Synthesis and SAR study of potent and selective PI3Kδ inhibitors.

2,3,4-Substituted quinolines such as (10a) were found to be potent inhibitors of PI3Kδ in both biochemical and cellular assays with good selectivity over three other class I PI3K isoforms. Some of those analogs showed favorable pharmacokinetic properties.

Inhibiting NF-κB-inducing kinase (NIK): discovery, structure-based design, synthesis, structure-activity relationship, and co-crystal structures.

The discovery, structure-based design, synthesis, and optimization of NIK inhibitors are described. Our work began with an HTS hit, imidazopyridinyl pyrimidinamine 1. We utilized homology modeling and conformational analysis to optimize the indole scaffold leading to the discovery of novel and potent conformationally constrained inhibitors such as compounds 25 and 28. Compounds 25 and 31 were co-crystallized with NIK kinase domain to provide structural insights.

A novel series of IKKß inhibitors part II: description of a potent and pharmacologically active series of analogs.

A novel series of (E)-1-((2-(1-methyl-1H-imidazol-5-yl) quinolin-4-yl) methylene) thiosemicarbazides was discovered as potent inhibitors of IKKß. In this Letter we document our efforts at further optimization of this series, culminating in 2 with submicromolar potency in a HWB assay and efficacy in a CIA mouse model.

A novel series of IKKß inhibitors part I: Initial SAR studies of a HTS hit.

A novel series of (E)-1-((2-(1-methyl-1H-imidazol-5-yl) quinolin-4-yl) methylene) thiosemicarbazides was discovered as potent inhibitors of IKKß. In this Letter we document our early efforts at optimization of the quinoline core, the imidazole and the semithiocarbazone moiety. Most potency gains came from substitution around the 6- and 7-positions of the quinoline ring. Replacement of the semithiocarbazone with a semicarbazone decreased potency but led to some measurable exposure.

Discovery of [1,2,4]Triazolo[1,5-a]pyridine Derivatives as Potent and Orally Bioavailable RORγt Inverse Agonists.

The retinoic acid receptor-related orphan nuclear receptor γt (RORγt), a promising therapeutic target, is a major transcription factor of genes related to psoriasis pathogenesis such as interleukin (IL)-17A, IL-22, and IL-23R. On the basis of the X-ray cocrystal structure of RORγt with 1a, an analogue of the known piperazine RORγt inverse agonist 1, triazolopyridine derivatives of 1 were designed and synthesized, and analogue 3a was found to be a potent RORγt inverse agonist. Structure-activity relationship studies on 3a, focusing on the treatment of its metabolically unstable cyclopentyl ring and the central piperazine core, led to a novel analogue, namely, 6-methyl-N-(7-methyl-8-(((2S,4S)-2-methyl-1-(4,4,4-trifluoro-3-(trifluoromethyl)butanoyl)piperidin-4-yl)oxy)[1,2,4]triazolo[1,5-a]pyridin-6-yl)nicotinamide (5a), which exhibited strong RORγt inhibitory activity and a favorable pharmacokinetic profile. Moreover, the in vitro and in vivo evaluation of 5a in a human whole-blood assay and a mouse IL-18/23-induced cytokine expression model revealed its robust and dose-dependent inhibitory effect on IL-17A production.

Discovery of a Covalent Inhibitor of KRASG12C (AMG 510) for the Treatment of Solid Tumors.

KRASG12C has emerged as a promising target in the treatment of solid tumors. Covalent inhibitors targeting the mutant cysteine-12 residue have been shown to disrupt signaling by this long-"undruggable" target; however clinically viable inhibitors have yet to be identified. Here, we report efforts to exploit a cryptic pocket (H95/Y96/Q99) we identified in KRASG12C to identify inhibitors suitable for clinical development. Structure-based design efforts leading to the identification of a novel quinazolinone scaffold are described, along with optimization efforts that overcame a configurational stability issue arising from restricted rotation about an axially chiral biaryl bond. Biopharmaceutical optimization of the resulting leads culminated in the identification of AMG 510, a highly potent, selective, and well-tolerated KRASG12C inhibitor currently in phase I clinical trials (NCT03600883).

Discovery of N-(1-Acryloylazetidin-3-yl)-2-(1H-indol-1-yl)acetamides as Covalent Inhibitors of KRASG12C.

KRAS regulates many cellular processes including proliferation, survival, and differentiation. Point mutants of KRAS have long been known to be molecular drivers of cancer. KRAS p.G12C, which occurs in approximately 14% of lung adenocarcinomas, 3-5% of colorectal cancers, and low levels in other solid tumors, represents an attractive therapeutic target for covalent inhibitors. Herein, we disclose the discovery of a class of novel, potent, and selective covalent inhibitors of KRASG12C identified through a custom library synthesis and screening platform called Chemotype Evolution and structure-based design. Identification of a hidden surface groove bordered by H95/Y96/Q99 side chains was key to the optimization of this class of molecules. Best-in-series exemplars exhibit a rapid covalent reaction with cysteine 12 of GDP-KRASG12C with submicromolar inhibition of downstream signaling in a KRASG12C-specific manner.

Discovery, Optimization, and in Vivo Evaluation of Benzimidazole Derivatives AM-8508 and AM-9635 as Potent and Selective PI3Kδ Inhibitors.

Lead optimization efforts resulted in the discovery of two potent, selective, and orally bioavailable PI3Kδ inhibitors, 1 (AM-8508) and 2 (AM-9635), with good pharmacokinetic properties. The compounds inhibit B cell receptor (BCR)-mediated AKT phosphorylation (pAKT) in PI3Kδ-dependent in vitro cell based assays. These compounds which share a benzimidazole bicycle are effective when administered in vivo at unbound concentrations consistent with their in vitro cell potency as a consequence of improved unbound drug concentration with lower unbound clearance. Furthermore, the compounds demonstrated efficacy in a Keyhole Limpet Hemocyanin (KLH) study in rats, where the blockade of PI3Kδ activity by inhibitors 1 and 2 led to effective inhibition of antigen-specific IgG and IgM formation after immunization with KLH.

Discovery and in Vivo Evaluation of the Potent and Selective PI3Kδ Inhibitors 2-((1S)-1-((6-Amino-5-cyano-4-pyrimidinyl)amino)ethyl)-6-fluoro-N-methyl-3-(2-pyridinyl)-4-quinolinecarboxamide (AM-0687) and 2-((1S)-1-((6-Amino-5-cyano-4-pyrimidinyl)amino)ethyl)-5-fluoro-N-methyl-3-(2-pyridinyl)-4-quinolinecarboxamide (AM-1430).

Optimization of the potency and pharmacokinetic profile of 2,3,4-trisubstituted quinoline, 4, led to the discovery of two potent, selective, and orally bioavailable PI3Kδ inhibitors, 6a (AM-0687) and 7 (AM-1430). On the basis of their improved profile, these analogs were selected for in vivo pharmacodynamic (PD) and efficacy experiments in animal models of inflammation. The in vivo PD studies, which were carried out in a mouse pAKT inhibition animal model, confirmed the observed potency of 6a and 7 in biochemical and cellular assays. Efficacy experiments in a keyhole limpet hemocyanin model in rats demonstrated that administration of either 6a or 7 resulted in a strong dose-dependent reduction of IgG and IgM specific antibodies. The excellent in vitro and in vivo profiles of these analogs make them suitable for further development.

Discovery and in vivo evaluation of (S)-N-(1-(7-fluoro-2-(pyridin-2-yl)quinolin-3-yl)ethyl)-9H-purin-6-amine (AMG319) and related PI3Kδ inhibitors for inflammation and autoimmune disease.

The development and optimization of a series of quinolinylpurines as potent and selective PI3Kδ kinase inhibitors with excellent physicochemical properties are described. This medicinal chemistry effort led to the identification of 1 (AMG319), a compound with an IC50 of 16 nM in a human whole blood assay (HWB), excellent selectivity over a large panel of protein kinases, and a high level of in vivo efficacy as measured by two rodent disease models of inflammation.

Synthesis of 2'-azidoethyl trisaccharide, alpha-D-Gal-(1-->2)-6d-alpha-D-altro-Hepp-(1-->3)-beta-D-GlcNAc, an O-antigenic repeating unit of C. jejuni O:23 and O:36.

A trisaccharide, the O-antigenic repeating unit of C. jejuni serotype O:23 and O:36, was synthesized as a 2'-azidoethyl glycoside by block addition of perbenzylated thiogalactoside donors to alpha-altroHepp-(1-->3)-GlcNPhth disaccharide acceptor in presence of IDCP promoter. The alpha-linked altroheptopyranoside moiety in the glycosyl acceptor was effectively prepared by Swern oxidation of alpha-mannohepp-(1-->3)-GlcNPhth disaccharide followed by mild reduction with NaCNBH3.

Discovery and in vivo evaluation of dual PI3Kß/δ inhibitors.

Structure-based rational design led to the synthesis of a novel series of potent PI3K inhibitors. The optimized pyrrolopyridine analogue 63 was a potent and selective PI3Kß/δ dual inhibitor that displayed suitable physicochemical properties and pharmacokinetic profile for animal studies. Analogue 63 was found to be efficacious in animal models of inflammation including a keyhole limpet hemocyanin (KLH) study and a collagen-induced arthritis (CIA) disease model of rheumatoid arthritis. These studies highlight the potential therapeutic value of inhibiting both the PI3Kß and δ isoforms in the treatment of a number of inflammatory diseases.