Discovery of GLPG3667, a Selective ATP Competitive Tyrosine Kinase 2 Inhibitor for the Treatment of Autoimmune Diseases.

Tyrosine kinase 2 (TYK2) mediates cytokine signaling through type 1 interferon, interleukin (IL)-12/IL-23, and the IL-10 family. There appears to be an association between TYK2 genetic variants and inflammatory conditions, and clinical evidence suggests that selective inhibition of TYK2 could produce a unique therapeutic profile. Here, we describe the discovery of compound 9 (GLPG3667), a reversible and selective TYK2 adenosine triphosphate competitive inhibitor in development for the treatment of inflammatory and autoimmune diseases. The preclinical pharmacokinetic profile was favorable, and TYK2 selectivity was confirmed in peripheral blood mononuclear cells and whole blood assays. Dermal ear inflammation was reduced in an IL-23-induced in vivo mouse model of psoriasis. GLPG3667 also completed a phase 1b study (NCT04594928) in patients with moderate-to-severe psoriasis where clinical effect was shown within the 4 weeks of treatment and it is now in phase 2 trials for the treatment of dermatomyositis (NCT05695950) and systemic lupus erythematosus (NCT05856448).

Discovery of GLPG2737, a Potent Type 2 Corrector of CFTR for the Treatment of Cystic Fibrosis in Combination with a Potentiator and a Type 1 Co-corrector.

Cystic fibrosis (CF) is caused by mutations in the CF transmembrane conductance regulator (CFTR) protein. This epithelial anion channel regulates the active transport of chloride and bicarbonate ions across membranes. Mutations result in reduced surface expression of CFTR channels with impaired functionality. Correctors are small molecules that support the trafficking of CFTR to increase its membrane expression. Such correctors can have different mechanisms of action. Combinations may result in a further improved therapeutic benefit. We describe the identification and optimization of a new pyrazolol3,4-bl pyridine-6-carboxylic acid series with high potency and efficacy in rescuing CFTR from the cell surface. Investigations showed that carboxylic acid group replacement with acylsulfonamides and acylsulfonylureas improved ADMET and PK properties, leading to the discovery of the structurally novel co-corrector GLPG2737. The addition of GLPG2737 to the combination of the potentiator GLPG1837 and C1 corrector 4 led to an 8-fold increase in the F508del CFTR activity.

Modulation of sleep behavior in zebrafish larvae by pharmacological targeting of the orexin receptor.

New pharmacological approaches that target orexin receptors (OXRs) are being developed to treat sleep disorders such as insomnia and narcolepsy, with fewer side effects than existing treatments. Orexins are neuropeptides that exert excitatory effects on postsynaptic neurons via the OXRs, and are important in regulating sleep/wake states. To date, there are three FDA-approved dual orexin receptor antagonists for the treatment of insomnia, and several small molecule oral OX2R (OXR type 2) agonists are in the pipeline for addressing the orexin deficiency in narcolepsy. To find new hypnotics and psychostimulants, rodents have been the model of choice, but they are costly and have substantially different sleep patterns to humans. As an alternative model, zebrafish larvae that like humans are diurnal and show peak daytime activity and rest at night offer several potential advantages including the ability for high throughput screening. To pharmacologically validate the use of a zebrafish model in the discovery of new compounds, we aimed in this study to evaluate the functionality of a set of known small molecule OX2R agonists and antagonists on human and zebrafish OXRs and to probe their effects on the behavior of zebrafish larvae. To this end, we developed an in vitro IP-One Homogeneous Time Resolved Fluorescence (HTRF) immunoassay, and in vivo locomotor assays that record the locomotor activity of zebrafish larvae under physiological light conditions as well as under dark-light triggers. We demonstrate that the functional IP-One test is a good predictor of biological activity in vivo. Moreover, the behavioral data show that a high-throughput assay that records the locomotor activity of zebrafish throughout the evening, night and morning is able to distinguish between OXR agonists and antagonists active on the zebrafish OXR. Conversely, a locomotor assay with alternating 30 min dark-light transitions throughout the day is not able to distinguish between the two sets of compounds, indicating the importance of circadian rhythm to their pharmacological activity. Overall, the results show that a functional IP-one test in combination with a behavioral assay using zebrafish is well-suited as a discovery platform to find novel compounds that target OXRs for the treatment of sleep disorders.

Accelerating GPCR Drug Discovery With Conformation-Stabilizing VHHs.

The human genome encodes 850 G protein-coupled receptors (GPCRs), half of which are considered potential drug targets. GPCRs transduce extracellular stimuli into a plethora of vital physiological processes. Consequently, GPCRs are an attractive drug target class. This is underlined by the fact that approximately 40% of marketed drugs modulate GPCRs. Intriguingly 60% of non-olfactory GPCRs have no drugs or candidates in clinical development, highlighting the continued potential of GPCRs as drug targets. The discovery of small molecules targeting these GPCRs by conventional high throughput screening (HTS) campaigns is challenging. Although the definition of success varies per company, the success rate of HTS for GPCRs is low compared to other target families (Fujioka and Omori, 2012; Dragovich et al., 2022). Beyond this, GPCR structure determination can be difficult, which often precludes the application of structure-based drug design approaches to arising HTS hits. GPCR structural studies entail the resource-demanding purification of native receptors, which can be challenging as they are inherently unstable when extracted from the lipid matrix. Moreover, GPCRs are flexible molecules that adopt distinct conformations, some of which need to be stabilized if they are to be structurally resolved. The complexity of targeting distinct therapeutically relevant GPCR conformations during the early discovery stages contributes to the high attrition rates for GPCR drug discovery programs. Multiple strategies have been explored in an attempt to stabilize GPCRs in distinct conformations to better understand their pharmacology. This review will focus on the use of camelid-derived immunoglobulin single variable domains (VHHs) that stabilize disease-relevant pharmacological states (termed ConfoBodies by the authors) of GPCRs, as well as GPCR:signal transducer complexes, to accelerate drug discovery. These VHHs are powerful tools for supporting in vitro screening, deconvolution of complex GPCR pharmacology, and structural biology purposes. In order to demonstrate the potential impact of ConfoBodies on translational research, examples are presented of their role in active state screening campaigns and structure-informed rational design to identify de novo chemical space and, subsequently, how such matter can be elaborated into more potent and selective drug candidates with intended pharmacology.

The synthesis and in vitro biological evaluation of novel fluorinated tetrahydrobenzo[j]phenanthridine-7,12-diones against Mycobacterium tuberculosis.

Tuberculosis (TB) still has a major impact on public health. In order to efficiently eradicate this life-threatening disease, the exploration of novel anti-TB drugs is of paramount importance. As part of our program to design new 2-azaanthraquinones with anti-mycobacterial activity, various "out-of-plane" tetrahydro- and octahydrobenzo[j]phenanthridinediones were synthesized. In this study, the scaffold of the most promising hits was further optimized in an attempt to improve the bioactivity and to decrease enzymatic degradation. The rudiment bio-evaluation of a small library of fluorinated tetrahydrobenzo[j]phenanthridine-7,12-dione derivatives indicated no significant improvement of the bio-activity against intracellular and extracellular Mycobacterium tuberculosis (Mtb). Though, the derivatives showed an acceptable toxicity against J774A.1 macrophages and early signs of genotoxicity were absent. All derivatives showed to be metabolic stabile in the presence of both phase I and phase II murine or human microsomes. Finally, the onset of reactive oxygen species within Mtb after exposure to the derivatives was measured by electron paramagnetic resonance (EPR). Results showed that the most promising fluorinated derivative is still a possible candidate for the subversive inhibition of mycothione reductase.

2,4-Dialkyl-8,9,10,11-tetrahydrobenzo[g]pyrimido[4,5-c]isoquinoline-1,3,7,12(2H,4H)-tetraones as new leads against Mycobacterium tuberculosis.

Given the re-emergence of tuberculosis in Europe and beyond, the search for novel bio-active compound classes against this disease is of utmost importance. As a result of a high intrinsic tolerance of the etiological agent, Mycobacterium tuberculosis, towards most antibiotics and xenobiotics, the search for such new compounds is far from trivial. Further exacerbated by the rapid generation and spread of drug resistant M. tuberculosis and fuelled by the HIV/AIDS pandemic, halting the tuberculosis epidemic is of paramount importance. As part of our program to design new 2-aza-anthraquinones with anti-mycobacterial activity, various dialkyltetrahydrobenzo[g]pyrimido[4,5-c]isoquinolinetetraones were designed and synthesised. The compounds were submitted to a biological evaluation in which the activity against M.tb H37Rv(lux) was observed, as well as the acute toxicity towards J774 A.1 macrophages. From these results, the selectivity index was calculated. Furthermore, the activity of the most promising compounds was further studied against a multi-drug resistant LAM-1 strain and against intracellular replicating M.tb. The study was further extended with a comet assay and a VITOTOX™ assay to investigate the possibility of observable genotoxic effects caused by these compounds.

1,2,3,4,8,9,10,11-octahydrobenzo[j]phenanthridine-7,12-diones as new leads against Mycobacterium tuberculosis.

Tuberculosis (TB) continues to be a worldwide health problem with over 1.4 million deaths each year. Despite efforts to develop more effective vaccines, more reliable diagnostics, and chemotherapeutics, tuberculosis remains a threat to global health, fueled by the HIV pandemic and the rapid generation of drug resistance. The exploration of novel drugs to serve as a companion drug for existing drugs is of paramount importance. As part of our program to design new 2-aza-anthraquinones with antimycobacterial activity, various tetrahydro- and octahydrobenzo[j]phenanthridinediones were synthesized. These compounds showed high in vitro potency against Mycobacterium tuberculosis, the etiological agent of TB and against other clinically relevant mycobacterial species at submicromolar concentrations. The susceptibility of a multidrug resistant strain toward these compounds and their ability to target intracellular replicating Mycobacterium tuberculosis was demonstrated. Next to the acute toxicity, the genotoxicity of these compounds was investigated. Often overlooked in studies, genotoxicity could be dismissed for the investigated compounds, making them a promising scaffold in TB drug research.

Palladium(II)-catalyzed synthesis of 2H,3'H-spiro[benzofuran-3,2'-naphthoquinones].

2H,3'H-Spiro[benzofuran-3,2'-naphthoquinones], constituting a new spiroheterocyclic skeleton, were synthesized starting from 2-aryloxymethyl-1,4-naphthoquinones by means of a palladium(II)-catalyzed reaction, which is a new spirocyclic transformation. Under optimal conditions, i.e. 10 mol % of palladium(II) acetate, 15 mol % of 3,5-dichloropyridine, and 5 mol % of trifluoroacetic acid in acetic acid at 110 °C, various 2H,3'H-spiro[benzofuran-3,2'-naphthoquinones] were synthesized in yields strongly dependent on the substitution pattern of the aryloxy group. Unsubstituted or ortho-substituted 2-aryloxymethyl-1,4-quinones were found to rearrange toward the corresponding 2-(4-hydroxyaryl)-1,4-quinones upon treatment with trifluoroacetic acid.

Synthesis and antimycobacterial activity of analogues of the bioactive natural products sampangine and cleistopholine.

Identification and investigation of novel classes and compounds for the treatment of tuberculosis remains of utmost importance in the fight against the disease. Despite many efforts, the weakly gram positive Mycobacterium tuberculosis keeps demanding its toll in human lives. For this reason a small library of substituted and unsubstituted aza analogues of cleistopholine and sampangine were synthesized in a short and straightforward manner and tested in vitro against M.tb. The compounds showed promising activity against the M.tb H37Rv strain and Minimal Inhibitory Concentrations (MIC) could be observed as low as 0.88 µM. Accompanied by moderate acute toxicity against C3A hepatocytes, the therapeutic index showed an acceptable range. Further tests confirmed the inhibition by up to 74% of intracellular growth of M.tb inside macrophages conferred by 1-hydroxybenzo[g]isoquinoline-5,10-diones. Activity of the library against other clinically relevant mycobacterial species such as Mycobacterium bovis, Mycobacterium avium and Mycobacterium ulcerans was confirmed. Furthermore the activity against a multi-drug-resistant MDR LAM-1 M.tb strain was tested and the MIC value situated around 1 µM. The lacking genotoxicity of a group of enamine substituted cleistopholine analogues indicates this group as a hit and encourages their use as a scaffold for further studies.