ABSTRACT
A series of unique macrocyclic HDACs 1, 2, and 3 selective inhibitors were identified with good enzymatic activity and high selectivity over HDACs 6 and 8. These macrocyclic HDAC inhibitors used an ethyl ketone as the zinc-binding group. Compounds 25 and 26 stood out as leads due to their low double-digit nM EC50s in the 2C4 cell-based HIV latency reactivation assay. The PK profiles of these macrocyclic HDAC inhibitors still needed improvement.
Subject(s)
Anti-HIV Agents/pharmacology , Drug Discovery , HIV/drug effects , Histone Deacetylase Inhibitors/pharmacology , Histone Deacetylases/metabolism , Anti-HIV Agents/chemical synthesis , Anti-HIV Agents/chemistry , Dose-Response Relationship, Drug , Histone Deacetylase Inhibitors/chemical synthesis , Histone Deacetylase Inhibitors/chemistry , Humans , Isoenzymes/antagonists & inhibitors , Isoenzymes/metabolism , Microbial Sensitivity Tests , Molecular Structure , Structure-Activity RelationshipABSTRACT
We describe the discovery of histone deacetylase (HDACs) 1, 2, and 3 inhibitors with ethyl ketone as the zinc-binding group. These HDACs 1, 2, and 3 inhibitors have good enzymatic and cellular activity. Their serum shift in cellular potency has been minimized, and selectivity against hERG has been improved. They are also highly selective over HDACs 6 and 8. These inhibitors contain a variety of substituted heterocycles on the imidazole or oxazole scaffold. Compounds 31 and 48 stand out due to their good potency, high selectivity over HDACs 6 and 8, reduced hERG activity, optimized serum shift in cellular potency, and good rat and dog PK profiles.
Subject(s)
ERG1 Potassium Channel/metabolism , HIV-1/physiology , Histone Deacetylase Inhibitors/chemistry , Histone Deacetylases/metabolism , Ketones/chemistry , Animals , Dogs , Drug Evaluation, Preclinical , Half-Life , Histone Deacetylase 1/antagonists & inhibitors , Histone Deacetylase 1/metabolism , Histone Deacetylase 2/antagonists & inhibitors , Histone Deacetylase 2/metabolism , Histone Deacetylase Inhibitors/metabolism , Histone Deacetylase Inhibitors/pharmacology , Histone Deacetylases/chemistry , Humans , Imidazoles/chemistry , Oxazoles/chemistry , Protein Isoforms/antagonists & inhibitors , Protein Isoforms/metabolism , Rats , Structure-Activity Relationship , Virus Activation/drug effectsABSTRACT
An integrated workflow has been established that enables the synthesis, purification, and subsequent biological testing of compound libraries on a microgram scale. This approach utilizes mass directed preparative HPLC in conjunction with charged aerosol detection (CAD) to generate solutions of investigational compounds at high purity and standardized concentrations, facilitating high fidelity biological testing. This new workflow successfully delivered libraries of histone deacetylase (HDAC) inhibitors that afforded biological data consistent with that obtained from standard scale parallel medicinal chemistry techniques. The advantages of this new approach to library synthesis include greatly reduced material requirements and amenability to high-throughput experimentation.
ABSTRACT
The selectivity of histone deacetylase inhibitors (HDACis) is greatly impacted by the zinc binding groups. In an effort to search for novel zinc binding groups, we applied a parallel medicinal chemistry (PMC) strategy to quickly synthesize substituted benzamide libraries. We discovered a series containing 2-substituted benzamides as the zinc binding group which afforded highly selective and potent HDAC3 inhibitors, exemplified by compound 16 with a 2-methylthiobenzamide. Compound 16 inhibited HDAC3 with an IC50 of 30 nM and with unprecedented selectivity of >300-fold over all other HDAC isoforms. Interestingly, a subtle change of the 2-methylthio to a 2-hydroxy benzamide in 20 retains HDAC3 potency but loses all selectivity over HDAC 1 and 2. This significant difference in selectivity was rationalized by X-ray crystal structures of HDACis 16 and 20 bound to HDAC2, revealing different binding modes to the catalytic zinc ion. This series of HDAC3 selective inhibitors served as tool compounds for investigating the minimal set of HDAC isoforms that must be inhibited for the HIV latency activation in a Jurkat 2C4 cell model and potentially as leads for selective HDAC3 inhibitors for other indications.
ABSTRACT
Bruton's tyrosine kinase (BTK) is a Tec family kinase with a well-defined role in the B cell receptor (BCR) pathway. It has become an attractive kinase target for selective B cell inhibition, and for the treatment of B cell related diseases. Many BTK inhibitors have been discovered for the treatment of cancer and rheumatoid arthritis, including a series of BTK inhibitors based on 8-amino-imidazo[1,5-a]pyrazine we recently reported. The X-ray crystal structures of BTK with inhibitors were also published, which provided great help for the SAR design. Here we report our SAR work introducing ring constraints for the 3-position piperidine amides on the BTK inhibitors based on 8-amino-imidazo[1,5-a]pyrazine. This modification improved the potency in BTK inhibitions, as well as the PK profile and the off-target selectivity. The dose-dependent efficacy of two BTK inhibitors was observed in the rat collagen induced arthritis (CIA) model.
Subject(s)
Agammaglobulinaemia Tyrosine Kinase/antagonists & inhibitors , Imidazoles/chemistry , Protein Kinase Inhibitors/chemistry , Pyrazines/chemistry , Agammaglobulinaemia Tyrosine Kinase/metabolism , Animals , Arthritis, Experimental/drug therapy , Binding Sites , Bridged Bicyclo Compounds/chemistry , Crystallography, X-Ray , Disease Models, Animal , Dogs , Dose-Response Relationship, Drug , Half-Life , Humans , Imidazoles/metabolism , Imidazoles/therapeutic use , Molecular Dynamics Simulation , Protein Kinase Inhibitors/metabolism , Protein Kinase Inhibitors/therapeutic use , Pyrazines/metabolism , Pyrazines/therapeutic use , Rats , Rats, Wistar , Structure-Activity Relationship , src-Family Kinases/antagonists & inhibitors , src-Family Kinases/metabolismABSTRACT
The synthesis and SAR development of a trisubstituted imidazole HDAC inhibitor is described. The compounds were synthesized with high diastereocontrol by leveraging Ellman sulfinyl imine chemistry. Structural elucidation provided insight into binding mode and supported design rational. Pharmacokinetic properties of lead compounds were determined.
Subject(s)
Histone Deacetylase Inhibitors/metabolism , Histone Deacetylases/metabolism , Animals , CD4-Positive T-Lymphocytes/virology , Crystallography, X-Ray , HIV-1/drug effects , HIV-1/physiology , Histone Deacetylase Inhibitors/chemistry , Histone Deacetylase Inhibitors/pharmacology , Histone Deacetylases/chemistry , Humans , Imidazoles/chemistry , Imidazoles/metabolism , Imidazoles/pharmacology , Inhibitory Concentration 50 , Isoenzymes/antagonists & inhibitors , Isoenzymes/metabolism , Rats , Structure-Activity RelationshipABSTRACT
HIV persistence in latently infected, resting CD4+ T cells is broadly considered a barrier to eradicate HIV. Activation of the provirus using latency-reversing agents (LRAs) followed by immune-mediated clearance to purge reservoirs has been touted as a promising therapeutic approach. Histone deacetylases (HDACs) and histone acetyltransferases (HATs) control the acetylation level of lysine residues in histones to regulate the gene transcription. Several clinical HDAC inhibitors had been examined as LRAs, which induced HIV activation in vitro and in vivo. Here we report the discovery of a series of selective and potent class I HDAC inhibitors based on aryl ketones as a zinc binding group, which reversed HIV latency using a Jurkat model of HIV latency in 2C4 cells. The SAR led to the discovery of a highly selective class I HDAC inhibitor 10 with excellent potency. HDACi 10 induces the HIV gag P24 protein in patient latent CD4+ T cells.
ABSTRACT
A novel series of ethyl ketone based HDACs 1, 2, and 3 selective inhibitors have been identified with good enzymatic and cellular activity and high selectivity over HDACs 6 and 8. These inhibitors contain a spirobicyclic group in the amide region. Compound 13 stands out as a lead due to its good potency, high selectivity, and reasonable rat and dog PK. Compounds 33 and 34 show good potency and rat PK profiles as well.
Subject(s)
Anti-HIV Agents/pharmacology , HIV-1/drug effects , Histone Deacetylase Inhibitors/pharmacology , Ketones/pharmacology , Virus Activation/drug effects , Virus Latency/drug effects , Animals , Anti-HIV Agents/chemical synthesis , Anti-HIV Agents/pharmacokinetics , Cell Line, Tumor , Dogs , Histone Deacetylase Inhibitors/chemical synthesis , Histone Deacetylase Inhibitors/pharmacokinetics , Humans , Ketones/chemical synthesis , Ketones/pharmacokinetics , Microbial Sensitivity Tests , Rats , Spiro Compounds/chemical synthesis , Spiro Compounds/pharmacokinetics , Spiro Compounds/pharmacologyABSTRACT
A series of novel tetracyclic core-containing HCV NS5A inhibitors has been discovered. Incorporation of tetrahydropyran-substituted amino acid moiety improved their potency and yielded HCV NS5A inhibitors with a minimum potency shift from the GT1a strain compared to other genotypes and mutants. Compounds 53 and 54 showed the best potency profile and had reasonable half-times in rat PK studies. However, further optimization of their oral bioavailability is still needed in order to advance them for further development. [BMCL ABSTRACT] ©2000 Elsevier Science Ltd. All rights reserved.
Subject(s)
Antiviral Agents/pharmacology , Drug Discovery , Genotype , Hepacivirus/drug effects , Viral Nonstructural Proteins/antagonists & inhibitors , Animals , Antiviral Agents/chemistry , Antiviral Agents/pharmacokinetics , Half-Life , RatsABSTRACT
There is increasing evidence that a healthy and safe workforce can provide a competitive business advantage. This article shares the efforts and experience of a large global employer as it builds on existing corporate wellness and safety programs to develop a corporate culture of health and well-being. Starting with a comprehensive review of the current state of employee health and culture, a small team established the business case, aligned strategic partners, created an implementation plan, and engaged the C-Suite. The aim of this article is to provide a case study that others might use to design their blueprint, to gain awareness and to build a culture of health and well-being within their organization.
Subject(s)
Occupational Health , Organizational Culture , Health Promotion , Humans , Organizational Case Studies , Population HealthABSTRACT
Inhibition of NS5A has emerged as an attractive strategy to intervene in hepatitis C virus (HCV) replication. Ruzasvir (formerly MK-8408) was developed as a novel NS5A inhibitor to improve upon the potency and barrier to resistance of early compounds. Ruzasvir inhibited HCV RNA replication with 50% effective concentrations (EC50s) of 1 to 4 pM in Huh7 or Huh7.5 cells bearing replicons for HCV genotype 1 (GT1) to GT7. The antiviral activity was modestly (10-fold) reduced in the presence of 40% normal human serum. The picomolar potency in replicon cells extended to sequences of clinical isolates available in public databases that were synthesized and tested as replicons. In GT1a, ruzasvir inhibited common NS5A resistance-associated substitutions (RASs), with the exception of M28G. De novo resistance selection studies identified pathways with certain amino acid substitutions at residues 28, 30, 31, and 93 across genotypes. Substitutions at position 93 were more common in GT1 to -4, while changes at position 31 emerged frequently in GT5 and -6. With the exception of GT4, the reintroduction of selected RASs conferred a ≥100-fold potency reduction in the antiviral activity of ruzasvir. Common RASs from other classes of direct-acting antiviral agents (DAAs) did not confer cross-resistance to ruzasvir. The interaction of ruzasvir with an NS3/4A protease inhibitor (grazoprevir) and an NS5B polymerase prodrug (uprifosbuvir) was additive to synergistic, with no evidence of antagonism or cytotoxicity. The antiviral profile of ruzasvir supported its further evaluation in human trials in combination with grazoprevir and uprifosbuvir.
Subject(s)
Antiviral Agents/pharmacology , Hepacivirus/drug effects , Heterocyclic Compounds, 4 or More Rings/pharmacology , Pyrrolidines/pharmacology , Thiazoles/pharmacology , Viral Nonstructural Proteins/antagonists & inhibitors , Amides , Carbamates , Cell Line, Tumor , Cyclopropanes , Drug Resistance, Viral/drug effects , Drug Therapy, Combination/methods , Genotype , Hepatitis C, Chronic/drug therapy , Hepatitis C, Chronic/virology , Humans , Protease Inhibitors/pharmacology , Quinoxalines/pharmacology , Replicon/drug effects , Sulfonamides , Uridine/analogs & derivatives , Uridine/pharmacologyABSTRACT
We describe the discovery of MK-6169, a potent and pan-genotype hepatitis C virus NS5A inhibitor with optimized activity against common resistance-associated substitutions. SAR studies around the combination of changes to both the valine and aminal carbon region of elbasvir led to the discovery of a series of compounds with substantially improved potency against common resistance-associated substitutions in the major genotypes, as well as good pharmacokinetics in both rat and dog. Through further optimization of key leads from this effort, MK-6169 (21) was discovered as a preclinical candidate for further development.
Subject(s)
Antiviral Agents/pharmacology , Drug Discovery , Drug Resistance, Viral/drug effects , Hepacivirus/drug effects , Viral Nonstructural Proteins/antagonists & inhibitors , Animals , Antiviral Agents/pharmacokinetics , Dogs , Genotype , Hepacivirus/genetics , Hepacivirus/metabolism , Male , Rats , Tissue DistributionABSTRACT
HCV NS5A inhibitors have shown impressive in vitro potency profiles in HCV replicon assays thus making them attractive components for inclusion in an all oral fixed dose combination regimen. Herein, we describe the discovery and characterization of silyl proline-containing HCV NS5A inhibitor MK-8325 with good pan-genotype activity and acceptable pharmacokinetic properties.
Subject(s)
Antiviral Agents/chemistry , Heterocyclic Compounds, 4 or More Rings/chemistry , Proline/chemistry , Viral Nonstructural Proteins/antagonists & inhibitors , Animals , Antiviral Agents/pharmacokinetics , Antiviral Agents/pharmacology , Cytochrome P-450 Enzyme System/metabolism , Dogs , Genotype , Half-Life , Haplorhini , Hepacivirus/drug effects , Hepacivirus/genetics , Hepacivirus/physiology , Heterocyclic Compounds, 4 or More Rings/pharmacokinetics , Heterocyclic Compounds, 4 or More Rings/pharmacology , Humans , Rats , Viral Nonstructural Proteins/metabolism , Virus Replication/drug effectsABSTRACT
8-Amino-imidazo[1,5-a]pyrazine-based Bruton's tyrosine kinase (BTK) inhibitors, such as 6, exhibited potent inhibition of BTK but required improvements in both kinase and hERG selectivity (Liu et al., 2016; Gao et al., 2017). In an effort to maintain the inhibitory activity of these analogs and improve their selectivity profiles, we carried out SAR exploration of groups at the 3-position of pyrazine compound 6. This effort led to the discovery of the morpholine group as an optimized pharmacophore. Compounds 13, 23 and 38 displayed excellent BTK potencies, kinase and hERG selectivities, and pharmacokinetic profiles.
Subject(s)
Arthritis, Rheumatoid/drug therapy , Drug Discovery , Imidazoles/pharmacology , Morpholines/pharmacology , Protein Kinase Inhibitors/pharmacology , Protein-Tyrosine Kinases/antagonists & inhibitors , Arthritis, Rheumatoid/metabolism , Dose-Response Relationship, Drug , Humans , Imidazoles/chemical synthesis , Imidazoles/chemistry , Leukocytes, Mononuclear/drug effects , Leukocytes, Mononuclear/metabolism , Models, Molecular , Molecular Structure , Morpholines/chemical synthesis , Morpholines/chemistry , Protein Kinase Inhibitors/chemical synthesis , Protein Kinase Inhibitors/chemistry , Protein-Tyrosine Kinases/metabolism , Structure-Activity Relationship , Transcriptional Regulator ERG/antagonists & inhibitors , Transcriptional Regulator ERG/metabolismABSTRACT
Our research on hydantoin based TNF-α converting enzyme (TACE) inhibitors led to fused bi-heteroaryl hydantoin series that demonstrate sub-nanomolar potency (Ki) as well as excellent activity in human whole blood (hWBA). However, lead compound 2 posed some formulation challenges which prevented it for further development. A prodrug approach was investigated to address this issue. The pivalate prodrug 3 can be formulated as stable neutral form and demonstrated improved DMPK properties when compared with parent compound.
Subject(s)
ADAM17 Protein/antagonists & inhibitors , Hydantoins/chemistry , Hydantoins/chemical synthesis , Hydantoins/pharmacology , Pentanoic Acids/chemistry , Prodrugs/chemical synthesis , Prodrugs/pharmacology , ADAM17 Protein/metabolism , Administration, Oral , Animals , Area Under Curve , Dogs , Enzyme Activation/drug effects , Half-Life , Haplorhini , Humans , Hydantoins/administration & dosage , Hydantoins/pharmacokinetics , Pentanoic Acids/administration & dosage , Pentanoic Acids/pharmacokinetics , Prodrugs/administration & dosage , Prodrugs/pharmacokinetics , ROC Curve , Rats , Structure-Activity RelationshipABSTRACT
We have identified a series of hydantoin-derived TNF-a converting enzyme (TACE) inhibitors containing a pendant fused bi-heteroaryl group, which demonstrate sub-nanomolar potency (Ki), excellent activity in human whole blood assay, and improved DMPK profiles over prior series.
Subject(s)
ADAM17 Protein/antagonists & inhibitors , Hydantoins/chemistry , Protease Inhibitors/chemistry , ADAM17 Protein/metabolism , Animals , Area Under Curve , Dogs , Enzyme Activation/drug effects , Half-Life , Haplorhini , Humans , Hydantoins/chemical synthesis , Hydantoins/pharmacology , Protease Inhibitors/chemical synthesis , Protease Inhibitors/pharmacology , ROC Curve , Rats , Structure-Activity RelationshipABSTRACT
We describe the research that led to the discovery of compound 40 (ruzasvir, MK-8408), a pan-genotypic HCV nonstructural protein 5A (NS5A) inhibitor with a "flat" GT1 mutant profile. This NS5A inhibitor contains a unique tetracyclic indole core while maintaining the imidazole-proline-valine Moc motifs of our previous NS5A inhibitors. Compound 40 is currently in early clinical trials and is under evaluation as part of an all-oral DAA regimen for the treatment of chronic HCV infection.
Subject(s)
Antiviral Agents/chemistry , Antiviral Agents/pharmacology , Hepacivirus/drug effects , Heterocyclic Compounds, 4 or More Rings/chemistry , Heterocyclic Compounds, 4 or More Rings/pharmacology , Polymorphism, Genetic , Pyrrolidines/chemistry , Pyrrolidines/pharmacology , Thiazoles/chemistry , Thiazoles/pharmacology , Viral Nonstructural Proteins/antagonists & inhibitors , Animals , Antiviral Agents/pharmacokinetics , Cell Line , Dogs , Haplorhini , Hepacivirus/genetics , Heterocyclic Compounds, 4 or More Rings/pharmacokinetics , Humans , Pyrrolidines/pharmacokinetics , Rats , Structure-Activity Relationship , Thiazoles/pharmacokineticsABSTRACT
The discovery of potent and pan-genotypic HCV NS5A inhibitors faces many challenges including the significant diversity among genotypes, substantial potency shift conferred on some key resistance-associated variants, inconsistent SARs between different genotypes and mutants, and the lacking of models of inhibitor/protein complexes for rational inhibitor design. As part of ongoing efforts on HCV NS5A inhibition at Merck, we now describe the discovery of a novel series of chromane containing NS5A inhibitors. SAR studies around the "Z" group of the tetracyclic indole scaffold explored fused bicyclic rings as alternates to the phenyl group of elbasvir (1, MK-8742) and identified novel chromane and 2,3-dihydrobenzofuran derivatives as "Z" group replacements offered good potency across all genotypes. This effort, incorporating the C-1 fluoro substitution at the tetracyclic indole core, led to the discovery of a new series of NS5A inhibitors, such as compounds 14 and 25-28, with significantly improved potency against resistance-associated variants, such as GT2b, GT1a Y93H, and GT1a L31V. Compound 14 also showed reasonable PK exposures in preclinical species (rat and dog).
Subject(s)
Antiviral Agents/pharmacology , Chromans/pharmacology , Drug Discovery , Drug Resistance, Viral/drug effects , Hepacivirus/drug effects , Viral Nonstructural Proteins/antagonists & inhibitors , Animals , Antiviral Agents/chemical synthesis , Antiviral Agents/chemistry , Chromans/chemical synthesis , Chromans/chemistry , Dogs , Dose-Response Relationship, Drug , Male , Microbial Sensitivity Tests , Molecular Structure , Rats , Rats, Wistar , Structure-Activity RelationshipABSTRACT
Herein, we describe our research efforts to develop unique cores in molecules which function as HCV nonstructural protein 5A (NS5A) inhibitors. In particular, various fused tetracyclic cores were identified which showed genotype and mutant activities comparable to the indole-based tetracyclic core.
Subject(s)
Indoles/pharmacology , Viral Nonstructural Proteins/antagonists & inhibitors , Antiviral Agents/pharmacology , Hepacivirus/drug effectsABSTRACT
We describe the impact of proline modifications, in our tetracyclic-indole based series of nonstructural protein 5A (NS5A) inhibitors, to their replicon profiles. This work identified NS5A inhibitors with an improved and flattened resistance profiles.