darexaban-glucuronide and darexaban

We investigated the effects of ketoconazole on the pharmacokinetics (PK) of the direct clotting factor Xa inhibitor darexaban (YM150) and its main active metabolite darexaban glucuronide (YM-222714) which almost entirely determines the antithrombotic effect. In this open-label, randomized, two-period crossover study, 26 healthy male volunteers received in one treatment period a single dose of darexaban 60 mg, and in the other treatment period, ketoconazole 400 mg once daily on Days 1-9 with a single dose of darexaban 60 mg on Day 4. Washout between periods was at least 1 week. The geometric mean ratio (90% confidence interval) of darexaban glucuronide (darexaban plus ketoconazole versus darexaban) for AUCinf was 1.11 (1.00, 1.23), and for Cmax 1.18 (1.03, 1.35). Darexaban concentrations remained very low (AUClast ∼196-fold lower) in relation to darexaban glucuronide concentrations. In conclusion, the PK of darexaban glucuronide was not affected to a clinically relevant degree by co-administration of the strong CYP3A/P-glycoprotein inhibitor, ketoconazole. The PK of the parent compound darexaban were changed, however, concentrations remained quantitatively insignificant in relation to the main active moiety, darexaban glucuronide.

Topics: Administration, Oral; Adolescent; Adult; Antifungal Agents; Area Under Curve; ATP Binding Cassette Transporter, Subfamily B; Azepines; Benzamides; Cross-Over Studies; Cytochrome P-450 CYP3A; Cytochrome P-450 CYP3A Inhibitors; Drug Interactions; Factor Xa Inhibitors; France; Glucuronides; Half-Life; Healthy Volunteers; Humans; Ketoconazole; Male; Metabolic Clearance Rate; Middle Aged; Young Adult

The oral direct factor Xa inhibitor darexaban administered intraduodenally prevented venous thrombus formation in both rats and rabbits with no effect on bleeding. The indirect parenteral Factor Xa inhibitor fondaparinux exerted similar properties, only prolonging bleeding time at extremely high doses. In contrast, the thrombin inhibitor ximelagatran and low-molecular-weight heparin enoxaparin prolonged bleeding time at antithrombotic doses. Studies using human platelets showed darexaban glucuronide, a darexaban metabolite that predominantly determines darexaban antithrombotic effects in vivo, had no effect on platelet activation and aggregation, while heparin and enoxaparin activated platelets. Melagatran, heparin, and enoxaparin all inhibited thrombin-induced platelet aggregation at clinically relevant concentrations. Taken together, these results suggest that thrombin-inhibiting drugs may increase the risk of bleeding, while darexaban may have potential as an orally available antithrombotic agent with a wide therapeutic window.

Topics: Animals; Anticoagulants; Antithrombins; Azepines; Benzamides; Blood Platelets; Disease Models, Animal; Dose-Response Relationship, Drug; Factor Xa Inhibitors; Glucuronides; Hemorrhage; Humans; Male; Rabbits; Rats; Rats, Sprague-Dawley; Species Specificity; Venous Thrombosis

Darexaban maleate is a novel oral direct factor Xa inhibitor, which is under development for the prevention of venous thromboembolism. Darexaban glucuronide was the major component in plasma after oral administration of darexaban to humans and is the pharmacologically active metabolite. In this study, we identified UDP-glucuronosyltransferases (UGTs) responsible for darexaban glucuronidation in human liver microsomes (HLM) and human intestinal microsomes (HIM). In HLM, the K(m) value for darexaban glucuronidation was >250 μM. In HIM, the reaction followed substrate inhibition kinetics, with a K(m) value of 27.3 μM. Among recombinant human UGTs, UGT1A9 showed the highest intrinsic clearance for darexaban glucuronidation, followed by UGT1A8, -1A10, and -1A7. All other UGT isoforms were inactive toward darexaban. The K(m) value of recombinant UGT1A10 for darexaban glucuronidation (34.2 μM) was comparable to that of HIM. Inhibition studies using typical UGT substrates suggested that darexaban glucuronidation in both HLM and HIM was mainly catalyzed by UGT1A8, -1A9, and -1A10. Fatty acid-free bovine serum albumin (2%) decreased the unbound K(m) for darexaban glucuronidation from 216 to 17.6 μM in HLM and from 35.5 to 18.3 μM in recombinant UGT1A9. Recent studies indicated that the mRNA expression level of UGT1A9 is extremely high among UGT1A7, -1A8, -1A9, and -1A10 in human liver, whereas that of UGT1A10 is highest in the intestine. Thus, the present results strongly suggest that darexaban glucuronidation is mainly catalyzed by UGT1A9 and UGT1A10 in human liver and intestine, respectively. In addition, UGT1A7, -1A8, and -1A9 play a minor role in human intestine.

Topics: Anticoagulants; Azepines; Benzamides; Drugs, Investigational; Enzyme Inhibitors; Factor Xa Inhibitors; Glucuronides; Glucuronosyltransferase; Humans; Isoenzymes; Jejunum; Kinetics; Liver; Microsomes; Microsomes, Liver; Organ Specificity; Recombinant Proteins; Substrate Specificity; UDP-Glucuronosyltransferase 1A9

Topics: Azepines; Benzamides; Blood Coagulation; Dose-Response Relationship, Drug; Factor Xa Inhibitors; Fibrinolytic Agents; Glucuronides; Humans; Morpholines; Predictive Value of Tests; Prothrombin Time; Pyrazoles; Pyridones; Rivaroxaban; Sensitivity and Specificity; Thiophenes

Darexaban maleate is a novel oral direct factor Xa inhibitor. Darexaban glucuronide (YM-222714) was the major component in plasma after oral administration of darexaban to humans and is the pharmacologically active metabolite. Additionally, YM-222714 N-oxides were detected as minor metabolites in human plasma and urine. It is possible that YM-222714 N-oxides are formed by the N-oxidation of YM-222714 and/or the glucuronidation of darexaban N-oxides (YM-542845) in vivo. The former reaction is the pharmacological inactivation process. In this study, we identified the human enzymes responsible for YM-222714 N-oxidation and the uridine 5'-diphosphate (UDP)-glucuronosyltransferase (UGT) isoforms involved in YM-542845 glucuronidation in vitro. YM-222714 N-oxidation activity was detected in human liver microsomes (HLM), but not in human intestinal microsomes. In HLM, YM-222714 N-oxidation activities were significantly correlated with flavin-containing monooxygenase (FMO) marker enzyme activities (p<0.001) and inhibited by methimazole, a typical inhibitor of FMOs. Recombinant human FMO3 and FMO1 were capable of efficiently catalyzing YM-222714 N-oxidation, but not FMO5 or any recombinant human cytochrome P450 (CYP) isoforms. Considering the mRNA expression levels of FMO isoforms in human liver, these results strongly suggest that YM-222714 N-oxidation in HLM is mainly catalyzed by FMO3. In HLM, YM-542845 glucuronidation was strongly inhibited by typical substrates for UGT1A8, UGT1A9, and UGT1A10. Recombinant human UGT1A7, UGT1A8, UGT1A9, and UGT1A10 were capable of catalyzing YM-542845 glucuronidation, and UGT1A9 exhibited the highest intrinsic clearance. Considered together with the expression levels of UGT isoforms in human liver, these results strongly suggest that YM-542845 glucuronidation in HLM is mainly catalyzed by UGT1A9.

Topics: Azepines; Benzamides; Cytochrome P-450 Enzyme System; Factor Xa Inhibitors; Glucuronides; Glucuronosyltransferase; Humans; Microsomes, Liver; Oxidation-Reduction; Oxygenases; Protein Isoforms; Recombinant Proteins

Darexaban (YM150) is an oral factor Xa inhibitor developed for the prophylaxis of venous and arterial thromboembolic disease. This study was conducted to investigate the biochemical and pharmacological profiles of darexaban and its active metabolite darexaban glucuronide (YM-222714), which predominantly determines the antithrombotic effect after oral administration of darexaban. In vitro activity was evaluated by enzyme and coagulation assays, and a prothrombin activation assay using reconstituted prothrombinase or whole blood clot. In vivo effects were examined in venous thrombosis, arterio-venous (A-V) shunt thrombosis, and bleeding models in rats. Both darexaban and darexaban glucuronide competitively and selectively inhibited human factor Xa with Ki values of 0.031 and 0.020 μM, respectively. They showed anticoagulant activity in human plasma, with doubling concentrations of darexaban and darexaban glucuronide for prothrombin time of 1.2 and 0.95 μM, respectively. Anticoagulant activity was independent of antithrombin. Darexaban and darexaban glucuronide inhibited the prothrombin activation induced by prothrombinase complex or whole blood clot with similar potency to free factor Xa. In contrast, prothrombinase- and clot-induced prothrombin activation were resistant to inhibition by enoxaparin. In venous and A-V shunt thrombosis models in rats, darexaban strongly suppressed thrombus formation without affecting bleeding time, with ID₅₀ values of 0.97 and 16.7 mg/kg, respectively. Warfarin also suppressed thrombus formation in these models, but caused a marked prolongation of bleeding time at antithrombotic dose. In conclusion, darexaban is a selective and direct factor Xa inhibitor and a promising oral anticoagulant for the prophylaxis and treatment of thromboembolic diseases.

Topics: Administration, Oral; Animals; Anticoagulants; Azepines; Benzamides; Bleeding Time; Disease Models, Animal; Dogs; Dose-Response Relationship, Drug; Enoxaparin; Factor Xa Inhibitors; Glucuronides; Humans; Macaca fascicularis; Male; Mice; Mice, Inbred ICR; Prothrombin Time; Rabbits; Rats; Rats, Sprague-Dawley; Thrombosis; Venous Thrombosis; Warfarin

Inhibitors of factor Xa (FXa), a crucial serine protease in the coagulation cascade, have attracted a great deal of attention as a target for developing antithrombotic agents. We previously reported findings from our optimization study of a high-throughput screening (HTS) derived lead compound 1a that resulted in the discovery of potent amidine-containing FXa inhibitors represented by compound 2. We also conducted an alternative optimization study of 1a without incorporating a strong basic amidine group, which generally has an adverse effect on the pharmacokinetic profile after oral administration. Replacement of 4-methoxybenzene with a 1,4-benzodiazepine structure and introduction of a hydroxy group at the central benzene led to the discovery of the potent and orally effective factor Xa inhibitor 14i (darexaban, YM150). Subsequent extensive study revealed a unique aspect to the pharmacokinetic profile of this compound, wherein the hydroxy moiety of 14i is rapidly transformed into its glucuronide conjugate 16 (YM-222714) as an active metabolite after oral administration and it plays a major role in expression of potent anticoagulant activity in plasma. The distinctive, potent activity of inhibitor 14i after oral dosing was explained by this unique pharmacokinetic profile and its favorable membrane permeability. Compound 14i is currently undergoing clinical development for prevention and treatment of thromboembolic diseases.

Topics: Administration, Oral; Animals; Anticoagulants; Azepines; Benzamides; Biological Availability; Catalytic Domain; Factor Xa; Factor Xa Inhibitors; Fibrinolytic Agents; Glucuronides; Humans; In Vitro Techniques; Male; Mice; Mice, Inbred ICR; Microsomes, Liver; Models, Molecular; Rats; Rats, Inbred F344; Structure-Activity Relationship