Optimization and biological evaluation of thiazole-bis-amide inverse agonists of RORγt

Discovery, Synthesis, and In Vitro Characterization of 2,3 Derivatives of 4,5,6,7-Tetrahydro-Benzothiophene as Potent Modulators of Retinoic Acid Receptor-Related Orphan Receptor γt

Retinoic acid receptor-related orphan receptor γt (RORγt) is a nuclear receptor that is expressed in a variety of tissues and is a potential drug target for the treatment of inflammatory and auto-immune diseases, metabolic diseases, and resistant cancer types. We herein report the discovery of 2,3 derivatives of 4,5,6,7-tetrahydro-benzothiophene modulators of RORγt. We also report the solubility in acidic/neutral pH, mouse/human/dog/rat microsomal stability, Caco-2, and MDR1-MDCKII permeabilities of a set of these derivatives. For this group of modulators, inverse agonism by steric clashes and push-pull mechanisms induce greater instability to protein conformation compared to agonist lock hydration. Independent of the two mechanisms, we observed a basal modulatory activity of the tested 2,3 derivatives of 4,5,6,7-tetrahydro-benzothiophene toward RORγt due to the interactions with the Cys320-Glu326 and Arg364-Phe377 hydrophilic regions. The drug discovery approach reported in the current study can be employed to discover modulators of nuclear receptors and other globular protein targets.

Statistical Analysis of Protein-Ligand Interaction Patterns in Nuclear Receptor RORγ

The receptor RORγ belongs to the nuclear receptor superfamily that senses small signaling molecules and regulates at the gene transcription level. Since RORγ has a high basal activity and plays an important role in immune responses, inhibitors targeting this receptor have been a focus for many studies. The receptor-ligand interaction is complex, and often subtle differences in ligand structure can determine its role as an inverse agonist or an agonist. We examined more than 130 existing RORγ crystal structures that have the same receptor complexed with different ligands. We reported the features of receptor-ligand interaction patterns and the differences between agonist and inverse agonist binding. Specific changes in the contact interaction map are identified to distinguish active and inactive conformations. Further statistical analysis of the contact interaction patterns using principal component analysis reveals a dominant mode which separates allosteric binding vs. canonical binding and a second mode which may indicate active vs. inactive structures. We also studied the nature of constitutive activity by performing a 100-ns computer simulation of apo RORγ. Using constitutively active nuclear receptor CAR as a comparison, we identified a group of conserved contacts that have similar contact strength between the two receptors. These conserved contact interactions, especially a couple key contacts in H11–H12 interaction, can be considered essential to the constitutive activity of RORγ. These protein-ligand and internal protein contact interactions can be useful in the development of new drugs that direct receptor activity.

Crystallographic landscape provides molecular insights into the modes of action of diverse ROR-γt modulators

ROR-γt, the master regulator of Th-17 cells, is activated by the binding of small molecules at its orthosteric site, followed by the recruitment of co-activators or co-repressors in the ligand binding domain (LBD). Th-17 cells provide immune-dependent protection against cancers and pathogens. Their dysregulation causes inflammation and is therefore implicated in various autoimmune diseases such as multiple sclerosis, rheumatoid arthritis, and psoriasis. Consequently, there is enormous interest in the development of ROR-γt modulators, both agonist and inverse-agonists. Here, we review advances in the development of ROR-γt modulators that have been made over the past decade, focusing on the rich crystallography landscape for ROR-γt co-crystals that has delineated the relationship between the binding patterns of modulators and the resulting biological activities.

The evolution paths of some reprehensive scaffolds of RORγt modulators, a perspective from medicinal chemistry

The ligand binding domain (LBD) of retinoid-related orphan nuclear receptor γt (RORγt) has been exploited as a promising target for the new small molecule therapeutics to cure autoimmune diseases via modulating the IL-17 and IL-22 production by Th17 cells. Diverse chemical scaffolds of these small molecules have been discovered by multiple groups with methods such as high throughput screening (HTS) and virtual screening. These different scaffolds are further developed by medicinal chemists to afford lead compounds the best of which enter clinical trials. In this review, we summarize these chemical scaffolds and their evolution paths according to the groups in which they have been discovered or studied. We combine the data of the chemistry, biological assays and structural biology of each chemical scaffold, in order to afford insight to develop new RORγt modulators with higher potency, less toxicity and elucidated working mechanism.

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.

Retinoic acid-related orphan receptor gamma t (RORγt) inverse agonists/antagonists for the treatment of inflammatory diseases - where are we presently?

Introduction: The transcription factor retinoic acid-related orphan receptor gamma t (RORγt) has been identified as the master regulator of T_H17 cell differentiation and IL-17/22 production and is therefore an attractive target for the treatment of inflammatory diseases. Several orally or topically administered small molecule RORγt inverse agonists (RIAs) have progressed up to the end of clinical Phase 2.Areas covered: Based on publications and patent evaluations this review summarizes the evolution of the chemical matter for all 16 pharmaceutical companies, who develop(ed) a clinical-stage RIAs (until March 2021). Structure proposals for some clinical stage RIAs are presented and the outcome of the clinical trials is discussed.Expert opinion: So far, the clinical trials have been plagued with a high attrition rate. Main reasons were lack of efficacy (topical) or safety signals (oral) as well as, amongst other things, thymic lymphomas as seen with BMS-986251 in a preclinical study and liver enzyme elevations in humans with VTP-43742. Possibilities to mitigate these risks could be the use of RIAs with different chemical structures not interfering with thymocytes maturation and no livertox-inducing properties. With new frontrunners (e.g., ABBV-157 (cedirogant), BI 730357 or IMU-935) this is still an exciting time for this treatment approach.

Discovery and Characterization of Benzimidazole Derivative XY123 as a Potent, Selective, and Orally Available RORγ Inverse Agonist

Receptor-related orphan receptor γ (RORγ) has emerged as an attractive therapeutic target for the treatment of cancer and inflammatory diseases. Herein, we report our effort on the discovery, optimization, and evaluation of benzothiazole and benzimidazole derivatives as novel inverse agonists of RORγ. The representative compound 27h (designated as XY123) potently inhibited the RORγ transcription activity with a half-maximal inhibitory concentration (IC50) value of 64 nM and showed excellent selectivity against other nuclear receptors. 27h also potently suppressed cell proliferation, colony formation, and the expression of androgen receptor (AR)-regulated genes in AR-positive prostate cancer cell lines. In addition, 27h demonstrated good metabolic stability and a pharmacokinetic property with reasonable oral bioavailability (32.41%) and moderate half-life (t1/2 = 4.98 h). Significantly, oral administration of compound 27h achieved complete and long-lasting tumor regression in the 22Rv1 xenograft tumor model in mice. Compound 27h may serve as a new valuable lead compound for further development of drugs for the treatment of prostate cancer.

Preclinical and clinical characterization of the RORγt inhibitor JNJ-61803534

The nuclear receptor retinoid-related orphan receptor gamma t (RORγt) plays a critical role in driving Th17 cell differentiation and expansion, as well as IL-17 production in innate and adaptive immune cells. The IL-23/IL-17 axis is implicated in several autoimmune and inflammatory diseases, and biologics targeting IL-23 and IL-17 have shown significant clinical efficacy in treating psoriasis and psoriatic arthritis. JNJ-61803534 is a potent RORγt inverse agonist, selectively inhibiting RORγt-driven transcription versus closely-related family members, RORα and RORβ. JNJ-61803534 inhibited IL-17A production in human CD4⁺ T cells under Th17 differentiation conditions, but did not inhibit IFNγ production under Th1 differentiation conditions, and had no impact on in vitro differentiation of regulatory T cells (Treg), nor on the suppressive activity of natural Tregs. In the mouse collagen-induced arthritis model, JNJ-61803534 dose-dependently attenuated inflammation, achieving ~ 90% maximum inhibition of clinical score. JNJ-61803534 significantly inhibited disease score in the imiquimod-induced mouse skin inflammation model, and dose-dependently inhibited the expression of RORγt-regulated genes, including IL-17A, IL-17F, IL-22 and IL-23R. Preclinical 1-month toxicity studies in rats and dogs identified doses that were well tolerated supporting progression into first-in-human studies. An oral formulation of JNJ-61803534 was studied in a phase 1 randomized double-blind study in healthy human volunteers to assess safety, pharmacokinetics, and pharmacodynamics. The compound was well tolerated in single ascending doses (SAD) up to 200 mg, and exhibited dose-dependent increases in exposure upon oral dosing, with a plasma half-life of 164 to 170 h. In addition, dose-dependent inhibition of ex vivo stimulated IL-17A production in whole blood was observed, demonstrating in vivo target engagement. In conclusion, JNJ-61803534 is a potent and selective RORγt inhibitor that exhibited acceptable preclinical safety and efficacy, as well as an acceptable safety profile in a healthy volunteer SAD study, with clear evidence of a pharmacodynamic effect in humans.

Designing Out PXR Activity on Drug Discovery Projects: A Review of Structure-Based Methods, Empirical and Computational Approaches

This perspective discusses the role of pregnane xenobiotic receptor (PXR) in drug discovery and the impact of its activation on CYP3A4 induction. The use of structural biology to reduce PXR activity on drug discovery projects has become more common in recent years. Analysis of this work highlights several important molecular interactions, and the resultant structural modifications to reduce PXR activity are summarized. The computational approaches undertaken to support the design of new drugs devoid of PXR activation potential are also discussed. Finally, the SAR of empirical design strategies to reduce PXR activity is reviewed, and the key SAR transformations are discussed and summarized. In conclusion, this perspective demonstrates that PXR activity can be greatly diminished or negated on active drug discovery projects with the knowledge now available. This perspective should be useful to anyone who seeks to reduce PXR activity on a drug discovery project.

Effects of N-Substituents on the Functional Activities of Naltrindole Derivatives for the δ Opioid Receptor: Synthesis and Evaluation of Sulfonamide Derivatives

We have recently reported that N-alkyl and N-acyl naltrindole (NTI) derivatives showed activities for the δ opioid receptor (DOR) ranging widely from full inverse agonists to full agonists. We newly designed sulfonamide-type NTI derivatives in order to investigate the effects of the N-substituent on the functional activities because the side chain and S=O part in the sulfonamide moiety located in spatially different positions compared with those in the alkylamine and amide moieties. Among the tested compounds, cyclopropylsulfonamide 9f (SYK-839) was the most potent full inverse agonist for the DOR, whereas phenethylsulfonamide 9e (SYK-901) showed full DOR agonist activity with moderate potency. These NTI derivatives are expected to be useful compounds for investigation of the molecular mechanism inducing these functional activities.