Discovery of the imidazole-derived GPR40 agonist AM-3189.

As a follow-up to the GPR40 agonist AMG 837, which was evaluated in clinical trials for the treatment of type II diabetes, further optimization led to the discovery of AM-3189 (13k). AM-3189 is representative of a new class of compounds with minimal CNS penetration, superior pharmacokinetic properties and in vivo efficacy comparable to AMG 837.

Discovery of INT131: a selective PPARγ modulator that enhances insulin sensitivity.

PPARγ is a member of the nuclear hormone receptor family and plays a key role in the regulation of glucose homeostasis. This Letter describes the discovery of a novel chemical class of diarylsulfonamide partial agonists that act as selective PPARγ modulators (SPPARγMs) and display a unique pharmacological profile compared to the thiazolidinedione (TZD) class of PPARγ full agonists. Herein we report the initial discovery of partial agonist 4 and the structure-activity relationship studies that led to the selection of clinical compound INT131 (3), a potent PPARγ partial agonist that displays robust glucose-lowering activity in rodent models of diabetes while exhibiting a reduced side-effects profile compared to marketed TZDs.

Identification and pharmacological characterization of multiple allosteric binding sites on the free fatty acid 1 receptor.

Activation of FFA1 (GPR40), a member of G protein-coupling receptor family A, is mediated by medium- and long-chain fatty acids and leads to amplification of glucose-stimulated insulin secretion, suggesting a potential role for free fatty acid 1 (FFA1) as a target for type 2 diabetes. It was assumed previously that there is a single binding site for fatty acids and synthetic FFA1 agonists. However, using members of two chemical series of partial and full agonists that have been identified, radioligand binding interaction studies revealed that the full agonists do not bind to the same site as the partial agonists but exhibit positive heterotropic cooperativity. Analysis of functional data reveals positive functional cooperativity between the full agonists and partial agonists in various functional assays (in vitro and ex vivo) and also in vivo. Furthermore, the endogenous fatty acid docosahexaenoic acid (DHA) shows negative or neutral cooperativity with members of both series of agonists in binding assays but displays positive cooperativity in functional assays. Another synthetic agonist is allosteric with members of both agonist series, but apparently competitive with DHA. Therefore, there appear to be three allosterically linked binding sites on FFA1 with agonists specific for each of these sites. Activation of free fatty acid 1 receptor (FFAR1) by each of these agonists is differentially affected by mutations of two arginine residues, previously found to be important for FFAR1 binding and activation. These ligands with their high potencies and strong positive functional cooperativity with endogenous fatty acids, demonstrated in vitro and in vivo, have the potential to deliver therapeutic benefits.

Discovery and optimization of a novel series of GPR142 agonists for the treatment of type 2 diabetes mellitus.

The discovery and initial optimization of a series of phenylalanine based agonists for GPR142 is described. The structure-activity-relationship around the major areas of the molecule was explored to give agonists 90 times more potent than the initial HTS hit in a human GPR142 inositol phosphate accumulation assay. Removal of CYP inhibition by exploration of the pyridine A-ring is also described.

Phenylalanine derivatives as GPR142 agonists for the treatment of type II diabetes.

GPR142 is a novel GPCR that is predominantly expressed in pancreatic ß-cells. GPR142 agonists potentiate glucose-dependent insulin secretion, and therefore can reduce the risk of hypoglycemia. Optimization of our lead pyridinone-phenylalanine series led to a proof-of-concept compound 22, which showed in vivo efficacy in mice with dose-dependent increase in insulin secretion and a decrease in glucose levels.

AMG 837: a potent, orally bioavailable GPR40 agonist.

The discovery that certain long chain fatty acids potentiate glucose stimulated insulin secretion through the previously orphan receptor GPR40 sparked interest in GPR40 agonists as potential antidiabetic agents. Optimization of a series of ß-substituted phenylpropanoic acids led to the identification of (S)-3-(4-((4'-(trifluoromethyl)biphenyl-3-yl)methoxy)phenyl)hex-4-ynoic acid (AMG 837) as a potent GPR40 agonist with a superior pharmacokinetic profile and robust glucose-dependent stimulation of insulin secretion in rodents.

Optimization of triazoles as novel and potent nonphlorizin SGLT2 inhibitors.

Previous efforts have led to the identification of a potent, selective, and nonphlorizin based SGLT2 inhibitor 1. This Letter describes efforts to further optimize the potency, microsomal stability, solubility and pharmacokinetic properties of this series of SGLT2 inhibitors. From these efforts, compounds 28 and 32 have improved solubility and pharmacokinetic properties compared to compound 1.

Cardiovascular response to small-molecule APJ activation.

Heart failure (HF) remains a grievous illness with poor prognosis even with optimal care. The apelin receptor (APJ) counteracts the pressor effect of angiotensin II, attenuates ischemic injury, and has the potential to be a novel target to treat HF. Intravenous administration of apelin improves cardiac function acutely in patients with HF. However, its short half-life restricts its use to infusion therapy. To identify a longer acting APJ agonist, we conducted a medicinal chemistry campaign, leading to the discovery of potent small-molecule APJ agonists with comparable activity to apelin by mimicking the C-terminal portion of apelin-13. Acute infusion increased systolic function and reduced systemic vascular resistance in 2 rat models of impaired cardiac function. Similar results were obtained in an anesthetized but not a conscious canine HF model. Chronic oral dosing in a rat myocardial infarction model reduced myocardial collagen content and improved diastolic function to a similar extent as losartan, a RAS antagonist standard-of-care therapy, but lacked additivity with coadministration. Collectively, this work demonstrates the feasibility of developing clinical, viable, potent small-molecule agonists that mimic the endogenous APJ ligand with more favorable drug-like properties and highlights potential limitations for APJ agonism for this indication.

Discovery and in Vivo Evaluation of Macrocyclic Mcl-1 Inhibitors Featuring an α-Hydroxy Phenylacetic Acid Pharmacophore or Bioisostere.

Overexpression of the antiapoptotic protein Mcl-1 provides a survival advantage to some cancer cells, making inhibition of this protein an attractive therapeutic target for the treatment of certain types of tumors. Herein, we report our efforts toward the identification of a novel series of macrocyclic Mcl-1 inhibitors featuring an α-hydroxy phenylacetic acid pharmacophore or bioisostere. This work led to the discovery of 1, a potent Mcl-1 inhibitor (IC50 = 19 nM in an OPM-2 cell viability assay) with good pharmacokinetic properties and excellent in vivo efficacy in an OPM-2 multiple myeloma xenograft model.

Discovery of AM-6226: A Potent and Orally Bioavailable GPR40 Full Agonist That Displays Efficacy in Nonhuman Primates.

GPR40 (FFA1) is a G-protein-coupled receptor, primarily expressed in pancreatic islets and enteroendocrine L-cells, and, when activated, elicits increased insulin secretion only in the presence of elevated glucose levels. We recently reported the discovery of AM-1638 (2), a full agonist of GPR40. Herein, we present further structure-activity relationships progressing from AM-1638 (2) to AM-6226 (14) that possesses a profile acceptable for dosing cynomolgus monkeys. The GPR40 full agonist AM-6226 (14) is the first molecule to display significant glucose lowering in cynomolgus monkeys providing additional evidence that GPR40 full agonists afford access to a powerful mechanism for maintaining glycemic control.

AMG 176, a Selective MCL1 Inhibitor, Is Effective in Hematologic Cancer Models Alone and in Combination with Established Therapies.

The prosurvival BCL2 family member MCL1 is frequently dysregulated in cancer. To overcome the significant challenges associated with inhibition of MCL1 protein-protein interactions, we rigorously applied small-molecule conformational restriction, which culminated in the discovery of AMG 176, the first selective MCL1 inhibitor to be studied in humans. We demonstrate that MCL1 inhibition induces a rapid and committed step toward apoptosis in subsets of hematologic cancer cell lines, tumor xenograft models, and primary patient samples. With the use of a human MCL1 knock-in mouse, we demonstrate that MCL1 inhibition at active doses of AMG 176 is tolerated and correlates with clear pharmacodynamic effects, demonstrated by reductions in B cells, monocytes, and neutrophils. Furthermore, the combination of AMG 176 and venetoclax is synergistic in acute myeloid leukemia (AML) tumor models and in primary patient samples at tolerated doses. These results highlight the therapeutic promise of AMG 176 and the potential for combinations with other BH3 mimetics. SIGNIFICANCE: AMG 176 is a potent, selective, and orally bioavailable MCL1 inhibitor that induces a rapid commitment to apoptosis in models of hematologic malignancies. The synergistic combination of AMG 176 and venetoclax demonstrates robust activity in models of AML at tolerated doses, highlighting the promise of BH3-mimetic combinations in hematologic cancers.See related commentary by Leber et al., p. 1511.This article is highlighted in the In This Issue feature, p. 1494.

5-Alkyl-2-urea-Substituted Pyridines: Identification of Efficacious Glucokinase Activators with Improved Properties.

Two 1-(4-aryl-5-alkyl-pyridin-2-yl)-3-methylurea glucokinase activators were identified with robust in vivo efficacy. These two compounds possessed higher solubilities than the previously identified triaryl compounds (i.e., AM-2394). Structure-activity relationship studies are presented along with relevant pharmacokinetic and in vivo data.

Novel Series of Potent Glucokinase Activators Leading to the Discovery of AM-2394.

Glucokinase (GK) catalyzes the phosphorylation of glucose to glucose-6-phosphate. We present the structure-activity relationships leading to the discovery of AM-2394, a structurally distinct GKA. AM-2394 activates GK with an EC50 of 60 nM, increases the affinity of GK for glucose by approximately 10-fold, exhibits moderate clearance and good oral bioavailability in multiple animal models, and lowers glucose excursion following an oral glucose tolerance test in an ob/ob mouse model of diabetes.

Convenient route to secondary sulfinates: application to the stereospecific synthesis of α-C-chiral sulfonamides.

A convenient synthesis of α-chiral sulfinates from readily available precursors has been accomplished via the corresponding heterocyclic thioethers and sulfones. Treatment of the sulfinates with hydroxylamine sulfonate in aqueous solution provides α-C-chiral primary sulfonamides in good yield (14 examples) with retention of stereochemical purity.

Discovery of 2-pyridylureas as glucokinase activators.

Glucokinase (GK) is the rate-limiting step for insulin release from the pancreas in response to high levels of glucose. Flux through GK also contributes to reducing hepatic glucose output. Since many individuals with type 2 diabetes appear to have an inadequacy or defect in one or both of these processes, identifying compounds that can allosterically activate GK may address this issue. Herein we report the identification and initial optimization of a novel series of glucokinase activators (GKAs). Optimization led to the identification of 33 as a compound that displayed activity in an oral glucose tolerance test (OGTT) in normal and diabetic mice.

Improving the Pharmacokinetics of GPR40/FFA1 Full Agonists.

We recently reported the discovery of a potent GPR40 full agonist AM-1638 (1). Herein, we describe our efforts in improving the drug-like properties of the full agonists through the systematic introduction of polar groups in the C-, D-, and A-rings. This led to the discovery of new GPR40 full agonists with significantly improved pharmacokinetic propeties. Compound 8 and 20 also showed potent in vivo efficacy in oral glucose tolerance tests in mice in addition to the improvement in properties.

Optimization of GPR40 Agonists for Type 2 Diabetes.

GPR40 (FFA1 and FFAR1) has gained significant interest as a target for the treatment of type 2 diabetes. TAK-875 (1), a GPR40 agonist, lowered hemoglobin A1c (HbA1c) and lowered both postprandial and fasting blood glucose levels in type 2 diabetic patients in phase II clinical trials. We optimized phenylpropanoic acid derivatives as GPR40 agonists and identified AMG 837 (2) as a clinical candidate. Here we report our efforts in searching for structurally distinct back-ups for AMG 837. These efforts led to the identification of more polar GPR40 agonists, such as AM-4668 (10), that have improved potency, excellent pharmacokinetic properties across species, and minimum central nervous system (CNS) penetration.

Discovery of AM-7209, a potent and selective 4-amidobenzoic acid inhibitor of the MDM2-p53 interaction.

Structure-based rational design and extensive structure-activity relationship studies led to the discovery of AMG 232 (1), a potent piperidinone inhibitor of the MDM2-p53 association, which is currently being evaluated in human clinical trials for the treatment of cancer. Further modifications of 1, including replacing the carboxylic acid with a 4-amidobenzoic acid, afforded AM-7209 (25), featuring improved potency (KD from ITC competition was 38 pM, SJSA-1 EdU IC50 = 1.6 nM), remarkable pharmacokinetic properties, and in vivo antitumor activity in both the SJSA-1 osteosarcoma xenograft model (ED50 = 2.6 mg/kg QD) and the HCT-116 colorectal carcinoma xenograft model (ED50 = 10 mg/kg QD). In addition, 25 possesses distinct mechanisms of elimination compared to 1.

Selective and potent morpholinone inhibitors of the MDM2-p53 protein-protein interaction.

We previously reported the discovery of AMG 232, a highly potent and selective piperidinone inhibitor of the MDM2-p53 interaction. Our continued search for potent and diverse analogues led to the discovery of novel morpholinone MDM2 inhibitors. This change to a morpholinone core has a significant impact on both potency and metabolic stability compared to the piperidinone series. Within this morpholinone series, AM-8735 emerged as an inhibitor with remarkable biochemical potency (HTRF IC50 = 0.4 nM) and cellular potency (SJSA-1 EdU IC50 = 25 nM), as well as pharmacokinetic properties. Compound 4 also shows excellent antitumor activity in the SJSA-1 osteosarcoma xenograft model with an ED50 of 41 mg/kg. Lead optimization toward the discovery of this inhibitor as well as key differences between the morpholinone and the piperidinone series will be described herein.

Novel inhibitors of the MDM2-p53 interaction featuring hydrogen bond acceptors as carboxylic acid isosteres.

We previously reported the discovery of potent and selective morpholinone and piperidinone inhibitors of the MDM2-p53 interaction. These inhibitors have in common a carboxylic acid moiety that engages in an electrostatic interaction with MDM2-His96. Our continued search for potent and diverse inhibitors led to the discovery of novel replacements for these acids uncovering new interactions with the MDM2 protein. In particular, using pyridine or thiazole as isosteres of the carboxylic acid moiety resulted in very potent analogues. From these, AM-6761 (4) emerged as a potent inhibitor with remarkable biochemical (HTRF IC50 = 0.1 nM) and cellular potency (SJSA-1 EdU IC50 = 16 nM), as well as favorable pharmacokinetic properties. Compound 4 also shows excellent antitumor activity in the SJSA-1 osteosarcoma xenograft model with an ED50 of 11 mg/kg. Optimization efforts toward the discovery of these inhibitors as well as the new interactions observed with the MDM2 protein are described herein.