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).

IRAK4 inhibition dampens pathogenic processes driving inflammatory skin diseases.

Innate immunity not only shapes the way epithelial barriers interpret environmental cues but also drives adaptive responses. Therefore, modulators of innate immune responses are expected to have high therapeutic potential across immune-mediated inflammatory diseases. IRAK4 is a kinase that integrates signaling downstream of receptors acting at the interface between innate and adaptive immune responses, such as Toll-like receptors (TLRs), interleukin-1R (IL-1R), and IL-18R. Because effects of IRAK4 inhibition are stimulus, cell type, and species dependent, the evaluation of the therapeutic potential of IRAK4 inhibitors requires a highly translational approach. Here, we profiled a selective IRAK4 inhibitor, GLPG2534, in an extensive panel of models of inflammatory skin diseases, translationally expanding evidence from in vitro to in vivo and from mouse to human. In vitro, IRAK4 inhibition resulted in substantial inhibition of TLR and IL-1 responses in dendritic cells, keratinocytes, granulocytes, and T cells but only weakly affected dermal fibroblast responses. Furthermore, disease activity in murine models of skin inflammation (IL-23-, IL-33-, imiquimod-, and MC903-induced) was markedly dampened by IRAK4 inhibition. Last, inhibiting IRAK4 reversed pathogenic molecular signatures in human lesional psoriasis and atopic dermatitis biopsies. Over the variety of models used, IRAK4 inhibition consistently affected central mediators of psoriasis (IL-17A) and atopic dermatitis (IL-4 and IL-13). Overall, our data highlight IRAK4 as a central player in skin inflammatory processes and demonstrate the potential of IRAK4 inhibition as a therapeutic strategy in chronic inflammatory skin diseases.

Autotaxin facilitates selective LPA receptor signaling.

Autotaxin (ATX; ENPP2) produces the lipid mediator lysophosphatidic acid (LPA) that signals through disparate EDG (LPA1-3) and P2Y (LPA4-6) G protein-coupled receptors. ATX/LPA promotes several (patho)physiological processes, including in pulmonary fibrosis, thus serving as an attractive drug target. However, it remains unclear if clinical outcome depends on how different types of ATX inhibitors modulate the ATX/LPA signaling axis. Here, we show that the ATX "tunnel" is crucial for conferring key aspects of ATX/LPA signaling and dictates cellular responses independent of ATX catalytic activity, with a preference for activation of P2Y LPA receptors. The efficacy of the ATX/LPA signaling responses are abrogated more efficiently by tunnel-binding inhibitors, such as ziritaxestat (GLPG1690), compared with inhibitors that exclusively target the active site, as shown in primary lung fibroblasts and a murine model of radiation-induced pulmonary fibrosis. Our results uncover a receptor-selective signaling mechanism for ATX, implying clinical benefit for tunnel-targeting ATX inhibitors.

Discovery and Optimization of Orally Bioavailable Phthalazone and Cinnolone Carboxylic Acid Derivatives as S1P2 Antagonists against Fibrotic Diseases.

Idiopathic pulmonary fibrosis (IPF) is a chronic and progressive lung disease. Current treatments only slow down disease progression, making new therapeutic strategies compelling. Increasing evidence suggests that S1P2 antagonists could be effective agents against fibrotic diseases. Our compound collection was mined for molecules possessing substructure features associated with S1P2 activity. The weakly potent indole hit 6 evolved into a potent phthalazone series, bearing a carboxylic acid, with the aid of a homology model. Suboptimal pharmacokinetics of a benzimidazole subseries were improved by modifications targeting potential interactions with transporters, based on concepts deriving from the extended clearance classification system (ECCS). Scaffold hopping, as a part of a chemical enablement strategy, permitted the rapid exploration of the position adjacent to the carboxylic acid. Compound 38, with good pharmacokinetics and in vitro potency, was efficacious at 10 mg/kg BID in three different in vivo mouse models of fibrotic diseases in a therapeutic setting.

Neutralization of IL-17C Reduces Skin Inflammation in Mouse Models of Psoriasis and Atopic Dermatitis.

IL-17C is a functionally distinct member of the IL-17 family that was believed to play a role in the pathogenesis of psoriasis. Here we confirmed that IL-17C is involved in psoriasis and explored potential roles for IL-17C in atopic dermatitis (AD). An anti-IL-17C antibody, MOR106, was generated that potently and selectively binds to human and mouse IL-17C, thereby inhibiting the binding of IL-17C to its IL-17RE receptor. The antibody inhibited cutaneous inflammation in an IL-23-induced psoriatic-like skin inflammation model. In lesional skin of patients with AD, IL-17C expression levels were increased and localized to keratinocytes and infiltrating immune cells. To determine the contribution of IL-17C to AD pathogenesis, MOR106 was tested in two distinct in vivo models. In the calcipotriol-induced AD model, ear skin inflammation, TSLP, and IL-33 protein production in ears was suppressed by MOR106. Consistently, in the flaky tail strain mouse model, spontaneous development of AD-like skin inflammation was reduced by MOR106. Moreover, serum IgE levels, number of mast cells in skin and T helper type 2-related cytokines IL-4 and CCL17 in serum were all reduced. Overall, our results indicate that IL-17C is a central mediator of skin inflammation beyond psoriasis and is relevant in particular in AD.

Effects of Nandrolone in the Counteraction of Skeletal Muscle Atrophy in a Mouse Model of Muscle Disuse: Molecular Biology and Functional Evaluation.

Muscle disuse produces severe atrophy and a slow-to-fast phenotype transition in the postural Soleus (Sol) muscle of rodents. Antioxidants, amino-acids and growth factors were ineffective to ameliorate muscle atrophy. Here we evaluate the effects of nandrolone (ND), an anabolic steroid, on mouse skeletal muscle atrophy induced by hindlimb unloading (HU). Mice were pre-treated for 2-weeks before HU and during the 2-weeks of HU. Muscle weight and total protein content were reduced in HU mice and a restoration of these parameters was found in ND-treated HU mice. The analysis of gene expression by real-time PCR demonstrates an increase of MuRF-1 during HU but minor involvement of other catabolic pathways. However, ND did not affect MuRF-1 expression. The evaluation of anabolic pathways showed no change in mTOR and eIF2-kinase mRNA expression, but the protein expression of the eukaryotic initiation factor eIF2 was reduced during HU and restored by ND. Moreover we found an involvement of regenerative pathways, since the increase of MyoD observed after HU suggests the promotion of myogenic stem cell differentiation in response to atrophy. At the same time, Notch-1 expression was down-regulated. Interestingly, the ND treatment prevented changes in MyoD and Notch-1 expression. On the contrary, there was no evidence for an effect of ND on the change of muscle phenotype induced by HU, since no effect of treatment was observed on the resting gCl, restCa and contractile properties in Sol muscle. Accordingly, PGC1α and myosin heavy chain expression, indexes of the phenotype transition, were not restored in ND-treated HU mice. We hypothesize that ND is unable to directly affect the phenotype transition when the specialized motor unit firing pattern of stimulation is lacking. Nevertheless, through stimulation of protein synthesis, ND preserves protein content and muscle weight, which may result advantageous to the affected skeletal muscle for functional recovery.

GLPG0492, a novel selective androgen receptor modulator, improves muscle performance in the exercised-mdx mouse model of muscular dystrophy.

Anabolic drugs may counteract muscle wasting and dysfunction in Duchenne muscular dystrophy (DMD); however, steroids have unwanted side effects. We focused on GLPG0492, a new non-steroidal selective androgen receptor modulator that is currently under development for musculo-skeletal diseases such as sarcopenia and cachexia. GLPG0492 was tested in the exercised mdx mouse model of DMD in a 4-week trial at a single high dose (30 mg/kg, 6 day/week s.c.), and the results were compared with those from the administration of α-methylprednisolone (PDN; 1 mg/kg, i.p.) and nandrolone (NAND, 5 mg/kg, s.c.). This assessment was followed by a 12-week dose-dependence study (0.3-30 mg/kg s.c.). The outcomes were evaluated in vivo and ex vivo on functional, histological and biochemical parameters. Similar to PDN and NAND, GLPG0492 significantly increased mouse strength. In acute exhaustion tests, a surrogate of the 6-min walking test used in DMD patients, GLPG0492 preserved running performance, whereas vehicle- or comparator-treated animals showed a significant increase in fatigue (30-50%). Ex vivo, all drugs resulted in a modest but significant increase of diaphragm force. In parallel, a decrease in the non-muscle area and markers of fibrosis was observed in GLPG0492- and NAND-treated mice. The drugs exerted minor effects on limb muscles; however, electrophysiological biomarkers were ameliorated in extensor digitorum longus muscle. The longer dose-dependence study confirmed the effect on mdx mouse strength and resistance to fatigue and demonstrated the efficacy of lower drug doses on in vivo and ex vivo functional parameters. These results support the interest of further studies of GLPG0492 as a potential treatment for DMD.

Identification of a 4-(hydroxymethyl)diarylhydantoin as a selective androgen receptor modulator.

Structural modification performed on a 4-methyl-4-(4-hydroxyphenyl)hydantoin series is described which resulted in the development of a new series of 4-(hydroxymethyl)diarylhydantoin analogues as potent, partial agonists of the human androgen receptor. This led to the identification of (S)-(-)-4-(4-(hydroxymethyl)-3-methyl-2,5-dioxo-4-phenylimidazolidin-1-yl)-2-(trifluoromethyl)benzonitrile ((S)-(-)-18a, GLPG0492) evaluated in vivo in a classical model of orchidectomized rat. In this model, (-)-18a exhibited anabolic activity on muscle, strongly dissociated from the androgenic activity on prostate after oral dosing. (-)-18a has very good pharmacokinetic properties, including bioavailability in rat (F > 50%), and is currently under evaluation in phase I clinical trials.

Discovery of diarylhydantoins as new selective androgen receptor modulators.

A novel selective androgen receptor modulator scaffold has been discovered through structural modifications of hydantoin antiandrogens. Several 4-(4-hydroxyphenyl)-N-arylhydantoins displayed partial agonism with nanomolar in vitro potency in transactivation experiments using androgen receptor (AR) transfected cells. In a standard castrated male rat model, several compounds showed good anabolic activity on levator ani muscle, dissociated from the androgenic activity on ventral prostate, after oral dosing at 30 mg/kg. (+)-4-[3,4-Dimethyl-2,5-dioxo-4-(4-hydroxyphenyl)imidazolidin-1-yl]-2-(trifluoromethyl)benzonitrile ((+)-11b) displayed anabolic potency with a strong dissociation between levator ani muscle and ventral prostate (A(50) = 0.5 mg/kg vs 70 mg/kg). The binding modes of two compounds, including (+)-11b, within the AR ligand-binding domain have been studied by cocrystallization experiments using a coactivator-like peptide. Both compounds bound to the same site, and the overall structures of the AR were very similar.

Crystallization and preliminary X-ray analysis of the human androgen receptor ligand-binding domain with a coactivator-like peptide and selective androgen receptor modulators.

The ligand-binding domain of the human androgen receptor has been cloned, overproduced and crystallized in the presence of a coactivator-like 11-mer peptide and two different nonsteroidal ligands. The crystals of the two ternary complexes were isomorphous and belonged to space group P2(1)2(1)2(1), with one molecule in the asymmetric unit. They diffracted to 1.7 and 1.95 A resolution, respectively. Structure determination of these two complexes will help in understanding the mode of binding of selective nonsteroidal androgens versus endogenous steroidal ligands and possibly the origin of their tissue selectivity.