Isoindolinone compounds active as Kv1.5 blockers identified using a multicomponent reaction approach.

A series of isoindolinone compounds have been developed showing good in vitro potency on the Kv1.5 ion channel. By modification of two side chains on the isoindolinone scaffold, metabolically stable compounds with good in vivo PK profile could be obtained leaving the core structure unsubstituted. In this way, low microsomal intrinsic clearance (CLint) could be achieved despite a relatively high logD. The compounds were synthesized using the Ugi reaction, in some cases followed by Suzuki and Diels-Alder reactions, giving a diverse set of compounds in a small number of reaction steps.

Lactam sulfonamides as potent inhibitors of the Kv1.5 potassium ion channel.

A series of lactam sulfonamides has been discovered and optimized as inhibitors of the Kv1.5 potassium ion channel for treatment of atrial fibrillation. In vitro structure-activity relationships from lead structure C to optimized structure 3y are described. Compound 3y was evaluated in a rabbit PD-model and was found to selectively prolong the atrial effective refractory period at submicromolar concentrations.

Synthesis and evaluation of diphenylphosphinic amides and diphenylphosphine oxides as inhibitors of Kv1.5.

Diphenylphosphinic amides and diphenylphosphine oxides have been synthesized and tested as inhibitors of the Kv1.5 potassium ion channel as a possible treatment for atrial fibrillation. In vitro structure-activity relationships are discussed and several compounds with Kv1.5 IC(50) values of <0.5 µM were discovered. Selectivity over the ventricular IKs current was monitored and selective compounds were found. Results from a rabbit PD-model are included.

AZD0284, a Potent, Selective, and Orally Bioavailable Inverse Agonist of Retinoic Acid Receptor-Related Orphan Receptor C2.

Inverse agonists of the nuclear receptor RORC2 have been widely pursued as a potential treatment for a variety of autoimmune diseases. We have discovered a novel series of isoindoline-based inverse agonists of the nuclear receptor RORC2, derived from our recently disclosed RORC2 inverse agonist 2. Extensive structure-activity relationship (SAR) studies resulted in AZD0284 (20), which combined potent inhibition of IL-17A secretion from primary human TH17 cells with excellent metabolic stability and good PK in preclinical species. In two preclinical in vivo studies, compound 20 reduced thymocyte numbers in mice and showed dose-dependent reduction of IL-17A containing γδ-T cells and of IL-17A and IL-22 RNA in the imiquimod induced inflammation model. Based on these data and a favorable safety profile, 20 was progressed to phase 1 clinical studies.

Novel thioamide derivatives as neutral CB1 receptor antagonists.

A novel class of cannabinoid-1 (CB1) receptor antagonists for the treatment of obesity is presented. The carboxamide linker in a set of 5,6-diaryl-pyrazine-2-amide derivatives was transformed into the corresponding thioamide, by using a one-pot synthesis. The structural series of thioamides not only showed retained CB1 potency (below 10nM), but also showed improved solubility. In addition, the neutral antagonist 2c significantly reduced body weight in cafeteria diet obese mice.

Discovery of Potent and Orally Bioavailable Inverse Agonists of the Retinoic Acid Receptor-Related Orphan Receptor C2.

The further optimization of a recently disclosed series of inverse agonists of the nuclear receptor RORC2 is described. Investigations into the left-hand side of compound 1, guided by X-ray crystal structures, led to the substitution of the 4-aryl-thiophenyl residue with the hexafluoro-2-phenyl-propan-2-ol moiety. This change resulted in to compound 28, which combined improved drug-like properties with good cell potency and a significantly lower dose, using an early dose to man prediction. Target engagement in vivo was demonstrated in the thymus of mice by a reduction in the number of double positive T cells after oral dosing.

Discovery of a Novel Oral Glucocorticoid Receptor Modulator (AZD9567) with Improved Side Effect Profile.

Synthetic glucocorticoids (GC) are essential for the treatment of a broad range of inflammatory diseases. However, their use is limited by target related adverse effects on, e.g., glucose homeostasis and bone metabolism. Starting from a nonsteroidal GR ligand (4) that is a full agonist in reporter gene assays, we exploited key functional triggers within the receptor, generating a range of structurally diverse partial agonists. Of these, only a narrow subset exhibited full anti-inflammatory efficacy and a significantly reduced impact on adverse effect markers in human cell assays compared to prednisolone. This led to the discovery of AZD9567 (15) with excellent in vivo efficacy when dosed orally in a rat model of joint inflammation. Compound 15 is currently being evaluated in clinical trials comparing the efficacy and side effect markers with those of prednisolone.

Potent and Orally Bioavailable Inverse Agonists of RORγt Resulting from Structure-Based Design.

Retinoic acid receptor related orphan receptor γt (RORγt), has been identified as the master regulator of TH17-cell function and development, making it an attractive target for the treatment of autoimmune diseases by a small-molecule approach. Herein, we describe our investigations on a series of 4-aryl-thienyl acetamides, which were guided by insights from X-ray cocrystal structures. Efforts in targeting the cofactor-recruitment site from the 4-aryl group on the thiophene led to a series of potent binders with nanomolar activity in a primary human-TH17-cell assay. The observation of a DMSO molecule binding in a subpocket outside the LBD inspired the introduction of an acetamide into the benzylic position of these compounds. Hereby, a hydrogen-bond interaction of the introduced acetamide oxygen with the backbone amide of Glu379 was established. This greatly enhanced the cellular activity of previously weakly cell-active compounds. The best compounds combined potent inhibition of IL-17 release with favorable PK in rodents, with compound 32 representing a promising starting point for future investigations.

Structure-Affinity Relationships and Structure-Kinetic Relationships of 1,2-Diarylimidazol-4-carboxamide Derivatives as Human Cannabinoid 1 Receptor Antagonists.

We report on the synthesis and biological evaluation of a series of 1,2-diarylimidazol-4-carboxamide derivatives developed as CB1 receptor antagonists. These were evaluated in a radioligand displacement binding assay, a [35S]GTPγS binding assay, and in a competition association assay that enables the relatively fast kinetic screening of multiple compounds. The compounds show high affinities and a diverse range of kinetic profiles at the CB1 receptor and their structure-kinetic relationships (SKRs) were established. Using the recently resolved hCB1 receptor crystal structures, we also performed a modeling study that sheds light on the crucial interactions for both the affinity and dissociation kinetics of this family of ligands. We provide evidence that, next to affinity, additional knowledge of binding kinetics is useful for selecting new hCB1 receptor antagonists in the early phases of drug discovery.

Benzoxazepines Achieve Potent Suppression of IL-17 Release in Human T-Helper 17 (TH 17) Cells through an Induced-Fit Binding Mode to the Nuclear Receptor RORγ.

RORγt, an isoform of the retinoic acid-related orphan receptor gamma (RORc, RORγ), has been identified as the master regulator of T-helper 17 (TH 17) cell function and development, making it an attractive target for the treatment of autoimmune diseases. Validation for this target comes from antibodies targeting interleukin-17 (IL-17), the signature cytokine produced by TH 17 cells, which have shown impressive results in clinical trials. Through focused screening of our compound collection, we identified a series of N-sulfonylated benzoxazepines, which displayed micromolar affinity for the RORγ ligand-binding domain (LBD) in a radioligand binding assay. Optimization of these initial hits resulted in potent binders, which dose-dependently decreased the ability of the RORγ-LBD to interact with a peptide derived from steroid receptor coactivator 1, and inhibited the release of IL-17 secretion from isolated and cultured human TH 17 cells with nanomolar potency. A cocrystal structure of inverse agonist 15 (2-chloro-6-fluoro-N-(4-{[3-(trifluoromethyl)phenyl]sulfonyl}-2,3,4,5-tetrahydro-1,4-benzoxazepin-7-yl)benzamide) bound to the RORγ-LBD illustrated that both hydrophobic interactions, leading to an induced fit around the substituted benzamide moiety of 15, as well as a hydrogen bond from the amide NH to His479 seemed to be important for the mechanism of action. This structure is compared with the structure of agonist 25 (N-(2-fluorophenyl)-4-[(4-fluorophenyl)sulfonyl]-2,3,4,5-tetrahydro-1,4-benzoxazepin-6-amine ) and structures of other known RORγ modulators.