RESUMO
We previously observed a cutaneous type IV immune response in nonhuman primates (NHP) with the mGlu5 negative allosteric modulator (NAM) 7. To determine if this adverse event was chemotype- or mechanism-based, we evaluated a distinct series of mGlu5 NAMs. Increasing the sp3 character of high-throughput screening hit 40 afforded a novel morpholinopyrimidone mGlu5 NAM series. Its prototype, (R)-6-neopentyl-2-(pyridin-2-ylmethoxy)-6,7-dihydropyrimido[2,1-c][1,4]oxazin-4(9H)-one (PF-06462894, 8), possessed favorable properties and a predicted low clinical dose (2 mg twice daily). Compound 8 did not show any evidence of immune activation in a mouse drug allergy model. Additionally, plasma samples from toxicology studies confirmed that 8 did not form any reactive metabolites. However, 8 caused the identical microscopic skin lesions in NHPs found with 7, albeit with lower severity. Holistically, this work supports the hypothesis that this unique toxicity may be mechanism-based although additional work is required to confirm this and determine clinical relevance.
Assuntos
Regulação Alostérica/efeitos dos fármacos , Compostos Heterocíclicos com 3 Anéis/farmacologia , Compostos Heterocíclicos com 3 Anéis/farmacocinética , Piridinas/farmacologia , Piridinas/farmacocinética , Receptor de Glutamato Metabotrópico 5/antagonistas & inibidores , Receptor de Glutamato Metabotrópico 5/metabolismo , Animais , Feminino , Células HEK293 , Compostos Heterocíclicos com 3 Anéis/efeitos adversos , Compostos Heterocíclicos com 3 Anéis/química , Humanos , Masculino , Simulação de Acoplamento Molecular , Piridinas/efeitos adversos , Piridinas/química , Ratos , Ratos Sprague-Dawley , Relação Estrutura-AtividadeRESUMO
Phosphodiesterases (PDEs) regulate the levels of the second messengers cAMP and cGMP and are important drug targets. PDE10A is highly enriched in medium spiny neurons of the striatum and is an attractive drug target for the treatment of basal ganglia diseases like schizophrenia, Parkinson's disease, or Huntington's disease. Here we describe the design, synthesis, and application of a variety of chemical biology probes, based on the first clinically tested PDE10A inhibitor MP-10, which were used to characterize the chemoproteomic profile of the clinical candidate in its native environment. A clickable photoaffinity probe was used to measure target engagement of MP-10 and revealed differences between whole cell and membrane preparations. Moreover, our results illustrate the importance of the linker design in the creation of functional probes. Biotinylated affinity probes allowed identification of drug-interaction partners in rodent and human tissue and quantitative mass spectrometry analysis revealed highly specific binding of MP-10 to PDE10A with virtually no off-target binding. The profiling of PDE10A chemical biology probes described herein illustrates a strategy by which high affinity inhibitors can be converted into probes for determining selectivity and target engagement of drug candidates in complex biological matrices from native sources.
Assuntos
Membrana Celular/efeitos dos fármacos , Sondas Moleculares/química , Neurônios/efeitos dos fármacos , Inibidores de Fosfodiesterase/química , Diester Fosfórico Hidrolases/metabolismo , Pirazóis/química , Quinolinas/química , Animais , Sítios de Ligação , Membrana Celular/enzimologia , Cromatografia de Afinidade , Corpo Estriado/citologia , Corpo Estriado/efeitos dos fármacos , Corpo Estriado/enzimologia , Cristalografia por Raios X , Humanos , Luz , Modelos Moleculares , Sondas Moleculares/síntese química , Neurônios/citologia , Neurônios/enzimologia , Inibidores de Fosfodiesterase/farmacologia , Diester Fosfórico Hidrolases/química , Processos Fotoquímicos , Cultura Primária de Células , Ligação Proteica , Pirazóis/farmacologia , Quinolinas/farmacologia , RatosRESUMO
1. In early discovery stages, 2-methyl-N-(2'-(pyrrolidinyl-1-ylsulfonyl)-[1,1'-biphenyl]-4-yl)propan-1-amine (PBPA) demonstrated monoamine oxidase A (MAO-A) and cytochrome P450 (CYP)-mediated clearance. While human liver microsomes predicted low CL(b) PBPA demonstrated a moderate CL(p)/F in humans. The plasma pharmacokinetic (PK) of PBPA was characterized by unexpected high inter-individual variability. Hence, a retrospective analysis was undertaken to understand the disposition processes of PBPA, by applying in vitro mechanistic tools. 2. The in vitro-to-in vivo of rat CL(b) of PBPA was calculated as similar to that of human, suggesting rat to be a better predictor of a MAO-A/CYP substrate, but not dog or monkey; this is consistent with differences in expression of MAO-A in rat, dog, monkey and human. Fraction metabolized (f(m)) of human MAO A (hMAO-A) (50%), CYP3A4 (8%), CYP3A5 (16%) and CYP2D6 (29%) was determined, in vitro. 3. While the fm of CYP3A5 was <50%, Michaelis-Menten kinetics demonstrated that it was a higher capacity pathway compared with MAO-A, 2D6 and 3A4. This was consistent with strong association of dose-normalized plasma C(max) and area under the plasma concentration time curve (AUC(0-tlast)) of PBPA with CYP3A5 genotype, but not with genotype of CYP2D6. 4. This investigation demonstrates the value of integrating in vitro mechanistic tools to gain comprehensive understanding of disposition properties of drug candidates, in a discovery paradigm and prior to the investment in clinical trials.
Assuntos
Compostos de Bifenilo/farmacocinética , Citocromo P-450 CYP2D6/genética , Citocromo P-450 CYP3A/genética , Monoaminoxidase/metabolismo , Sulfonamidas/farmacocinética , Animais , Compostos de Bifenilo/metabolismo , Citocromo P-450 CYP2D6/metabolismo , Citocromo P-450 CYP3A/metabolismo , Cães , Eritrócitos/efeitos dos fármacos , Hepatócitos/efeitos dos fármacos , Hepatócitos/metabolismo , Humanos , Inativação Metabólica , Macaca fascicularis , Masculino , Microssomos Hepáticos/efeitos dos fármacos , Microssomos Hepáticos/metabolismo , Monoaminoxidase/genética , Ratos , Ratos Sprague-Dawley , Sulfonamidas/metabolismoRESUMO
A series of aryl hydroxamates recently have been disclosed as irreversible inhibitors of kynurenine amino transferase II (KAT II), an enzyme that may play a role in schizophrenia and other psychiatric and neurological disorders. The utilization of structure-activity relationships (SAR) in conjunction with X-ray crystallography led to the discovery of hydroxamate 4, a disubstituted analogue that has a significant potency enhancement due to a novel interaction with KAT II. The use of k inact/K i to assess potency was critical for understanding the SAR in this series and for identifying compounds with improved pharmacodynamic profiles.
RESUMO
Kynurenine aminotransferase (KAT) II has been identified as a potential new target for the treatment of cognitive impairment associated with schizophrenia and other psychiatric disorders. Following a high-throughput screen, cyclic hydroxamic acid PF-04859989 was identified as a potent and selective inhibitor of human and rat KAT II. An X-ray crystal structure and (13)C NMR studies of PF-04859989 bound to KAT II have demonstrated that this compound forms a covalent adduct with the enzyme cofactor, pyridoxal phosphate (PLP), in the active site. In vivo pharmacokinetic and efficacy studies in rat show that PF-04859989 is a brain-penetrant, irreversible inhibitor and is capable of reducing brain kynurenic acid by 50% at a dose of 10 mg/kg (sc). Preliminary structure-activity relationship investigations have been completed and have identified the positions on this scaffold best suited to modification for further optimization of this novel series of KAT II inhibitors.
RESUMO
By use of parallel chemistry coupled with physicochemical property design, a series of selective κ opioid antagonists have been discovered. The parallel chemistry strategy utilized key monomer building blocks to rapidly expand the desired SAR space. The potency and selectivity of the in vitro κ antagonism were confirmed in the tail-flick analgesia model. This model was used to build an exposure-response relationship between the κ K(i) and the free brain drug levels. This strategy identified 2-methyl-N-((2'-(pyrrolidin-1-ylsulfonyl)biphenyl-4-yl)methyl)propan-1-amine, PF-4455242, which entered phase 1 clinical testing and has demonstrated target engagement in healthy volunteers.
Assuntos
Compostos de Bifenilo/farmacologia , Desenho de Fármacos , Descoberta de Drogas , Antagonistas de Entorpecentes/farmacologia , Receptores Opioides kappa/antagonistas & inibidores , Sulfonamidas/farmacologia , (trans)-Isômero de 3,4-dicloro-N-metil-N-(2-(1-pirrolidinil)-ciclo-hexil)-benzenoacetamida/farmacologia , Analgésicos/química , Analgésicos/farmacocinética , Analgésicos/farmacologia , Animais , Área Sob a Curva , Compostos de Bifenilo/química , Compostos de Bifenilo/farmacocinética , Encéfalo/metabolismo , Modelos Animais de Doenças , Cães , Haplorrinos , Humanos , Taxa de Depuração Metabólica , Camundongos , Microssomos Hepáticos/metabolismo , Modelos Químicos , Estrutura Molecular , Morfina/farmacologia , Antagonistas de Entorpecentes/química , Antagonistas de Entorpecentes/farmacocinética , Dor/metabolismo , Dor/prevenção & controle , Ratos , Ratos Sprague-Dawley , Receptores Opioides kappa/agonistas , Receptores Opioides kappa/metabolismo , Receptores Opioides mu/agonistas , Relação Estrutura-Atividade , Sulfonamidas/química , Sulfonamidas/farmacocinéticaRESUMO
We describe a generalized approach to stereocontrolled synthesis of substituted cyclic hydroxamic acids (3-amino-1-hydroxy-3,4-dihydroquinolinones) by selective reduction of substituted 2-nitrophenylalanine substrates. Compounds in this series have antibacterial properties and have also recently been reported as KAT II inhibitors. The key nitrophenyl alanine intermediates are prepared enantioselectively in excellent yield by phase transfer catalyzed alkylation of the corresponding nitrobenzyl bromides. The scope and limitations of the reductive cyclization transformation have been explored with attention to the effects of substitution pattern and electronics on reaction efficiency and byproduct formation. In addition, a novel activated trifluoroethyl ester cyclization strategy has been developed as an alternate approach to the most sterically demanding systems in this series.
Assuntos
Ácidos Hidroxâmicos/química , Ácidos Hidroxâmicos/síntese química , Nitrocompostos/química , Ciclização , Ésteres , Oxirredução , Fenilalanina/análogos & derivados , Fenilalanina/síntese química , Fenilalanina/química , Acetato de Sódio/química , Especificidade por Substrato , Compostos de Estanho/químicaRESUMO
A novel (4,5-dihydroimidazol-2-yl)-biphenylamine series of 5-HT(7) agonist compounds was developed from a structurally related lead compound 1. The newly discovered series is exemplified by compound 2 that possesses high affinity for 5-HT(7) receptors and shows intrinsic agonist activity in functional assays. This new series has significant alpha(1) and alpha(2) activities perhaps due to the presence of the 2-aminoimidazoline moiety.