ABSTRACT
Janus kinases (JAKs) are intracellular tyrosine kinases that mediate the signaling of numerous cytokines and growth factors involved in the regulation of immunity, inflammation, and hematopoiesis. As JAK1 pairs with JAK2, JAK3, and TYK2, a JAK1-selective inhibitor would be expected to inhibit many cytokines involved in inflammation and immune function while avoiding inhibition of the JAK2 homodimer regulating erythropoietin and thrombopoietin signaling. Our efforts began with tofacitinib, an oral JAK inhibitor approved for the treatment of rheumatoid arthritis. Through modification of the 3-aminopiperidine linker in tofacitinib, we discovered highly selective JAK1 inhibitors with nanomolar potency in a human whole blood assay. Improvements in JAK1 potency and selectivity were achieved via structural modifications suggested by X-ray crystallographic analysis. After demonstrating efficacy in a rat adjuvant-induced arthritis (rAIA) model, PF-04965842 (25) was nominated as a clinical candidate for the treatment of JAK1-mediated autoimmune diseases.
Subject(s)
Autoimmune Diseases/drug therapy , Cyclobutanes/pharmacology , Janus Kinase 1/antagonists & inhibitors , Protein Kinase Inhibitors/pharmacology , Pyrimidines/pharmacology , Pyrroles/pharmacology , Sulfonamides/pharmacology , Animals , Arthritis, Experimental/drug therapy , Cyclobutanes/chemistry , Cyclobutanes/pharmacokinetics , Cyclobutanes/therapeutic use , Dogs , Drug Evaluation, Preclinical , Humans , Inhibitory Concentration 50 , Janus Kinase 1/chemistry , Janus Kinase 2/antagonists & inhibitors , Models, Molecular , Protein Conformation , Protein Kinase Inhibitors/chemistry , Protein Kinase Inhibitors/pharmacokinetics , Protein Kinase Inhibitors/therapeutic use , Pyrimidines/chemistry , Pyrimidines/pharmacokinetics , Pyrimidines/therapeutic use , Pyrroles/chemistry , Pyrroles/pharmacokinetics , Pyrroles/therapeutic use , Rats , Substrate Specificity , Sulfonamides/chemistry , Sulfonamides/pharmacokinetics , Sulfonamides/therapeutic use , Tissue DistributionABSTRACT
Herein we report the identification of two new fatty acid amide hydrolase (FAAH) inhibitor lead series with FAAH k(inact)/K(i) potency values greater than 1500M(-1)s(-1). The two novel spirocyclic cores, 7-azaspiro[3.5]nonane and 1-oxa-8-azaspiro[4.5]decane, clearly distinguished themselves from the other spirocyclic cores on the basis of their superior potency for FAAH. Lead compounds from these two series have suitable FAAH potency and selectivity for additional medicinal chemistry optimization.
Subject(s)
Amidohydrolases/antagonists & inhibitors , Aza Compounds/pharmacology , Drug Discovery , Enzyme Inhibitors/pharmacology , Spiro Compounds/pharmacology , Aza Compounds/chemistry , Enzyme Inhibitors/chemistry , Models, Molecular , Spiro Compounds/chemistry , Structure-Activity RelationshipABSTRACT
Janus kinases (JAKs) are critical regulators of cytokine pathways and attractive targets of therapeutic value in both inflammatory and myeloproliferative diseases. Although the crystal structures of active JAK1 and JAK2 kinase domains have been reported recently with the clinical compound CP-690550, the structures of both TYK2 and JAK3 with CP-690550 have remained outstanding. Here, we report the crystal structures of TYK2, a first in class structure, and JAK3 in complex with PAN-JAK inhibitors CP-690550 ((3R,4R)-3-[4-methyl-3-[N-methyl-N-(7H-pyrrolo[2,3-d]pyrimidin-4-yl)amino]piperidin-1-yl]-3-oxopropionitrile) and CMP-6 (tetracyclic pyridone 2-t-butyl-9-fluoro-3,6-dihydro-7H-benz[h]-imidaz[4,5-f]isoquinoline-7-one), both of which bind in the ATP-binding cavities of both JAK isozymes in orientations similar to that observed in crystal structures of JAK1 and JAK2. Additionally, a complete thermodynamic characterization of JAK/CP-690550 complex formation was completed by isothermal titration calorimetry, indicating the critical role of the nitrile group from the CP-690550 compound. Finally, computational analysis using WaterMap further highlights the critical positioning of the CP-690550 nitrile group in the displacement of an unfavorable water molecule beneath the glycine-rich loop. Taken together, the data emphasize the outstanding properties of the kinome-selective JAK inhibitor CP-690550, as well as the challenges in obtaining JAK isozyme-selective inhibitors due to the overall structural and sequence similarities between the TYK2, JAK1, JAK2 and JAK3 isozymes. Nevertheless, subtle amino acid variations of residues lining the ligand-binding cavity of the JAK enzymes, as well as the global positioning of the glycine-rich loop, might provide the initial clues to obtaining JAK-isozyme selective inhibitors.
Subject(s)
Benzimidazoles/metabolism , Enzyme Inhibitors/metabolism , Janus Kinase 3/chemistry , Pyridones/metabolism , Pyrimidines/metabolism , Pyrroles/metabolism , TYK2 Kinase/chemistry , Binding Sites , Calorimetry , Humans , Janus Kinase 3/metabolism , Kinetics , Models, Molecular , Piperidines , Protein Binding , Protein Structure, Tertiary , TYK2 Kinase/metabolismABSTRACT
Herein we describe the design and synthesis of a novel series of potent thienopyrimidine P2Y12 inhibitors and the negative impact protein binding has on the inhibition of platelet aggregation.
Subject(s)
Fibrinolytic Agents/chemistry , Platelet Aggregation Inhibitors/chemistry , Platelet Aggregation/drug effects , Purinergic P2 Receptor Antagonists , Pyrimidines/chemistry , Fibrinolytic Agents/chemical synthesis , Fibrinolytic Agents/pharmacology , Humans , Platelet Aggregation Inhibitors/chemical synthesis , Platelet Aggregation Inhibitors/pharmacology , Protein Binding , Pyrimidines/chemical synthesis , Pyrimidines/pharmacology , Receptors, Purinergic P2/metabolism , Receptors, Purinergic P2Y12 , Structure-Activity RelationshipABSTRACT
Fatty acid amide hydrolase (FAAH) has attracted significant attention due to its promise as an analgesic target. This has resulted in the discovery of numerous chemical classes as inhibitors of this potential therapeutic target. In this paper we disclose a new series of novel FAAH irreversible azetidine urea inhibitors. In general these compounds illustrate potent activity against the rat FAAH enzyme. Our SAR studies allowed us to optimize this series resulting in the identification of compounds 13 which were potent inhibitors of both human and rat enzyme. This series of compounds illustrated good hydrolase selectivity along with good PK properties.
Subject(s)
Amidohydrolases/antagonists & inhibitors , Analgesics/chemistry , Azetidines/chemistry , Enzyme Inhibitors/chemistry , Pyridazines/chemistry , Urea/chemistry , Amidohydrolases/metabolism , Analgesics/chemical synthesis , Analgesics/pharmacokinetics , Animals , Azetidines/chemical synthesis , Azetidines/pharmacokinetics , Binding Sites , Crystallography, X-Ray , Drug Design , Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/pharmacokinetics , Humans , Pyridazines/chemical synthesis , Pyridazines/pharmacokinetics , Rats , Structure-Activity Relationship , Urea/chemical synthesis , Urea/pharmacokineticsABSTRACT
The design and synthesis of a novel series of potent BACE1 hydroxyethylamine inhibitors. These inhibitors feature hydrogen bonding substituents at the C-5 position of the isophthalamide ring with improved selectivity over cathepsin D.
