ABSTRACT
Herein, we describe our strategy to design metabolically stable γ-secretase inhibitors which are selective for inhibition of Aß generation over Notch. We highlight our synthetic strategy to incorporate diversity and chirality. Compounds 30 (ELND006) and 34 (ELND007) both entered human clinical trials. The in vitro and in vivo characteristics for these two compounds are described. A comparison of inhibition of Aß generation in vivo between 30, 34, Semagacestat 41, Begacestat 42, and Avagacestat 43 in mice is made. 30 lowered Aß in the CSF of healthy human volunteers.
Subject(s)
Amyloid Precursor Protein Secretases/antagonists & inhibitors , Amyloid beta-Peptides/antagonists & inhibitors , Enzyme Inhibitors/pharmacology , Heterocyclic Compounds, 3-Ring/pharmacology , Pyrazoles/pharmacology , Quinolines/pharmacology , Receptors, Notch/antagonists & inhibitors , Sulfonamides/pharmacology , Amyloid Precursor Protein Secretases/metabolism , Amyloid beta-Peptides/cerebrospinal fluid , Amyloid beta-Peptides/metabolism , Animals , Area Under Curve , Basic Helix-Loop-Helix Transcription Factors/genetics , Dogs , Dose-Response Relationship, Drug , Drug Design , Drug Stability , Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/pharmacokinetics , Gene Expression/drug effects , Heterocyclic Compounds, 3-Ring/chemistry , Homeodomain Proteins/genetics , Humans , Male , Mice , Microsomes, Liver/drug effects , Microsomes, Liver/metabolism , Models, Chemical , Molecular Structure , Pyrazoles/chemical synthesis , Pyrazoles/pharmacokinetics , Quinolines/chemical synthesis , Quinolines/pharmacokinetics , RNA, Messenger/genetics , RNA, Messenger/metabolism , Rats , Rats, Sprague-Dawley , Receptors, Notch/metabolism , Structure-Activity Relationship , Sulfonamides/chemistry , Time Factors , Transcription Factor HES-1ABSTRACT
Mutations in leucine-rich repeat kinase 2 (LRRK2) are associated with familial Parkinson's disease (PD). The kinase activity of this complex protein is increased by pathogenic mutations. Inhibition of LRRK2 kinase activity has therefore emerged as a promising approach for the treatment of PD. Herein we report our findings on a series of 4-alkylamino-7-aryl-3-cyanoquinolines that exhibit kinase inhibitory activity against both wild type and G2019S mutant LRRK2. Activity was determined in both biochemical and cellular assays. Compound 14 was further evaluated in an in vivo pharmacodynamic study and found to significantly inhibit Ser935 phosphorylation after oral dosing.
Subject(s)
Drug Discovery , Protein Kinase Inhibitors/pharmacology , Protein Serine-Threonine Kinases/antagonists & inhibitors , Quinolines/pharmacology , Animals , Dose-Response Relationship, Drug , HEK293 Cells , Humans , Leucine-Rich Repeat Serine-Threonine Protein Kinase-2 , Mice , Mice, Knockout , Mice, Transgenic , Models, Molecular , Molecular Structure , Mutation , Protein Kinase Inhibitors/chemical synthesis , Protein Kinase Inhibitors/chemistry , Protein Serine-Threonine Kinases/genetics , Protein Serine-Threonine Kinases/metabolism , Quinolines/chemical synthesis , Quinolines/chemistry , Structure-Activity RelationshipABSTRACT
Polo like kinase 2 (PLK2) phosphorylates α-synuclein and is considered a putative therapeutic target for Parkinson's disease. Several lines of evidence indicate that PLK2 is involved with proper centriole duplication and cell cycle regulation, inhibition of which could impact chromosomal integrity during mitosis. The objectives of the series of experiments presented herein were to assess whether specific inhibition of PLK2 is genotoxic and determine if PLK2 could be considered a tractable pharmacological target for Parkinson's disease. Several selective PLK2 inhibitors, ELN 582175 and ELN 582646, and their inactive enantiomers, ELN 582176 and ELN 582647, did not significantly increase the number of micronuclei in the in vitro micronucleus assay. ELN 582646 was administered to male Sprague Dawley rats in an exploratory 14-day study where flow cytometric analysis of peripheral blood identified a dose-dependent increase in the number of micronucleated reticulocytes. A follow-up investigative study demonstrated that ELN 582646 administered to PLK2 deficient and wildtype mice significantly increased the number of peripheral micronucleated reticulocytes in both genotypes, suggesting that ELN 582646-induced genotoxicity is not through the inhibition of PLK2. Furthermore, significant reduction of retinal phosphorylated α-synuclein levels was observed at three non-genotoxic doses, additional data to suggest that pharmacological inhibition of PLK2 is not the cause of the observed genotoxicity. These data, in aggregate, indicate that PLK2 inhibition is a tractable CNS pharmacological target that does not cause genotoxicity at doses and exposures that engage the target in the sensory retina.
Subject(s)
Chromosome Aberrations/chemically induced , Lymphocytes/drug effects , Micronuclei, Chromosome-Defective/chemically induced , Protein Kinase Inhibitors/toxicity , Protein Serine-Threonine Kinases/antagonists & inhibitors , Reticulocytes/drug effects , Animals , Dose-Response Relationship, Drug , Flow Cytometry , HEK293 Cells , Humans , Lymphocytes/enzymology , Lymphocytes/pathology , Male , Mice , Mice, 129 Strain , Mice, Inbred C57BL , Mice, Knockout , Micronucleus Tests , Phosphorylation , Protein Kinase Inhibitors/pharmacokinetics , Protein Serine-Threonine Kinases/deficiency , Protein Serine-Threonine Kinases/genetics , Protein Serine-Threonine Kinases/metabolism , Rats , Rats, Sprague-Dawley , Reticulocytes/enzymology , Reticulocytes/pathology , Retina/drug effects , Retina/metabolism , Risk Assessment , Time Factors , Transfection , alpha-Synuclein/genetics , alpha-Synuclein/metabolismABSTRACT
Leucine-rich repeat kinase 2 (LRRK2) has been implicated in the pathogenesis of Parkinson's disease (PD). Inhibition of LRRK2 kinase activity is a therapeutic approach that may lead to new treatments for PD. Herein we report the discovery of a series of [1,2,4]triazolo[4,3-b]pyridazines that are potent against both wild-type and mutant LRRK2 kinase activity in biochemical assays and show an unprecedented selectivity towards the G2019S mutant. A structural rational for the observed selectivity is proposed.
Subject(s)
Protein Kinase Inhibitors/pharmacology , Protein Serine-Threonine Kinases/antagonists & inhibitors , Pyridazines/pharmacology , Dose-Response Relationship, Drug , HEK293 Cells , Humans , Leucine-Rich Repeat Serine-Threonine Protein Kinase-2 , Models, Molecular , Molecular Structure , Protein Kinase Inhibitors/chemical synthesis , Protein Kinase Inhibitors/chemistry , Protein Serine-Threonine Kinases/metabolism , Pyridazines/chemical synthesis , Pyridazines/chemistry , Structure-Activity RelationshipABSTRACT
Structure-activity relationship (SAR) of a novel, potent and metabolically stable series of benzo [3.2.1] bicyclic sulfonamide-pyrazoles as γ-secretase inhibitors are described. Compounds that are efficacious in reducing the cortical Aßx-40 levels in FVB mice via oral dose, as well as those with high selectivity over Notch, are highlighted.
Subject(s)
Amyloid Precursor Protein Secretases/antagonists & inhibitors , Pyrazoles/pharmacology , Sulfonamides/pharmacology , Amyloid Precursor Protein Secretases/metabolism , Animals , Bridged Bicyclo Compounds, Heterocyclic/chemistry , Bridged Bicyclo Compounds, Heterocyclic/pharmacology , Mice , Pyrazoles/chemistry , Structure-Activity Relationship , Sulfonamides/chemistryABSTRACT
Leucine rich repeat kinase 2 (LRRK2) has been implicated in the pathogenesis of Parkinson's disease (PD). Inhibition of LRRK2 kinase activity is a therapeutic approach that may lead to new treatments for PD. Herein we report the discovery of a series of cinnoline-3-carboxamides that are potent against both wild-type and mutant LRRK2 kinase activity in biochemical assays. These compounds are also shown to be potent inhibitors in a cellular assay and to have good to excellent CNS penetration.
Subject(s)
Heterocyclic Compounds, 2-Ring/chemistry , Protein Kinase Inhibitors/chemistry , Protein Serine-Threonine Kinases/antagonists & inhibitors , Amides/chemical synthesis , Amides/chemistry , Amides/metabolism , Animals , Binding Sites , HEK293 Cells , Humans , Leucine-Rich Repeat Serine-Threonine Protein Kinase-2 , Mice , Molecular Docking Simulation , Mutation , Protein Binding , Protein Kinase Inhibitors/chemical synthesis , Protein Kinase Inhibitors/metabolism , Protein Serine-Threonine Kinases/genetics , Protein Serine-Threonine Kinases/metabolism , Protein Structure, Tertiary , TransfectionABSTRACT
CONTEXT: Hydrophilic, non-aqueous solvents are frequently used to solubilize poorly water soluble compounds for use in ALZET® osmotic pumps used during the discovery and preclinical stages. Though these solvents exhibit the potential to solubilize several poorly soluble compounds, the solubilized compounds are prone to crystallization up on contact with aqueous fluids in vitro and in vivo. Crystallization of a compound can potentially cause pain at the release site, erratic blood levels, and uneven or delayed pharmacokinetic profiles. OBJECTIVE: In this study, we discussed the development of ALZET® pump compatible hydrophilic, non-aqueous vehicles that solubilized two poorly soluble model compounds (ELND006 and ELN 481594) and prevented their crystallization from solutions in vitro and in vivo. METHODS: The selected formulations were filled into the pumps at three concentrations for each model compound and investigated for their compatibility with the pumps and the subcutaneous tissue of mice where the pump was inserted. RESULTS AND DISCUSSION: The results showed that the formulations were stable physically with no crystallization and chemically with no degradation and were compatible with the pump and animal tissue. The plasma concentration of ELND006 decreased with time at each dose. The extent of the time-dependent decrease in ELND006 plasma levels increased as the amount of dose delivered increased. This time and dose dependent decrease in ELND006 plasma concentrations was attributed to the known auto-induction of hepatic enzymes by the compound. In contrast, the plasma concentration of ELN 481594 increased significantly at higher dose, likely due to accumulation of the compound.
Subject(s)
Pharmaceutical Preparations/chemistry , Water/chemistry , Animals , Chemistry, Pharmaceutical/methods , Crystallization , Drug Delivery Systems , Female , Hydrophobic and Hydrophilic Interactions , Mice , Osmosis , Solubility , Solvents/chemistryABSTRACT
ELND006 is a novel gamma secretase inhibitor previously under investigation for the oral treatment of Alzheimer's disease. ELND006 shows poor solubility and has moderate to high permeability, suggesting it is a Biopharmaceutics Classification System Class II compound. The poor absolute oral bioavailability of the compound in fasted dogs (F â¼11%) is attributed to poor aqueous solubility. In addition, inhibiting amyloid precursor protein but not Notch cleavage is an important goal for gamma secretase inhibitors; therefore, significant variation in bioavailability resulting from food consumption is a potential liability for this class of compounds. The objective of the present study was to determine if an ELND006 nanocrystalline formulation would offer improved and predictable pharmacokinetics. ELND006 was formulated as a nanosuspension with a mean particle size of less than 200 nm, which was stable in particle size and crystallinity for over 1 year. In addition, ELND006 nanosuspension exhibited rapid dissolution in comparison with reference active pharmaceutical ingredient (API). The in vivo performance of the ELND006 nanosuspension was tested in fed and fasted beagle dogs and compared with a gelatin capsule containing reference API. The results show that nanosizing ELND006 profoundly improved the oral bioavailability and virtually eliminated variation resulting from food intake.
Subject(s)
Amyloid Precursor Protein Secretases/antagonists & inhibitors , Food-Drug Interactions , Nanoparticles/chemistry , Protease Inhibitors/chemistry , Protease Inhibitors/pharmacokinetics , Pyrazoles/chemistry , Quinolines/chemistry , Animals , Area Under Curve , Biological Availability , Biopharmaceutics , Cell Line , Chemistry, Pharmaceutical , Dogs , Pyrazoles/pharmacokinetics , Quinolines/pharmacokinetics , Solubility , Suspensions , X-Ray DiffractionABSTRACT
The structure-activity relationship (SAR) of a novel, potent and metabolically stable series of sulfonamide-pyrazoles that attenuate ß-amyloid peptide synthesis via γ-secretase inhibition is detailed herein. Sulfonamide-pyrazoles that are efficacious in reducing the cortical Aßx-40 levels in FVB mice via a single PO dose, as well as sulfonamide-pyrazoles that exhibit selectivity for inhibition of APP versus Notch processing by γ-secretase, are highlighted.
Subject(s)
Amyloid Precursor Protein Secretases/antagonists & inhibitors , Amyloid beta-Protein Precursor/antagonists & inhibitors , Drug Design , Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/pharmacology , Heterocyclic Compounds, 3-Ring/chemical synthesis , Heterocyclic Compounds, 3-Ring/pharmacology , Sulfonamides/chemical synthesis , Sulfonamides/pharmacology , Amyloid beta-Peptides/metabolism , Animals , Drug Evaluation, Preclinical , Enzyme Inhibitors/chemistry , Heterocyclic Compounds, 3-Ring/chemistry , Inhibitory Concentration 50 , Mice , Mice, Inbred Strains , Structure-Activity Relationship , Sulfonamides/chemistryABSTRACT
The SAR of a series of brain penetrant, trisubstituted thiophene based JNK inhibitors with improved pharmacokinetic properties is described. These compounds were designed based on information derived from metabolite identification studies which led to compounds such as 42 with lower clearance, greater brain exposure and longer half life compared to earlier analogs.
Subject(s)
Brain/metabolism , Drug Design , Nerve Degeneration/prevention & control , Protein Kinase Inhibitors/chemical synthesis , Protein Kinase Inhibitors/pharmacology , Thiophenes/pharmacology , Thiophenes/pharmacokinetics , Animals , Chemistry Techniques, Synthetic , Crystallography, X-Ray , Dose-Response Relationship, Drug , Half-Life , JNK Mitogen-Activated Protein Kinases/antagonists & inhibitors , JNK Mitogen-Activated Protein Kinases/metabolism , Mice , Models, Molecular , Molecular Structure , Protein Kinase Inhibitors/chemistry , Protein Kinase Inhibitors/pharmacokinetics , Stereoisomerism , Structure-Activity Relationship , Thiophenes/chemical synthesis , Thiophenes/chemistryABSTRACT
Herein we describe the structure-activity relationship (SAR) of amino-caprolactam analogs derived from amino-caprolactam benzene sulfonamide 1, highlighting affects on the potency of γ-secretase inhibition, selectivity for the inhibition of APP versus Notch processing by γ-secretase and selected pharmakokinetic properties. Amino-caprolactams that are efficacious in reducing the cortical Aß(x-40) levels in FVB mice via a single 100 mpk IP dose are highlighted.
Subject(s)
Amyloid Precursor Protein Secretases/antagonists & inhibitors , Caprolactam/analogs & derivatives , Enzyme Inhibitors/pharmacology , Alzheimer Disease/drug therapy , Amyloid beta-Peptides/metabolism , Animals , Caprolactam/chemical synthesis , Caprolactam/chemistry , Caprolactam/pharmacology , Enzyme Activation/drug effects , Enzyme Inhibitors/chemical synthesis , Infusions, Parenteral , Inhibitory Concentration 50 , Mice , Molecular Structure , Peptide Fragments/metabolismABSTRACT
INTRODUCTION: Inhibition of gamma-secretase presents a direct target for lowering Aß production in the brain as a therapy for Alzheimer's disease (AD). However, gamma-secretase is known to process multiple substrates in addition to amyloid precursor protein (APP), most notably Notch, which has limited clinical development of inhibitors targeting this enzyme. It has been postulated that APP substrate selective inhibitors of gamma-secretase would be preferable to non-selective inhibitors from a safety perspective for AD therapy. METHODS: In vitro assays monitoring inhibitor potencies at APP γ-site cleavage (equivalent to Aß40), and Notch ε-site cleavage, in conjunction with a single cell assay to simultaneously monitor selectivity for inhibition of Aß production vs. Notch signaling were developed to discover APP selective gamma-secretase inhibitors. In vivo efficacy for acute reduction of brain Aß was determined in the PDAPP transgene model of AD, as well as in wild-type FVB strain mice. In vivo selectivity was determined following seven days x twice per day (b.i.d.) treatment with 15 mg/kg/dose to 1,000 mg/kg/dose ELN475516, and monitoring brain Aß reduction vs. Notch signaling endpoints in periphery. RESULTS: The APP selective gamma-secretase inhibitors ELN318463 and ELN475516 reported here behave as classic gamma-secretase inhibitors, demonstrate 75- to 120-fold selectivity for inhibiting Aß production compared with Notch signaling in cells, and displace an active site directed inhibitor at very high concentrations only in the presence of substrate. ELN318463 demonstrated discordant efficacy for reduction of brain Aß in the PDAPP compared with wild-type FVB, not observed with ELN475516. Improved in vivo safety of ELN475516 was demonstrated in the 7d repeat dose study in wild-type mice, where a 33% reduction of brain Aß was observed in mice terminated three hours post last dose at the lowest dose of inhibitor tested. No overt in-life or post-mortem indications of systemic toxicity, nor RNA and histological end-points indicative of toxicity attributable to inhibition of Notch signaling were observed at any dose tested. CONCLUSIONS: The discordant in vivo activity of ELN318463 suggests that the potency of gamma-secretase inhibitors in AD transgenic mice should be corroborated in wild-type mice. The discovery of ELN475516 demonstrates that it is possible to develop APP selective gamma-secretase inhibitors with potential for treatment for AD.
ABSTRACT
In this Letter, we describe our efforts to design HEA BACE-1 inhibitors that are highly permeable coupled with negligible levels of permeability-glycoprotein activity. These efforts culminate in producing 16 which lowers Αß by 28% and 32% in the cortex and CSF, respectively, in the preclinical wild type Hartley guinea pig animal model when dosed orally at 30mpk BID for 2.5days.
Subject(s)
Amyloid Precursor Protein Secretases/antagonists & inhibitors , Aspartic Acid Endopeptidases/antagonists & inhibitors , Ethylamines/chemical synthesis , Ethylamines/pharmacology , Protease Inhibitors/chemical synthesis , Protease Inhibitors/pharmacology , Alkylation , Alzheimer Disease , Animals , Brain/metabolism , Cell Line , Dogs , Drug Design , Guinea Pigs , Humans , Indicators and Reagents , Protease Inhibitors/pharmacokinetics , Protein Binding , Structure-Activity RelationshipABSTRACT
Significant improvement in metabolic stability on the pyrazolopiperidine scaffold over the original series were achieved and this stability improvement translated in an improved in vivo efficacy.
Subject(s)
Amyloid Precursor Protein Secretases/antagonists & inhibitors , Piperidines/chemistry , Sulfonamides/chemistry , Animals , Drug Discovery , Drug Stability , Microsomes, Liver/metabolism , Piperidines/chemical synthesis , Piperidines/pharmacology , Protease Inhibitors/chemical synthesis , Protease Inhibitors/chemistry , Protease Inhibitors/pharmacology , Sulfonamides/chemical synthesis , Sulfonamides/pharmacologyABSTRACT
Discovery of a series of pyrazolopiperidine sulfonamide based gamma-secretase inhibitors and its SAR evolution is described. Significant increases in APP potency on the pyrazolopiperidine scaffold over the original N-bicyclic sulfonamide scaffold were achieved and this potency increase translated in an improved in vivo efficacy.
Subject(s)
Amyloid Precursor Protein Secretases/antagonists & inhibitors , Amyloid Precursor Protein Secretases/metabolism , Piperidines/chemistry , Piperidines/pharmacology , Sulfonamides/chemistry , Sulfonamides/pharmacology , Alzheimer Disease/drug therapy , Animals , Humans , Mice , Models, Molecular , Piperidines/therapeutic use , Structure-Activity Relationship , Sulfonamides/therapeutic useABSTRACT
Utilizing a pharmacophore hypothesis, previously described gamma-secretase inhibiting HTS hits were evolved into novel tricyclic sulfonamide-pyrazoles, with high in vitro potency, good brain penetration, low metabolic stability, and high clearance.
Subject(s)
Alzheimer Disease/drug therapy , Amyloid Precursor Protein Secretases/antagonists & inhibitors , Amyloid Precursor Protein Secretases/metabolism , Pyrazoles/pharmacology , Sulfonamides/pharmacology , Animals , Crystallography, X-Ray , Humans , Inhibitory Concentration 50 , Models, Molecular , Pyrazoles/chemistry , Pyrazoles/pharmacokinetics , Rats , Rats, Sprague-Dawley , Structure-Activity Relationship , Sulfonamides/chemistry , Sulfonamides/pharmacokineticsABSTRACT
The structural modification of a series of [3.3.1] bicyclic sulfonamide based gamma-secretase inhibitors is described. Appropriate substitution on the bicyclic scaffold provides a significant increase in the metabolic stability of the compounds resulting in an improved in vivo metabolic profile.
Subject(s)
Alzheimer Disease/enzymology , Amyloid Precursor Protein Secretases/antagonists & inhibitors , Bridged Bicyclo Compounds/chemistry , Protease Inhibitors/chemistry , Sulfonamides/chemistry , Alzheimer Disease/drug therapy , Bridged Bicyclo Compounds/pharmacology , Bridged Bicyclo Compounds/therapeutic use , Humans , Protease Inhibitors/pharmacology , Protease Inhibitors/therapeutic use , Structure-Activity Relationship , Sulfonamides/pharmacology , Sulfonamides/therapeutic useABSTRACT
In this Letter, we report our strategy to design potent and metabolically stable gamma-secretase inhibitors that are efficacious in reducing the cortical Abetax-40 levels in FVB mice via a single PO dose.
Subject(s)
Amyloid Precursor Protein Secretases/antagonists & inhibitors , Protease Inhibitors/chemical synthesis , Pyrazoles/chemistry , Quinolines/chemistry , Sulfonamides/chemistry , Administration, Oral , Amyloid Precursor Protein Secretases/metabolism , Animals , Drug Design , Mice , Protease Inhibitors/chemistry , Protease Inhibitors/pharmacology , Quinolines/chemical synthesis , Quinolines/pharmacology , Structure-Activity RelationshipABSTRACT
Potent, small molecule A beta inhibitors have been prepared that incorporate an alanine core bracketed by an N-terminal arylacetyl group and various C-terminal amino alcohols. The compounds exhibit stereospecific inhibition as demonstrated in an in vitro assay.