Identification and Optimization of Small Molecule Pyrazolopyrimidine TLR7 Agonists for Applications in Immuno-oncology

Small molecule toll-like receptor (TLR) 7 agonists have gathered considerable interest as promising therapeutic agents for applications in cancer immunotherapy. Herein, we describe the development and optimization of a series of novel TLR7 agonists through systematic structure-activity relationship studies focusing on modification of the phenylpiperidine side chain. Additional refinement of ADME properties culminated in the discovery of compound 14, which displayed nanomolar reporter assay activity and favorable drug-like properties. Compound 14 demonstrated excellent in vivo pharmacokinetic/pharmacodynamic profiles and synergistic antitumor activity when administered in combination with aPD1 antibody, suggesting opportunities of employing 14 in immuno-oncology therapies with immune checkpoint blockade agents.

Discovery of Novel TLR7 Agonists as Systemic Agent for Combination With aPD1 for Use in Immuno-oncology

We have designed and developed novel and selective TLR7 agonists that exhibited potent receptor activity in a cell-based reporter assay. In vitro, these agonists significantly induced secretion of cytokines IL-6, IL-1β, IL-10, TNFa, IFNa, and IP-10 in human and mouse whole blood. Pharmacokinetic and pharmacodynamic studies in mice showed a significant secretion of IFNα and TNFα cytokines. When combined with aPD1 in a CT-26 tumor model, the lead compound showed strong synergistic antitumor activity with complete tumor regression in 8/10 mice dosed using the intravenous route. Structure-activity relationship studies enabled by structure-based designs of TLR7 agonists are disclosed.

Selective FPR2 Agonism Promotes a Proresolution Macrophage Phenotype and Improves Cardiac Structure-Function Post Myocardial Infarction

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MI leads to ischemic damage of myocardium and activation of inflammatory programs as part of the wound healing response.

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Selective activation of FPR2 on macrophages potentiates key cellular activities that enable wound healing.

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MI was induced in rodents to study the effects of treatment with BMS-986235, a selective small molecule agonist of FPR2.

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BMS-986235 stimulated proresolution macrophage activities, induced neutrophil apoptosis and clearance, improved LV and infarct structure, and preserved cardiac function post MI.

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The findings suggest that targeted activation of FPR2 can improve post-MI outcome and may diminish the development of HF.

Dysregulated inflammation following myocardial infarction (MI) leads to maladaptive healing and remodeling. The study characterized and evaluated a selective formyl peptide receptor 2 (FPR2) agonist BMS-986235 in cellular assays and in rodents undergoing MI. BMS-986235 activated G proteins and promoted β-arrestin recruitment, enhanced phagocytosis and neutrophil apoptosis, regulated chemotaxis, and stimulated interleukin-10 and monocyte chemoattractant protein-1 gene expression. Treatment with BMS-986235 improved mouse survival, reduced left ventricular area, reduced scar area, and preserved wall thickness. Treatment increased macrophage arginase-1 messenger RNA and CD206 receptor levels indicating a proresolution phenotype. In rats following MI, BMS-986235 preserved viable myocardium, attenuated left ventricular remodeling, and increased ejection fraction relative to control animals. Therefore, FPR2 agonism improves post-MI healing, limits remodeling and preserves function, and may offer an innovative therapeutic option to improve outcomes.

Azatricyclic Inverse Agonists of RORγt That Demonstrate Efficacy in Models of Rheumatoid Arthritis and Psoriasis

Structure-activity relationship studies directed toward the replacement of the fused phenyl ring of the lead hexahydrobenzoindole RORγt inverse agonist series represented by 1 with heterocyclic moieties led to the identification of three novel aza analogs 5-7. The hexahydropyrrolo[3,2-f]quinoline series 5 (X = N, Y = Z=CH) showed potency and metabolic stability comparable to series 1 but with improved in vitro membrane permeability and serum free fraction. This structural modification was applied to the hexahydrocyclopentanaphthalene series 3, culminating in the discovery of 8e as a potent and selective RORγt inverse agonist with an excellent in vitro profile, good pharmacokinetic properties, and biologic-like in vivo efficacy in preclinical models of rheumatoid arthritis and psoriasis.

Optimization of Nicotinamides as Potent and Selective IRAK4 Inhibitors with Efficacy in a Murine Model of Psoriasis

IRAK4 is an attractive therapeutic target for the treatment of inflammatory conditions. Structure guided optimization of a nicotinamide series of inhibitors has been expanded to explore the IRAK4 front pocket. This has resulted in the identification of compounds such as 12 with improved potency and selectivity. Additionally 12 demonstrated activity in a pharmacokinetics/pharmacodynamics (PK/PD) model. Further optimization efforts led to the identification of the highly kinome selective 21, which demonstrated a robust PD effect and efficacy in a TLR7 driven model of murine psoriasis.

Diminished responses to monoaminergic antidepressants but not ketamine in a mouse model for neuropsychiatric lupus

BACKGROUND

A significant proportion of patients suffering from major depression fail to remit following treatment and develop treatment-resistant depression. Developing novel treatments requires animal models with good predictive validity. MRL/lpr mice, an established model of systemic lupus erythematosus, show depression-like behavior.

AIMS

We evaluated responses to classical antidepressants, and associated immunological and biochemical changes in MRL/lpr mice.

METHODS AND RESULTS

MRL/lpr mice showed increased immobility in the forced swim test, decreased wheel running and sucrose preference when compared with the controls, MRL/MpJ mice. In MRL/lpr mice, acute fluoxetine (30 mg/kg, intraperitoneally (i.p.)), imipramine (10 mg/kg, i.p.) or duloxetine (10 mg/kg, i.p.) did not decrease the immobility time in the Forced Swim Test. Interestingly, acute administration of combinations of olanzapine (0.03 mg/kg, subcutaneously)+fluoxetine (30 mg/kg, i.p.) or bupropion (10 mg/kg, i.p.)+fluoxetine (30 mg/kg, i.p.) retained efficacy. A single dose of ketamine but not three weeks of imipramine (10 mg/kg, i.p.) or escitalopram (5 mg/kg, i.p.) treatment in MRL/lpr mice restored sucrose preference. Further, we evaluated inflammatory, immune-mediated and neuronal mechanisms. In MRL/lpr mice, there was an increase in autoantibodies' titers, [3H]PK11195 binding and immune complex deposition. There was a significant infiltration of the brain by macrophages, neutrophils and T-lymphocytes. p11 mRNA expression was decreased in the prefrontal cortex. Further, there was an increase in the 5-HT_2aR expression, plasma corticosterone and indoleamine 2,3-dioxygenase activity.

CONCLUSION

In summary, the MRL/lpr mice could be a useful model for Treatment Resistant Depression associated with immune dysfunction with potential to expedite antidepressant drug discovery.

Bruton's tyrosine kinase inhibitor BMS-986142 in experimental models of rheumatoid arthritis enhances efficacy of agents representing clinical standard-of-care

Bruton’s tyrosine kinase (BTK) regulates critical signal transduction pathways involved in the pathobiology of rheumatoid arthritis (RA) and other autoimmune disorders. BMS-986142 is a potent and highly selective reversible small molecule inhibitor of BTK currently being investigated in clinical trials for the treatment of both RA and primary Sjögren’s syndrome. In the present report, we detail the in vitro and in vivo pharmacology of BMS-986142 and show this agent provides potent and selective inhibition of BTK (IC50 = 0.5 nM), blocks antigen receptor-dependent signaling and functional endpoints (cytokine production, co-stimulatory molecule expression, and proliferation) in human B cells (IC50 ≤ 5 nM), inhibits Fcγ receptor-dependent cytokine production from peripheral blood mononuclear cells, and blocks RANK-L-induced osteoclastogenesis. Through the benefits of impacting these important drivers of autoimmunity, BMS-986142 demonstrated robust efficacy in murine models of rheumatoid arthritis (RA), including collagen-induced arthritis (CIA) and collagen antibody-induced arthritis (CAIA). In both models, robust efficacy was observed without continuous, complete inhibition of BTK. When a suboptimal dose of BMS-986142 was combined with other agents representing the current standard of care for RA (e.g., methotrexate, the TNFα antagonist etanercept, or the murine form of CTLA4-Ig) in the CIA model, improved efficacy compared to either agent alone was observed. The results suggest BMS-986142 represents a potential therapeutic for clinical investigation in RA, as monotherapy or co-administered with agents with complementary mechanisms of action.

Effect of pioglitazone on metabolic features in endotoxemia model in obese diabetic db/db mice

BACKGROUND

Infectious diseases are more frequent in diabetic patients, leading to increased morbidity and mortality. Endotoxemia affects glucose metabolism and lipolytic capacity. The aims of the present study were to determine whether endotoxemia exacerbates metabolic features (adipose inflammation, adipogenesis, and insulin resistance [IR]) in an animal model of diabetes (i.e. db/db mice) after acute infection and the effects of pioglitazone.

METHODS

Female db/db mice treated with pioglitazone (3 and 30 mg/kg, p.o.) for 14 days were challenged with lipopolysaccharide (LPS; 200 μg/kg), followed by an oral glucose tolerance test (OGTT). Quantitative real-time polymerase chain reaction (PCR) was used to evaluate the expression of genes in white adipose tissue (WAT) involved in: (i) adipogenesis (lipoprotein lipase [Lpl], fatty acid binding protein-4 [Ap2] and adiponectin [Adipoq]); (ii) insulin signaling (peroxisome proliferator-activated receptor gamma [Pparg], suppressor of cytokine signaling 3 [Socs3], solute carrier family 2 [facilitated glucose transporter], member 4 [Slc2a4]); and (iii) inflammation (tumor necrosis factor [Tnf], interleukin-6 [Il6], monocyte chemoattractant protein-1 [Ccl2], cyclo-oxygenase-2 [prostaglandin-endoperoxide synthase 2; Ptgs2]).

RESULTS

Experimental endotoxemia downregulated mRNA expression of Pparg, Slc2a4, Adipoq, Lpl, and Ap2, which coincided with upregulation of Il6, Tnf, Ccl2, Ptgs2, and Socs3 expression. Pioglitazone dose-dependently decreased Tnf, Il6, Ccl2, Ptgs2, and Socs3 expression in WAT, in association with upregulation of Lpl, Ap2, Slc2a4, and Adipoq expression, indicating improvement in endotoxin-induced IR.

CONCLUSIONS

The findings suggest that LPS challenge exacerbates IR in db/db mice by altering the expression of genes in WAT involved in adipogenesis and inflammation, which is effectively controlled by pioglitazone treatment.

Nidotherapy compared with enhanced care programme approach training for adults with aggressive challenging behaviour and intellectual disability (NIDABID): cluster-randomised controlled trial

BACKGROUND

Aggressive challenging behaviour is very common in care homes for people with intellectual disability, and better psychological treatments are needed. Nidotherapy aims to change the environment of people with mental illness and is an appropriate treatment for this group of disorders.

METHOD

The design was a cluster randomised trial of 20 care homes in which the staff either received training in nidotherapy or the enhanced care programme approach (ECPA), with equivalent duration of treatment in each arm. Cluster randomisation of care homes was carried out at the beginning of the study by an independent statistician. Primary and secondary outcomes were not specified exactly in view of absence of previous study data, but changes over time in scores on two scales, the Modified Overt Aggression Scale and the Problem Behaviour Check List were the main outcome measures. Serious violent incidents were recorded using the Quantification of Violence Scale. All these measures were recorded monthly by research assistants who were carefully kept blind to the allocation of treatment.

RESULTS

A total of 200 residents entered the trial, 115 allocated to the ECPA arm and 85 to the nidotherapy one. Seven residents left the care homes in the course of the study, and six were replaced; these were included 79 in the analysis as the trial was a pragmatic one. There were no material reductions in challenging behaviour in the first 8 months of the trial in either group, but in the last 7 months, those allocated to nidotherapy had a 33% reduction in Modified Overt Aggression Scale (MOAS) scores and a 43% reduction in Problem Behaviour Check List scores compared with 5% and 13%, respectively, for the ECPA group, differences which for the MOAS were close to statistical significance.

DISCUSSION

Nidotherapy shows promise in the management of aggressive challenging behaviour in care homes, but a delay in its benefit might be expected if given to staff only. The treatment is worthy of further evaluation and development.

Selective IRAK4 Inhibition Attenuates Disease in Murine Lupus Models and Demonstrates Steroid Sparing Activity

The serine/threonine kinase IL-1R-associated kinase (IRAK)4 is a critical regulator of innate immunity. We have identified BMS-986126, a potent, highly selective inhibitor of IRAK4 kinase activity that demonstrates equipotent activity against multiple MyD88-dependent responses both in vitro and in vivo. BMS-986126 failed to inhibit assays downstream of MyD88-independent receptors, including the TNF receptor and TLR3. Very little activity was seen downstream of TLR4, which can also activate an MyD88-independent pathway. In mice, the compound inhibited cytokine production induced by injection of several different TLR agonists, including those for TLR2, TLR7, and TLR9. The compound also significantly suppressed skin inflammation induced by topical administration of the TLR7 agonist imiquimod. BMS-986126 demonstrated robust activity in the MRL/lpr and NZB/NZW models of lupus, inhibiting multiple pathogenic responses. In the MRL/lpr model, robust activity was observed with the combination of suboptimal doses of BMS-986126 and prednisolone, suggesting the potential for steroid sparing activity. BMS-986126 also demonstrated synergy with prednisolone in assays of TLR7- and TLR9-induced IFN target gene expression using human PBMCs. Lastly, BMS-986126 inhibited TLR7- and TLR9-dependent responses using cells derived from lupus patients, suggesting that inhibition of IRAK4 has the potential for therapeutic benefit in treating lupus.

Therapeutic potential of chloroquine in a murine model of inflammatory bowel disease

Inflammatory bowel disease (IBD) is an idiopathic chronic inflammation of the gastrointestinal tract which is mainly caused by dysregulated gut immune response to commensal flora. Very limited treatment options with marginal efficacy are available along with surgery which has high risk of reoccurrence. As both innate and adaptive immune responses have been found altered in IBD, a good therapeutic strategy could be to restrict both of them under chronic inflammatory conditions. Effect of chloroquine on TLR9 signaling is well reported, while there are limited studies on non-endosomal TLRs as well as T cell responses. Hence, we studied its effect on other TLRs as well as T cell response along with testing it as a potential therapeutics in IBD using murine preclinical colitis model. Chloroquine significantly suppressed the TLR2 as well as TLR9 signaling in both in vitro as well as in vivo experimental settings, while it had no effect on TLR4 pathway. It also suppressed the T cell cytokine and proliferative responses. In, DSS-induced murine colitis model, chloroquine administration, significantly improved body weight loss, colon length shortening, tissue damage and inflammatory cell infiltration. Based on our findings in preclinical murine model of IBD, chloroquine has the potential to be considered as a therapeutic option in clinics through inhibition of diverse TLR and T cell responses.