RESUMO
Calcitonin gene-related peptide (CGRP) is a potent neuropeptide whose agonist interaction with the CGRP receptor (CGRP-R) in the periphery promotes vasodilation, neurogenic inflammation and trigeminovascular sensory activation. This process is implicated in the cause of migraine headaches, and CGRP-R antagonists in clinical development have proven effective in treating migraine-related pain in humans. CGRP-R is expressed on blood vessel smooth muscle and sensory trigeminal neurons and fibers in the periphery as well as in the central nervous system. However, it is not clear what role the inhibition of central CGRP-R plays in migraine pain relief. To this end, the CGRP-R positron emission tomography (PET) tracer [(11)C]MK-4232 (2-[(8R)-8-(3,5-difluorophenyl)-6,8-[6-(11)C]dimethyl-10-oxo-6,9-diazaspiro[4.5]decan-9-yl]-N-[(2R)-2'-oxospiro[1,3-dihydroindene-2,3'-1H-pyrrolo[2,3-b]pyridine]-5-yl]acetamide) was discovered and developed for use in clinical PET studies. In rhesus monkeys and humans, [(11)C]MK-4232 displayed rapid brain uptake and a regional brain distribution consistent with the known distribution of CGRP-R. Monkey PET studies with [(11)C]MK-4232 after intravenous dosing with CGRP-R antagonists validated the ability of [(11)C]MK-4232 to detect changes in CGRP-R occupancy in proportion to drug plasma concentration. Application of [(11)C]MK-4232 in human PET studies revealed that telcagepant achieved only low receptor occupancy at an efficacious dose (140 mg PO). Therefore, it is unlikely that antagonism of central CGRP-R is required for migraine efficacy. However, it is not known whether high central CGRP-R antagonism may provide additional therapeutic benefit.
Assuntos
Acetanilidas/farmacocinética , Analgésicos/farmacocinética , Azepinas/farmacocinética , Encéfalo/metabolismo , Antagonistas do Receptor do Peptídeo Relacionado ao Gene de Calcitonina , Imidazóis/farmacocinética , Tomografia por Emissão de Pósitrons/métodos , Compostos Radiofarmacêuticos/farmacocinética , Compostos de Espiro/farmacocinética , Acetanilidas/química , Adulto , Analgésicos/uso terapêutico , Animais , Azepinas/uso terapêutico , Encéfalo/diagnóstico por imagem , Radioisótopos de Carbono , Feminino , Humanos , Imidazóis/uso terapêutico , Macaca mulatta , Masculino , Pessoa de Meia-Idade , Transtornos de Enxaqueca/tratamento farmacológico , Transtornos de Enxaqueca/metabolismo , Estrutura Molecular , Ligação Proteica , Compostos Radiofarmacêuticos/química , Especificidade da Espécie , Compostos de Espiro/química , Distribuição Tecidual , Adulto JovemRESUMO
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.
Assuntos
Analgésicos/síntese química , Analgésicos/farmacologia , Antagonistas do Receptor do Peptídeo Relacionado ao Gene de Calcitonina , Transtornos de Enxaqueca/tratamento farmacológico , Piridinas/síntese química , Piridinas/farmacologia , Compostos de Espiro/síntese química , Compostos de Espiro/farmacologia , Administração Oral , Analgésicos/sangue , Animais , Disponibilidade Biológica , Modelos Animais de Doenças , Cães , Humanos , Macaca mulatta , Camundongos , Piridinas/sangue , Ratos , Receptores de Peptídeo Relacionado com o Gene de Calcitonina/metabolismo , Especificidade da Espécie , Compostos de Espiro/sangueRESUMO
Identification of an HIV integrase inhibitor with micromolar affinity for the CGRP receptor led to the discovery of a series of structurally novel CGRP receptor antagonists. Optimization of this series produced compound 16, a low-molecular weight CGRP receptor antagonist with good pharmacokinetic properties in both rat and dog. In contrast to other nonpeptide antagonists, the activity of 16 was affected by the presence of divalent cations and showed evidence of an alternative, RAMP-independent CGRP receptor binding site.
Assuntos
Antagonistas do Receptor do Peptídeo Relacionado ao Gene de Calcitonina , Inibidores de Integrase de HIV/química , Inibidores de Integrase de HIV/farmacologia , Piridinas/química , Piridinas/farmacologia , Proteínas Modificadoras da Atividade de Receptores/metabolismo , Receptores de Peptídeo Relacionado com o Gene de Calcitonina/metabolismo , Animais , Linhagem Celular , Cães , HIV/enzimologia , Inibidores de Integrase de HIV/farmacocinética , Humanos , Ligação Proteica , Piridinas/farmacocinética , RatosRESUMO
A novel series of histone deacetylase (HDAC) inhibitors lacking a zinc-binding moiety has been developed and described herein. HDAC isozyme profiling and kinetic studies indicate that these inhibitors display a selectivity preference for HDACs 1, 2, 3, 10, and 11 via a rapid equilibrium mechanism, and crystal structures with HDAC2 confirm that these inhibitors do not interact with the catalytic zinc. The compounds are nonmutagenic and devoid of electrophilic and mutagenic structural elements and exhibit off-target profiles that are promising for further optimization. The efficacy of this new class in biochemical and cell-based assays is comparable to the marketed HDAC inhibitors belinostat and vorinostat. These results demonstrate that the long-standing pharmacophore model of HDAC inhibitors requiring a metal binding motif should be revised and offers a distinct class of HDAC inhibitors.
RESUMO
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.
Assuntos
Compostos Bicíclicos Heterocíclicos com Pontes/farmacologia , Antagonistas do Receptor do Peptídeo Relacionado ao Gene de Calcitonina , Compostos de Espiro/farmacologia , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/metabolismo , Animais , Autorradiografia , Ligação Competitiva , Transporte Biológico , Encéfalo/metabolismo , Compostos Bicíclicos Heterocíclicos com Pontes/sangue , Compostos Bicíclicos Heterocíclicos com Pontes/líquido cefalorraquidiano , Linhagem Celular , Chlorocebus aethiops , Feminino , Humanos , Cinética , Macaca mulatta , Masculino , Camundongos , Ensaio Radioligante , Receptores de Adrenomedulina , Receptores da Calcitonina/metabolismo , Receptores de Peptídeo Relacionado com o Gene de Calcitonina/fisiologia , Receptores de Polipeptídeo Amiloide de Ilhotas Pancreáticas , Receptores de Peptídeos/metabolismo , Compostos de Espiro/sangue , Compostos de Espiro/líquido cefalorraquidiano , Vasodilatação/efeitos dos fármacosRESUMO
A novel series of potent CGRP receptor antagonists containing a central quinoline ring constraint was identified. The combination of the quinoline constraint with a tricyclic benzimidazolinone left hand fragment produced an analog with picomolar potency (14, CGRP K(i)=23 pM). Further optimization of the tricycle produced a CGRP receptor antagonist that exhibited subnanomolar potency (19, CGRP K(i)=0.52 nM) and displayed a good pharmacokinetic profile in three preclinical species.
Assuntos
Antagonistas do Receptor do Peptídeo Relacionado ao Gene de Calcitonina , Quinolinas/farmacologia , Animais , Disponibilidade Biológica , Cães , Avaliação Pré-Clínica de Medicamentos , Macaca mulatta , Quinolinas/química , Quinolinas/farmacocinética , RatosRESUMO
Rational modification of a previously identified spirohydantoin lead structure has identified a series of potent spiroazaoxindole CGRP receptor antagonists. The azaoxindole was found to be a general replacement for the hydantoin that consistently improved in vitro potency. The combination of the indanylspiroazaoxindole and optimized benzimidazolinones led to highly potent antagonists (e.g., 25, CGRP K(i)=40pM). The closely related compound 27 demonstrated good oral bioavailability in dog and rhesus.
Assuntos
Antagonistas do Receptor do Peptídeo Relacionado ao Gene de Calcitonina , Indóis/síntese química , Compostos de Espiro/síntese química , Administração Oral , Animais , Disponibilidade Biológica , Cães , Descoberta de Drogas , Humanos , Indóis/farmacologia , Macaca mulatta , Oxindóis , Compostos de Espiro/farmacologia , Relação Estrutura-AtividadeRESUMO
A series of tricyclic CGRP receptor antagonists was optimized in order to improve oral bioavailability. Attenuation of polar surface area and incorporation of a weakly basic indoline nitrogen led to compound 5, a potent antagonist with good oral bioavailability in three species.
Assuntos
Antagonistas do Receptor do Peptídeo Relacionado ao Gene de Calcitonina , Compostos Heterocíclicos com 3 Anéis/farmacocinética , Compostos de Espiro/farmacocinética , Administração Oral , Animais , Disponibilidade Biológica , Linhagem Celular , Cães , Haplorrinos , Compostos Heterocíclicos com 3 Anéis/administração & dosagem , Compostos Heterocíclicos com 3 Anéis/química , Humanos , Ratos , Receptores de Peptídeo Relacionado com o Gene de Calcitonina/metabolismo , Compostos de Espiro/administração & dosagemRESUMO
A series of macrocyclic 3-aminopyrrolidinone farnesyltransferase inhibitors (FTIs) has been synthesized. Compared with previously described linear 3-aminopyrrolidinone FTIs such as compound 1, macrocycles such as 49 combined improved pharmacokinetic properties with a reduced potential for side effects. In dogs, oral bioavailability was good to excellent, and increases in plasma half-life were due to attenuated clearance. It was observed that in vivo clearance correlated with the flexibility of the molecules and this concept proved useful in the design of FTIs that exhibited low clearance, such as FTI 78. X-ray crystal structures of compounds 49 and 66 complexed with farnesyltransferase (FTase)-farnesyl diphosphate (FPP) were determined, and they provide details of the key interactions in such ternary complexes. Optimization of this 3-aminopyrrolidinone series of compounds led to significant increases in potency, providing 83 and 85, the most potent inhibitors of FTase in cells described to date.
Assuntos
Alquil e Aril Transferases/antagonistas & inibidores , Hidrocarboneto de Aril Hidroxilases , Proteínas de Transporte de Cátions , Proteínas de Ligação a DNA , Inibidores Enzimáticos/síntese química , Naftalenos/síntese química , Canais de Potássio de Abertura Dependente da Tensão da Membrana , Pirrolidinas/síntese química , Transativadores , Animais , Linhagem Celular , Cromatografia Líquida , Cristalografia por Raios X , Citocromo P-450 CYP3A , Inibidores das Enzimas do Citocromo P-450 , Cães , Canal de Potássio ERG1 , Eletrocardiografia , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacocinética , Canais de Potássio Éter-A-Go-Go , Farnesiltranstransferase , Humanos , Técnicas In Vitro , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Microssomos Hepáticos/efeitos dos fármacos , Microssomos Hepáticos/enzimologia , Modelos Moleculares , Estrutura Molecular , Naftalenos/química , Naftalenos/farmacocinética , Oxirredutases N-Desmetilantes/antagonistas & inibidores , Canais de Potássio/metabolismo , Ligação Proteica , Pirrolidinas/química , Pirrolidinas/farmacocinética , Estereoisomerismo , Relação Estrutura-Atividade , Regulador Transcricional ERGRESUMO
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.
RESUMO
Incorporation of polar functionality into a series of highly potent calcitonin gene-related peptide (CGRP) receptor antagonists was explored in an effort to improve pharmacokinetics. This strategy identified piperazinone analogues that possessed improved solubility at acidic pH and increased oral bioavailability in monkeys. Further optimization led to the discovery of the clinical candidate 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) (4), the most potent orally active CGRP receptor antagonist described to date.
RESUMO
High-throughput screening of the Merck sample collection identified benzodiazepinone tetralin-spirohydantoin 1 as a CGRP receptor antagonist with micromolar activity. Comparing the structure of 1 with those of earlier peptide-based antagonists such as BIBN 4096 BS, a key hydrogen bond donor-acceptor pharmacophore was hypothesized. Subsequent structure activity studies supported this hypothesis and led to benzodiazepinone piperidinyldihydroquinazolinone 7, CGRP receptor K(i)=44nM and IC(50)=38nM. Compound 7 was orally bioavailabile in rats and is a lead in the development of orally bioavailable CGRP antagonists for the treatment of migraine.
Assuntos
Benzodiazepinonas/farmacologia , Antagonistas do Receptor do Peptídeo Relacionado ao Gene de Calcitonina , Animais , Benzodiazepinonas/farmacocinética , Disponibilidade Biológica , Linhagem Celular , Humanos , Ligação de Hidrogênio , Ratos , Relação Estrutura-AtividadeRESUMO
A rapid analogue approach to identification of spirohydantoin-based CGRP antagonists provided novel, low molecular weight leads. Modification of these leads afforded a series of nanomolar benzimidazolinone-based CGRP receptor antagonists. The oral bioavailability of these antagonists was inversely correlated with polar surface area, suggesting that membrane permeability was a key limitation to absorption. Optimization provided compound 12, a potent CGRP receptor antagonist (K(i)=21nM) with good oral bioavailability in three species.
Assuntos
Antagonistas do Receptor do Peptídeo Relacionado ao Gene de Calcitonina , Hidantoínas/farmacologia , Hidantoínas/farmacocinética , Compostos de Espiro/farmacologia , Compostos de Espiro/farmacocinética , Administração Oral , Benzimidazóis/química , Benzimidazóis/farmacocinética , Benzimidazóis/farmacologia , Disponibilidade Biológica , Linhagem Celular , Humanos , Hidantoínas/química , Rim , Modelos Moleculares , Estrutura Molecular , Compostos de Espiro/química , Relação Estrutura-AtividadeRESUMO
The type 1 insulin-like growth factor receptor (IGF-1R) is often overexpressed on tumor cells and is believed to play an important role in anchorage-independent proliferation. Additionally, cell culture studies have indicated that IGF-1R confers increased resistance to apoptosis caused by radiation or chemotherapeutic agents. Thus, inhibitors of the intracellular kinase domain of this receptor may have utility for the clinical treatment of cancer. As part of an effort to develop clinically useful inhibitors of IGF-1R kinase, a novel class of pyrrole-5-carboxaldehyde compounds was investigated. The compounds exhibited selectivity against the closely related insulin receptor kinase intrinsically and in cell-based assays. The inhibitors formed a reversible, covalent adduct at the kinase active site, and treatment of such adducts with sodium borohydride irreversibly inactivated the enzyme. Analysis of a tryptic digest of a covalently modified IGF-1R kinase fragment revealed that the active site Lys1003 had been reductively alkylated with the aldehyde inhibitor. Reductive alkylation of the insulin receptor kinase with one of these inhibitors led to a similarly inactivated enzyme which was examined by X-ray crystallography. The crystal structure confirmed the modification of the active site lysine side chain and revealed details of the key interactions between the inhibitor and enzyme.