RESUMEN
BACKGROUND: The trigeminal sensory neuropeptide calcitonin gene-related peptide (CGRP) is identified as an essential element in migraine pathogenesis. METHODS: In vitro and in vivo studies evaluated pharmacologic properties of the CGRP receptor antagonist atogepant. Radioligand binding using 125I-CGRP and cyclic adenosine monophosphate (cAMP) accumulation assays were conducted in human embryonic kidney 293 cells to assess affinity, functional potency and selectivity. Atogepant in vivo potency was assessed in the rat nitroglycerine model of facial allodynia and primate capsaicin-induced dermal vasodilation (CIDV) pharmacodynamic model. Cerebrospinal fluid/brain penetration and behavioral effects of chronic dosing and upon withdrawal were evaluated in rats. RESULTS: Atogepant exhibited high human CGRP receptor-binding affinity and potently inhibited human α-CGRP-stimulated cAMP responses. Atogepant exhibited significant affinity for the amylin1 receptor but lacked appreciable affinities for adrenomedullin, calcitonin and other known neurotransmitter receptor targets. Atogepant dose-dependently inhibited facial allodynia in the rat nitroglycerine model and produced significant CIDV inhibition in primates. Brain penetration and behavioral/physical signs during chronic dosing and abrupt withdrawal were minimal in rats. CONCLUSIONS: Atogepant is a competitive antagonist with high affinity, potency and selectivity for the human CGRP receptor. Atogepant demonstrated a potent, concentration-dependent exposure/efficacy relationship between atogepant plasma concentrations and inhibition of CGRP-dependent effects.
Asunto(s)
Péptido Relacionado con Gen de Calcitonina , Piperidinas , Piridinas , Pirroles , Receptores de Péptido Relacionado con el Gen de Calcitonina , Compuestos de Espiro , Humanos , Ratas , Animales , Péptido Relacionado con Gen de Calcitonina/metabolismo , Receptores de Péptido Relacionado con el Gen de Calcitonina/metabolismo , Antagonistas del Receptor Peptídico Relacionado con el Gen de la Calcitonina/farmacología , Antagonistas del Receptor Peptídico Relacionado con el Gen de la Calcitonina/uso terapéutico , Hiperalgesia/tratamiento farmacológicoRESUMEN
A growing body of evidence has implicated the calcitonin gene-related peptide (CGRP) receptors in migraine pathophysiology. With the recent approval of monoclonal antibodies targeting CGRP or the CGRP receptor, the inhibition of CGRP-mediated signaling has emerged as a promising approach for preventive treatments of migraine in adults. However, there are no small-molecule anti-CGRP treatments available for treating migraine. The current studies aimed to characterize the pharmacologic properties of ubrogepant, an orally bioavailable, CGRP receptor antagonist for the acute treatment of migraine. In a series of ligand binding assays, ubrogepant exhibited a high binding affinity for native (K i=0.067 nM) and cloned human (K i=0.070 nM) and rhesus CGRP receptors (K i=0.079 nM), with relatively lower affinities for CGRP receptors from rat, mouse, rabbit and dog. In functional assays, ubrogepant potently blocked human α-CGRP stimulated cAMP response (IC50 of 0.08 nM) and exhibited highly selective antagonist activity for the CGRP receptor compared with other members of the human calcitonin receptor family. Furthermore, the in vivo CGRP receptor antagonist activity of ubrogepant was evaluated in a pharmacodynamic model of capsaicin-induced dermal vasodilation (CIDV) in rhesus monkeys and humans. Results demonstrated that ubrogepant produced concentration-dependent inhibition of CIDV with a mean EC50 of 3.2 and 2.6 nM in rhesus monkeys and humans, respectively. Brain penetration studies with ubrogepant in monkeys showed a CSF/plasma ratio of 0.03 and low CGRP receptor occupancy. In summary, ubrogepant is a competitive antagonist with high affinity, potency, and selectivity for the human CGRP receptor. SIGNIFICANCE STATEMENT: Ubrogepant is a potent, selective, orally delivered, small-molecule competitive antagonist of the human calcitonin generelated peptide receptor. In vivo studies using a pharmacodynamic model of capsaicin-induced dermal vasodilation (CIDV) in rhesus monkeys and humans demonstrated that ubrogepant produced concentration-dependent inhibition of CIDV, indicating a predictable pharmacokinetic-pharmacodynamic relationship.
RESUMEN
In our efforts to develop CGRP receptor antagonists as backups to MK-3207, 2, we employed a scaffold hopping approach to identify a series of novel oxazolidinone-based compounds. The development of a structurally diverse, potent (20, cAMP+HS IC50=0.67 nM), and selective compound (hERG IC50=19 µM) with favorable rodent pharmacokinetics (F=100%, t1/2=7h) is described. Key to this development was identification of a 3-substituted spirotetrahydropyran ring that afforded a substantial gain in potency (10 to 35-fold).
Asunto(s)
Antagonistas del Receptor Peptídico Relacionado con el Gen de la Calcitonina , Trastornos Migrañosos/tratamiento farmacológico , Oxazolidinonas/farmacología , Oxazolidinonas/uso terapéutico , Animales , Relación Dosis-Respuesta a Droga , Humanos , Simulación del Acoplamiento Molecular , Estructura Molecular , Oxazolidinonas/síntesis química , Oxazolidinonas/química , Ratas , Relación Estructura-ActividadRESUMEN
A new series of CB2-selective agonists containing a benzimidazole core is reported. Design, synthesis, SAR and pharmacokinetic data for selected compounds are described.
Asunto(s)
Bencimidazoles/farmacología , Diseño de Fármacos , Receptor Cannabinoide CB2/agonistas , Bencimidazoles/síntesis química , Bencimidazoles/química , Relación Dosis-Respuesta a Droga , Humanos , Modelos Moleculares , Estructura Molecular , Relación Estructura-ActividadRESUMEN
Rational modification of the clinically tested CGRP receptor antagonist MK-3207 (3) afforded an analogue with increased unbound fraction in rat plasma and enhanced aqueous solubility, 2-[(8R)-8-(3,5-difluorophenyl)-8-methyl-10-oxo-6,9-diazaspiro[4.5]dec-9-yl]-N-[(6S)-2'-oxo-1',2',5,7-tetrahydrospiro[cyclopenta[b]pyridine-6,3'-pyrrolo[2,3-b]pyridin]-3-yl]acetamide (MK-8825) (6). Compound 6 maintained similar affinity to 3 at the human and rat CGRP receptors but possessed significantly improved in vivo potency in a rat pharmacodynamic model. The overall profile of 6 indicates it should find utility as a rat tool to investigate effects of CGRP receptor blockade in vivo.
Asunto(s)
Analgésicos/síntesis química , Analgésicos/farmacología , Antagonistas del Receptor Peptídico Relacionado con el Gen de la Calcitonina , Trastornos Migrañosos/tratamiento farmacológico , Piridinas/síntesis química , Piridinas/farmacología , Compuestos de Espiro/síntesis química , Compuestos de Espiro/farmacología , Administración Oral , Analgésicos/sangre , Animales , Disponibilidad Biológica , Modelos Animales de Enfermedad , Perros , Humanos , Macaca mulatta , Ratones , Piridinas/sangre , Ratas , Receptores de Péptido Relacionado con el Gen de Calcitonina/metabolismo , Especificidad de la Especie , Compuestos de Espiro/sangreRESUMEN
A novel series of decahydroquinoline CB2 agonists is described. Optimization of the amide substituent led to improvements in CB2/CB1 selectivity as well as physical properties. Two key compounds were examined in the rat CFA model of acute inflammatory pain. A moderately selective CB2 agonist was active in this model. A CB2 agonist lacking functional CB1 activity was inactive in this model despite high in vivo exposure both peripherally and centrally.
Asunto(s)
Amidas/química , Analgésicos/química , Quinolinas/química , Receptor Cannabinoide CB2/agonistas , Amidas/síntesis química , Amidas/uso terapéutico , Analgésicos/síntesis química , Analgésicos/uso terapéutico , Animales , Modelos Animales de Enfermedad , Humanos , Ratones , Ratones Transgénicos , Dolor/tratamiento farmacológico , Ratas , Receptor Cannabinoide CB1/agonistas , Receptor Cannabinoide CB1/metabolismo , Receptor Cannabinoide CB2/metabolismo , Relación Estructura-ActividadRESUMEN
Although the S3 pocket of the thrombin active site is lined with lipophilic amino acid residues, the accommodation of polarity within the lipophilic P3 moiety of small molecule inhibitors is possible provided that the polar functionality is capable of pointing away from the binding pocket outwards toward solvent while simultaneously allowing the lipophilic portion of the P3 ligand to interact with the S3 amino acid residues. Manipulation of this motif provided the means to effect optimization of functional potency, in vivo antithrombotic efficacy and oral bioavailability in a series of 3-aminopyrazinone thrombin inhibitors which contained non-charged groups at the P1 position.
Asunto(s)
Anticoagulantes/síntesis química , Trastornos de la Coagulación Sanguínea/tratamiento farmacológico , Diseño de Fármacos , Pirazinas/síntesis química , Trombina/antagonistas & inhibidores , Administración Oral , Animales , Anticoagulantes/química , Anticoagulantes/farmacología , Sitios de Unión , Disponibilidad Biológica , Perros , Estructura Molecular , Pirazinas/química , Pirazinas/farmacología , Ratas , Relación Estructura-ActividadRESUMEN
A new series of imidazopyridine CB2 agonists is described. Structural optimization improved CB2/CB1 selectivity in this series and conferred physical properties that facilitated high in vivo exposure, both centrally and peripherally. Administration of a highly selective CB2 agonist in a rat model of analgesia was ineffective despite substantial CNS exposure, while administration of a moderately selective CB2/CB1 agonist exhibited significant analgesic effects.
Asunto(s)
Analgésicos/química , Piridinas/química , Receptor Cannabinoide CB1/agonistas , Receptor Cannabinoide CB2/agonistas , Analgésicos/síntesis química , Analgésicos/uso terapéutico , Animales , Modelos Animales de Enfermedad , Adyuvante de Freund/farmacología , Humanos , Hiperalgesia/tratamiento farmacológico , Piridinas/síntesis química , Piridinas/uso terapéutico , Ratas , Receptor Cannabinoide CB1/metabolismo , Receptor Cannabinoide CB2/metabolismoRESUMEN
Calcitonin gene-related peptide (CGRP) has long been hypothesized to play a key role in migraine pathophysiology, and the advent of small-molecule antagonists has clearly demonstrated a clinical link between blocking the CGRP receptor and migraine efficacy. 2-[(8R)-8-(3,5-Difluorophenyl)-10-oxo-6,9-diazaspiro[4.5]dec-9-yl]-N-[(2R)-2'-oxo-1,1',2',3-tetrahydrospiro[indene-2,3'-pyrrolo[2,3-b]pyridin]-5-yl]acetamide (MK-3207) represents the third CGRP receptor antagonist to display clinical efficacy in migraine trials. Here, we report the pharmacological characterization of MK-3207, a potent and orally bioavailable CGRP receptor antagonist. In vitro, MK-3207 is a potent antagonist of the human and rhesus monkey CGRP receptors (K(i) = 0.024 nM). In common with other CGRP receptor antagonists, MK-3207 displays lower affinity for CGRP receptors from other species, including canine and rodent. As a consequence of species selectivity, the in vivo potency was assessed in a rhesus monkey pharmacodynamic assay measuring capsaicin-induced changes in forearm dermal blood flow via laser Doppler imaging. MK-3207 produced a concentration-dependent inhibition of dermal vasodilation, with plasma concentrations of 0.8 and 7 nM required to block 50 and 90% of the blood flow increase, respectively. The tritiated analog [3H]MK-3207 was used to study the binding characteristics on the human CGRP receptor. [3H]MK-3207 displayed reversible and saturable binding (K(D) = 0.06 nM), and the off-rate was determined to be 0.012 min(-1), with a t(1/2) value of 59 min. In vitro autoradiography studies on rhesus monkey brain slices identified the highest level of binding in the cerebellum, brainstem, and meninges. Finally, as an index of central nervous system penetrability, the in vivo cerebrospinal fluid/plasma ratio was determined to be 2 to 3% in cisterna magna-ported rhesus monkeys.
Asunto(s)
Compuestos Bicíclicos Heterocíclicos con Puentes/farmacología , Antagonistas del Receptor Peptídico Relacionado con el Gen de la Calcitonina , Compuestos de Espiro/farmacología , Miembro 1 de la Subfamilia B de Casetes de Unión a ATP/metabolismo , Animales , Autorradiografía , Unión Competitiva , Transporte Biológico , Encéfalo/metabolismo , Compuestos Bicíclicos Heterocíclicos con Puentes/sangre , Compuestos Bicíclicos Heterocíclicos con Puentes/líquido cefalorraquídeo , Línea Celular , Chlorocebus aethiops , Femenino , Humanos , Cinética , Macaca mulatta , Masculino , Ratones , Ensayo de Unión Radioligante , Receptores de Adrenomedulina , Receptores de Calcitonina/metabolismo , Receptores de Péptido Relacionado con el Gen de Calcitonina/fisiología , Receptores de Polipéptido Amiloide de Islotes Pancreáticos , Receptores de Péptidos/metabolismo , Compuestos de Espiro/sangre , Compuestos de Espiro/líquido cefalorraquídeo , Vasodilatación/efectos de los fármacosRESUMEN
A series of triarylethanolamine inhibitors of the Kv1.5 potassium channel have been prepared and evaluated for their effects in vitro and in vivo. The structure-activity relationship (SAR) studies described herein led to the development of potent, selective and orally active inhibitors of Kv1.5.
Asunto(s)
Etanolaminas/farmacología , Bloqueadores de los Canales de Potasio/farmacología , Canales de Potasio con Entrada de Voltaje/antagonistas & inhibidores , Animales , Relación Dosis-Respuesta a Droga , Descubrimiento de Drogas , Evaluación Preclínica de Medicamentos , Etanolaminas/química , Humanos , Bloqueadores de los Canales de Potasio/química , Relación Estructura-ActividadRESUMEN
Novel 3-cyanoisoquinoline Kv1.5 antagonists have been prepared and evaluated in in vitro and in vivo assays for inhibition of the Kv1.5 potassium channel and its associated cardiac potassium current, IKur. Structural modifications of isoquinolinone lead 1 afforded compounds with excellent potency, selectivity, and oral bioavailability.
Asunto(s)
Antiarrítmicos/síntesis química , Fibrilación Atrial/tratamiento farmacológico , Isoquinolinas/síntesis química , Canal de Potasio Kv1.5/antagonistas & inhibidores , Nitrilos/síntesis química , Administración Oral , Animales , Antiarrítmicos/química , Antiarrítmicos/farmacología , Disponibilidad Biológica , Electrofisiología , Corazón/efectos de los fármacos , Corazón/fisiología , Humanos , Isoquinolinas/química , Isoquinolinas/farmacología , Canal de Potasio Kv1.5/fisiología , Nitrilos/química , Nitrilos/farmacología , Técnicas de Placa-Clamp , Ratas , Estereoisomerismo , Relación Estructura-ActividadRESUMEN
Optimization of a previously reported thrombin inhibitor, 9-hydroxy-9-fluorenylcarbonyl-l-prolyl-trans-4-aminocyclohexylmethylamide (1), by replacing the aminocyclohexyl P1 group provided a new lead structure, 9-hydroxy-9-fluorenylcarbonyl-l-prolyl-2-aminomethyl-5-chlorobenzylamide (2), with improved potency (K(i) = 0.49 nM for human thrombin, 2x APTT = 0.37 microM in human plasma) and pharmacokinetic properties (F = 39%, iv T(1/2) = 13 h in dogs). An effective strategy for reducing plasma protein binding of 2 and improving efficacy in an in vivo thrombosis model in rats was to replace the lipophilic fluorenyl group in P3 with an azafluorenyl group. Systematic investigation of all possible azafluorenyl P3 isomers and azafluorenyl-N-oxide analogues of 2 led to the identification of an optimal compound, 3-aza-9-hydroxyfluoren-9(R)-ylcarbonyl-l-prolyl-2-aminomethyl-5-chlorobenzylamide (19b), with high potency (K(i) = 0.40 nM, 2x APTT = 0.18 microM), excellent pharmacokinetic properties (F = 55%, T(1/2) = 14 h in dogs), and complete efficacy in the in vivo thrombosis model in rats (inhibition of FeCl(3)-induced vessel occlusions in six of six rats receiving an intravenous infusion of 10 microg/kg/min of 19b). The stereochemistry of the azafluorenyl group in 19b was determined by X-ray crystallographic analysis of its N-oxide derivative (23b) bound in the active site of human thrombin.
Asunto(s)
Fluorenos/síntesis química , Prolina/análogos & derivados , Prolina/síntesis química , Trombina/antagonistas & inhibidores , Administración Oral , Animales , Disponibilidad Biológica , Proteínas Sanguíneas/metabolismo , Cristalografía por Rayos X , Perros , Fluorenos/química , Fluorenos/farmacología , Semivida , Humanos , Técnicas In Vitro , Macaca mulatta , Masculino , Microsomas Hepáticos/metabolismo , Modelos Moleculares , Prolina/química , Prolina/farmacología , Unión Proteica , Ratas , Ratas Sprague-Dawley , Estereoisomerismo , Relación Estructura-ActividadRESUMEN
In an effort to discover potent, clinically useful thrombin inhibitors, a rapid analogue synthetic approach was used to explore the P(1) region. Various benzylamines were coupled to a pyridine/pyrazinone P(2)-P(3) template. One compound with an o-thiadiazole benzylic substitution was found to have a thrombin K(i) of 0.84 nM. A study of ortho-substituted five-membered-ring heterocycles was undertaken and subsequently demonstrated that the o-triazole and tetrazole rings were optimal. Combination of these potent P(1) aryl heterocycles with a variety of P(2)-P(3) groups produced a compound with an extraordinary thrombin inhibitory activity of 1.4 pM. It is hoped that this potency enhancement in P(1) will allow for more diversification in the P(2)-P(3) region to ultimately address additional pharmacological concerns.
Asunto(s)
Compuestos Heterocíclicos/síntesis química , Trombina/antagonistas & inhibidores , Bencilaminas/síntesis química , Bencilaminas/química , Sitios de Unión , Compuestos Heterocíclicos/química , Modelos Moleculares , Pirazinas/síntesis química , Pirazinas/química , Piridinas/síntesis química , Piridinas/química , Relación Estructura-Actividad , Tetrazoles/síntesis química , Tetrazoles/química , Tiadiazoles/síntesis química , Tiadiazoles/química , Trombina/química , Triazoles/síntesis química , Triazoles/químicaRESUMEN
Recent efforts in the field of thrombin inhibitor research have focused on the identification of compounds with good oral bioavailability and pharmacokinetics. In this manuscript we describe a metabolism-based approach to the optimization of the 3-(2-phenethylamino)-6-methylpyrazinone acetamide template (e.g., 1) which resulted in the modification of each of the three principal components (i.e., P1, P2, P3) comprising this series. As a result of these studies, several potent thrombin inhibitors (e.g., 20, 24, 25) were identified which exhibit high levels of oral bioavailability and long plasma half-lives.
Asunto(s)
Acetamidas/farmacocinética , Anticoagulantes/farmacocinética , Inhibidores de Proteasas/síntesis química , Pirazinas/farmacocinética , Piridinas/farmacocinética , Trombina/antagonistas & inhibidores , Acetamidas/síntesis química , Acetamidas/farmacología , Administración Oral , Animales , Anticoagulantes/síntesis química , Anticoagulantes/farmacología , Disponibilidad Biológica , Cristalografía por Rayos X , Perros , Macaca mulatta , Modelos Moleculares , Inhibidores de Proteasas/química , Inhibidores de Proteasas/farmacología , Pirazinas/síntesis química , Pirazinas/farmacología , Piridinas/síntesis química , Piridinas/farmacología , Ratas , Relación Estructura-ActividadRESUMEN
Rational modification of the potent calcitonin gene-related peptide (CGRP) receptor antagonist MK-3207 led to a series of analogues with enhanced CNS penetrance and a convenient chemical handle for introduction of a radiolabel. A number of (11)C-tracers were synthesized and evaluated in vivo, leading to the identification of [(11)C]8 ([(11)C]MK-4232), the first positron emission tomography tracer for the CGRP receptor.
RESUMEN
Previous reports from our laboratories described potent tripeptide thrombin inhibitors which incorporate heterocycle-substituted chlorophenyl groups in the P1 position. Using these as lead compounds for further optimization, we identified sites of metabolism and designed analogs with 4-fluoroproline in P2 and cyclopropane-containing side chains in P3 as an approach to reducing metabolism and improving their oral pharmacokinetic performance. The large (300-fold) difference in potency between analogs containing (4R)- and (4S)-4-fluoroproline was rationalized by analyzing inhibitor-enzyme interactions in crystal structures of related compounds and by molecular modeling which indicated that the more potent (4R)-4-fluoroproline isomer stabilizes a proline ring conformation that is preferred for binding to the enzyme. An optimal compound from this work, 41, exhibits high potency in a coagulation assay in human plasma (2xAPTT=190 nM), excellent selectivity versus the digestive enzyme trypsin (K(i)=3300 nM), and excellent oral bioavailability in dogs with moderate clearance (F=100%, CL=12 mL/min/kg).
Asunto(s)
Inhibidores Enzimáticos/farmacología , Prolina/análogos & derivados , Trombina/antagonistas & inhibidores , Sitios de Unión , Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/química , Humanos , Técnicas In Vitro , Modelos Moleculares , Conformación Molecular , Prolina/química , Conformación Proteica , Estructura Terciaria de Proteína , Estereoisomerismo , Relación Estructura-Actividad , Trombina/metabolismo , Tripsina/efectos de los fármacos , Tripsina/metabolismoRESUMEN
In this study, we have demonstrated that the critical hydrogen bonding motif of the established 3-aminopyrazinone thrombin inhibitors can be effectively mimicked by a 2-aminopyridine N-oxide. As this peptidomimetic core is more resistant toward oxidative metabolism, it also overcomes the metabolic liability associated with the pyrazinones. An optimization study of the P(1) benzylamide delivered the potent thrombin inhibitor 21 (K(i) = 3.2 nM, 2xaPTT = 360 nM), which exhibited good plasma levels and half-life after oral dosing in the dog (C(max) = 2.6 microM, t(1/2) = 4.5 h).
Asunto(s)
Antitrombinas/química , Pirimidinas/química , Enlace de Hidrógeno , Modelos Moleculares , Imitación MolecularRESUMEN
Modification of lead compound 1 by reducing lipophilicity in the P3 group produced a series of low molecular weight thrombin inhibitors with excellent potency in functional assays, metabolic stability, and oral bioavailability. These modifications led to the identification of two optimized compounds, 14 and 16.
Asunto(s)
Antitrombinas/farmacología , Administración Oral , Antitrombinas/administración & dosificación , Antitrombinas/farmacocinética , Disponibilidad Biológica , Estabilidad de Medicamentos , Peso MolecularRESUMEN
In this manuscript we demonstrate that a modification principally directed toward the improvement of the aqueous solubility (i.e., introduction a P3 pyridine N-oxide) of the previous lead compound afforded a new series of potent orally bioavailable P1 N-benzylamide thrombin inhibitors. An expedited investigation of the P1 SAR with respect to oral bioavailability, plasma half-life, and human liver microsome stability revealed 5 as the best candidate for advanced evaluation.