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.

OP0242 EFFECTS OF THE AUTOTAXIN INHIBITOR ZIRITAXESTAT ON SKIN AND LUNG FIBROSIS IN A MURINE GRAFT-VERSUS-HOST DISEASE MODEL OF SYSTEMIC SCLEROSIS

Background:

There is an unmet medical need for new drugs to treat systemic sclerosis (SSc). Autotaxin (ATX) is a widely expressed enzyme that regulates diverse cellular processes, including proliferation, differentiation and migration, and has been implicated in the pathogenesis of SSc. Targeting ATX is a promising new strategy for treating SSc. The autotaxin inhibitor ziritaxestat (GLPG1690) is a potential first-in-class disease-modifying drug for SSc that has been shown to improve skin score in the Phase 2a NOVESA (NCT03798366) trial in patients with SSc.

Objectives:

To investigate the effects of ziritaxestat in a chronic graft-versus-host disease (cGvHD) murine model of SSc.

Methods:

Effects of ziritaxestat (10 or 30 mg/kg twice daily [bid]) on disease activity were assessed in a cGvHD murine model of SSc (allogeneic bone marrow transplantation [BMT] with B10.D2 donor and BALB/c recipient; syngeneic mice as controls). Ziritaxestat or nintedanib (60 mg/kg once daily [qd]) as active comparator was administered 21 d after BMT and continued for 35 d. Effects of ziritaxestat were assessed by clinical monitoring, histologic assessment of skin and lungs (dermal thickness, Ashcroft scores and collagen-covered area), immunofluorescence staining with Trichrome and Sirius Red for myofibroblasts, and biochemical analysis of collagen content, as measured by hydroxyproline levels.

Results:

Ziritaxestat 30 mg/kg bid for 35 days significantly reduced the clinical cutaneous score in the murine cGvHD model by 57% (p<0.05) compared with vehicle, and to a similar extent when compared with nintedanib 60 mg/kg (38%; p<0.05). Dermal accumulation of collagen and dermal thickness (Figure) were reduced with ziritaxestat 10 and 30 mg/kg compared with vehicle. At 30 mg/kg, ziritaxestat reversed the increase in the allogeneic model (p<0.001), returning dermal thickness to the levels in non-fibrotic control mice. Ziritaxestat also significantly reduced pulmonary fibrosis in the cGvHD model, with reductions in the fibrotic lung area (ziritaxestat 10 and 30 mg/kg; p<0.001 for both) and Ashcroft scores (ziritaxestat 30 mg/kg; p<0.05). Ziritaxestat was generally well tolerated.

Conclusion:

Ziritaxestat improved the histological, biochemical and clinical symptom readouts of dermal and pulmonary fibrosis in a murine model, consistent with a broad and rapid disease-modifying effect in SSc.

Acknowledgements:

This study was funded by Galapagos NV (Mechelen, Belgium). Medical writing/editorial support was provided by Ian Faulkner, PhD (Aspire Scientific, Bollington, UK) funded by Galapagos NV.

Disclosure of Interests:

Yun Zhang Employee of: 4D Science, Lena Summa Employee of: 4D Science, Bertrand Heckmann Shareholder of: Galapagos, Employee of: Galapagos, Jörg H.W. Distler Shareholder of: 4D Science, Consultant of: Actelion, Active Biotech, Anamar, ARXX, Bayer Pharma, Boehringer Ingelheim, Celgene, Galapagos, GlaxoSmithKline, Inventiva, JB Therapeutics, Medac, Pfizer, RuiYi and UCB, Grant/research support from: Anamar, Active Biotech, Array Biopharma, ARXX, aTyr, Bristol Myers Squibb, Bayer Pharma, Boehringer Ingelheim, Celgene, Galapagos, GlaxoSmithKline, Inventiva, Novartis, Sanofi-Aventis, RedX and UCB

Discovery of the S1P2 Antagonist GLPG2938 (1-[2-Ethoxy-6-(trifluoromethyl)-4-pyridyl]-3-[[5-methyl-6-[1-methyl-3-(trifluoromethyl)pyrazol-4-yl]pyridazin-3-yl]methyl]urea), a Preclinical Candidate for the Treatment of Idiopathic Pulmonary Fibrosis

Mounting evidence from the literature suggests that blocking S1P2 receptor (S1PR2) signaling could be effective for the treatment of idiopathic pulmonary fibrosis (IPF). However, only a few antagonists have been so far disclosed. A chemical enablement strategy led to the discovery of a pyridine series with good antagonist activity. A pyridazine series with improved lipophilic efficiency and with no CYP inhibition liability was identified by scaffold hopping. Further optimization led to the discovery of 40 (GLPG2938), a compound with exquisite potency on a phenotypic IL8 release assay, good pharmacokinetics, and good activity in a bleomycin-induced model of pulmonary fibrosis.

Inhibition of Autotaxin with GLPG1690 Increases the Efficacy of Radiotherapy and Chemotherapy in a Mouse Model of Breast Cancer

Autotaxin catalyzes the formation of lysophosphatidic acid, which stimulates tumor growth and metastasis and decreases the effectiveness of cancer therapies. In breast cancer, autotaxin is secreted mainly by breast adipocytes, especially when stimulated by inflammatory cytokines produced by tumors. In this work, we studied the effects of an ATX inhibitor, GLPG1690, which is in phase III clinical trials for idiopathic pulmonary fibrosis, on responses to radiotherapy and chemotherapy in a syngeneic orthotopic mouse model of breast cancer. Tumors were treated with fractionated external beam irradiation, which was optimized to decrease tumor weight by approximately 80%. Mice were also dosed twice daily with GLPG1690 or vehicle beginning at 1 day before the radiation until 4 days after radiation was completed. GLPG1690 combined with irradiation did not decrease tumor growth further compared with radiation alone. However, GLPG1690 decreased the uptake of 3'-deoxy-3'-[¹⁸F]-fluorothymidine by tumors and the percentage of Ki67-positive cells. This was also associated with increased cleaved caspase-3 and decreased Bcl-2 levels in these tumors. GLPG1690 decreased irradiation-induced C-C motif chemokine ligand-11 in tumors and levels of IL9, IL12p40, macrophage colony-stimulating factor, and IFNγ in adipose tissue adjacent to the tumor. In other experiments, mice were treated with doxorubicin every 2 days after the tumors developed. GLPG1690 acted synergistically with doxorubicin to decrease tumor growth and the percentage of Ki67-positive cells. GLPG1690 also increased 4-hydroxynonenal-protein adducts in these tumors. These results indicate that inhibiting ATX provides a promising adjuvant to improve the outcomes of radiotherapy and chemotherapy for breast cancer.

Safety, Pharmacokinetics, and Pharmacodynamics of the Autotaxin Inhibitor GLPG1690 in Healthy Subjects: Phase 1 Randomized Trials

GLPG1690 is a novel autotaxin inhibitor in development for the treatment of idiopathic pulmonary fibrosis (IPF). We report phase 1 studies investigating the safety, tolerability, pharmacokinetics (PK), and pharmacodynamics (PD) of GLPG1690 in healthy subjects. We performed a first-in-human randomized, double-blind, placebo-controlled trial of single (20, 60, 150, 300, 600, 1000, 1500 mg) and multiple (14 days: 150 mg twice daily; 600 and 1000 mg once daily) ascending oral doses of GLPG1690 (NCT02179502), and a randomized, open-label, crossover relative bioavailability study to compare the PK of tablet and capsule formulations of GLPG1690 600 mg and to assess the effect of food on PK of the tablet formulation (NCT03143712). Forty and 13 subjects were randomized in the first-in-human and relative bioavailability studies, respectively. GLPG1690 was well tolerated, with no dose-limiting toxicity at all single and multiple doses. GLPG1690 was rapidly absorbed and eliminated, with a median t_max and mean t_1/2 of approximately 2 and 5 hours, respectively. GLPG1690 exposure increased with increasing dose (mean C_max , 0.09-19.01 µg/mL; mean AUC_0-inf , 0.501-168 µg·h/mL, following single doses of GLPG1690 20-1500 mg). PD response, evidenced by rapid reduction in plasma lysophosphatidic acid (LPA) C18:2 levels, increased with increasing GLPG1690 plasma levels, plateauing at approximately 80% reduction in LPA C18:2 at around 0.6 µg/mL GLPG1690. Tablet and capsule formulations had similar PK profiles, and no clinically significant food effect was observed when comparing tablets taken in fed and fasted states. The safety, tolerability, and PK/PD profiles of GLPG1690 support continued clinical development for IPF.

Discovery of 2-[[2-Ethyl-6-[4-[2-(3-hydroxyazetidin-1-yl)-2-oxoethyl]piperazin-1-yl]-8-methylimidazo[1,2-a]pyridin-3-yl]methylamino]-4-(4-fluorophenyl)thiazole-5-carbonitrile (GLPG1690), a First-in-Class Autotaxin Inhibitor Undergoing Clinical Evaluation for the Treatment of Idiopathic Pulmonary Fibrosis

Autotaxin is a circulating enzyme with a major role in the production of lysophosphatic acid (LPA) species in blood. A role for the autotaxin/LPA axis has been suggested in many disease areas including pulmonary fibrosis. Structural modifications of the known autotaxin inhibitor lead compound 1, to attenuate hERG inhibition, remove CYP3A4 time-dependent inhibition, and improve pharmacokinetic properties, led to the identification of clinical candidate GLPG1690 (11). Compound 11 was able to cause a sustained reduction of LPA levels in plasma in vivo and was shown to be efficacious in a bleomycin-induced pulmonary fibrosis model in mice and in reducing extracellular matrix deposition in the lung while also reducing LPA 18:2 content in bronchoalveolar lavage fluid. Compound 11 is currently being evaluated in an exploratory phase 2a study in idiopathic pulmonary fibrosis patients.

Targeting of alpha-v integrins reduces malignancy of bladder carcinoma

Low survival rates of metastatic cancers emphasize the need for a drug that can prevent and/or treat metastatic cancer. αv integrins are involved in essential processes for tumor growth and metastasis and targeting of αv integrins has been shown to decrease angiogenesis, tumor growth and metastasis. In this study, the role of αv integrin and its potential as a drug target in bladder cancer was investigated. Treatment with an αv integrin antagonist as well as knockdown of αv integrin in the bladder carcinoma cell lines, resulted in reduced malignancy in vitro, as illustrated by decreased proliferative, migratory and clonogenic capacity. The CDH1/CDH2 ratio increased, indicating a shift towards a more epithelial phenotype. This shift appeared to be associated with downregulation of EMT-inducing transcription factors including SNAI2. The expression levels of the self-renewal genes NANOG and BMI1 decreased as well as the number of cells with high Aldehyde Dehydrogenase activity. In addition, self-renewal ability decreased as measured with the urosphere assay. In line with these observations, knockdown or treatment of αv integrins resulted in decreased metastatic growth in preclinical in vivo models as assessed by bioluminescence imaging. In conclusion, we show that αv integrins are involved in migration, EMT and maintenance of Aldehyde Dehydrogenase activity in bladder cancer cells. Targeting of αv integrins might be a promising approach for treatment and/or prevention of metastatic bladder cancer.

Sulfonylureas and sulfonylcarbamates as new non-tetrazole angiotensin II receptor antagonists. Discovery of a highly potent orally active (imidazolylbiphenylyl)sulfonylurea (HR 720)

The synthesis and pharmacological activity of new potent nonpeptide non-tetrazole angiotensin II (AII) receptor antagonists are described. These compounds are 4-thioimidazole derivatives linked on N1 to a biphenylsulfonyl fragment by a methylene spacer. Different acidic sulfonamides such as sulfonylureas 12, sulfonylcarbamates 15, sulfonylamides 16, and sulfonylsulfonamides 17 have been investigated as replacements to the known potent tetrazole moiety at the 2'-biphenyl position. Their activity were evaluated by AII receptor binding assay as well as by in vivo (i.v. and po) assays such as inhibition of the AII-induced pressor response in pithed rats. Most of the synthesized sulfonyl derivatives showed nanomolar affinity for the AT1 receptor subtype. The N-propylsulfonylurea 12d and the ethyl sulfonylcarbamate 15b as representative members of this series exhibited high oral activity in the pithed rat model with ID50 values of 0.38 and 0.4 mg/kg, respectively. Structure-activity relationships on the imidazole ring linked to the methylbiphenyl N-propylsulfonylurea fragment demonstrated similar features to those found in the corresponding tetrazole series. For both class of compounds, the linear butyl chain in position 2 and a carboxylic acid in position 5 were important for high in vitro and in vivo activity. In most cases, replacement of the carboxylic acid was detrimental to in vivo activity while maintaining the in vitro binding affinity. Introduction of a methylthio group in position 4 was found to enhance oral activity compared to compounds with chloro or other alkylthio, (polyfluoroalkyl)thio, and arylthio groups. 2-Butyl-4-(methylthio)-1-[[2'- [[[(propylamino)carbonyl]amino[sulfonyl](1,1'-biphenyl)-4- yl]methyl]-1-H-imidazole-5-carboxylic acid (12d) as the most promising example of the series was synthesized as its dipotassium salt (50, HR 720). This compound 50 inhibited the specific binding of [125I]-AII to rat liver membranes with an IC50 value of 0.48 nM. In vivo, 50 dose-dependently inhibited the AII-induced pressor response in normotensive pithed rats (ID50 = 0.11 mg/kg i.v. and 0.7 mg/kg po). In addition, this compound produced a marked and long-lasting decrease in blood pressure in high renin animal models and proved to be superior to the corresponding tetrazole 45 as well as to DuP 753 or its active metabolite EXP 3174. Compound 50 has been selected for in-depth investigations and is currently undergoing phase II clinical trials.