Discovery of a Potent and Selective Tyrosine Kinase 2 Inhibitor: TAK-279.

TYK2 is a key mediator of IL12, IL23, and type I interferon signaling, and these cytokines have been implicated in the pathogenesis of multiple inflammatory and autoimmune diseases such as psoriasis, rheumatoid arthritis, lupus, and inflammatory bowel diseases. Supported by compelling data from human genome-wide association studies and clinical results, TYK2 inhibition through small molecules is an attractive therapeutic strategy to treat these diseases. Herein, we report the discovery of a series of highly selective pseudokinase (Janus homology 2, JH2) domain inhibitors of TYK2 enzymatic activity. A computationally enabled design strategy, including the use of FEP+, was instrumental in identifying a pyrazolo-pyrimidine core. We highlight the utility of computational physics-based predictions used to optimize this series of molecules to identify the development candidate 30, a potent, exquisitely selective cellular TYK2 inhibitor that is currently in Phase 2 clinical trials for the treatment of psoriasis and psoriatic arthritis.

Optimization of a series of novel, potent and selective Macrocyclic SYK inhibitors.

Spleen tyrosine kinase (SYK) is a non-receptor cytoplasmic kinase. Due to its pivotal role in B cell receptor and Fc-receptor signalling, inhibition of SYK has been a target of interest in a variety of diseases. Herein, we report the use of structure-based drug design to discover a series of potent macrocyclic inhibitors of SYK, with excellent kinome selectivity and in vitro metabolic stability. We were able to remove hERG inhibition through the optimization of physical properties, and utilized a pro-drug strategy to address permeability challenges.

Potent and selective TYK2-JH1 inhibitors highly efficacious in rodent model of psoriasis.

TYK2 is a member of the JAK family of kinases and a key mediator of IL-12, IL-23, and type I interferon signaling. These cytokines have been implicated in the pathogenesis of multiple inflammatory and autoimmune diseases such as psoriasis, rheumatoid arthritis, lupus, and inflammatory bowel diseases. Supported by compelling data from human genetic association studies, TYK2 inhibition is an attractive therapeutic strategy for these diseases. Herein, we report the discovery of a series of highly selective catalytic site TYK2 inhibitors designed using FEP+ and structurally enabled design starting from a virtual screen hit. We highlight the structure-based optimization to identify a lead candidate 30, a potent cellular TYK2 inhibitor with excellent selectivity, pharmacokinetic properties, and in vivo efficacy in a mouse psoriasis model.

Discovery of 5-{4-[(7-Ethyl-6-oxo-5,6-dihydro-1,5-naphthyridin-3-yl)methyl]piperazin-1-yl}-N-methylpyridine-2-carboxamide (AZD5305): A PARP1-DNA Trapper with High Selectivity for PARP1 over PARP2 and Other PARPs.

Poly-ADP-ribose-polymerase (PARP) inhibitors have achieved regulatory approval in oncology for homologous recombination repair deficient tumors including BRCA mutation. However, some have failed in combination with first-line chemotherapies, usually due to overlapping hematological toxicities. Currently approved PARP inhibitors lack selectivity for PARP1 over PARP2 and some other 16 PARP family members, and we hypothesized that this could contribute to toxicity. Recent literature has demonstrated that PARP1 inhibition and PARP1-DNA trapping are key for driving efficacy in a BRCA mutant background. Herein, we describe the structure- and property-based design of 25 (AZD5305), a potent and selective PARP1 inhibitor and PARP1-DNA trapper with excellent in vivo efficacy in a BRCA mutant HBCx-17 PDX model. Compound 25 is highly selective for PARP1 over other PARP family members, with good secondary pharmacology and physicochemical properties and excellent pharmacokinetics in preclinical species, with reduced effects on human bone marrow progenitor cells in vitro.

Novel potent and selective pyrazolylpyrimidine-based SYK inhibitors.

Hybridisation of amino-pyrimidine based SYK inhibitors (e.g. 1a) with previously reported diamine-based SYK inhibitors (e.g. TAK-659) led to the identification and optimisation of a novel pyrimidine-based series of potent and selective SYK inhibitors, where the original aminomethylene group was replaced by a 3,4-diaminotetrahydropyran group. The initial compound 5 achieved excellent SYK potency. However, it suffered from poor permeability and modest kinase selectivity. Further modifications of the 3,4-diaminotetrahydropyran group were identified and the interactions of those groups with Asp512 were characterised by protein X-ray crystallography. Further optimisation of this series saw mixed results where permeability and kinase selectivity were increased and oral bioavailability was achieved in the series, but at the expense of potent hERG inhibition.

Discovery of Proteolysis-Targeting Chimera Molecules that Selectively Degrade the IRAK3 Pseudokinase.

We report the first disclosure of IRAK3 degraders in the scientific literature. Taking advantage of an opportune byproduct obtained during our efforts to identify IRAK4 inhibitors, we identified ready-to-use, selective IRAK3 ligands in our compound collection with the required properties for conversion into proteolysis-targeting chimera (PROTAC) degraders. This work culminated with the discovery of PROTAC 23, which we demonstrated to be a potent and selective degrader of IRAK3 after 16 h in THP1 cells. 23 induced proteasome-dependent degradation of IRAK3 and required both CRBN and IRAK3 binding for activity. We conclude that PROTAC 23 constitutes an excellent in vitro tool with which to interrogate the biology of IRAK3.

Identification of a novel series of azabenzimidazole-derived inhibitors of spleen tyrosine kinase.

Spleen Tyrosine Kinase (SYK) is a well-studied enzyme with therapeutic applications in oncology and autoimmune diseases. We identified an azabenzimidazole (ABI) series of SYK inhibitors by mining activity data of 86,000 compounds from legacy biochemical assays with SYK and other homologous kinases as target enzymes. A structure-based design and hybridization approach was then used to improve the potency and kinase selectivity of the hits. Lead compound 23 from this novel ABI series has a SYK IC50 = 0.21 nM in a biochemical assay and inhibits growth of SUDHL-4 cells at a GI50 = 210 nM.

Optimization of a series of potent, selective and orally bioavailable SYK inhibitors.

Spleen tyrosine kinase (SYK) is a non-receptor cytosolic kinase. Due to its pivotal role in B cell receptor and Fc-receptor signaling, inhibition of SYK has been targeted in a variety of disease areas. Herein, we report the optimization of a series of potent and selective SYK inhibitors, focusing on improving metabolic stability, pharmacokinetics and hERG inhibition. As a result, we identified 30, which exhibited no hERG activity but unfortunately was poorly absorbed in rats and mice. We also identified a SYK chemical probe, 17, which exhibits excellent potency at SYK, and an adequate rodent PK profile to support in vivo efficacy/PD studies.

Design and synthesis of novel proline based factor XIa selective inhibitors as leads for potential new anticoagulants.

A series of 4, 4-disubstituted proline analogs were designed, synthesized, and tested for selective inhibition of blood coagulation factor XIa in search of new non-vitamin K antagonists based oral anticoagulants for potential prevention and treatment of thrombotic diseases. Starting from a potent thrombin (FIIa) inhibitor chemotype with FIIa IC50 = 1 nM and FXIa IC50 = 160 nM, medicinal chemistry iterations guided by molecular modeling and structure-based drug design led to steady improvement of FXIa potency while dialing down thrombin activity and improving selectivity. Through this exercise, a thousand-fold enhancement of selectivity over thrombin was achieved with some analogs carrying factor XIa inhibition potencies in the 10 nM range. In this communication, we discuss the design principles and structure activity relationship (SAR) of these novel FXIa selective inhibitors.

Proteolysis targeting chimeras (PROTACs) in 'beyond rule-of-five' chemical space: Recent progress and future challenges.

Proteolysis targeting chimeras (PROTACs) are heterobifunctional compounds with molecular weights and other properties that lie outside the classic 'rule-of-five' space. Consequently, PROTACs have unique challenges associated with their development as potential therapeutic agents. This review summarizes and analyzes a representative set of recent PROTACs and highlights some of the potential future challenges facing this promising modality.

Discovery of phenyl acetamides as potent and selective GPR119 agonists.

The paper describes the SAR/SPR studies that led to the discovery of phenoxy cyclopropyl phenyl acetamide derivatives as potent and selective GPR119 agonists. Based on a cis cyclopropane scaffold discovered previously, phenyl acetamides such as compound 17 were found to have excellent GPR119 potency and improved physicochemical properties. Pharmacokinetic data of compound 17 in rat, dog and rhesus will be described. Compound 17 was suitable for QD dosing based on its predicted human half-life, and its projected human dose was much lower than that of the recently reported structurally-related benzyloxy compound 2. Compound 17 was selected as a tool compound candidate for NHP (Non-Human Primate) efficacy studies.

Discovery of Chromane Propionic Acid Analogues as Selective Agonists of GPR120 with in Vivo Activity in Rodents.

GPR120 (FFAR4) is a fatty acid sensing G protein coupled receptor (GPCR) that has been identified as a target for possible treatment of type 2 diabetes. A selective activator of GPR120 containing a chromane scaffold has been designed, synthesized, and evaluated in vivo. Results of these efforts suggest that chromane propionic acid 18 is a suitable tool molecule for further animal studies. Compound 18 is selective over the closely related target GPR40 (FFAR1), has a clean off-target profile, demonstrates suitable pharmacokinetic properties, and has been evaluated in wild-type/knockout GPR120 mouse oGTT studies.

Investigation of piperazine benzamides as human ß3 adrenergic receptor agonists for the treatment of overactive bladder.

The synthesis of a novel class of piperazine benzamide (reverse amides) targeting the human ß3-adrenergic receptor for the treatment of overactive bladder (OAB) is described. The SAR studies directed towards maintaining well established ß3 potency and selectivities while improving the overall pharmacokinetic profile in the reverse amide class will be evaluated. The results and consequences associated with functional activity at the norepinephrine transporter (NET) will also be discussed.

Discovery and Optimization of a Novel Triazole Series of GPR142 Agonists for the Treatment of Type 2 Diabetes.

GPR142 has been identified as a potential glucose-stimulated insulin secretion (GSIS) target for the treatment of type 2 diabetes mellitus (T2DM). A class of triazole GPR142 agonists was discovered through a high throughput screen. The lead compound 4 suffered from poor metabolic stability and poor solubility. Lead optimization strategies to improve potency, efficacy, metabolic stability, and solubility are described. This optimization led to compound 20e, which showed significant reduction of glucose excursion in wild-type but not in GPR142 deficient mice in an oral glucose tolerance test (oGTT) study. These studies provide strong evidence that reduction of glucose excursion through treatment with 20e is GPR142-mediated, and GPR142 agonists could be used as a potential treatment for type 2 diabetes.

Discovery of benzamides as potent human ß3 adrenergic receptor agonists.

The paper will describe the synthesis and SAR studies that led to the discovery of benzamide (reverse amide) as potent and selective human ß3-adrenergic receptor agonist. Based on conformationally restricted pyrrolidine scaffold we discovered earlier, pyrrolidine benzoic acid intermediate 22 was synthesized. From library synthesis and further optimization efforts, several structurally diverse reverse amides such as 24c and 24i were found to have excellent human ß3-adrenergic potency and good selectivity over the ß1 and ß2 receptors. In addition to human ß1, ß2, ß3 and hERG data, PK of selected compounds will be described.

Discovery of Vibegron: A Potent and Selective ß3 Adrenergic Receptor Agonist for the Treatment of Overactive Bladder.

The discovery of vibegron, a potent and selective human ß3-AR agonist for the treatment of overactive bladder (OAB), is described. An early-generation clinical ß3-AR agonist MK-0634 (3) exhibited efficacy in humans for the treatment of OAB, but development was discontinued due to unacceptable structure-based toxicity in preclinical species. Optimization of a series of second-generation pyrrolidine-derived ß3-AR agonists included reducing the risk for phospholipidosis, the risk of formation of disproportionate human metabolites, and the risk of formation of high levels of circulating metabolites in preclinical species. These efforts resulted in the discovery of vibegron, which possesses improved druglike properties and an overall superior preclinical profile compared to MK-0634. Structure-activity relationships leading to the discovery of vibegron and a summary of its preclinical profile are described.

Design of Potent and Orally Active GPR119 Agonists for the Treatment of Type II Diabetes.

We report herein the design and synthesis of a series of potent and selective GPR119 agonists. Our objective was to develop a GPR119 agonist with properties that were suitable for fixed-dose combination with a DPP4 inhibitor. Starting from a phenoxy analogue (1), medicinal chemistry efforts directed toward reducing half-life and increasing solubility led to the synthesis of a series of benzyloxy analogues. Compound 28 was chosen for further profiling because of its favorable physicochemical properties and excellent GPR119 potency across species. This compound exhibited a clean off-target profile in counterscreens and good in vivo efficacy in mouse oGTT.

Design, synthesis, and evaluation of conformationally restricted acetanilides as potent and selective ß3 adrenergic receptor agonists for the treatment of overactive bladder.

A series of conformationally restricted acetanilides were synthesized and evaluated as ß3-adrenergic receptor agonists (ß3-AR) for the treatment of overactive bladder (OAB). Optimization studies identified a five-membered ring as the preferred conformational lock of the acetanilide. Further optimization of both the aromatic and thiazole regions led to compounds such as 19 and 29, which have a good balance of potency and selectivity. These compounds have significantly reduced intrinsic clearance compared to our initial series of pyridylethanolamine ß3-AR agonists and thus have improved unbound drug exposures. Both analogues demonstrated dose dependent ß3-AR mediated responses in a rat bladder hyperactivity model.

Discovery of pyrimidine carboxamides as potent and selective CCK1 receptor agonists.

A series of six-membered heterocycle carboxamides were synthesized and evaluated as cholecystokinin 1 receptor (CCK1R) agonists. A pyrimidine core proved to be the best heterocycle, and SAR studies resulted in the discovery of analog 5, a potent and structurally diverse CCK1R agonist.

Design of a novel pyrrolidine scaffold utilized in the discovery of potent and selective human ß3 adrenergic receptor agonists.

A novel class of human ß(3)-adrenergic receptor agonists was designed in effort to improve selectivity and metabolic stability versus previous disclosed ß(3)-AR agonists. As observed, many of the ß(3)-AR agonists seem to need the acyclic ethanolamine core for agonist activity. We have synthesized derivatives that constrained this moiety by introduction of a pyrrolidine. This unique modification maintains human ß(3) functional potency with improved selectivity versus ancillary targets and also eliminates the possibility of the same oxidative metabolites formed from cleavage of the N-C bond of the ethanolamine. Compound 39 exhibited excellent functional ß(3) agonist potency across species with good pharmacokinetic properties in rat, dog, and rhesus monkeys. Early de-risking of this novel pyrrolidine core (44) via full AMES study supports further research into various new ß(3)-AR agonists containing the pyrrolidine moiety.