Identification and optimisation of a pyrimidopyridone series of IRAK4 inhibitors.

In this article, we report the discovery of a series of pyrimidopyridones as inhibitors of IRAK4 kinase. From a previously disclosed 5-azaquinazoline series, we found that switching the pyridine ring for an N-substituted pyridone gave a novel hinge binding scaffold which retained potency against IRAK4. Importantly, introduction of the carbonyl established an internal hydrogen bond with the 4-NH, establishing a conformational lock and allowing truncation of the large basic substituent to a 1-methylcyclopyl group. Subsequent optimisation, facilitated by X-ray crystal structures, allowed identification of preferred substituents at both the pyridone core and pyrazole. Subsequent combinations of optimal groups allowed control of lipophilicity and identification of potent and selective inhibitors of IRAK4 with better in vitro permeability and lower clearance.

Tricyclic Indazoles-A Novel Class of Selective Estrogen Receptor Degrader Antagonists.

Herein, we report the identification and synthesis of a series of tricyclic indazoles as a novel class of selective estrogen receptor degrader antagonists. Replacement of a phenol, present in our previously reported tetrahydroisoquinoline scaffold, with an indazole group led to the removal of a reactive metabolite signal in an in vitro glutathione trapping assay. Further optimization, guided by X-ray crystal structures and NMR conformational work, varied the alkyl side chain and pendant aryl group and resulted in compounds with low turnover in human hepatocytes and enhanced chemical stability. Compound 9 was profiled as a representative of the series in terms of pharmacology and demonstrated the desired estrogen receptor α degrader-antagonist profile and demonstrated activity in a xenograft model of breast cancer.

Optimization of permeability in a series of pyrrolotriazine inhibitors of IRAK4.

We have developed a series of orally efficacious IRAK4 inhibitors, based on a scaffold hopping strategy and using rational structure based design. Efforts to tackle low permeability and high efflux in our previously reported pyrrolopyrimidine series (Scott et al., 2017) led to the identification of pyrrolotriazines which contained one less formal hydrogen bond donor and were intrinsically more lipophilic. Further optimisation of substituents on this pyrrolotriazine core culminated with the discovery of 30 as a promising in vivo probe to assess the potential of IRAK4 inhibition for the treatment of MyD88 mutant DLBCL in combination with a BTK inhibitor. When tested in an ABC-DLBCL model with a dual MyD88/CD79 mutation (OCI-LY10), 30 demonstrated tumour regressions in combination with ibrutinib.

The acute glucose lowering effect of specific GPR120 activation in mice is mainly driven by glucagon-like peptide 1.

The mechanism behind the glucose lowering effect occurring after specific activation of GPR120 is not completely understood. In this study, a potent and selective GPR120 agonist was developed and its pharmacological properties were compared with the previously described GPR120 agonist Metabolex-36. Effects of both compounds on signaling pathways and GLP-1 secretion were investigated in vitro. The acute glucose lowering effect was studied in lean wild-type and GPR120 null mice following oral or intravenous glucose tolerance tests. In vitro, in GPR120 overexpressing cells, both agonists signaled through Gαq, Gαs and the ß-arrestin pathway. However, in mouse islets the signaling pathway was different since the agonists reduced cAMP production. The GPR120 agonists stimulated GLP-1 secretion both in vitro in STC-1 cells and in vivo following oral administration. In vivo GPR120 activation induced significant glucose lowering and increased insulin secretion after intravenous glucose administration in lean mice, while the agonists had no effect in GPR120 null mice. Exendin 9-39, a GLP-1 receptor antagonist, abolished the GPR120 induced effects on glucose and insulin following an intravenous glucose challenge. In conclusion, GLP-1 secretion is an important mechanism behind the acute glucose lowering effect following specific GPR120 activation.

Discovery and Optimization of Pyrrolopyrimidine Inhibitors of Interleukin-1 Receptor Associated Kinase 4 (IRAK4) for the Treatment of Mutant MYD88L265P Diffuse Large B-Cell Lymphoma.

Herein we report the optimization of a series of pyrrolopyrimidine inhibitors of interleukin-1 receptor associated kinase 4 (IRAK4) using X-ray crystal structures and structure based design to identify and optimize our scaffold. Compound 28 demonstrated a favorable physicochemical and kinase selectivity profile and was identified as a promising in vivo tool with which to explore the role of IRAK4 inhibition in the treatment of mutant MYD88L265P diffuse large B-cell lymphoma (DLBCL). Compound 28 was shown to be capable of demonstrating inhibition of NF-κB activation and growth of the ABC subtype of DLBCL cell lines in vitro at high concentrations but showed greater effects in combination with a BTK inhibitor at lower concentrations. In vivo, the combination of compound 28 and ibrutinib led to tumor regression in an ABC-DLBCL mouse model.

Structure-Based Design of Potent and Selective Inhibitors of the Metabolic Kinase PFKFB3.

A weak screening hit with suboptimal physicochemical properties was optimized against PFKFB3 kinase using critical structure-guided insights. The resulting compounds demonstrated high selectivity over related PFKFB isoforms and modulation of the target in a cellular context. A selected example demonstrated exposure in animals following oral dosing. Examples from this series may serve as useful probes to understand the emerging biology of this metabolic target.

Optimization of brain penetrant 11ß-hydroxysteroid dehydrogenase type I inhibitors and in vivo testing in diet-induced obese mice.

11ß-Hydroxysteroid dehydrogenase type 1 (11ß-HSD1) has been widely considered by the pharmaceutical industry as a target to treat metabolic syndrome in type II diabetics. We hypothesized that central nervous system (CNS) penetration might be required to see efficacy. Starting from a previously reported pyrimidine compound, we removed hydrogen-bond donors to yield 3, which had modest CNS penetration. More significant progress was achieved by changing the core to give 40, which combines good potency and CNS penetration. Compound 40 was dosed to diet-induced obese (DIO) mice and gave excellent target engagement in the liver and high free exposures of drug, both peripherally and in the CNS. However, no body weight reduction or effects on glucose or insulin were observed in this model. Similar data were obtained with a structurally diverse thiazole compound 51. This work casts doubt on the hypothesis that localized tissue modulation of 11ß-HSD1 activity alleviates metabolic syndrome.

Conformational restriction in a series of GPR119 agonists: differences in pharmacology between mouse and human.

A series of conformationally restricted GPR119 agonists were prepared based around a 3,8-diazabicyclo[3.2.1]octane scaffold. Examples were found to have markedly different pharmacology in mouse and human despite similar levels of binding to the receptor. This highlights the large effects on GPCR phamacology that can result from small structural changes in the ligand, together with inter-species differences between receptors.

Free-Wilson and structural approaches to co-optimizing human and rodent isoform potency for 11ß-hydroxysteroid dehydrogenase type 1 (11ß-HSD1) inhibitors.

11ß-Hydroxysteroid dehydrogenase 1 (11ß-HSD1) has been a target of intensive research efforts across the pharmaceutical industry, due to its potential for the treatment of type II diabetes and other elements of the metabolic syndrome. To demonstrate the value of 11ß-HSD1 in preclinical models, we required inhibitors with good potency against both human and rodent isoforms. Herein, we describe our efforts to understand how to co-optimize human and murine potency within the (5-hydroxy-2-adamantyl)-pyrimidine-5-carboxamide series. Two approaches are described-a data-driven (Free-Wilson) analysis and a structure-based design approach. The conclusions from these approaches were used to inform an efficient campaign to design compounds with consistently good human/murine potency within a logD(7.4) range of 1-3. Compounds 20 and 26 demonstrated good rodent PK, which allowed us to demonstrate a PK/PD relationship in rat and mouse. We then evaluated 26 against glycemic and body weight end points in murine disease models, where it demonstrated glucose and body weight efficacy at 300 mg/kg/day but only body weight efficacy at 50 mg/kg/day, despite providing >90% target engagement in the liver.

Optimisation of pharmacokinetic properties in a neutral series of 11ß-HSD1 inhibitors.

11ß-HSD1 is increasingly seen as an attractive target for the treatment of type II diabetes and other elements of the metabolic syndrome. In this program of work we describe how a series of neutral 2-thioalkyl-pyridine 11ß-HSD1 inhibitors were optimized in terms of their pharmacokinetic properties to give compounds with excellent bioavailability in both rat and dog through a core change to pyrimidine. A potential reactive metabolite issue with 4-thioalkyl-pyrimidines was circumvented by a switch from sulfur to carbon substitution.

Use of small-molecule crystal structures to address solubility in a novel series of G protein coupled receptor 119 agonists: optimization of a lead and in vivo evaluation.

G protein coupled receptor 119 (GPR119) is viewed as an attractive target for the treatment of type 2 diabetes and other elements of the metabolic syndrome. During a program toward discovering agonists of GPR119, we herein describe optimization of an initial lead compound, 2, into a development candidate, 42. A key challenge in this program of work was the insolubility of the lead compound. Small-molecule crystallography was utilized to understand the intermolecular interactions in the solid state and resulted in a switch from an aryl sulphone to a 3-cyanopyridyl motif. The compound was shown to be effective in wild-type but not knockout animals, confirming that the biological effects were due to GPR119 agonism.

Rationally designing safer anilines: the challenging case of 4-aminobiphenyls.

We describe how we have been able to design 4-aminobiphenyls that are nonmutagenic (inactive in the Ames test). No such 4-aminobiphenyls were known to us, but insights provided by quantum mechanical calculations have permitted us to design and synthesize some examples. Importantly, the quantum mechanical calculations could be combined with predictions of other properties of the compounds that contained the 4-aminobiphenyls so that these remained druglike. Having found compounds that are not active, the calculations can provide insight into which factors (electronic and conformational in this case) are important. The calculations provided SAR-like information that was able guide the design of further examples of 4-aminobiphenyls that are not active in the Ames test.

Discovery, optimisation and in vivo evaluation of novel GPR119 agonists.

GPR119 is increasingly seen as an attractive target for the treatment of type II diabetes and other elements of the metabolic syndrome. During a programme aimed at developing agonists of the GPR119 receptor, we identified compounds that were potent with reduced hERG liabilities, that had good pharmacokinetic properties and that displayed excellent glucose-lowering effects in vivo. However, further profiling in a GPR119 knock-out (KO) mouse model revealed that the biological effects were not exclusively due to GPR119 agonism, highlighting the value of transgenic animals in drug discovery programs.