RESUMO
Highly selective orexin receptor antagonists (SORAs) of the orexin 2 receptor (OX2R) have become attractive targets both as potential therapeutics for insomnia as well as biological tools to help further elucidate the underlying pharmacology of the orexin signaling pathway. Herein, we describe the discovery of a novel piperidine ether 2-SORA class identified by systematic lead optimization beginning with filorexant, a dual orexin receptor antagonist (DORA) that recently completed Phase 2 clinical trials. Changes to the ether linkage and pendant heterocycle of filorexant were found to impart significant selectivity for OX2R, culminating in lead compound PE-6. PE-6 displays sub-nanomolar binding affinity and functional potency on OX2R while maintaining >1600-fold binding selectivity and >200-fold functional selectivity versus the orexin 1 receptor (OX1R). PE-6 bears a clean off-target profile, a good overall preclinical pharmacokinetic (PK) profile, and reduces wakefulness with increased NREM and REM sleep when evaluated in vivo in a rat sleep study. Importantly, subtle structural changes to the piperidine ether class impart dramatic changes in receptor selectivity. To this end, our laboratories have identified multiple piperidine ether 2-SORAs, 1-SORAs, and DORAs, providing access to a number of important biological tool compounds from a single structural class.
Assuntos
Éteres/química , Antagonistas dos Receptores de Orexina , Piperidinas/química , Pirimidinas/química , Animais , Cães , Avaliação Pré-Clínica de Medicamentos , Éteres/síntese química , Éteres/farmacocinética , Meia-Vida , Humanos , Receptores de Orexina/metabolismo , Piperidinas/metabolismo , Ligação Proteica , Pirimidinas/metabolismo , Ratos , Sono/efeitos dos fármacos , Relação Estrutura-AtividadeRESUMO
The orexin (or hypocretin) system has been identified as a novel target for the treatment of insomnia due to the wealth of biological and genetic data discovered over the past decade. Recently, clinical proof-of-concept was achieved for the treatment of primary insomnia using dual (OX1R/OX2R) orexin receptor antagonists. However, elucidation of the pharmacology associated with selective orexin-2 receptor antagonists (2-SORAs) has been hampered by the lack of orally bioavailable, highly selective small molecule probes. Herein, the discovery and optimization of a novel series of 2,5-diarylnicotinamides as potent and orally bioavailable orexin-2 receptor selective antagonists is described. A compound from this series demonstrated potent sleep promotion when dosed orally to EEG telemetrized rats.
Assuntos
Ácidos Nicotínicos/química , Ácidos Nicotínicos/farmacologia , Antagonistas dos Receptores de Orexina , Animais , Cães , Avaliação Pré-Clínica de Medicamentos , Meia-Vida , Humanos , Ácidos Nicotínicos/síntese química , Ácidos Nicotínicos/farmacocinética , Receptores de Orexina/metabolismo , Ligação Proteica/efeitos dos fármacos , Ratos , Relação Estrutura-AtividadeRESUMO
Recently, the US Food and Drug Administration and European Medicines Agency have issued new guidance for industry on drug interaction studies, which outline comprehensive recommendations on a broad range of in vitro and in vivo studies to evaluate drug-drug interaction (DDI) potential. This paper aims to provide an overview of these new recommendations and an in-depth scientifically based perspective on issues surrounding some of the recommended approaches in emerging areas, particularly, transporters and complex DDIs. We present a number of theoretical considerations and several case examples to demonstrate complexities in applying (1) the proposed transporter decision trees and associated criteria for studying a broad spectrum of transporters to derive actionable information and (2) the recommended model-based approaches at an early stage of drug development to prospectively predict DDIs involving time-dependent inhibition and mixed inhibition/induction of drug metabolizing enzymes. We hope to convey the need for conducting DDI studies on a case-by-case basis using a holistic scientifically based interrogative approach and to communicate the need for additional research to fill in knowledge gaps in these areas where the science is rapidly evolving to better ensure the safety and efficacy of new therapeutic agents.
Assuntos
Interações Medicamentosas/fisiologia , União Europeia , Preparações Farmacêuticas/metabolismo , Preparações Farmacêuticas/normas , United States Food and Drug Administration/legislação & jurisprudência , United States Food and Drug Administration/normas , Animais , Humanos , Guias de Prática Clínica como Assunto/normas , Estados UnidosRESUMO
The discovery of a novel series of potent and selective T-type calcium channel antagonists is reported. Initial optimization of high-throughput screening leads afforded a 1,4-substituted piperidine amide 6 with good potency and limited selectivity over hERG and L-type channels and other off-target activities. Further SAR on reducing the basicity of the piperidine and introducing polarity led to the discovery of 3-axial fluoropiperidine 30 with a significantly improved selectivity profile. Compound 30 showed good oral bioavailability and brain penetration across species. In a rat genetic model of absence epilepsy, compound 30 demonstrated a robust reduction in the number and duration of seizures at 33 nM plasma concentration, with no cardiovascular effects at up to 5.6 microM. Compound 30 also showed good efficacy in rodent models of essential tremor and Parkinson's disease. Compound 30 thus demonstrates a wide margin between CNS and peripheral effects and is a useful tool for probing the effects of T-type calcium channel inhibition.
Assuntos
Bloqueadores dos Canais de Cálcio/síntese química , Bloqueadores dos Canais de Cálcio/farmacologia , Canais de Cálcio Tipo T/metabolismo , Piperidinas/síntese química , Piperidinas/farmacologia , Animais , Bloqueadores dos Canais de Cálcio/química , Sistema Cardiovascular/efeitos dos fármacos , Avaliação Pré-Clínica de Medicamentos , Humanos , Estrutura Molecular , Piperidinas/química , Ratos , Relação Estrutura-AtividadeRESUMO
In this study, induction and inhibition of rhesus monkey CYP3A64 versus human CYP3A4 were characterized in vitro, and the corresponding pharmacokinetic consequences were evaluated in rhesus monkeys. In monkey hepatocytes, rifampin markedly induced CYP3A64 mRNA (EC50 = 0.5 microM; Emax = 6-fold) and midazolam (MDZ) 1'-hydroxylase activity (EC50 = 0.2 microM; Emax = 2-fold). Compound A (N-[2(R)-hydroxy-1(S)-indanyl-5-[2(S)-(1,1-dimethylethylaminocarbonyl)-4-[(furo[2,3-b]pyridin-5-yl)-methyl]piperazin-1-yl]-4(S)-hydroxy-2(R)-phenylmethylpentanamide), a known potent and mechanism-based inhibitor of CYP3A4, strongly inhibited the formation of 1'-hydroxy MDZ by recombinant CYP3A64 in a concentration- and time-dependent manner (KI = 0.25 microM; k(inact) = 0.4 min(-1)). Similar corresponding results also were obtained with human CYP3A4 in the presence of rifampin or compound A. In rhesus monkeys, MDZ exhibited a relatively high metabolic clearance (primarily via 1'-hydroxylation followed by glucuronidation) and a low hepatic availability (Fh = 16%). Consistent with the induction of hepatic metabolism of a high-clearance compound, pretreatment with rifampin (18 mg/kg p.o. for 5 days) did not significantly affect the i.v. kinetics of MDZ, but caused a pronounced reduction (approximately 10-fold) in the systemic exposure to MDZ and, consequently, its Fh following intrahepatic portal vein administration (i.pv.) of MDZ. A comparable extent of the pharmacokinetic interaction also was obtained after a 1.8 mg/kg rifampin dose. Also consistent with the in vitro CYP3A64 inhibition finding, compound A (6 mg/kg i.v.) markedly increased (10-fold) the i.pv. administered MDZ exposure. At the doses studied, plasma concentrations of rifampin or compound A reached or exceeded their respective in vitro EC50 or KI values. These findings suggest the potential applicability of the in vitro-in vivo relationship approach in rhesus monkeys for studying CYP3A-mediated interactions in humans.
Assuntos
Citocromo P-450 CYP3A/biossíntese , Sistema Enzimático do Citocromo P-450/biossíntese , Avaliação Pré-Clínica de Medicamentos , Hepatócitos/enzimologia , Adolescente , Adulto , Idoso , Animais , Células Cultivadas , Citocromo P-450 CYP3A/genética , Inibidores do Citocromo P-450 CYP3A , Inibidores das Enzimas do Citocromo P-450 , Sistema Enzimático do Citocromo P-450/genética , Avaliação Pré-Clínica de Medicamentos/métodos , Interações Medicamentosas , Indução Enzimática , Inibidores Enzimáticos/farmacocinética , Inibidores Enzimáticos/farmacologia , Éteres/farmacocinética , Éteres/farmacologia , Feminino , Hepatócitos/efeitos dos fármacos , Humanos , Hidrocarbonetos Fluorados/farmacocinética , Hidrocarbonetos Fluorados/farmacologia , Hidroxilação , Infusões Intravenosas , Isoenzimas/antagonistas & inibidores , Isoenzimas/biossíntese , Isoenzimas/genética , Macaca mulatta , Masculino , Midazolam/administração & dosagem , Midazolam/farmacocinética , Pessoa de Meia-Idade , Modelos Animais , RNA Mensageiro/biossíntese , Proteínas Recombinantes/antagonistas & inibidores , Proteínas Recombinantes/metabolismo , Rifampina/farmacocinética , Rifampina/farmacologiaRESUMO
Subtle modifications were incorporated into the structure of clinical candidate 1. These changes were designed to maintain potency and selectivity while inducing changes in physical properties leading to improved pharmacokinetics in three species. This approach led to the identification of 4 as a potent, selective alphaVbeta3 receptor antagonist that was selected for clinical development based on an improved PK profile and efficacy demonstrated in an in vivo model of bone turnover.
Assuntos
Integrina alfaVbeta3/antagonistas & inibidores , Naftiridinas/química , Animais , Cães , Avaliação Pré-Clínica de Medicamentos/métodos , Humanos , Integrina alfaVbeta3/metabolismo , Macaca mulatta , Masculino , Naftiridinas/metabolismo , Naftiridinas/farmacologia , Ligação Proteica/efeitos dos fármacos , Ligação Proteica/fisiologia , RatosRESUMO
3-(S)-Pyrimidin-5-yl-9-(5,6,7,8-tetrahydro-[1,8]naphthyridin-2-yl)-nonanoic acid (5e) and 3-(S)-(methylpyrimidin-5-yl)-9-(5,6,7,8-tetrahydro-[1,8]naphthyridin-2-yl)-nonanoic acid (5f) were identified as potent and selective antagonists of the alpha(v)beta(3) receptor. These compounds have excellent in vitro profiles (IC(50) = 0.07 and 0.08 nM, respectively), significant unbound fractions in human plasma (6 and 4%), and good pharmacokinetics in rat, dog, and rhesus monkey. On the basis of the efficacy shown in an in vivo model of bone turnover following once-daily oral administration, these two compounds were selected for clinical development for the treatment of osteoporosis.
Assuntos
Integrinas/antagonistas & inibidores , Naftiridinas/farmacologia , Osteoporose/tratamento farmacológico , Receptores de Vitronectina/antagonistas & inibidores , Administração Oral , Animais , Disponibilidade Biológica , Densidade Óssea/efeitos dos fármacos , Reabsorção Óssea/tratamento farmacológico , Cães , Relação Dose-Resposta a Droga , Avaliação Pré-Clínica de Medicamentos/métodos , Feminino , Humanos , Concentração Inibidora 50 , Integrinas/metabolismo , Macaca mulatta , Modelos Moleculares , Naftiridinas/química , Naftiridinas/farmacocinética , Osteoporose/prevenção & controle , Ovariectomia , Ratos , Ratos Sprague-Dawley , Receptores de Vitronectina/metabolismo , Relação Estrutura-AtividadeRESUMO
A series of novel, highly potent alpha(v)beta(3) receptor antagonists with favorable pharmacokinetic profiles has been identified. In this series of antagonists, 2-aryl beta-amino acids function as potent aspartic acid replacements.
Assuntos
Aminoácidos/química , Ésteres/química , Receptores de Vitronectina/antagonistas & inibidores , Aminoácidos/síntese química , Aminoácidos/farmacocinética , Animais , Ácido Aspártico/química , Materiais Biomiméticos/síntese química , Materiais Biomiméticos/química , Materiais Biomiméticos/farmacocinética , Cães , Avaliação Pré-Clínica de Medicamentos , Ésteres/síntese química , Ésteres/farmacocinética , Humanos , Concentração Inibidora 50 , Oligopeptídeos/química , Oligopeptídeos/farmacocinética , Ligação Proteica , Receptores de Vitronectina/metabolismo , Relação Estrutura-AtividadeRESUMO
The active forms of all marketed hydroxymethylglutaryl (HMG)-CoA reductase inhibitors share a common dihydroxy heptanoic or heptenoic acid side chain. In this study, we present evidence for the formation of acyl glucuronide conjugates of the hydroxy acid forms of simvastatin (SVA), atorvastatin (AVA), and cerivastatin (CVA) in rat, dog, and human liver preparations in vitro and for the excretion of the acyl glucuronide of SVA in dog bile and urine. Upon incubation of each statin (SVA, CVA or AVA) with liver microsomal preparations supplemented with UDP-glucuronic acid, two major products were detected. Based on analysis by high-pressure liquid chromatography, UV spectroscopy, and/or liquid chromatography (LC)-mass spectrometry analysis, these metabolites were identified as a glucuronide conjugate of the hydroxy acid form of the statin and the corresponding delta-lactone. By means of an LC-NMR technique, the glucuronide structure was established to be a 1-O-acyl-beta-D-glucuronide conjugate of the statin acid. The formation of statin glucuronide and statin lactone in human liver microsomes exhibited modest intersubject variability (3- to 6-fold; n = 10). Studies with expressed UDP glucuronosyltransferases (UGTs) revealed that both UGT1A1 and UGT1A3 were capable of forming the glucuronide conjugates and the corresponding lactones for all three statins. Kinetic studies of statin glucuronidation and lactonization in liver microsomes revealed marked species differences in intrinsic clearance (CL(int)) values for SVA (but not for AVA or CVA), with the highest CL(int) observed in dogs, followed by rats and humans. Of the statins studied, SVA underwent glucuronidation and lactonization in human liver microsomes, with the lowest CL(int) (0.4 microl/min/mg of protein for SVA versus approximately 3 microl/min/mg of protein for AVA and CVA). Consistent with the present in vitro findings, substantial levels of the glucuronide conjugate (approximately 20% of dose) and the lactone form of SVA [simvastatin (SV); approximately 10% of dose] were detected in bile following i.v. administration of [(14)C]SVA to dogs. The acyl glucuronide conjugate of SVA, upon isolation from an in vitro incubation, underwent spontaneous cyclization to SV. Since the rate of this lactonization was high under conditions of physiological pH, the present results suggest that the statin lactones detected previously in bile and/or plasma following administration of SVA to animals or of AVA or CVA to animals and humans, might originate, at least in part, from the corresponding acyl glucuronide conjugates. Thus, acyl glucuronide formation, which seems to be a common metabolic pathway for the hydroxy acid forms of statins, may play an important, albeit previously unrecognized, role in the conversion of active HMG-CoA reductase inhibitors to their latent delta-lactone forms.
Assuntos
Glucuronídeos/metabolismo , Ácidos Heptanoicos/metabolismo , Inibidores de Hidroximetilglutaril-CoA Redutases/metabolismo , Lactonas/metabolismo , Piridinas/metabolismo , Pirróis/metabolismo , Sinvastatina/metabolismo , Animais , Atorvastatina , Bile/química , Cães , Glucuronídeos/urina , Glucuronosiltransferase/metabolismo , Ácidos Heptanoicos/farmacocinética , Ácidos Heptanoicos/urina , Humanos , Inibidores de Hidroximetilglutaril-CoA Redutases/farmacocinética , Inibidores de Hidroximetilglutaril-CoA Redutases/urina , Lactonas/farmacocinética , Lactonas/urina , Espectroscopia de Ressonância Magnética , Microssomos Hepáticos/metabolismo , Isoformas de Proteínas , Piridinas/farmacocinética , Piridinas/urina , Pirróis/farmacocinética , Pirróis/urina , Ratos , Proteínas Recombinantes/metabolismo , Sinvastatina/farmacocinética , Sinvastatina/urina , Uridina Difosfato Ácido Glucurônico/metabolismoRESUMO
Potent non-peptidic alpha(v)beta(3) antagonists have been prepared incorporating various beta-amino acids as aspartic acid mimetics. Modification of the beta-alanine 3-substituents alters the potency and physicochemical properties of these receptor antagonists and in some cases provides orally bioavailable alpha(v)beta(3) inhibitors.