oral direct thrombin inhibitors in clinical development

Area of Science:

• Pharmacology
• Cardiovascular Medicine
• Drug Development

Background:

• Thrombin inhibitors are crucial for anticoagulation, but developing oral agents with optimal properties is challenging.
• Existing anticoagulants like warfarin have limitations in their dose-response and monitoring requirements.

Purpose of the Study:

• To evaluate the pharmacodynamic and pharmacokinetic profiles of two novel oral direct thrombin inhibitors (DTIs): ximelagatran and BIBR 1048.
• To compare the efficacy and safety of these DTIs against existing anticoagulation therapies in experimental and clinical settings.

Main Methods:

• Development of oral prodrugs (ximelagatran, BIBR 1048) releasing active melagatran and BIBR 953.
• Assessment of oral bioavailability, half-life, and elimination routes (renal).
• Evaluation in experimental thrombosis models and clinical studies for various indications.

Main Results:

• Melagatran exhibits a shallower dose-response curve than warfarin, suggesting a better efficacy-bleeding separation.
• Ximelagatran shows higher oral bioavailability (20%) compared to BIBR 1048 (estimated 5%).
• Ximelagatran offers a low inter-individual variability, no significant food or CYP450 interactions, and a fixed-dose, twice-daily regimen without monitoring.

Conclusions:

• Oral DTIs like ximelagatran represent a significant advancement in anticoagulation therapy.
• The fixed-dose, non-monitored regimen of ximelagatran is anticipated to simplify anticoagulant use.
• Promising clinical results in Phase III studies suggest broad applicability for VTE prevention, treatment, and stroke prevention in atrial fibrillation.