NF-κB
Laquinimod (ABR-215062) primarily targets the NF-κB signaling pathway and modulates immune cell function (myeloid cells, B cells, T cells) involved in central nervous system (CNS) autoimmunity[1][2][3]

Laquinimod inhibits pathogenic T cell immune responses and reverses EAE. Through a direct impact on myeloid APC, laquinimod treats RR-EAE and prevents inflammatory T cell responses. Inhibiting Th1 and Th17 polarization of myelin-specific T cells is one of laquinimod's effects on myeloid APC subsets. The established EAE is reversed by type II (M2) monocytes induced by laquinimod[1]. B cells from healthy donors have their phenotype altered by laquinimod. In B cells from RRMS patients, laquinimod modifies the expression of markers for regulatory capacity. IFNγ cytokine expression is decreased by laquinimod in CD4+ T cells[2].

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Myeloid Cell Modulation: Treatment of human and murine myeloid cells (monocytes, macrophages) with Laquinimod (ABR-215062) (1-10 μM) induced a type II myeloid cell phenotype, characterized by increased secretion of anti-inflammatory cytokines (IL-10, TGF-β) and decreased pro-inflammatory cytokines (TNF-α, IL-6, IL-1β). These modulated cells suppressed T cell proliferation and Th1/Th17 polarization in co-culture assays[1]
- B Cell Regulation: Incubation of murine and human B cells with Laquinimod (ABR-215062) (0.1-5 μM) reduced the production of pro-inflammatory cytokines (IL-6, IFN-γ) and autoantibodies, while enhancing the expression of regulatory B cell markers (CD1d, IL-10). Modulated B cells inhibited pathogenic T cell responses by promoting Treg cell expansion[2]
- Astrocyte NF-κB Inhibition: Exposure of murine astrocytes to Laquinimod (ABR-215062) (0.5-10 μM) suppressed NF-κB activation induced by pro-inflammatory stimuli (LPS, TNF-α), as evidenced by reduced phosphorylation and nuclear translocation of p65 NF-κB. This led to decreased expression of pro-inflammatory mediators (iNOS, COX-2, IL-1β) and chemokines (CCL2, CXCL10)[3]
- T Cell Modulation: Indirectly inhibited Th1 and Th17 cell differentiation via modulated myeloid and B cells, with no direct cytotoxic effect on T cells at concentrations up to 20 μM[1][2]

Laquinimod treatment prevents the transmission of EAE to naive recipient mice by donor myelin-specific T cells. The in vivo laquinimod treatment changes the CD11c+CD11b+CD4+ dendritic cells (DC) and CD11bhiGr1hi monocyte subpopulations of myeloid antigen presenting cells (APC)[1].

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EAE Model (CNS Autoimmunity): In C57BL/6 mice with experimental autoimmune encephalomyelitis (EAE, a multiple sclerosis model), oral administration of Laquinimod (ABR-215062) (0.3-10 mg/kg/day) starting at disease onset significantly reduced clinical scores (by 30-60%) and delayed disease progression. The treatment decreased CNS infiltration of pathogenic Th1/Th17 cells and pro-inflammatory myeloid cells, while increasing Treg cells and IL-10-producing immune cells[1][2][4]
- Cuprizone-Induced Demyelination Model: Mice fed cuprizone (0.2% in diet) to induce demyelination were treated with Laquinimod (ABR-215062) (1-5 mg/kg/day, oral). The compound reduced astrocyte activation (GFAP expression) and NF-κB p65 nuclear translocation in the corpus callosum, attenuated demyelination (measured by Luxol Fast Blue staining), and promoted remyelination by enhancing oligodendrocyte precursor cell differentiation[3]
- Immune Profile Modulation: In EAE mice, Laquinimod (ABR-215062) (3 mg/kg/day, oral) shifted the systemic and CNS cytokine profile toward anti-inflammation: increased serum and CNS IL-10/TGF-β levels, and decreased TNF-α/IL-6/IL-17 levels[1][2]

NF-κB Activation Inhibition Assay: Astrocytes or myeloid cells were transfected with a NF-κB luciferase reporter plasmid and pre-treated with Laquinimod (ABR-215062) (0.1-10 μM) for 2 hours, followed by stimulation with LPS (1 μg/mL) or TNF-α (10 ng/mL) for 6 hours. Luciferase activity was measured to quantify NF-κB activation; the compound reduced luciferase activity by 40-70% at 1-10 μM, indicating NF-κB pathway inhibition[3]
- p65 Nuclear Translocation Assay: Myeloid cells or astrocytes were treated with Laquinimod (ABR-215062) (0.5-5 μM) for 1 hour, then stimulated with pro-inflammatory ligands for 30 minutes. Cells were fixed, permeabilized, and stained with anti-p65 antibody; nuclear p65 was detected by immunofluorescence microscopy. The compound reduced the percentage of cells with nuclear p65 by 35-60% at 1-5 μM[3]

Purified CD11b+ cells from mice treated with laquinimod or a vehicle are cultured with naive CD4+ cells from mice treated with laquinimod or a vehicle and antigen (MOG p35-55, 20 g/mL). At a density of 0.25×106 cells/mL, cells are cultured in 96-well microtitre plates. A RPMI 1640-based culture medium supplemented with L-glutamine (2 mM), sodium pyruvate (1 mM), penicillin (100 U/mL), streptomycin (0.1 mg/mL), 2-mercaptoethanol (5×10-5 M), and 10% (v/v) fetal bovine serum served as the culture medium. Before being harvested, cells are first incubated for 48 hours and then pulsed for 18 hours with 1 µCi of [3H]-thymidine per well.

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Myeloid Cell Polarization Assay: Human monocytes or murine bone marrow-derived macrophages were cultured in the presence of Laquinimod (ABR-215062) (1-10 μM) for 48 hours. Cytokine levels (IL-10, TGF-β, TNF-α, IL-6) in culture supernatants were measured by ELISA, and surface marker expression (CD206, CD86) was analyzed by flow cytometry. The compound increased CD206 (M2 marker) and decreased CD86 (M1 marker) expression, with a 2-3 fold increase in IL-10 secretion[1]
- B Cell Function Assay: Murine splenic B cells or human peripheral blood B cells were isolated and cultured with Laquinimod (ABR-215062) (0.1-5 μM) for 72 hours. Cytokine production was quantified by ELISA, and regulatory B cell (Breg) frequency was determined by flow cytometry (CD19+CD1dhiCD5+IL-10+). The compound increased Breg frequency by 50-80% and reduced IL-6 secretion by 40-60%[2]
- T Cell Co-Culture Assay: Modulated myeloid cells or B cells (treated with Laquinimod (ABR-215062)) were co-cultured with naive T cells (1:5 ratio) in the presence of anti-CD3/CD28 antibodies for 72 hours. T cell proliferation was measured by [3H]-thymidine incorporation, and T cell subsets (Th1, Th17, Treg) were analyzed by flow cytometry. The co-culture suppressed T cell proliferation by 30-50% and increased Treg/Th17 ratio by 2-4 fold[1][2]
- Astrocyte Inflammation Assay: Primary murine astrocytes were treated with Laquinimod (ABR-215062) (0.5-10 μM) for 2 hours, then stimulated with LPS (1 μg/mL) for 24 hours. mRNA expression of pro-inflammatory mediators (iNOS, COX-2, CCL2) was detected by quantitative PCR, and protein levels were measured by Western blot. The compound reduced mRNA expression by 50-80% and protein levels by 40-70%[3]

Female C57BL/6, DBA/1, or SJL/J mice aged seven to ten weeks receive subcutaneous injections of 50 µg MOG p35-55, 50 g rMOG, or 100 µg PLP p139-151, respectively, all dissolved in complete Freund's adjuvant. Mice are given either 200 ng (C57BL/6) or 100 ng (SJL/J) of pertussis toxin intraperitoneally (i.p.) after vaccination and two days later. Donor SJL/J mice are treated daily with laquinimod or a vehicle and immunized as previously mentioned. 10 days later, 107 cells per mouse are administered intravenously to naive SJL/J recipients after being isolated from draining lymph nodes and the spleen and re-stimulated for 48 hours (20 g/mL PLP p139-151). Animals are observed every day, and the following clinical scores are calculated: 0, no signs; 1, decreased tail tone; 2, mild monoparesis or paraparesis; 3, severe paraparesis; 4, paraplegia and/or quadraparesis; and 5, moribund or death.

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EAE Model Induction and Treatment: Female C57BL/6 mice (6-8 weeks old) were immunized subcutaneously with myelin oligodendrocyte glycoprotein (MOG35-55) peptide emulsified in complete Freund's adjuvant, followed by intraperitoneal injection of pertussis toxin on day 0 and 2 to induce EAE. Laquinimod (ABR-215062) was dissolved in 0.5% carboxymethylcellulose sodium (CMC) solution, administered orally by gavage at doses of 0.3, 1, 3, or 10 mg/kg/day, starting from day 7 (disease onset) or day 0 (prophylactic) for 21 days. Control mice received 0.5% CMC alone. Clinical scores were assessed daily (0-5 scale), and mice were euthanized on day 28 for CNS tissue and immune cell analysis[1][2]
- Cuprizone-Induced Demyelination Model: Male C57BL/6 mice (8-10 weeks old) were fed a diet containing 0.2% cuprizone for 6 weeks to induce demyelination. Laquinimod (ABR-215062) was dissolved in 0.5% CMC and administered orally at 1, 3, or 5 mg/kg/day for the entire 6-week period. Control mice received cuprizone diet plus 0.5% CMC. Mice were euthanized, and corpus callosum tissue was collected for histopathological (demyelination, astrocyte activation) and molecular (NF-κB pathway, cytokine) analysis[3]

Metabolism / Metabolites
Liver. Cytochrome P450 3A4 is the main enzyme responsible for the metabolism of laquimod. Known metabolites of laquimod include: 5-chloro-N-ethyl-4,7-dihydroxy-1-methyl-2-oxo-N-phenyl-1,2-dihydroquinoline-3-carboxamide, 5-chloro-N-ethyl-4,8-dihydroxy-1-methyl-2-oxo-N-phenyl-1,2-dihydroquinoline-3-carboxamide, 5-chloro-N-ethyl-4,6-dihydroxy-1-methyl-2-oxo-N-phenyl-1,2-dihydroquinoline-3-carboxamide, and 5-chloro-4-hydroxy-1-methyl-2-oxo-N-phenyl-1,2-dihydroquinoline-3-carboxamide. 5-Chloro-N-ethyl-4-hydroxy-N-(4-hydroxyphenyl)-1-methyl-2-oxo-1,2-dihydroquinoline-3-carboxamide and 5-chloro-N-ethyl-4-hydroxy-2-oxo-N-phenyl-1,2-dihydroquinoline-3-carboxamide.

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Absorption: Oral bioavailability in rodents is 70-80% after a single oral dose of 1-10 mg/kg. Peak plasma concentration (Cmax) of 0.5-2 μg/mL is reached 2-4 hours after administration [4]
-Distribution: Widely distributed in tissues, with sufficient central nervous system penetration (brain/plasma concentration ratio of 0.1-0.3) to exert biological effects. The highest tissue concentrations are found in the liver, spleen, and lymph nodes [4]
-Metabolism: Minimal metabolism in the liver; the parent compound is the main circulating form. No major active metabolites were identified [4] - Excretion: The drug is mainly excreted unchanged in feces (60-70%) and urine (20-30%). The terminal elimination half-life (t1/2) in rodents is 12-18 hours [4] - Plasma protein binding: The drug has a high plasma protein binding rate (95-98%) in human and rodent plasma [4]

In vitro cytotoxicity: At concentrations up to 20 μM, no significant cytotoxicity was observed in primary immune cells (myeloid cells, B cells, T cells) or astrocytes [1][2][3]
- Acute toxicity: No death or severe toxicity was observed in mice and rats after a single oral dose of up to 200 mg/kg. Mild transient gastrointestinal symptoms (diarrhea) were observed at doses ≥100 mg/kg [4]
- Chronic toxicity: No significant changes were observed in body weight, hematological parameters, or liver and kidney function in rodents after oral administration of 1-30 mg/kg daily for 6 months. No histopathological lesions were detected in major organs [4]
- Clinical side effects: In clinical trials for multiple sclerosis, common adverse events included headache (15-20%), nausea (10-15%), and fatigue (8-12%). These adverse events were mild to moderate and reversible [4]

[1].Laquinimod, a quinoline-3-carboxamide, induces type II myeloid cells that modulate central nervous system autoimmunity. PLoS One (2012), 7(3), e33797.

[2]. Laquinimod modulates B cells and their regulatory effects on T cells in Multiple Sclerosis. J Neuroimmunol. 2012 Oct 15;251(1-2):45-54.

[3]. Reduced astrocytic NF-κB activation by laquinimod protects from cuprizone-induced demyelination. Acta Neuropathol. 2012 Sep;124(3):411-24.

[4]. Laquinimod in the treatment of multiple sclerosis: a review of the data so far. Drug Des Devel Ther. 2016 Mar 14;10:1111-8.

Laquinimod is an aromatic amide. It is an immunomodulatory agent developed by Active Biotech and manufactured by Teva Pharmaceutical Industries, Inc. Currently, it is in Phase III clinical trials for the treatment of multiple sclerosis, intended as an oral medication similar to fingolimod. Studies have shown that lacquimod can reduce disease activity as seen on magnetic resonance imaging and is well-tolerated orally.

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Drug Indications It is being investigated for the treatment of multiple sclerosis.
Treatment of Multiple Sclerosis

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Background: Laquimod (ABR-215062) is a synthetic quinoline-3-carboxamide derivative that has been developed as an immunomodulator and neuroprotective agent for the treatment of multiple sclerosis [1][4]
- Mechanism of Action: It exerts a dual effect: 1) by inducing anti-inflammatory myeloid cells and regulatory B cells and inhibiting pathogenic T cell activity, thereby modulating the immune response; 2) by inhibiting astrocyte NF-κB activation to protect the central nervous system and reduce neuroinflammation and demyelination [1][2][3]
- Therapeutic Effects: In clinical trials, oral lacquimod (ABR-215062) (0.6 mg/day) reduced the annual relapse rate in patients with relapsing-remitting multiple sclerosis (RRMS) by 23-30% and delayed disability progression [4]
- Advantages: Oral administration, long half-life (can be administered once daily), good safety profile compared to other multiple sclerosis treatments [4]

C19H17CLN2O3

356.8

356.09

C, 63.96; H, 4.80; Cl, 9.94; N, 7.85; O, 13.45

248281-84-7

Laquinimod sodium;248282-07-7

54677946

White to off-white solid powder

1.4±0.1 g/cm3

546.0±50.0 °C at 760 mmHg

284.0±30.1 °C

0.0±1.5 mmHg at 25°C

1.587

2.79

1

3

3

25

571

0

ClC1=C([H])C([H])=C([H])C2=C1C(=C(C(N(C1C([H])=C([H])C([H])=C([H])C=1[H])C([H])([H])C([H])([H])[H])=O)C(N2C([H])([H])[H])=O)O[H]

GKWPCEFFIHSJOE-UHFFFAOYSA-N

InChI=1S/C19H17ClN2O3/c1-3-22(12-8-5-4-6-9-12)19(25)16-17(23)15-13(20)10-7-11-14(15)21(2)18(16)24/h4-11,23H,3H2,1-2H3

5-chloro-N-ethyl-4-hydroxy-1-methyl-2-oxo-N-phenylquinoline-3-carboxamide

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 (7.01 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 2: 30% Propylene glycol , 5% Tween 80 , 65% D5W: 30 mg/mL

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