Discovery of Nelutroctiv (CK-136), a Selective Cardiac Troponin Activator for the Treatment of Cardiovascular Diseases Associated with Reduced Cardiac Contractility.

Cardiac myosin activation has been shown to be a viable approach for the treatment of heart failure with reduced ejection fraction. Here, we report the discovery of nelutroctiv (), a selective cardiac troponin activator intended for patients with cardiovascular conditions where cardiac contractility is reduced. Discovery of nelutroctiv began with a high-throughput screen that identified compound , a muscle selective cardiac sarcomere activator devoid of phosphodiesterase-3 activity.

Cardiac Troponin Activator Increases Cardiac Contractility in Rats.

Novel cardiac troponin activators were identified using a high throughput cardiac myofibril ATPase assay and confirmed using a series of biochemical and biophysical assays. HTS hit increased rat cardiomyocyte fractional shortening without increasing intracellular calcium concentrations, and the biological target of and was determined to be the cardiac thin filament. Subsequent optimization to increase solubility and remove PDE-3 inhibition led to the discovery of and enabled pharmacological evaluation of cardiac troponin activation without the competing effects of PDE-3 inhibition.

Distinct Mechanisms for Increased Cardiac Contraction Through Selective Alteration of Either Myosin or Troponin Activity.

Modulation of sarcomere contractility represents a new therapeutic opportunity for the treatment of heart failure by directly targeting the thick and thin filament proteins of the sarcomere to increase cardiac muscle contraction. This study compared the effect of 2 small molecules (M and T) that selectively alter myosin thick filament (M) or troponin thin filament (T) activity on overall cardiac muscle mechanics. This study revealed key differences related to the mechanism utilized by M and T to increase contractile force generation and suggests that targeting different proteins within the sarcomere may result in differentiating therapeutic profiles.

Novel Small-Molecule Troponin Activator Increases Cardiac Contractile Function Without Negative Impact on Energetics.

Background: Current heart failure therapies unload the failing heart without targeting the underlying problem of reduced cardiac contractility. Traditional inotropes (ie, calcitropes) stimulate contractility via energetically costly augmentation of calcium cycling and worsen patient survival. A new class of agents-myotropes-activates the sarcomere directly, independent of calcium.

Malonyl CoA Decarboxylase Inhibition Improves Cardiac Function Post-Myocardial Infarction.

Alterations in cardiac energy metabolism after a myocardial infarction contribute to the severity of heart failure (HF). Although fatty acid oxidation can be impaired in HF, it is unclear if stimulating fatty acid oxidation is a desirable approach to treat HF. Both immediate and chronic malonyl coenzyme A decarboxylase inhibition, which decreases fatty acid oxidation, improved cardiac function through enhancing cardiac efficiency in a post-myocardial infarction rat that underwent permanent left anterior descending coronary artery ligation.

Aminopyrazole-Phenylalanine Based GPR142 Agonists: Discovery of Tool Compound and in Vivo Efficacy Studies.

Herein, we report the lead optimization of amrinone-phenylalanine based GPR142 agonists. Structure-activity relationship studies led to the discovery of aminopyrazole-phenylalanine carboxylic acid 22, which exhibited good agonistic activity, high target selectivity, desirable pharmacokinetic properties, and no cytochrome P450 or hERG liability. Compound 22, together with its orally bioavailable ethyl ester prodrug 23, were found to be suitable for in vivo proof-of-concept studies.

Potent and Orally Bioavailable GPR142 Agonists as Novel Insulin Secretagogues for the Treatment of Type 2 Diabetes.

GPR142 is a G protein-coupled receptor that is predominantly expressed in pancreatic β-cells. GPR142 agonists stimulate insulin secretion in the presence of high glucose concentration, so that they could be novel insulin secretagogues with reduced or no risk of hypoglycemia. We report here the optimization of HTS hit compound 1 toward a proof of concept compound 33, which showed potent glucose lowering effects during an oral glucose tolerance test in mice and monkeys.

Structure-assisted discovery of the first non-retinoid ligands for Retinol-Binding Protein 4.

Retinol-Binding Protein 4 (RBP4) is a plasma protein that transports retinol (vitamin A) from the liver to peripheral tissues. This Letter highlights our efforts in discovering the first, to our knowledge, non-retinoid small molecules that bind to RBP4 at the retinol site and reduce serum RBP4 levels in mice, by disrupting the interaction between RBP4 and transthyretin (TTR), a plasma protein that binds RBP4 and protects it from renal excretion. Potent compounds were discovered and optimized quickly from high-throughput screen (HTS) hits utilizing a structure-based approach.

Evaluation of AMG 076, a potent and selective MCHR1 antagonist, in rodent and primate obesity models.

Melanin-concentrating hormone (MCH) regulates food intake through activation of the receptor, MCHR1. We have identified AMG 076 as an orally bioavailable potent and selective small molecule antagonist of MCHR1. In mouse models of obesity, AMG 076 caused a reduction in body weight gain in wild-type (MCHR1+/+) but not in knockout (MCHR1-/-) mice.

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.

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

GPR142 is a novel GPCR that is predominantly expressed in pancreatic β-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.

Discovery of a novel melanin concentrating hormone receptor 1 (MCHR1) antagonist with reduced hERG inhibition.

An initial SAR study resulted in the identification of the novel, potent MCHR1 antagonist 2. After further profiling, compound 2 was discovered to be a potent inhibitor of the hERG potassium channel, which prevented its further development. Additional optimization of this structure resulted in the discovery of the potent MCHR1 antagonist 11 with a dramatically reduced hERG liability.

Glucagon receptor antagonist-mediated improvements in glycemic control are dependent on functional pancreatic GLP-1 receptor.

Antagonism of the glucagon receptor (GCGR) is associated with increased circulating levels of glucagon-like peptide-1 (GLP-1). To investigate the contribution of GLP-1 to the antidiabetic actions of GCGR antagonism, we administered an anti-GCGR monoclonal antibody (mAb B) to wild-type mice and GLP-1 receptor knockout (GLP-1R KO) mice. Treatment of wild-type mice with mAb B lowered fasting blood glucose, improved glucose tolerance, and enhanced glucose-stimulated insulin secretion during an intraperitoneal glucose tolerance test (ipGTT).

Identification of piperazine-bisamide GHSR antagonists for the treatment of obesity.

Piperazine-bisamide analogs were discovered as partial agonists of human growth hormone secretagogue receptor (GHSR) in a high throughput screen. The partial agonists were optimized for potency and converted into antagonists through structure-activity relationship (SAR) studies. The efforts also led to the identification of potent antagonist with favorable PK profile suitable as a tool compound for in vivo studies.

INT131: a selective modulator of PPAR gamma.

The nuclear hormone receptor peroxisome proliferator-activated receptor gamma (PPAR gamma; NR1C3) plays a central role in adipogenesis and is the molecular target of the thiazolidinedione class of antidiabetic drugs. To overcome the well-known shortcomings of thiazolidinediones, we have identified INT131 (formerly T131 and AMG131) as a potent selective ligand for PPAR gamma that is structurally and pharmacologically distinct from glitazone agonists. In vitro biochemical and cell-based functional assays showed that INT131 mediates a distinct pattern of coregulator recruitment to PPAR gamma.

Identification and characterization of a non-retinoid ligand for retinol-binding protein 4 which lowers serum retinol-binding protein 4 levels in vivo.

Retinol-binding protein 4 (RBP4) transports retinol from the liver to extrahepatic tissues, and RBP4 lowering is reported to improve insulin sensitivity in mice. We have identified A1120, a high affinity (K(i) = 8.3 nm) non-retinoid ligand for RBP4, which disrupts the interaction between RBP4 and its binding partner transthyretin.

CCR8 is not essential for the development of inflammation in a mouse model of allergic airway disease.

Chemokine receptors play an important role in the trafficking of various immune cell types to sites of inflammation. Several chemokine receptors are differentially expressed in Th1 and Th2 effector populations. Th2 cells selectively express CCR3, CCR4, and CCR8, which could direct their trafficking to sites of allergic inflammation.