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Publications (6)

  • [Show abstract] [Hide abstract] ABSTRACT: Spiropiperidine indoline-substituted diaryl ureas had been identified as antagonists of the P2Y1 receptor. Enhancements in potency were realized through the introduction of a 7-hydroxyl substitution on the spiropiperidinylindoline chemotype. SAR studies were conducted to improve PK and potency, resulting in the identification of compound 3e, a potent, orally bioavailable P2Y1 antagonist with a suitable PK profile in preclinical species. Compound 3e demonstrated a robust antithrombotic effect in vivo and improved bleeding risk profile compared to the P2Y12 antagonist clopidogrel in rat efficacy/bleeding models.
    Article · Jan 2014 · Bioorganic & medicinal chemistry letters
  • [Show abstract] [Hide abstract] ABSTRACT: Preclinical data suggests that P2Y1 antagonists, such as diarylurea compound 1, may provide antithrombotic efficacy similar to P2Y12 antagonists and may have the potential of providing reduced bleeding liabilities. This manuscript describes a series of diarylureas bearing solublizing amine side chains as potent P2Y1 antagonists. Among them, compounds 2l and 3h had improved aqueous solubility and maintained antiplatelet activity compared with compound 1. Compound 2l was moderately efficacious in both rat and rabbit thrombosis models and had a moderate prolongation of bleeding time in rats similar to that of compound 1.
    Article · Apr 2013 · Bioorganic & medicinal chemistry letters
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    [Show abstract] [Hide abstract] ABSTRACT: Two distinct G protein-coupled purinergic receptors, P2Y1 and P2Y12, mediate ADP driven platelet activation. The clinical effectiveness of P2Y12 blockade is well established. Recent preclinical data suggest that P2Y1 and P2Y12 inhibition provide equivalent antithrombotic efficacy, while targeting P2Y1 has the potential for reduced bleeding liability. In this account, the discovery of a 2-(phenoxypyridine)-3-(phenyl)urea chemotype that inhibited ADP-mediated platelet aggregation in human blood samples is described. Optimization of this series led to the identification of compound 16, 1-(2-(2-tert-butylphenoxy)pyridin-3-yl)-3-4-(trifluoromethoxy)phenylurea, which demonstrated a 68 ± 7% thrombus weight reduction in an established rat arterial thrombosis model (10 mg/kg plus 10 mg/kg/h) while only prolonging cuticle and mesenteric bleeding times by 3.3- and 3.1-fold, respectively in provoked rat bleeding time models. These results suggest that a P2Y1 antagonist could potentially provide a safe and efficacious antithrombotic profile.
    Full-text available · Article · Jan 2013 · Journal of Medicinal Chemistry
  • William A Schumacher · Jeffrey S Bostwick · Anne B Stewart · [...] · Pancras C Wong
    [Show abstract] [Hide abstract] ABSTRACT: Apixaban is an oral, direct, and highly selective factor Xa inhibitor in late-stage clinical development for the prevention and treatment of thromboembolic diseases. Apixaban was evaluated in rat thrombosis and hemostasis models. Thrombosis was produced in the carotid artery by FeCl2 application, in the vena cava by either FeCl2 application or tissue factor injection, and in an arterial-venous shunt. Hemostasis was assessed using cuticle, renal cortex, and mesenteric artery bleeding times. Intravenous apixaban infusions of 0.1, 0.3, 1, and 3 mg/kg per hour increased the ex vivo prothrombin time to 1.24, 1.93, 2.75, and 3.98 times control, respectively. The 0.3, 1, and 3-mg/kg per hour doses inhibited thrombosis in all models. Concentrations for 50% thrombus reduction ranged from 1.84 to 7.57 microM. The 3-mg/kg per hour dose increased cuticle, renal, and mesenteric bleeding times to 1.92, 2.13, and 2.98 times control, respectively. Lower doses had variable (1 mg/kg per hour) or no effect (0.1, 0.3 mg/kg per hour) on hemostasis. Heparin's prolongation of renal and cuticle bleeding time was twice that of apixaban when administered at a dose that approximated apixaban (3 mg/kg per hour) efficacy in arterial thrombosis. In summary, apixaban was effective in a broad range of thrombosis models at doses producing modest increases in multiple bleeding time models.
    Article · Mar 2010 · Journal of cardiovascular pharmacology
  • [Show abstract] [Hide abstract] ABSTRACT: The effect of inhibiting activated blood coagulation factor XIa was determined in rat models of thrombosis and hemostasis. BMS-262084 is an irreversible and selective small molecule inhibitor of factor XIa with an IC(50) of 2.8 nM against human factor XIa. BMS-262084 doubled the activated thromboplastin time in human and rat plasma at 0.14 and 2.2 microM, respectively. Consistent with factor XIa inhibition, the prothrombin time was unaffected at up to 100 microM. BMS-262084 administered as an intravenous loading plus sustaining infusion was effective against FeCl(2)-induced thrombosis in both the vena cava and carotid artery. Maximum thrombus weight reductions of 97 and 73%, respectively (P<0.05), were achieved at a pretreatment dose of 12 mg/kg+12 mg/kg/h which increased the ex vivo activated thromboplastin time to 3.0 times control. This dose level also arrested growth of venous and arterial thrombi when administered after partial thrombus formation. BMS-262084 was most potent in FeCl(2)-induced venous thrombosis, decreasing thrombus weight 38% (P<0.05) at a threshold dose of 0.2 mg/kg+0.2 mg/kg/h. In contrast, doses of up to 24 mg/kg+24 mg/kg/h had no effect on either tissue factor-induced venous thrombosis or the ex vivo prothrombin time. Doses of up to 24 mg/kg+24 mg/kg/h also did not significantly prolong bleeding time provoked by either puncture of small mesenteric blood vessels, template incision of the renal cortex, or cuticle incision. These results demonstrate that pharmacologic inhibition of factor XIa achieves antithrombotic efficacy with minimal effects on provoked bleeding.
    Article · Oct 2007 · European Journal of Pharmacology
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    [Show abstract] [Hide abstract] ABSTRACT: We determined the dose response of the ADP antagonist clopidogrel (0.3-50 mg/kg p.o.) in rat models of thrombosis and provoked bleeding and correlated these activities to ex vivo platelet activation. Carotid artery thrombosis was induced by FeCl(2). Bleeding time was measured by mesenteric vessel puncture and renal cortex or cuticle incision. Platelet biomarkers included standard ADP-induced aggregation, P2Y(12) receptor occupancy, and phosphorylation of vasodilator-stimulated phosphoprotein. Clopidogrel decreased thrombus weight up to 78%, caused maximal prolongation of cuticle and mesenteric bleeding, but had little effect on renal bleeds. Due to the steep mesenteric dose response, further comparisons concentrated on cuticle bleeding. The half-maximal inhibitory dose (ED(50)) for thrombus reduction was 2.4 +/- 0.4 mg/kg, with 10 mg/kg providing optimal blood flow preservation and thrombus reduction. The ED(50) for bleeding was 10.5 +/- 3.4 mg/kg. Increased bleeding was intermediate (3-fold) at 10 mg/kg and maximal (6-fold) at 30 mg/kg. All biomarkers were affected, but with differing sensitivity. ED(50)s for peak platelet aggregation to 10 microM ADP (11.9 +/- 0.4 mg/kg) and the vasodilator-stimulated phosphoprotein index (16.4 +/- 1.3 mg/kg) approximated the higher ED(50) for bleeding. ED(50)s for ligand binding (3.0 +/- 0.3 mg/kg) and late aggregation (5.1 +/- 0.4 mg/kg) better matched the lower ED(50) for antithrombotic activity. Aspirin exerted lesser effects on bleeding (42-70% increase in all models) and thrombosis (24% inhibition). In summary, antithrombotic doses of clopidogrel have limited effects on bleeding and standard measures of platelet aggregation. Other biomarkers may be more sensitive for tracking antithrombotic efficacy.
    Full-text available · Article · Aug 2007 · Journal of Pharmacology and Experimental Therapeutics