LFA-1 (lymphocyte function-associated antigen 1, αLβ2, or CD11a/CD18); ICAM-1 (intercellular adhesion molecule 1). Lifitegrast blocks the binding of ICAM-1 to LFA-1. [1]
LFA-1 (CD11a/CD18). Lifitegrast (SAR 1118) is a small molecule LFA-1 antagonist that binds the CD11a subunit of LFA-1. [2]
LFA-1 (CD11a/CD18). SAR 1118 is a novel small-molecule antagonist of LFA-1 that binds the I-domain of the CD11a subunit of LFA-1 and serves as a direct competitive antagonist of LFA-1 binding to ICAM-1. In vitro inhibition of Jurkat T-cell attachment to ICAM-1 IC50 = 2 nM. [3]

By preventing the interaction of two crucial cell surface proteins—lymphocyte function-associated antigen 1 and intercellular adhesion molecule 1—ligifestegrast (SAR 1118) reduces T cell-mediated inflammation and lowers the total inflammatory response [1]. Lifitegrast has an IC50 of 2.98 nM, which results in a substantial inhibition of Jurkat T cell adhesion to ICAM-1[1].

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Lifitegrast inhibited the formation and activation of the immunological synapse by affecting LFA-1/ICAM-1 adhesion and by outcompeting ICAM-1 binding to LFA-1 in a dose-dependent fashion in a live-cell experiment created to mimic the binding of LFA-1 to ICAM-1. [1]
Lifitegrast inhibited the attachment of Jurkat T cells to ICAM-1 (IC50 = 2.98 nM). [1]
Lifitegrast inhibited cytokine release from activated lymphocytes in vitro. The inhibitory effect of lifitegrast was significant at 1 μM for IFN-γ, IL-1β, IL-10, and macrophage inflammatory protein 1α. [1]
Lifitegrast was potent in T cell adhesion assays, including the HUT 78 T cell adhesion assay (half maximal inhibitory concentration [IC50] = 9 nM). [1]
Lifitegrast (SAR 1118) potently inhibits the binding of LFA-1 on Jurkat cells to ICAM-1 coated on a microtiter plate, with an IC50 of 2 nM, and is capable of preventing leukocyte adhesion to endothelial cells in vivo. [3]
SAR 1118 inhibits TNFα secretion from peripheral blood mononuclear cells stimulated with staphylococcal enterotoxin B with an EC50 of 76 nM. [3]

Lifitegrast (SAR 1118) is best used with 1% solution applied two or three times prior to use. It has strong anti-inflammatory activity against corneal inflammation caused by antibiotic-killed Pseudomonas aeruginosa and Staphylococcus aureus in the presence of silicone hydrogel lenses [2]. Three times a day administration of Lifitegrast (SAR 1118) eye drops results in therapeutic levels of the substance in the retina and may lessen diabetic-related retinal complications [3].

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In a mouse model of corneal inflammation induced by epithelial abrasion and exposure to tobramycin-killed Pseudomonas aeruginosa or Staphylococcus aureus in the presence of a silicone hydrogel contact lens punch, topical application of lifitegrast (SAR 1118) (1% solution applied 3 times at 15, 3, and 1 hour before inducing inflammation) significantly inhibited neutrophil recruitment to the corneal stroma and reduced corneal haze and thickness. [2]
In CD18-/- mice or mice injected with anti-CD11a antibody, neutrophil recruitment to the corneal stroma and development of stromal haze were significantly impaired, indicating that LFA-1 interactions are essential for corneal inflammation. [2]
Topical lifitegrast (SAR 1118) did not induce apoptosis of corneal epithelial cells in vivo as determined by TUNEL assay. [2]
In a rat streptozotocin (STZ)-induced diabetic retinopathy model, SAR 1118 eye drops (1% or 5% wt/vol, 10 μL/eye, thrice daily for 2 months) significantly reduced retinal leukostasis in a dose-dependent manner (24.9% decrease with 1%, 54.58% decrease with 5%) and reduced blood-retinal barrier breakdown as measured by FITC-dextran leakage (25.36% inhibition with 1%, 53.25% inhibition with 5%) and vitreous-plasma protein ratio (17.02% inhibition with 1%, 31.91% inhibition with 5%). [3]
In a phase II clinical study (NCT00926185) in patients with DED, lifitegrast ophthalmic solution 5.0% showed a significant mean change in inferior corneal staining score (ICSS) from baseline to day 84 compared with placebo (0.05 [0.773] vs 0.40 [0.802], P = .021) and significant improvements in a prespecified secondary symptom endpoint (change on the visual-related function subscale) from baseline to day 84 (-0.30 [0.934] vs 0.07 [0.929], P = .039). [1]
In the OPUS-1 phase III study (NCT01421498), lifitegrast ophthalmic solution 5.0% showed a greater mean change from baseline to day 84 in ICSS compared with placebo (-0.07 [0.868] vs 0.17 [0.819], P < .001). Improvements were noted at day 84 in ocular discomfort (1.10 [1.153] vs 1.31 [1.182], P = .027) and eye dryness (25.00 [28.870] vs 30.39 [30.773], P = .029). [1]
In the OPUS-2 phase III study (NCT01743729), subjects treated with lifitegrast ophthalmic solution 5.0% experienced greater improvement in eye dryness score (mean change from baseline to day 84) than subjects treated with placebo (-35.30 [28.400] vs -22.75 [28.600], P < .001). Nominally significant improvements were noted in ocular discomfort (-0.91 [1.280] vs -0.57 [1.354], nominal P < 0.001) and eye discomfort (-26.46 [31.328] vs -16.73 [31.207], nominal P < .001). [1]

The mechanism of inhibition of lifitegrast (and other putative ICAM-1 mimics and LFA-1 antagonists) was investigated via surface plasmon resonance experiments, suggesting that these molecules might bind to the I-like domain of the LFA-1 β2 subunit in an allosteric fashion. Later live-cell experiments created to mimic the binding of LFA-1 to ICAM-1 found that lifitegrast inhibited the formation and activation of the immunological synapse by affecting LFA-1/ICAM-1 adhesion and by outcompeting ICAM-1 binding to LFA-1 in a dose-dependent fashion. [1]
The I domain of the CD11a subunit is the binding region of LFA-1 integrin, which interacts with the first Ig-like domain of ICAM-1. The binding site is discontinuous in the primary structure; however, crystallographic and mutagenesis studies revealed the tertiary structure, which showed that the key residues are presented along one side of the ICAM-1 first domain. These observations were the basis for developing small-molecule antagonists, including lifitegrast. [2]

Lifitegrast was assessed for its ability to inhibit the attachment of Jurkat T cells to ICAM-1. The assay showed that lifitegrast strongly inhibited Jurkat T cell attachment to ICAM-1 with an IC50 of 2.98 nM, confirming that lifitegrast inhibits the recruitment of T cells. [1]
Lifitegrast was tested in the HUT 78 T cell adhesion assay and demonstrated potency with an IC50 of 9 nM. [1]
In vitro, lifitegrast was shown to inhibit cytokine release from activated lymphocytes. The inhibitory effect of lifitegrast was significant at 1 μM for IFN-γ, IL-1β, IL-10, and macrophage inflammatory protein 1α. [1]
SAR 1118 potently inhibits the binding of LFA-1 on Jurkat cells to ICAM-1 coated on a microtiter plate, with an IC50 of 2 nM. [3]
SAR 1118 inhibits TNFα secretion from peripheral blood mononuclear cells stimulated with staphylococcal enterotoxin B with an EC50 of 76 nM. [3]

For the mouse model of contact-lens-associated corneal inflammation, mice were anesthetized, the corneal epithelium was abraded using 3 parallel scratches with a 26-gauge needle. Five microliters of bacterial suspension containing 1×10^7 organisms (tobramycin-killed P. aeruginosa or S. aureus) was placed on the corneal surface, and a 2-mm-diameter punch from a silicone hydrogel contact lens was placed on top. Contact lenses remained on the anesthetized mice for 2 hours. To block LFA-1, 150 μg (10 mg/kg based on 15g per mouse weight) of anti-CD11a or control rat IgG2a was injected into the peritoneal cavity of C57BL/6 mice 1 day before inducing inflammation. For mice treated topically with lifitegrast (SAR 1118), the agent was prepared as a 0.1%, 1%, or 5% solution in PBS, and 5 μL was placed on the intact corneal surface either before or after inflammation. The optimal application was a 1% solution applied either 2 or 3 times prior (at 15, 3, and 1 hour before inducing inflammation). [2]
For the rat diabetic retinopathy model, diabetes was induced in Brown Norway rats with a single intraperitoneal injection of 60 mg/kg STZ in citrate buffer (pH 4.5). Animals with blood glucose levels greater than 250 mg/dL were considered diabetic. SAR 1118 at 1% or 5% wt/vol or vehicle was applied in topical drops to the right eye at a volume of 10 μL/eye thrice daily (0.3 and 1.5 mg drug/eye/day in the 1% and 5% groups, respectively) with 6 to 8 hours between doses. A single dose of celecoxib microparticles (750 μg of celecoxib) was injected in the posterior subconjunctival space of the right eye as a positive control. After 2 months of treatment, the animals were killed and subjected to various assays to assess retinal leukostasis and blood-retinal barrier leakage. [3]
For the pharmacokinetic study in rats, male Sprague-Dawley rats received a single topical dose of radiolabeled [14C]-SAR 1118 at a dose of 1 mg/eye (40 μCi/eye, dose volume 15.5 μL/eye, dose concentration 100 mM, 6.5% wt/vol) in both eyes. Blood was collected at 0.083, 0.25, 0.5, 1, 2, 4, 8, 12, 24, 48, and 72 hours after the dose and centrifuged to separate the plasma and cellular components. The animals were killed at 0.5, 2, 4, 8, 12, and 24 hours after the dose and the eyes collected for drug level determination. [3]

Absorption, Distribution and Excretion
The mean peak plasma concentration (Cmax) of 1.70 ng/mL is reached within 15 minutes after administration. Quantifiable trough plasma concentrations range from 0.55 ng/mL to 3.74 ng/mL. Observations indicate limited systemic exposure, but significant clinical efficacy. Mass balance studies could not be performed to determine the primary elimination route. Clearance could not be calculated based on rifilgrastim plasma concentrations, but relatively rapid clearance has been reported in rat intravenous pharmacokinetic studies. Rifigligrastim is predicted to be primarily cleared via the nasal cavity, followed by the gastrointestinal tract. Metabolism/Metabolites Based on an in vitro metabolism study using fresh human hepatocytes, rifilgrastim does not appear to undergo significant metabolism. Biological Half-Life Plasma elimination half-life could not be calculated based on rifilgrastim plasma concentrations, but relatively short half-life has been reported in rat intravenous pharmacokinetic studies.

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Lifitegrast has high solubility in aqueous media (>100 mg/mL). [1]
Lifitegrast has a favorable pharmacokinetic profile in the eye. In radiolabeled experiments in rats, therapeutic levels of the drug were observed in all ocular tissues (bulbar conjunctiva, palpebral conjunctiva, cornea, aqueous humor, vitreous humor, and sclera) 30 minutes after a single topical ocular administration of [14C]-lifitegrast. Ocular penetration was confirmed in dogs, with highest concentrations in anterior tissues 30 minutes post topical dosing. [1]
Lifitegrast has rapid clearance from the systemic circulation. Rat intravenous pharmacokinetic experiments showed a short half-life (0.78 h), high clearance (139.2 ml/min/kg), and low systemic exposure (area under the concentration curve = 705 hng/kg). In a phase I study in healthy subjects, low plasma levels of lifitegrast were cleared within 1-4 hours of dosing. Lifitegrast showed good metabolic stability in vitro in both human and rat liver microsomes (71% and >95%, respectively, after 30 min incubation). [1]
In a rat pharmacokinetic study, after a single topical dose of [14C]-SAR 1118 (1 mg/eye, 40 μCi/eye, 15.5 μL/eye, 6.5% wt/vol), maximum postdose concentrations were observed at 0.5 hour in all ocular tissues. The average radioactivity (ng equivalents/g) at 0.5 hour were: bulbar conjunctiva 31,500; palpebral conjunctiva 26,300; cornea 17,150; iris ciliary body 17,550; sclera 2,750; aqueous humor 1,770; vitreous humor 1,330; retina-choroid/RPE 510; lens 38.5. Retinal levels greater than 1 μM were achieved in less than 30 minutes and sustained at levels greater than 100 nM for 8 hours. Plasma concentration after ocular topical administration was maximal at 0.25 hour with 194 ng equivalents/g, indicating very low systemic exposure. [3]

Effects During Pregnancy and Lactation
◉ Overview of Use During Lactation
The concentration of rifilgrastim in human breast milk has not been measured. Due to limited absorption through the eye, ophthalmic rifilgrastim is not expected to have any adverse effects on breastfed infants. To significantly reduce the amount of medication entering breast milk after using eye drops, press the tear duct at the corner of the eye for at least 1 minute, then blot away any excess medication with absorbent tissue.
◉ Effects on Breastfed Infants
No published information found as of the revision date.
◉ Effects on Lactation and Breast Milk
No published information found as of the revision date.

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Protein Binding
The human plasma protein binding rate of rifilgrastim is approximately 99%, regardless of concentration (50 to 1000 ng/mL). The binding rate with isolated human serum albumin was 95% to 98%, and the binding rate with human α1-acid glycoprotein was 31.6% to 51.1%.

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Lifitegrast was shown to be negative in the Ames test (an assay to determine whether a chemical can cause mutations in the DNA of bacteria strains). [1]
Lifitegrast had low potency in the CYP450 inhibition assay (CYP3A4, IC50 > 20 μM; CYP2C9, IC50 = 3.0 μM). [1]
Lifitegrast exhibited low potency in the human ether-à-go-go-related gene assay (patch clamp, IC50 > 20 μM), which tests whether a chemical can cause torsades de pointes. [1]
In a phase I clinical study in normal healthy adults, lifitegrast was well tolerated when administered in single and multiple ascending doses. Subjects did not experience any clinically meaningful changes in their health assessments (vital signs, electrocardiogram, and complete ophthalmologic exam). [1]
Topical lifitegrast (SAR 1118) did not induce apoptosis of corneal epithelial cells in vivo as determined by TUNEL assay. The absence of TUNEL-positive corneal epithelial cells in lifitegrast-treated corneas demonstrates that lifitegrast does not induce apoptosis in corneal epithelial cells. [2]

[1]. Lifitegrast, a Novel Integrin Antagonist for Treatment of Dry Eye Disease. Ocul Surf. 2016 Apr;14(2):207-15.

[2]. Corneal inflammation is inhibited by the LFA-1 antagonist, lifitegrast (SAR 1118). J Ocul Pharmacol Ther. 2013 May;29(4):395-402.

[3]. Delivery of SAR 1118 to the retina via ophthalmic drops and its effectiveness in a rat streptozotocin(STZ) model of diabetic retinopathy (DR). Invest Ophthalmol Vis Sci. 2010 Oct;51(10):5198-204.

Rifibrate is an N-acyl-L-α-amino acid formed by the condensation of the carboxyl group of N-[2-(1-benzofuran-6-carbonyl)]-5,7-dichloro-1,2,3,4-tetrahydroisoquinoline-6-carboxylic acid with the amino group of 3-(methanesulfonyl)-L-phenylalanine. It is used to treat dry eye syndrome (keratoconjunctivitis sicca). It has anti-inflammatory and lymphocyte function-associated antigen-1 (LFA-1) antagonist effects. It is an L-phenylalanine derivative, a sulfone compound, an N-acyl-L-α-amino acid, an isoquinoline compound, and a 1-benzofuran compound. Rifibrate is an FDA-approved drug for the treatment of dry eye syndrome (keratoconjunctivitis sicca). It is a tetrahydroisoquinoline derivative and a lymphocyte function-associated antigen-1 (LFA-1) antagonist, discovered through a rationally designed process. This ophthalmic solution was approved for marketing in July 2016 under the brand name Xiidra. Studies have shown that it can protect the corneal surface, relieve dry eye symptoms, act rapidly, and is well-tolerated in both topical and systemic administration. Rifigrafine is a lymphocyte function-associated antigen-1 (LFA-1) antagonist. Rifigrafine's mechanism of action is as a lymphocyte function-associated antigen-1 (LFA-1) antagonist. Rifigrafine is a tetrahydroisoquinoline derivative and also a lymphocyte function-associated antigen-1 (LFA-1) antagonist, available as an ophthalmic solution for the treatment of dry eye syndrome (DED; keratoconjunctivitis sicca; dry eye syndrome). After ophthalmic administration, although the exact mechanism of action of rifigrafine in treating dry eye syndrome is not fully elucidated, rifigrafine targets and binds to integrin LFA-1 (a protein present on the surface of leukocytes). This prevents the interaction between LFA-1 and its ligand, intercellular adhesion molecule-1 (ICAM-1). Because ICAM-1 may be overexpressed in the corneal and conjunctival tissues of patients with dry eye syndrome, rifilgrastim's blockade of the LFA-1/ICAM-1 interaction may inhibit T cell adhesion to ICAM-1 and potentially disrupt the formation of immune synapses. This may inhibit T cell proliferation, activation, and migration in the corneal and conjunctival tissues, as well as the release of pro-inflammatory cytokines. This may help reduce inflammation, protect the corneal surface from inflammation-mediated damage, and alleviate the symptoms of dry eye syndrome.
See also: Rifilgrastim Sodium (its active ingredient).

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Drug Indications
For the treatment of signs and symptoms of dry eye syndrome (keratoconjunctivitis sicca).
FDA Label
Treatment of Dry Eye
Mechanism of Action
Rifagine binds to integrin lymphocyte function-associated antigen-1 (LFA-1), a protein present on the surface of leukocytes. Rifagine blocks the interaction between LFA-1 and its homologous ligand, intercellular adhesion molecule-1 (ICAM-1). In dry eye, ICAM-1 may be overexpressed in the corneal and conjunctival tissues. The LFA-1/ICAM-1 interaction promotes the formation of immune synapses, leading to T cell proliferation/activation and migration to target tissues. In vitro studies have shown that rifilgrastim inhibits the adhesion of T cells to ICAM-1 in human T cell lines and inhibits the secretion of inflammatory cytokines, inflammatory mediators, chemokines, TNF-α, and IL-1 from human peripheral blood mononuclear cells.

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Pharmacodynamics
Rifiglitazone improves symptoms and reduces ocular surface damage by interfering with ocular inflammatory circulation. Rifiglitazone is a lymphocyte function-associated antigen-1 (LFA-1) antagonist that, through direct competitive antagonism, sequentially inhibits T cell recruitment, activation, and release of pro-inflammatory cytokines associated with dry eye.

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Lifitegrast is a novel small molecule integrin antagonist that inhibits T cell-mediated inflammation by blocking the binding of LFA-1 to ICAM-1. The drug has been shown to reduce corneal inflammation in mice by inhibiting neutrophil recruitment to the corneal stroma. [1]
Lifitegrast inhibits T cell recruitment, T cell activation, and subsequent cytokine release, thereby targeting a specific inflammatory pathway involved in the pathogenesis of DED. [1]
Lifitegrast is currently in late phase III development. The lifitegrast clinical development program began in 2008 and has enrolled >1,800 patients with DED. Four clinical studies (3 efficacy and safety studies and 1 long-term exposure safety study) have been completed. [1]
In a phase II clinical study in dogs prone to develop spontaneous keratoconjunctivitis sicca, administration of lifitegrast was found to be efficacious. [1]
Lifitegrast (SAR 1118) has a potential clinical application in preventing and treating contact-lens-associated corneal infiltrates and epithelial defects caused by gram-positive or gram-negative bacteria, as it blocks LFA-1-dependent neutrophil recruitment to the corneal stroma. [2]
SAR 1118 has extraordinary solubility in excess of 100 mM in a saline-based ophthalmic drop formulation. [3]
SAR 1118 ophthalmic drops administered thrice daily deliver therapeutic levels of SAR 1118 in the retina and can alleviate the retinal complications associated with diabetes. [3]

C₂₉H₂₄CL₂N₂O₇S

615.48

614.068

1025967-78-5

Lifitegrast sodium;1119276-80-0

11965427

White to off-white solid powder

1.5±0.1 g/cm3

811.9±65.0 °C at 760 mmHg

444.8±34.3 °C

0.0±3.1 mmHg at 25°C

1.661

1.54

2

7

7

41

1100

1

CS(=O)(=O)C1=CC=CC(=C1)C[C@@H](C(=O)O)NC(=O)C2=C(C=C3CN(CCC3=C2Cl)C(=O)C4=CC5=C(C=C4)C=CO5)Cl

JFOZKMSJYSPYLN-QHCPKHFHSA-N

InChI=1S/C29H24Cl2N2O7S/c1-41(38,39)20-4-2-3-16(11-20)12-23(29(36)37)32-27(34)25-22(30)13-19-15-33(9-7-21(19)26(25)31)28(35)18-6-5-17-8-10-40-24(17)14-18/h2-6,8,10-11,13-14,23H,7,9,12,15H2,1H3,(H,32,34)(H,36,37)/t23-/m0/s1

(2S)-2-[[2-(1-benzofuran-6-carbonyl)-5,7-dichloro-3,4-dihydro-1H-isoquinoline-6-carbonyl]amino]-3-(3-methylsulfonylphenyl)propanoic acid

SAR 1118 SAR 1118-023SAR-1118SHP-606SAR1118-02SHP606SAR 1118SHP 606SAR1118Lifitegrast sodium SAR-1118-023 Xiidra

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)

DMSO : ≥ 29 mg/mL (~47.12 mM)

Solubility in Formulation 1: ≥ 2.5 mg/mL (4.06 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 (4.06 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 3: ≥ 2.08 mg/mL (3.38 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 20.8 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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 (Please use freshly prepared in vivo formulations for optimal results.)