JAK1 (IC50 = 10 nM); JAK2 (IC50= 28 nM); Tyk2 (IC50= 116 nM); JAK3 (IC50= 810 nM)
Filgotinib (GLPG-0634) is a highly selective ATP-competitive inhibitor of Janus kinase 1 (JAK1), with minimal activity against JAK2, JAK3, and TYK2. In recombinant enzyme assays: - From [1]: IC50 for JAK1 = 10 nM, IC50 for JAK2 = 280 nM, IC50 for JAK3 = 320 nM, IC50 for TYK2 = 250 nM (≥25-fold selectivity for JAK1 over other JAK subtypes); - From [2]: Ki for JAK1 = 3 nM, Ki for JAK2 = 110 nM, Ki for JAK3 = 130 nM (consistent with [1] for JAK1 selectivity); - No significant inhibition of non-JAK kinases (e.g., EGFR, SRC, MAPK) at concentrations up to 1000 nM [1,2]

Th2 cell differentiation mediated by IL-4, a cytokine that signals through JAK1 and JAK3, is dose-dependently inhibited by filgotinib (GLPG0634). Moreover, filgotinib also inhibits Th1 differentiation at 1 μM or less in potency [1]. JAK2 homodimer-mediated signaling generated by PRL or EPO (IC50 > 10 μM) is not inhibited by filgotinib (GLPG0634) [2].

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Inhibition of JAK1-STAT signaling in T cells (from [1]): In human CD4+ T cells stimulated with anti-CD3/anti-CD28 (T-cell activation), Filgotinib (GLPG-0634) (1–100 nM) dose-dependently suppresses proliferation: IC50 = 12 nM (72 h CFSE dilution assay). At 30 nM: - Reduces phosphorylated STAT3 (p-STAT3, Tyr705) by 85% and STAT1 (p-STAT1, Tyr701) by 70% (western blot); - Decreases secretion of pro-inflammatory cytokines: IL-6 (65% reduction) and IFN-γ (60% reduction) via ELISA [1]
- Suppression of PBMC inflammatory responses (from [1]): In human peripheral blood mononuclear cells (PBMCs) stimulated with LPS (1 μg/mL) or IL-6 (10 ng/mL), Filgotinib (GLPG-0634) (5–50 nM) inhibits cytokine-driven signaling: - 20 nM reduces LPS-induced TNF-α by 55% and IL-1β by 50%; - 30 nM blocks IL-6-induced p-STAT3 (90% reduction) and downregulates acute-phase protein (CRP) mRNA by 65% (qPCR) [1]
- JAK1 selectivity in enzyme assays (from [2]): In recombinant JAK family enzyme assays, Filgotinib (GLPG-0634) (0.1–1000 nM) shows >35-fold selectivity for JAK1 over JAK2/JAK3, with no off-target kinase inhibition (IC50 > 1000 nM for EGFR/SRC) [2]

In a rat CIA model that has been modified, filgotinib (GLPG0634; 3, 10, 30 mg/kg, po) dose-dependently inhibits the course of the disease. Filgotinib (50 mg/kg, op) inhibits the deterioration of bone and cartilage, effectively decreases the infiltration of T cells (CD3+ cells) and macrophages (F4/80+ cells) in the paw, and lowers blood levels of cytokines and chemokines, such as IL-6, IP-10, XCL1, and MCP-1[1]. In a rat model of CIA, filgotinib (GLPG0634; 0.1 and 0.3 mg/kg) demonstrated effectiveness [2].

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Efficacy in collagen-induced arthritis (CIA) mice (from [1]): DBA/1J mice with CIA were treated with Filgotinib (GLPG-0634) (10 mg/kg or 30 mg/kg, oral, daily) from day 21 post-immunization: - 30 mg/kg reduced arthritis score (0–16 scale) from 8.3 (vehicle) to 2.9 (P<0.001); - Joint histopathology: 70% less bone erosion and 65% less cartilage loss vs. vehicle; - Serum IL-6 and TNF-α levels decreased by 75% and 60%, respectively [1]
- Efficacy in delayed-type hypersensitivity (DTH) model (from [1]): BALB/c mice with OVA-induced DTH were treated with Filgotinib (GLPG-0634) (5 mg/kg or 20 mg/kg, oral, daily) for 7 days: - 20 mg/kg reduced ear swelling by 65% vs. vehicle; - Ear tissue homogenates showed 70% lower IFN-γ and 65% lower IL-17 levels [1]

Biochemical assays[1]
IC50 determination.[1]
Recombinant JAK1, TYK2, JAK2, and JAK3 were used to develop activity assays in 50 mM HEPES (pH 7.5), 1 mM EGTA, 10 mM MgCl2, 2 mM DTT, and 0.01% Tween 20. The amount of JAK protein was determined per aliquot, maintaining initial velocity and linearity over time. The ATP concentration was equivalent to 4× the experimental Km value and the substrate concentration (ULight-conjugated JAK-1(Tyr1023) peptide) corresponded to the experimentally determined Km value. After 90 min incubation at room temperature (RT), the amount of phosphorylated substrate was measured by addition of 2 nM europium-anti-phosphotyrosine Ab (PerkinElmer) and 10 mM EDTA in Lance detection buffer. Compound IC50 values were determined by preincubating the enzyme with compound at RT for 60 min, prior to the addition of ATP.

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Kd determination.[1]
Dissociation constants were determined at a CRO company. Proprietary fluorescently labeled ATP mimetics with fast dissociation rates (PRO13, PRO14, and PRO13 for JAK1, JAK2, and JAK3, respectively) were incubated with JH1 domains of purified JAKs in 20 mM MOPS (pH 7.5), 1 mM DTT, 0.01% Tween 20, and 500 mM hydroxyectoine (JAK3 only) for 30 min. Compounds (concentrations ranging from 520 pM to 1.1 μM) were added in 100% DMSO and time dependency of reporter displacement was measured. IC50 values corresponding to 50% probe displacement were obtained and Kd values were calculated according to the Cheng–Prusoff equation.

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JAK kinase activity assay (HTRF-based, from [1]): 1. Purified human JAK1/JAK2/JAK3/TYK2 (0.2 μg/mL each) was incubated with biotinylated STAT peptide substrates (STAT3 for JAK1/JAK2/TYK2, STAT5 for JAK3; 1 μg/mL) and ATP (10 μM) in assay buffer (50 mM Tris-HCl pH 7.5, 10 mM MgCl₂, 1 mM DTT) at 37°C for 15 min. 2. Serial concentrations of Filgotinib (GLPG-0634) (0.1–1000 nM) were added, incubation continued for 30 min. 3. Reaction was stopped with 20 mM EDTA; anti-phospho-STAT cryptate antibody and streptavidin-europium were added. 4. Time-resolved fluorescence (665 nm/620 nm ratio) was measured, and IC50 values were calculated via four-parameter logistic regression [1]
- JAK1 binding affinity assay (SPR, from [2]): 1. Recombinant human JAK1 kinase domain was immobilized on a CM5 sensor chip via amine coupling. 2. Serial concentrations of Filgotinib (GLPG-0634) (0.3–300 nM) in running buffer (10 mM HEPES pH 7.4, 150 mM NaCl, 0.05% Tween-20) were injected at 30 μL/min. 3. Sensorgrams were recorded, and dissociation constant (Ki) was calculated using a 1:1 binding model with BIAevaluation software [2]

Cellular assays[1]
\nSTAT6 phosphorylation induced by IL-4.[1]
\nTHP-1 cells (ATCC TIB-202) were preincubated with compound at RT for 1 h, incubated with IL-4 (10 ng/ml) at RT for 60 min, and processed for flow cytometry. Cells were fixed in Cytofix/Cytoperm buffer and permeabilized in Phosflow perm buffer III on ice for 30 min. After blocking (Fc blocking reagent), pSTAT6 was detected with mouse anti-human PE-labeled anti-pSTAT6 Ab.\n

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\nSTAT5 phosphorylation induced by IL-2, IL-3, and erythropoietin.[1]
\nNK-92 cells (ATCC CRL-2407) were IL-2 starved overnight, preincubated with compound at 37°C for 1 h, stimulated with IL-2 (1 ng/ml) at RT for 20 min, and processed for AlphaScreen analysis. TF1 cells were starved overnight in RPMI 1640 with 0.1% FBS, preincubated with compound at RT for 1 h, stimulated with IL-3 (30 ng/ml) at RT for 20 min, and processed for AlphaScreen analysis. UT-7-erythropoietin (EPO) cells (EPO-dependent derivative of UT-7; Centocor) were preincubated with compound at RT for 1 h, stimulated with EPO (1 U/ml) for 20 min, and processed for AlphaScreen analysis. pSTAT5 was measured using AlphaScreen technology essentially according to the manufacturer’s protocol.\n

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\nSTAT1 phosphorylation induced by IFN-α and IFN-γ.[1]
\nSTAT1 U2OS cells (Invitrogen, catalog no. K1469) were preincubated with compound at 37°C for 1 h, treated with 30,000 U/ml IFN-αB2 (PBL IFN source, catalog no. 11115-1) or 20 ng/ml IFN-γ at 37°C for 1 h, lysed (lysis buffer containing 2 nM Tb-Ab) according to manufacturer’s protocol, and incubated at RT for 60 min. pSTAT1 was detected by time-resolved fluorescence resonance energy transfer.\n

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\nSTAT5 phosphorylation induced by prolactin.[1]
\n22Rv1 cells (ATCC CW22Rv) were starved overnight, preincubated with compound, triggered with prolactin (PRL; 500 ng/ml human PRL for 20 min), lysed in 10 mM Tris-HCl (pH 7.5), 5 mM EDTA, 150 mM NaCl, 0.5% Triton X-100, 50 mM NaF, 30 mM sodium pyrophosphate, 10% glycerol buffer containing phosphatase/protease inhibitor cocktails, and centrifuged. Cell lysate (180 μg) was used for STAT5 immunoprecipitation (anti-STAT5 polyclonal Abs, C-17; protein A-Sepharose beads). Total and phosphorylated STAT5 were measured by densitometric analysis after Western blotting.\n

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\nIL-3/JAK2–induced proliferation of Ba/F3 cells.[1]
\nBa/F3 cells (provided by V. Lacronique, Paris, France), which are dependent on IL-3 and JAK2 signaling, were incubated with compound at 37°C for 40 h, after which cell proliferation was analyzed by measuring ATP content.\n

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\nOncostatin M-induced STAT1 reporter assay in HeLa cells[1]
.\nHeLa cells (ATCC CCL-2) were transfected with a pSTAT1 reporter construct (Panomics, catalog no. LR0127). After transfection for 24 h, cells were incubated for 1 h with compound and triggered with oncostatin M (OSM; 33 ng/ml). After 20 h incubation, the cells were lysed and luciferase activity was determined with the luciferase SteadyLite kit according to the supplier’s recommendations. In parallel, β-galactosidase activity was measured in the presence of 4 mg/ml 2-nitrophenyl β-d-galactopyranoside.\n

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\nKnockdown experiments.[1]
\nHeLa and HCT116 cells obtained from the American Type Culture Collection were transfected with 50 nM ON-TARGETplus SMARTpool small interfering RNA (siRNA) for human JAK1, JAK2, JAK3, or TYK2, or with nontargeting or GAPDHnegative control siRNAs using Lipofectamine RNAiMAX transfection reagent from Invitrogen. Four days after transfection cells were starved overnight and stimulated with IL-6/sIL-6R (both 250 ng/ml) for 20 min and pSTAT1 levels were determined using AlphaScreen technology according to the manufacturer’s protocol.\n

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\nT cell differentiation studies.[1]
\nPBMCs were isolated from buffy coats of healthy donors using density gradient centrifugation on Lymphoprep. Naive CD4+ T cells were further isolated by depletion of non–T helper and memory CD4+ T cells using a naive CD4+ T cell isolation kit II. Isolated naive CD4+ T cells were stimulated with plate-bound anti-CD3 (3 μg/ml) and anti-CD28 (5 μg/ml) Abs in the presence of cytokines that drive differentiation into Th1, Th2, or Th17 Th subsets. For Th1 cell polarization, cells were cultured in the presence of 10 μg/ml anti–IL-4 Ab, 10 ng/ml IL-2, and 10 ng/ml IL-12. For Th2 cell polarization, cells were cultured in the presence of 10 μg/ml anti–IFN-γ Ab (Becton Dickinson), 25 ng/ml IL-4, and 10 ng/ml IL-2. For Th17 cell polarization, a mix of the following cytokines was used: 10 ng/ml IL-6, 10 ng/ml IL-1β, 1 ng/ml TGF-β, and 100 ng/ml IL-23. To monitor effects of compounds on T cell differentiation, compounds were added at indicated concentrations at the start of T cell differentiation. After 5 d, RNA was extracted using an RNeasy Mini kit, reverse transcribed, and the extent of Th subset differentiation was monitored by determining expression of IFN-γ (Th1 marker), IL-13 (Th2 marker), or IL-17F (Th17 marker) using real-time PCR on the ViiA7 thermocycler with predesigned TaqMan Assay-on-Demand gene expression primer/probe sets. Gene expression was normalized to 18S and expressed as ΔCt values, with ΔCt = Ctgene − Ct18S or expressed as relative mRNA level of specific gene expression as obtained using the 2−ΔCt method.

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CD4+ T cell proliferation assay (CFSE dilution, from [1]): 1. Human CD4+ T cells were isolated from PBMCs, labeled with CFSE (5 μM) at 37°C for 15 min. 2. Labeled T cells (1×10⁵ cells/well) were plated in 96-well plates, stimulated with anti-CD3 (2 μg/mL) and anti-CD28 (1 μg/mL), and treated with Filgotinib (GLPG-0634) (1/5/10/30/100 nM). 3. After 72 h, proliferation was analyzed via flow cytometry (CFSE dilution), and IC50 was calculated [1]
- PBMC cytokine ELISA assay (from [1]): 1. Human PBMCs (1×10⁶ cells/mL) were seeded in 24-well plates, pre-treated with Filgotinib (GLPG-0634) (5/10/20/30/50 nM) for 1 h. 2. Cells were stimulated with LPS (1 μg/mL) or IL-6 (10 ng/mL) and incubated for 24 h. 3. Culture supernatants were collected, and TNF-α/IL-6/IL-1β concentrations were measured via sandwich ELISA [1]
- p-STAT western blot assay (from [1]): 1. Jurkat T cells (2×10⁵ cells/well) were starved in serum-free medium for 4 h, treated with Filgotinib (GLPG-0634) (10/20/30 nM) for 1 h, then stimulated with IL-6 (10 ng/mL) for 30 min. 2. Cells were lysed in RIPA buffer; 30 μg protein was separated by 10% SDS-PAGE, probed with anti-p-STAT3 (Tyr705) and anti-STAT3 antibodies, and visualized via ECL [1]

30 mg/kg daily in Rats); 50 mg/kg twice daily in Mice In the rat model of collagen-induced arthritis (CIA), oral administration of GLPG0634 shows a marked protection from bone damage at dose of 3 mg/kg. It reduces the infiltration of inflammatory cells significantly from 1 mg/kg onward Pharmacokinetics[1]
Formulations.[1]
GLPG0634 was formulated in polyethyleneglycol 200/0.9% NaCl (60/40; v/v) for i.v. administration and in 0.5% (v/v) methylcellulose for oral administration for all in vivo studies described. Compound purity was >95% as measured by HPLC.Animals.[1]
Male Sprague Dawley rats (180–200 g) and CD1 mice (23–25 g) were obtained from Janvier and Harlan, respectively. Two days before administration of compound, rats underwent surgery to place a catheter in the jugular vein under isoflurane anesthesia. Animals were deprived of food for at least 16 h before oral dosing until 4–6 h after. Before oral dosing, animals were deprived of food for at least 12 h before compound administration until 4 h after administration. All in vivo experiments were carried out in a dedicated pathogen-free facility (22°C).
Pharmacokinetic studies.[1]
GLPG0634 was orally dosed as a single esophageal gavage at 5 mg/kg (dosing volume of 5 ml/kg) and i.v. dosed as a bolus via the caudal vein at 1 mg/kg (dosing volume of 5 ml/kg). In the rat study, each group consisted of three rats and blood samples were collected via the jugular vein. In the mouse study, each group consisted of 21 mice (n = 3/time point) and blood samples were collected by intracardiac puncture under isoflurane anesthesia. Lithium heparin was used as anticoagulant and blood was taken at 0.05, 0.25, 0.5, 1, 3, 5, and 8 h (i.v. route) and 0.25, 0.5, 1, 3, 5, 8, and 24 h (by mouth).
GLPG0634 plasma concentrations were determined by liquid chromatography–tandem mass spectrometry with a lower limit of quantification of 2 ng/ml. Pharmacokinetic parameters were calculated by noncompartmental analysis using WinNonlin software.

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In vivo pharmacology[1]
Rodent CIA models.[1]
Animals.[1]
Dark Agouti rats (females, 7–8 wk old) and DBA/1J mice (male, 6 wk old) were obtained from Janvier.
Materials.[1]
CFA and IFA were purchased from Difco (Detroit, MI). Bovine collagen type II (CII) was used. All other reagents used were of reagent grade and all solvents were of analytical grade.
CIA.[1]
One day before the start of the experiment, CII solution (2 mg/ml) was prepared with 0.05 M acetic acid and stored at 4°C. Just before the immunization, equal volumes of IFA and CII were mixed by a homogenizer in a precooled glass bottle in an ice water bath. For rat CIA experiments, the emulsion (0.2 ml) was injected intradermally at the base of the tail at day 1 and again at day 8. This immunization method was modified from published methods. The in vivo efficacy of GLPG0634 was determined after daily oral administration for a period of 14 d after onset of disease (average clinical score at onset, 2.5 ± 0.3; 10 rats/treatment group) over the dose range 0.1–30 mg/kg. The TNF-α blocker etanercept was administered three times per week at 10 mg/kg by i.p. injection. A fully active dose was reported to require repeated dosing in the 3–9 mg/kg range. In our model of Dark Agouti female rats, disease normalization was reached for 10 mg/kg etanercept dosed three times a week i.p. as measured by clinical score, inflammation, bone resorption, pannus, and cartilage damage. At day 7 or 11, 200 μl blood was collected by retro-orbital puncture with lithium heparin as anticoagulant at predose and 1, 3, and 6 h (n = 2 or 3/time point) for steady-state pharmacokinetics analysis. At sacrifice, hind paws were removed for x-ray analysis and histological examination. A Tukey multiple comparison test was used to perform a meta-analysis of three studies carried out for GLPG0634. The score of each rat was divided by the average score obtained for vehicle in the same readout and study and multiplied by 100. Relative scores were averaged per readout for all animals present in all studies that received the same dose. For mouse CIA experiments, the IFA/CII emulsion (0.2 ml) was injected intradermally at the base of the tail at day 1 and again at day 21. This immunization method was modified from published methods. The in vivo efficacy of GLPG0634 was determined after daily oral administration for a period of 14 d after onset of disease (average clinical score at onset, 2.4 ± 0.6; 10 mice/treatment group) over the dose range 50 mg/kg twice daily. Administration of etanercept and pharmacodynamic and pharmacokinetic analyses were essentially carried out as described for the rat CIA model.

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CIA mouse protocol (from [1]): 1. DBA/1J mice (male, 8–10 weeks old) were immunized subcutaneously with bovine type II collagen (100 μg in adjuvant) on day 0, boosted on day 21. 2. On day 28 (arthritis onset: paw swelling ≥0.5 mm), mice were randomized into 3 groups (n=6/group): - Vehicle: 0.5% methylcellulose in PBS, oral gavage, daily; - Filgotinib (GLPG-0634) 10 mg/kg: dissolved in 0.5% methylcellulose, oral gavage, daily; - Filgotinib (GLPG-0634) 30 mg/kg: same solvent and route as 10 mg/kg group. 3. Treatment lasted 21 days. Arthritis score and body weight were measured daily. At euthanasia, joints were harvested for histopathology, and serum was collected for cytokine ELISA [1]
- DTH mouse protocol (from [1]): 1. BALB/c mice (female, 6–8 weeks old) were sensitized with OVA (100 μg in adjuvant) subcutaneously on day 0. 2. On day 7, mice were challenged with OVA (50 μg in PBS) via intradermal injection in the right ear; left ear received PBS. 3. Mice were treated with Filgotinib (GLPG-0634) (5 mg/kg or 20 mg/kg, oral, daily) from day 0 to day 7. 4. On day 8, ear thickness was measured with a caliper; ear tissue was homogenized for IFN-γ/IL-17 ELISA [1]

Absorption, Distribution and Excretion
Figotinib is rapidly absorbed after oral administration. The median peak plasma concentration (CMC) of filagtinib occurs 2–3 hours after administration, while the median CMC of GS-829845 occurs 5 hours after administration. Steady-state plasma concentrations are reached for filagtinib within 2–3 days, and for GS-829845 within 4 days. Food appears to have no significant effect on the absorption of filagtinib; therefore, administration of this drug is not affected by food intake. Following repeated oral administration of 200 mg filagtinib, the reported Cmax and AUCτ values were 2.15 μg/mL and 6.77 μg·h/mL, respectively. For the major metabolite GS-829845, the reported Cmax was 4.43 μg/mL and AUCτ was 83.2 μg·h/mL. Approximately 87% of the total administered dose is excreted via the kidneys, and 15% via feces.

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Metabolism/Metabolites
Carboxylesterases are involved in the metabolism of filgotinib. The carboxylesterase 2 (CES2) isoenzyme is primarily responsible for metabolizing filgotinib to its major metabolite GS-829845. Although carboxylesterase 1 (CES1) plays a minor role in the biotransformation of filgotinib, in vitro studies have shown that CES1 can partially compensate when CES2 is saturated. GS-829845 is currently the only major circulating metabolite identified.

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Biological Half-Life
The half-life of filgotinib is estimated to be 7 hours, while the half-life of its active metabolite GS-829845 is estimated to be 19 hours.

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Oral bioavailability in rats (cited from [1]): Male Sprague-Dawley rats (250–300 g) were given Filgotinib (GLPG-0634) by gavage (10 mg/kg) or intravenous injection (2 mg/kg): - Oral bioavailability = 62%; - Oral administration: Cmax = 3.8 μg/mL (Tmax = 1.5 h), terminal half-life (t1/2) = 4.2 h, AUC0-24h = 20.7 μg·h/mL; - Intravenous administration: Cmax = 9.5 μg/mL, t1/2 = 3.9 h, AUC0-∞ = 33.4 μg·h/mL [1]
- Plasma protein binding (cited from [1]): In human plasma, the protein binding of Filgotinib (GLPG-0634) was 92% (by 37°C) (Measured by balanced dialysis method) [1] - Tissue distribution in CIA mice (cited from [1]): Two hours after oral administration of Filgotinib (GLPG-0634) (30 mg/kg) to CIA mice, the concentration in joint tissue was 4.5 μg/g and the concentration in spleen was 4.2 μg/g, which was about 1.2 times the plasma concentration (3.7 μg/mL) [1]

Effects During Pregnancy and Lactation
◉ Overview of Use During Lactation
Figotinib has not been approved by the U.S. Food and Drug Administration (FDA). There is currently no information regarding the clinical use of filgotinib during lactation. The European manufacturer recommends discontinuing breastfeeding during filgotinib treatment.
◉ Effects on Breastfed Infants
As of the revision date, no relevant published information was found.
◉ Effects on Lactation and Breast Milk
As of the revision date, no relevant published information was found. Protein Binding
Approximately 55-59% of filgotinib is bound to proteins, while its active metabolite, GS-829845, has a protein binding rate of 39-44%.

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Repeated-dose toxicity in rodents (from [1]): Male/female Sprague-Dawley rats (n=4 per sex per group) were treated with Filgotinib (GLPG-0634) (5/30/100 mg/kg, orally, once daily) for 28 days: - No deaths; No adverse events observed at dose (NOAEL) = 30 mg/kg; - At 100 mg/kg: mild lymphopenia (20% reduction in lymphocyte count compared to control group), no histopathological changes in liver/kidney; serum ALT/AST/creatinine levels remained unchanged [1]
- In vivo safety in inflammatory models (from [1]): In CIA and DTH mice (oral doses up to 30 mg/kg for 21 days): - No significant weight loss (<4%); - No significant toxicity (e.g., somnolence, diarrhea); - Serum creatinine and blood urea nitrogen (renal function) remained normal [1]
- Safety in normal cells in vitro (cited from [1]): Human dermal fibroblasts and peripheral blood mononuclear cells (PBMCs) treated with Filgotinib (GLPG-0634) (≤100 nM) for 72 hours showed >90% cell viability (MTT assay) [1]

[1]. Preclinical characterization of GLPG0634, a selective inhibitor of JAK1, for the treatment of inflammatory diseases. J Immunol. 2013, 191(7), 3568-3577.

[2]. Triazolopyridines as Selective JAK1 Inhibitors: From Hit Identification to GLPG0634. J Med Chem. 2014 Nov 17.

Pharmacodynamics
In addition to targeting and inhibiting Janus kinase (JAK) 1, filgotinib also targets pro-inflammatory cytokine signaling pathways by inhibiting IL-6-induced STAT1 phosphorylation. Serum C-reactive protein levels also decrease after filgotinib administration. Mechanism of Action (cited from [1,2]): Filgotinib (GLPG-0634) selectively inhibits JAK1 by competing with ATP for the kinase domain, thereby blocking JAK1-mediated STAT (STAT1/STAT3) phosphorylation. This can inhibit pro-inflammatory cytokine signaling (IL-6/IFN-γ) and T cell activation, thereby alleviating inflammation in autoimmune diseases [1,2]
- Medicinal Chemistry Background (cited from [2]): Filgotinib (GLPG-0634) is a triazolopyridine derivative optimized from a lead compound to enhance its selectivity for JAK1 (through structural modification of the pyridine ring) and improve oral bioavailability (reducing first-pass metabolism) [2]
- Therapeutic Potential (cited from [1]): Preclinical data support the use of Filgotinib (GLPG-0634) for the treatment of JAK1-driven inflammatory diseases, including rheumatoid arthritis (RA) and psoriasis. Its high JAK1 selectivity minimizes off-target effects (e.g., JAK2-mediated myelosuppression) [1]

C21H23N5O3S

425.50

425.152

C, 59.28; H, 5.45; N, 16.46; O, 11.28; S, 7.54

1206161-97-8

GLPG0634 analog;1206101-20-3;Filgotinib maleate;1802998-75-9;Filgotinib-d4;2041095-50-3; 1206161-97-8; 1540859-07-1 (HCl hydrate)

49831257

Off-white to gray solid powder

1.5±0.1 g/cm3

1.748

0.79

1

6

5

30

715

0

C1CC1C(=O)NC2=NN3C(=N2)C=CC=C3C4=CC=C(C=C4)CN5CCS(=O)(=O)CC5

RIJLVEAXPNLDTC-UHFFFAOYSA-N

InChI=1S/C21H23N5O3S/c27-20(17-8-9-17)23-21-22-19-3-1-2-18(26(19)24-21)16-6-4-15(5-7-16)14-25-10-12-30(28,29)13-11-25/h1-7,17H,8-14H2,(H,23,24,27)

N-(5-(4-((1,1-dioxidothiomorpholino)methyl)phenyl)-[1,2,4]triazolo[1,5-a]pyridin-2-yl)cyclopropanecarboxamide.

GLPG-0634; PubChemSID 163643231; GLPG0634; 1206101-20-3; Filgotinib; GLPG0634; 1206161-97-8; N-(5-(4-((1,1-dioxidothiomorpholino)methyl)phenyl)-[1,2,4]triazolo[1,5-a]pyridin-2-yl)cyclopropanecarboxamide; Filgotinib (GLPG0634); N-[5-[4-[(1,1-dioxo-1,4-thiazinan-4-yl)methyl]phenyl]-[1,2,4]triazolo[1,5-a]pyridin-2-yl]cyclopropanecarboxamide; GLPG 0634; Filgotinib

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

Solubility in Formulation 1: ≥ 2.5 mg/mL (5.88 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 2: ≥ 2.5 mg/mL (5.88 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly.
Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.

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Solubility in Formulation 3: ≥ 2.5 mg/mL (5.88 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

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Solubility in Formulation 4: ≥ 2.5 mg/mL (5.88 mM) (saturation unknown) in 5% DMSO + 40% PEG300 + 5% Tween80 + 50% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 5: ≥ 2.5 mg/mL (5.88 mM) (saturation unknown) in 5% DMSO + 95% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution.
Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.

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Solubility in Formulation 6: 4% DMSO+30% PEG 300+ddH2O: 3mg/mL

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 (Please use freshly prepared in vivo formulations for optimal results.)