Structure-Based Design of Novel Class II c-Met Inhibitors: 1. Identification of Pyrazolone-Based Derivatives

Deregulation of c-Met receptor tyrosine kinase activity leads to tumorigenesis and metastasis in animal models. More importantly, the identification of activating mutations in c-Met, as well as <i>MET</i> gene amplification in human cancers, points to c-Met as an important target for cancer therapy. We have previously described two classes of c-Met kinase inhibitors (class I and class II) that differ in their binding modes and selectivity profiles. The class II inhibitors tend to have activities on multiple kinases. Knowledge of the binding mode of these molecules in the c-Met protein led to the design and evaluation of several new class II c-Met inhibitors that utilize various 5-membered cyclic carboxamides to conformationally restrain key pharmacophoric groups within the molecule. These investigations resulted in the identification of a potent and novel class of pyrazolone c-Met inhibitors with good in vivo activity

Small Molecule Disruptors of the Glucokinase–Glucokinase Regulatory Protein Interaction: 5. A Novel Aryl Sulfone Series, Optimization Through Conformational Analysis

The glucokinase–glucokinase regulatory protein (GK-GKRP) complex plays an important role in controlling glucose homeostasis in the liver. We have recently disclosed a series of arylpiperazines as in vitro and in vivo disruptors of the GK-GKRP complex with efficacy in rodent models of type 2 diabetes mellitus (T2DM). Herein, we describe a new class of aryl sulfones as disruptors of the GK-GKRP complex, where the central piperazine scaffold has been replaced by an aromatic group. Conformational analysis and exploration of the structure–activity relationships of this new class of compounds led to the identification of potent GK-GKRP disruptors. Further optimization of this novel series delivered thiazole sulfone <b>93</b>, which was able to disrupt the GK-GKRP interaction in vitro and in vivo and, by doing so, increases cytoplasmic levels of unbound GK

Structure-Based Design of Novel Class II c-Met Inhibitors: 2. SAR and Kinase Selectivity Profiles of the Pyrazolone Series

As part of our effort toward developing an effective therapeutic agent for c-Met-dependent tumors, a pyrazolone-based class II c-Met inhibitor, <i>N</i>-(4-((6,7-dimethoxyquinolin-4-yl)­oxy)-3-fluorophenyl)-1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1<i>H</i>-pyrazole-4-carboxamide (<b>1</b>), was identified. Knowledge of the binding mode of this molecule in both c-Met and VEGFR-2 proteins led to a novel strategy for designing more selective analogues of <b>1</b>. Along with detailed SAR information, we demonstrate that the low kinase selectivity associated with class II c-Met inhibitors can be improved significantly. This work resulted in the discovery of potent c-Met inhibitors with improved selectivity profiles over VEGFR-2 and IGF-1R that could serve as useful tools to probe the relationship between kinase selectivity and in vivo efficacy in tumor xenograft models. Compound <b>59e</b> (AMG 458) was ultimately advanced into preclinical safety studies

Small Molecule Disruptors of the Glucokinase–Glucokinase Regulatory Protein Interaction: 3. Structure–Activity Relationships within the Aryl Carbinol Region of the <i>N</i>‑Arylsulfonamido‑<i>N</i>′‑arylpiperazine Series

We have recently reported a novel approach to increase cytosolic glucokinase (GK) levels through the binding of a small molecule to its endogenous inhibitor, glucokinase regulatory protein (GKRP). These initial investigations culminated in the identification of 2-(4-((2<i>S</i>)-4-((6-amino-3-pyridinyl)­sulfonyl)-2-(1-propyn-1-yl)-1-piperazinyl)­phenyl)-1,1,1,3,3,3-hexafluoro-2-propanol (<b>1</b>, AMG-3969), a compound that effectively enhanced GK translocation and reduced blood glucose levels in diabetic animals. Herein we report the results of our expanded SAR investigations that focused on modifications to the aryl carbinol group of this series. Guided by the X-ray cocrystal structure of compound <b>1</b> bound to hGKRP, we identified several potent GK–GKRP disruptors bearing a diverse set of functionalities in the aryl carbinol region. Among them, sulfoximine and pyridinyl derivatives <b>24</b> and <b>29</b> possessed excellent potency as well as favorable PK properties. When dosed orally in <i>db</i>/<i>db</i> mice, both compounds significantly lowered fed blood glucose levels (up to 58%)

Small Molecule Disruptors of the Glucokinase–Glucokinase Regulatory Protein Interaction: 2. Leveraging Structure-Based Drug Design to Identify Analogues with Improved Pharmacokinetic Profiles

In the previous report, we described the discovery and optimization of novel small molecule disruptors of the GK-GKRP interaction culminating in the identification of <b>1</b> (AMG-1694). Although this analogue possessed excellent in vitro potency and was a useful tool compound in initial proof-of-concept experiments, high metabolic turnover limited its advancement. Guided by a combination of metabolite identification and structure-based design, we have successfully discovered a potent and metabolically stable GK-GKRP disruptor (<b>27</b>, AMG-3969). When administered to <i>db</i>/<i>db</i> mice, this compound demonstrated a robust pharmacodynamic response (GK translocation) as well as statistically significant dose-dependent reductions in fed blood glucose levels

Structure-Based Design of a Novel Series of Potent, Selective Inhibitors of the Class I Phosphatidylinositol 3-Kinases

A highly selective series of inhibitors of the class I phosphatidylinositol 3-kinases (PI3Ks) has been designed and synthesized. Starting from the dual PI3K/mTOR inhibitor <b>5</b>, a structure-based approach was used to improve potency and selectivity, resulting in the identification of <b>54</b> as a potent inhibitor of the class I PI3Ks with excellent selectivity over mTOR, related phosphatidylinositol kinases, and a broad panel of protein kinases. Compound <b>54</b> demonstrated a robust PD–PK relationship inhibiting the PI3K/Akt pathway in vivo in a mouse model, and it potently inhibited tumor growth in a U-87 MG xenograft model with an activated PI3K/Akt pathway

Discovery and Structure-Guided Optimization of Diarylmethanesulfonamide Disrupters of Glucokinase–Glucokinase Regulatory Protein (GK–GKRP) Binding: Strategic Use of a N → S (n_N → σ*_S–X) Interaction for Conformational Constraint

The HTS-based discovery and structure-guided optimization of a novel series of GKRP-selective GK–GKRP disrupters are revealed. Diarylmethane­sulfonamide hit <b>6</b> (hGK–hGKRP IC₅₀ = 1.2 μM) was optimized to lead compound <b>32</b> (AMG-0696; hGK–hGKRP IC₅₀ = 0.0038 μM). A stabilizing interaction between a nitrogen atom lone pair and an aromatic sulfur system (n_N → σ*_S–X) in <b>32</b> was exploited to conformationally constrain a biaryl linkage and allow contact with key residues in GKRP. Lead compound <b>32</b> was shown to induce GK translocation from the nucleus to the cytoplasm in rats (IHC score = 0; 10 mg/kg po, 6 h) and blood glucose reduction in mice (POC = −45%; 100 mg/kg po, 3 h). X-ray analyses of <b>32</b> and several precursors bound to GKRP were also obtained. This novel disrupter of GK–GKRP binding enables further exploration of GKRP as a potential therapeutic target for type II diabetes and highlights the value of exploiting unconventional nonbonded interactions in drug design

Selective Class I Phosphoinositide 3‑Kinase Inhibitors: Optimization of a Series of Pyridyltriazines Leading to the Identification of a Clinical Candidate, AMG 511

The phosphoinositide 3-kinase family catalyzes the phosphorylation of phosphatidylinositol-4,5-diphosphate to phosphatidylinositol-3,4,5-triphosphate, a secondary messenger which plays a critical role in important cellular functions such as metabolism, cell growth, and cell survival. Our efforts to identify potent, efficacious, and orally available phosphatidylinositol 3-kinase (PI3K) inhibitors as potential cancer therapeutics have resulted in the discovery of 4-(2-((6-methoxypyridin-3-yl)­amino)-5-((4-(methylsulfonyl)­piperazin-1-yl)­methyl)­pyridin-3-yl)-6-methyl-1,3,5-triazin-2-amine (<b>1</b>). In this paper, we describe the optimization of compound <b>1</b>, which led to the design and synthesis of pyridyltriazine <b>31</b>, a potent pan inhibitor of class I PI3Ks with a superior pharmacokinetic profile. Compound <b>31</b> was shown to potently block the targeted PI3K pathway in a mouse liver pharmacodynamic model and inhibit tumor growth in a U87 malignant glioma glioblastoma xenograft model. On the basis of its excellent in vivo efficacy and pharmacokinetic profile, compound <b>31</b> was selected for further evaluation as a clinical candidate and was designated AMG 511