BMS-262084 is a 4-carboxy-2-azetidinone-containing irreversible inhibitor of FXIa, which is selective over other coagulation
proteases. We evaluated the in vitro and in vivo properties of
BMS-262084 in rabbits. Studies were conducted in arteriovenous-shunt
thrombosis (AVST),
venous thrombosis (VT), electrolytic-mediated carotid arterial
thrombosis (ECAT) and cuticle bleeding time (BT) models.
BMS-262084 was infused IV from 1 h before
thrombus induction or cuticle transection to the end of the experiment. In vitro,
BMS-262084 prolonged activated partial thromboplastin time (aPTT) with EC(2x) (concentration required to double aPTT) of 10.6 μM in rabbit plasma, and did not prolong prothrombin time (PT), thrombin time (TT) and HepTest. In vivo,
BMS-262084 produced dose-dependent antithrombotic effects in rabbits with antithrombotic ED(50) (dose that reduced
thrombus weight or increased blood flow by 50% of the control) in AVST, VT and ECAT of 0.4, 0.7 and 1.5 mg/kg/h IV, respectively.
BMS-262084 increased ex vivo aPTT dose-dependently without changes in PT and TT. The antithrombotic effect of
BMS-262084 was significantly correlated with its ex vivo aPTT, supporting the use of ex vivo aPTT as a pharmacodynamic
biomarker.
BMS-262084 did not alter ex vivo rabbit platelet aggregation to
ADP and
collagen. BT (fold-increase) determined at 3 and 10 mg/kg/h of
BMS-262084 were 1.17 ± 0.04 and 1.52 ± 0.07*, respectively (*P < 0.05 vs. control). This study demonstrated that
BMS-262084 prevented experimental
thrombosis at doses with low BT effects in rabbits, and suggests that a small molecule FXIa inhibitor may represent a promising antithrombotic
therapy.