ABSTRACT
KRASG12C has emerged as a promising target in the treatment of solid tumors. Covalent inhibitors targeting the mutant cysteine-12 residue have been shown to disrupt signaling by this long-"undruggable" target; however clinically viable inhibitors have yet to be identified. Here, we report efforts to exploit a cryptic pocket (H95/Y96/Q99) we identified in KRASG12C to identify inhibitors suitable for clinical development. Structure-based design efforts leading to the identification of a novel quinazolinone scaffold are described, along with optimization efforts that overcame a configurational stability issue arising from restricted rotation about an axially chiral biaryl bond. Biopharmaceutical optimization of the resulting leads culminated in the identification of AMG 510, a highly potent, selective, and well-tolerated KRASG12C inhibitor currently in phase I clinical trials (NCT03600883).
Subject(s)
Antineoplastic Agents/therapeutic use , Neoplasms/drug therapy , Piperazines/therapeutic use , Proto-Oncogene Proteins p21(ras)/antagonists & inhibitors , Pyridines/therapeutic use , Pyrimidines/therapeutic use , Pyrimidinones/therapeutic use , Animals , Antineoplastic Agents/chemistry , Antineoplastic Agents/pharmacokinetics , Clinical Trials as Topic , Dogs , Drug Discovery , Humans , Isomerism , Madin Darby Canine Kidney Cells , Mice, Inbred BALB C , Mice, Nude , Mutation , Piperazines/chemistry , Piperazines/pharmacology , Proto-Oncogene Proteins p21(ras)/genetics , Pyridines/chemistry , Pyridines/pharmacokinetics , Pyridines/pharmacology , Pyrimidines/chemistry , Pyrimidines/pharmacology , Pyrimidinones/chemistry , Pyrimidinones/pharmacokinetics , Rats , Structure-Activity RelationshipABSTRACT
We report the discovery of a novel series of 2-(3-alkoxy-1-azetidinyl) quinolines as potent and selective PDE10A inhibitors. Structure-activity studies improved the solubility (pH 7.4) and maintained high PDE10A activity compared to initial lead compound 3, with select compounds demonstrating good oral bioavailability. X-ray crystallographic studies revealed two distinct binding modes to the catalytic site of the PDE10A enzyme. An ex vivo receptor occupancy assay in rats demonstrated that this series of compounds covered the target within the striatum.
Subject(s)
Phosphodiesterase Inhibitors/pharmacology , Phosphoric Diester Hydrolases/metabolism , Quinolines/pharmacology , Dose-Response Relationship, Drug , Humans , Models, Molecular , Molecular Structure , Phosphodiesterase Inhibitors/chemical synthesis , Phosphodiesterase Inhibitors/chemistry , Quinolines/chemical synthesis , Quinolines/chemistry , Solubility , Structure-Activity RelationshipABSTRACT
A series of aminooxadiazoles was optimized for inhibition of Cdc7. Early lead isoquinoline 1 suffered from modest cell potency (cellular IC50=0.71 µM measuring pMCM2), low selectivity against structurally related kinases, and high IV clearance in rats (CL=18 L/h/kg). Extensive optimization resulted in azaindole 26 (Cdc7 IC50=1.1 nM, pMCM2 IC50=32 nM) that demonstrated robust lowering of pMCM2 in a mouse pharmacodynamic (PD) model when dosed orally. Modifications to improve the pharmacokinetic profile of this series were guided by trapping experiments with glutathione in rat hepatocytes.
Subject(s)
Cell Cycle Proteins/antagonists & inhibitors , Oxadiazoles/chemistry , Protein Kinase Inhibitors/pharmacology , Protein Serine-Threonine Kinases/antagonists & inhibitors , Animals , Cell Cycle Proteins/chemistry , Cell Cycle Proteins/metabolism , Disease Models, Animal , Female , Mice , Mice, Nude , Molecular Structure , Oxadiazoles/chemical synthesis , Oxadiazoles/pharmacology , Protein Kinase Inhibitors/chemical synthesis , Protein Kinase Inhibitors/chemistry , Protein Serine-Threonine Kinases/chemistry , Protein Serine-Threonine Kinases/metabolism , Rats , Structure-Activity Relationship , Xenograft Model Antitumor AssaysABSTRACT
Replacement of the azetidine carboxylate of an S1P(1) agonist development candidate, AMG 369, with a range of acyclic head-groups led to the identification of a novel, S1P(3)-sparing S1P(1) agonist, (-)-2-amino-4-(3-fluoro-4-(5-(1-phenylcyclopropyl)thiazolo[5,4-b]pyridin-2-yl)phenyl)-2-methylbutanoic acid (8c), which possessed good in vivo efficacy and pharmacokinetic properties. A 0.3mg/kg oral dose of 8c produced a statistically significant reduction in blood lymphocyte counts 24h post-dosing in female Lewis rats.
Subject(s)
Amines/chemistry , Carboxylic Acids/chemistry , Protein Isoforms/chemistry , Pyridines/chemistry , Pyridines/chemical synthesis , Pyridines/pharmacology , Receptors, Lysosphingolipid/agonists , Thiazoles/chemistry , Administration, Oral , Animals , Cyclization , Female , Inhibitory Concentration 50 , Molecular Structure , Protein Binding/drug effects , Rats , Rats, Inbred Lew , Thiazoles/chemical synthesis , Thiazoles/pharmacologyABSTRACT
An SAR campaign designed to increase polarity in the 'tail' region of benzothiazole 1 resulted in two series of structurally novel 5-and 6-substituted S1P(1) agonists. Structural optimization for potency ultimately delivered carboxamide (+)-11f, which in addition to possessing improved physicochemical properties relative to starting benzothiazole 1, also displayed good S1P(3) selectivity and acceptable in vivo lymphocyte-depleting activity.
Subject(s)
Benzothiazoles/chemistry , Lymphocytes/drug effects , Receptors, Lysosphingolipid/agonists , Receptors, Lysosphingolipid/chemistry , Animals , CHO Cells , Cell Line, Tumor , Chemistry, Pharmaceutical/methods , Chemistry, Physical/methods , Cricetinae , Cricetulus , Drug Design , Female , Green Fluorescent Proteins/metabolism , Humans , Ketones , Lymphocytes/cytology , Models, Chemical , Rats , Rats, Inbred Lew , Receptors, G-Protein-Coupled/metabolismABSTRACT
The optimization of a series of S1P1 agonists with limited activity against S1P3 is reported. A polar headgroup was used to improve the physicochemical and pharmacokinetic parameters of lead quinolinone 6. When dosed orally at 1 and 3 mg/kg, the azahydroxymethyl analogue 22 achieved statistically significant lowering of circulating blood lymphocytes 24 h postdose. In rats, a dose-proportional increase in exposure was measured when 22 was dosed orally at 2 and 100 mg/kg.
ABSTRACT
We reveal how a N-scan SAR strategy (systematic substitution of each CH group with a N atom) was employed for quinolinone-based S1P(1) agonist 5 to modulate physicochemical properties and optimize in vitro and in vivo activity. The diaza-analog 17 displays improved potency (hS1P(1) RI; 17: EC(50)=0.020 µM, 120% efficacy; 5: EC(50)=0.070 µM, 110% efficacy) and selectivity (hS1P(3) Ca(2+) flux; 17: EC(50) >25 µM; 5: EC(50)=1.5 µM, 92% efficacy), as well as enhanced pharmacokinetics (17: CL=0.15 L/h/kg, V(dss)=5.1L/kg, T(1/2)=24h, %F=110; 5: CL=0.93L/h/kg, V(dss)=11L/kg, T(1/2)=15 h, %F=60) and pharmacodynamics (17: 1.0mg/kg po, 24h PLC POC=-67%; 5: 3mg/kg po, 24h PLC POC=-51%) in rat.
Subject(s)
Chemistry, Physical/methods , Quinolones/pharmacology , Receptors, Lysosphingolipid/agonists , Receptors, Lysosphingolipid/chemistry , Animals , Area Under Curve , Cardiovascular Diseases/metabolism , Drug Design , Female , Humans , Immunosuppressive Agents/pharmacology , In Vitro Techniques , Kinetics , Lymphocytes/cytology , Lymphocytes/metabolism , Models, Chemical , Multiple Sclerosis/drug therapy , Quinolones/chemistry , Rats , Rats, Inbred Lew , Structure-Activity RelationshipABSTRACT
The sphingosine-1-phosphate-1 receptor (S1P1) and its endogenous ligand sphingosine-1-phosphate (S1P) cooperatively regulate lymphocyte trafficking from the lymphatic system. Herein, we disclose 4-methoxy-N-[2-(trifluoromethyl)biphenyl-4-ylcarbamoyl]nicotinamide (8), an uncommon example of a synthetic S1P1 agonist lacking a polar headgroup, which is shown to effect dramatic reduction of circulating lymphocytes (POC = -78%) in rat 24 h after a single oral dose (1 mg/kg). The excellent potency that 8 exhibits toward S1P1 (EC50 = 0.035 µM, 96% efficacy) and the >100-fold selectivity that it displays against receptor subtypes S1P2-5 suggest that it may serve as a valuable tool to understand the clinical relevance of selective S1P1 agonism.
ABSTRACT
Optimization of a benzofuranyl S1P1 agonist lead compound (3) led to the discovery of 1-(3-fluoro-4-(5-(2-fluorobenzyl)benzo[d]thiazol-2-yl)benzyl)azetidine-3-carboxylic acid (14), a potent S1P1 agonist with minimal activity at S1P3. Dosed orally at 0.3 mg/kg, 14 significantly reduced blood lymphocyte counts 24 h postdose and attenuated a delayed type hypersensitivity (DTH) response to antigen challenge.
ABSTRACT
We report the structure-based design and synthesis of a novel series of aza-benzimidazoles as PHD2 inhibitors. These efforts resulted in compound 22, which displayed highly potent inhibition of PHD2 function in vitro.
