ABSTRACT
Understanding the metabolic transformations of a potential drug molecule is important to understanding the safety profile of a drug candidate. Liquid chromatography-mass spectrometry is a standard method for detecting metabolites in the drug discovery stage, but this can lead to an incomplete understanding of the molecule's metabolism. In this manuscript, we highlight the role radiolabeling played in determining the metabolism and in quantifying the metabolites of AZD8529, AZD7325, and AZD6280. A quantitative whole-body autoradiography study can detect covalent adducts in vivo as was the case with AZD5248 in which the compound was bound to the aorta. Ultimately another compound free of aortic binding was developed, AZD7986.
Subject(s)
Drug Development/methods , Gas Chromatography-Mass Spectrometry/methods , Heterocyclic Compounds, 2-Ring/chemistry , Indoles/chemistry , Oxadiazoles/chemistry , Animals , Carbon Radioisotopes/chemistry , Heterocyclic Compounds, 2-Ring/pharmacokinetics , Humans , Indoles/pharmacokinetics , Oxadiazoles/pharmacokineticsABSTRACT
The RAS/MAPK pathway is a major driver of oncogenesis and is dysregulated in approximately 30% of human cancers, primarily by mutations in the BRAF or RAS genes. The extracellular-signal-regulated kinases (ERK1 and ERK2) serve as central nodes within this pathway. The feasibility of targeting the RAS/MAPK pathway has been demonstrated by the clinical responses observed through the use of BRAF and MEK inhibitors in BRAF V600E/K metastatic melanoma; however, resistance frequently develops. Importantly, ERK1/2 inhibition may have clinical utility in overcoming acquired resistance to RAF and MEK inhibitors, where RAS/MAPK pathway reactivation has occurred, such as relapsed BRAF V600E/K melanoma. We describe our structure-based design approach leading to the discovery of AZD0364, a potent and selective inhibitor of ERK1 and ERK2. AZD0364 exhibits high cellular potency (IC50 = 6 nM) as well as excellent physicochemical and absorption, distribution, metabolism, and excretion (ADME) properties and has demonstrated encouraging antitumor activity in preclinical models.
Subject(s)
Antineoplastic Agents/pharmacology , Carcinoma, Non-Small-Cell Lung/drug therapy , Drug Discovery , Imidazoles/therapeutic use , Lung Neoplasms/drug therapy , Mitogen-Activated Protein Kinase 1/antagonists & inhibitors , Mitogen-Activated Protein Kinase 3/antagonists & inhibitors , Protein Kinase Inhibitors/pharmacology , Pyrazines/therapeutic use , Pyrimidines/pharmacology , Administration, Oral , Animals , Antineoplastic Agents/administration & dosage , Apoptosis , Carcinoma, Non-Small-Cell Lung/enzymology , Carcinoma, Non-Small-Cell Lung/pathology , Cell Proliferation , Drug Therapy, Combination , Female , Humans , Imidazoles/pharmacology , Lung Neoplasms/enzymology , Lung Neoplasms/pathology , Mice , Mice, Nude , Molecular Structure , Protein Kinase Inhibitors/administration & dosage , Pyrazines/pharmacology , Pyrimidines/administration & dosage , Pyrimidines/therapeutic use , Tumor Cells, Cultured , Xenograft Model Antitumor AssaysABSTRACT
There are a number of small-molecule inhibitors targeting the RAS/RAF/MEK/ERK signaling pathway that have either been approved or are in clinical development for oncology across a range of disease indications. The inhibition of ERK1/2 is of significant current interest, as cell lines with acquired resistance to BRAF and MEK inhibitors have been shown to maintain sensitivity to ERK1/2 inhibition in preclinical models. This article reports on our recent work to identify novel, potent, and selective reversible ERK1/2 inhibitors from a low-molecular-weight, modestly active, and highly promiscuous chemical start point, compound 4. To guide and inform the evolution of this series, inhibitor binding mode information from X-ray crystal structures was critical in the rapid exploration of this template to compound 35, which was active when tested in in vivo antitumor efficacy experiments.
Subject(s)
MAP Kinase Signaling System/drug effects , Protein Kinase Inhibitors/pharmacology , Animals , Biological Availability , Cell Line, Tumor , Dogs , Drug Discovery , Humans , Methylation , Protein Kinase Inhibitors/pharmacokineticsABSTRACT
A novel series of second generation DPP1 inhibitors free from aorta binding liabilities found for earlier compound series was discovered. This work culminated in the identification of compound 30 (AZD7986) as a highly potent, reversible, and selective clinical candidate for COPD, with predicted human PK properties suitable for once daily human dosing.
Subject(s)
Benzoxazoles/pharmacology , Cathepsin C/antagonists & inhibitors , Drug Discovery , Oxazepines/pharmacology , Protease Inhibitors/pharmacology , Administration, Oral , Animals , Benzoxazoles/administration & dosage , Benzoxazoles/chemistry , Cathepsin C/metabolism , Dogs , Dose-Response Relationship, Drug , Humans , Mice , Molecular Structure , Oxazepines/administration & dosage , Oxazepines/chemistry , Protease Inhibitors/administration & dosage , Protease Inhibitors/chemistry , Rabbits , Rats , Structure-Activity Relationship , U937 CellsABSTRACT
The oral dipeptidyl peptidase 1 (DPP1) inhibitor AZD5248 showed aortic binding in a rat quantitative whole-body autoradiography (QWBA) study, and its development was terminated prior to human dosing. A mechanistic hypothesis for this finding was established invoking reactivity with aldehydes involved in the cross-linking of elastin, a major component of aortic tissue. This was tested by developing a simple aldehyde chemical reactivity assay and a novel in vitro competitive covalent binding assay. Results obtained with AZD5248, literature compounds, and close analogues of AZD5248 support the mechanistic hypothesis and provide validation for the use of these assays in a two tier screening approach to support lead optimization. The strengths and limitations of these assays are discussed.
Subject(s)
Aorta/metabolism , Biphenyl Compounds/metabolism , Cathepsin C/antagonists & inhibitors , Protease Inhibitors/metabolism , Animals , Autoradiography , Biphenyl Compounds/chemistry , Cathepsin C/metabolism , Microscopy, Electron , Protease Inhibitors/chemistry , Rats , Rats, WistarABSTRACT
A novel method for the synthesis of a wide range of 1,5-disubstituted 1,2-dihydro-1,2,4-triazol-3-ones is described. The key step involves a reaction between a dilithiated BOC-hydrazine and a N-alkoxycarbonylcarboximidothioate. A broad range of aryl and alkyl functional groups are tolerated, providing a versatile route for the synthesis of triazolones.
Subject(s)
Lithium/chemistry , Organometallic Compounds/chemistry , Triazoles/chemical synthesis , Molecular Structure , Triazoles/chemistryABSTRACT
Idiosyncratic adverse drug reactions (IADRs) in humans can result in a broad range of clinically significant toxicities leading to attrition during drug development as well as postlicensing withdrawal or labeling. IADRs arise from both drug and patient related mechanisms and risk factors. Drug related risk factors, resulting from parent compound or metabolites, may involve multiple contributory mechanisms including organelle toxicity, effects related to compound disposition, and/or immune activation. In the current study, we evaluate an in vitro approach, which explored both cellular effects and covalent binding (CVB) to assess IADR risks for drug candidates using 36 drugs which caused different patterns and severities of IADRs in humans. The cellular effects were tested in an in vitro Panel of five assays which quantified (1) toxicity to THLE cells (SV40 T-antigen-immortalized human liver epithelial cells), which do not express P450s, (2) toxicity to a THLE cell line which selectively expresses P450 3A4, (3) cytotoxicity in HepG2 cells in glucose and galactose media, which is indicative of mitochondrial injury, (4) inhibition of the human bile salt export pump, BSEP, and (5) inhibition of the rat multidrug resistance associated protein 2, Mrp2. In addition, the CVB Burden was estimated by determining the CVB of radiolabeled compound to human hepatocytes and factoring in both the maximum prescribed daily dose and the fraction of metabolism leading to CVB. Combining the aggregated results from the in vitro Panel assays with the CVB Burden data discriminated, with high specificity (78%) and sensitivity (100%), between 27 drugs, which had severe or marked IADR concern, and 9 drugs, which had low IADR concern, we propose that this integrated approach has the potential to enable selection of drug candidates with reduced propensity to cause IADRs in humans.
Subject(s)
Prodrugs/adverse effects , ATP Binding Cassette Transporter, Subfamily B, Member 11 , ATP-Binding Cassette Transporters/chemistry , ATP-Binding Cassette Transporters/metabolism , Animals , Cell Line , Cell Survival/drug effects , Cytochrome P-450 CYP3A/metabolism , Galactose/pharmacology , Glucose/pharmacology , Hep G2 Cells , Humans , Mitochondria/drug effects , Mitochondria/metabolism , Multidrug Resistance-Associated Protein 2 , Multidrug Resistance-Associated Proteins/metabolism , Prodrugs/metabolism , Prodrugs/toxicity , Rats , Rats, Sprague-Dawley , Risk FactorsABSTRACT
A novel, potent and selective quinazolinone series of inhibitors of p38α MAP kinase has been identified. Modifications designed to address the issues of poor aqueous solubility and high plasma protein binding as well as embedded aniline functionalities resulted in the identification of a clinical candidate N-cyclopropyl-4-methyl-3-[6-(4-methylpiperazin-1-yl)-4-oxoquinazolin-3(4H)-yl]benzamide (AZD6703). Optimisation was guided by understanding of the binding modes from X-ray crystallographic studies which showed a switch from DFG 'out' to DFG 'in' as the inhibitor size was reduced to improve overall properties.
Subject(s)
Anti-Inflammatory Agents, Non-Steroidal/chemical synthesis , Mitogen-Activated Protein Kinase 14/antagonists & inhibitors , Piperazines/chemical synthesis , Protein Kinase Inhibitors/chemical synthesis , Animals , Anti-Inflammatory Agents, Non-Steroidal/chemistry , Anti-Inflammatory Agents, Non-Steroidal/pharmacology , Blood Proteins/chemistry , Crystallography, X-Ray , Dogs , Drug Discovery , Humans , Inflammation/drug therapy , Mitogen-Activated Protein Kinase 14/metabolism , Models, Molecular , Molecular Weight , Piperazines/chemistry , Piperazines/pharmacology , Protein Binding , Protein Kinase Inhibitors/chemistry , Protein Kinase Inhibitors/pharmacology , Rats , Solubility , Structure-Activity RelationshipABSTRACT
A valid PLS-DA model to predict attrition in pre-clinical toxicology for basic oral candidate drugs was built. A combination of aromatic/aliphatic balance, flatness, charge distribution and size descriptors helped predict the successful progression of compounds through a wide range of toxicity testing. Eighty percent of an independent test set of marketed post-2000 basic drugs could be successfully classified using the model, indicating useful forward predictivity. The themes within this work provide additional guidance for medicinal design chemists and complement other literature property guidelines.
Subject(s)
Drug Design , Drug Evaluation, Preclinical/methods , Drug Industry/methods , Models, Statistical , Toxicity Tests/methods , Animals , Discriminant Analysis , Humans , Molecular Structure , Pharmaceutical Preparations/chemistry , Pharmaceutical Preparations/metabolismABSTRACT
It has become evident that fluorinated compounds have a remarkable record in medicinal chemistry and will play a continuing role in providing lead compounds for therapeutic applications. This tutorial review provides a sampling of renowned fluorinated drugs and their mode of action with a discussion clarifying the role and impact of fluorine substitution on drug potency.
