| Size | Price | Stock | Qty |
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| 1mg |
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| Other Sizes |
| Targets |
Antithrombin (AT) mRNA. Fitusiran is an siRNA that specifically targets antithrombin mRNA. It recruits the RNA-induced silencing complex (RISC), which cleaves the AT mRNA, preventing its translation and leading to a sustained reduction in AT protein levels in the liver.
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| ln Vitro |
In vitro, Fitusiran is an siRNA molecule that targets antithrombin (AT) messenger RNA. By binding to the AT mRNA, it triggers its degradation, leading to a reduction in AT protein expression in hepatocytes. This loss of antithrombin, the primary endogenous inhibitor of thrombin, shifts the hemostatic balance toward a procoagulant state, enhancing thrombin generation. The IC50 for AT mRNA knockdown is in the low nanomolar range.
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| ln Vivo |
In vivo, Fitusiran increases thrombin generation and has been shown to improve hemostasis in mouse and non-human primate models of hemophilia. When administered subcutaneously to mice, it reduces AT activity in a dose-dependent manner. This leads to increased thrombin generation and a reduction in bleeding in models of tail-clip injury. In hemophilia patients, Fitusiran dramatically increases thrombin generation and reduces the annualized bleeding rate (ABR).
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| Enzyme Assay |
Fitusiran is an siRNA that functions by RNA interference, not by direct enzyme inhibition. Target engagement is confirmed by measuring the reduction in antithrombin (AT) mRNA levels. A cell-free system uses a luciferase reporter assay. A plasmid containing the antithrombin 3′ untranslated region (UTR) linked to a luciferase gene is co-transfected into HEK293T cells. The cells are lysed, and the luciferase signal is measured. A decrease in luminescence indicates successful mRNA knockdown.
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| Cell Assay |
For cellular assays, primary human hepatocytes (PHH) or hepatoma cell lines (e.g., HepG2, Huh-7) are treated with Fitusiran at concentrations of 0.1-100 nM. Cells are harvested at 24-72 hours. Antithrombin mRNA levels are measured by RT-qPCR, and antithrombin protein levels in the cell culture supernatant are measured by ELISA. A reduction in both indicates successful target engagement. For functional assays, the thrombin generation capacity of the conditioned media is measured in a thrombin generation assay (TGA) to confirm the functional consequence of AT knockdown.
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| Animal Protocol |
In vivo studies are performed in hemophilia A and B mouse models (e.g., FVIII-/- or FIX-/- mice). Fitusiran is administered subcutaneously at doses of 1-10 mg/kg. Blood samples are collected at various time points (up to 28 days) to measure antithrombin activity (by chromogenic assay) and thrombin generation (by TGA). Efficacy is assessed using a tail-clip bleeding model. The time to hemostasis (bleeding cessation) or the reduction in blood loss is measured. Tissue sections of the liver are analyzed for antithrombin mRNA by in situ hybridization.
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| ADME/Pharmacokinetics |
Fitusiran is administered subcutaneously. It is conjugated to a ligand for the asialoglycoprotein receptor (ASGPR) on hepatocytes, enabling efficient delivery to the liver. It has a long duration of action (half-life of 10-12 weeks in humans), supporting monthly or once-quarterly dosing. It is not metabolized by CYP enzymes. The siRNA is cleared primarily by nuclease degradation. Its PK is characterized by rapid absorption from the subcutaneous injection site into the circulation.
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| Toxicity/Toxicokinetics |
In clinical trials, Fitusiran has demonstrated a manageable safety profile. The most common adverse events are injection site reactions (erythema, pain). Elevated liver transaminases (ALT/AST) have been observed in some patients, which is a known class effect for GalNAc-siRNA conjugates. A dose-limiting toxicity has been thrombotic events (e.g., sinus thrombosis) in patients receiving higher doses without concomitant factor replacement. Low-dose regimens with improved safety are under investigation. Fitusiran is not approved for clinical use.
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| References | |
| Additional Infomation |
Fitusiran is being investigated in the clinical trial NCT02554773 (an open-label extension study of the investigational drug ALN-AT3SC in patients with moderate to severe hemophilia A or B). Fitusiran is a small interfering RNA (siRNA) that targets the human glycoprotein antithrombin (AT) and has potential coagulation activity. Following subcutaneous injection of Fitusiran, the siRNA binds to AT mRNA, potentially inhibiting AT protein translation. By inhibiting AT expression, the level of the coagulation factor thrombin increases and is activated, thereby promoting the conversion of fibrinogen to fibrin, ultimately leading to thrombus formation. This can reduce bleeding in hemophilia patients and rebalance hemostasis.
Fitusiran is a novel, first-in-class RNAi therapeutic being developed by Alnylam Pharmaceuticals and Sanofi (formerly Genzyme). It represents a paradigm shift in hemophilia treatment by rebalancing hemostasis through the inhibition of a natural anticoagulant (antithrombin), rather than replacing the missing clotting factor. This approach is applicable to both hemophilia A and B, as well as patients with inhibitors. It is not yet FDA-approved. |
| Molecular Formula |
C78H139N11O30
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|---|---|
| Molecular Weight |
1710.99398446083
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| Exact Mass |
1709.968
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| CAS # |
1499251-18-1
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| PubChem CID |
119058042
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| Appearance |
White to off-white solid powder
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| LogP |
-5.9
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| Hydrogen Bond Donor Count |
20
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| Hydrogen Bond Acceptor Count |
30
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| Rotatable Bond Count |
63
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| Heavy Atom Count |
119
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| Complexity |
2730
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| Defined Atom Stereocenter Count |
17
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| SMILES |
O1[C@H]([C@@H]([C@H]([C@H]([C@H]1CO)O)O)NC(C)=O)OCCCCC(NCCCNC(CCOCC(COCCC(NCCCNC(CCCCO[C@H]1[C@@H]([C@H]([C@H]([C@@H](CO)O1)O)O)NC(C)=O)=O)=O)(COCCC(NCCCNC(CCCCO[C@H]1[C@@H]([C@H]([C@H]([C@@H](CO)O1)O)O)NC(C)=O)=O)=O)NC(CCCCCCCCCCC(N1C[C@@H](C[C@H]1C)O)=O)=O)=O)=O
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| InChi Key |
RUPXJRIDSUCQAN-PQNNUJSWSA-N
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| InChi Code |
InChI=1S/C78H139N11O30/c1-50-42-54(96)43-89(50)65(104)26-12-10-8-6-5-7-9-11-25-64(103)88-78(47-111-39-27-61(100)82-33-19-30-79-58(97)22-13-16-36-114-75-66(85-51(2)93)72(108)69(105)55(44-90)117-75,48-112-40-28-62(101)83-34-20-31-80-59(98)23-14-17-37-115-76-67(86-52(3)94)73(109)70(106)56(45-91)118-76)49-113-41-29-63(102)84-35-21-32-81-60(99)24-15-18-38-116-77-68(87-53(4)95)74(110)71(107)57(46-92)119-77/h50,54-57,66-77,90-92,96,105-110H,5-49H2,1-4H3,(H,79,97)(H,80,98)(H,81,99)(H,82,100)(H,83,101)(H,84,102)(H,85,93)(H,86,94)(H,87,95)(H,88,103)/t50-,54-,55-,56-,57-,66-,67-,68-,69+,70+,71+,72-,73-,74-,75-,76-,77-/m1/s1
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| Chemical Name |
N-[1,3-bis[3-[3-[5-[(2R,3R,4R,5R,6R)-3-acetamido-4,5-dihydroxy-6-(hydroxymethyl)oxan-2-yl]oxypentanoylamino]propylamino]-3-oxopropoxy]-2-[[3-[3-[5-[(2R,3R,4R,5R,6R)-3-acetamido-4,5-dihydroxy-6-(hydroxymethyl)oxan-2-yl]oxypentanoylamino]propylamino]-3-oxopropoxy]methyl]propan-2-yl]-12-[(2R,4R)-4-hydroxy-2-methylpyrrolidin-1-yl]-12-oxododecanamide
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| HS Tariff Code |
2934.99.9001
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| Storage |
Powder -20°C 3 years 4°C 2 years In solvent -80°C 6 months -20°C 1 month Note: Please store this product in a sealed and protected environment, avoid exposure to moisture. |
| Shipping Condition |
Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)
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| Solubility (In Vitro) |
H2O: 50 mg/mL
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|---|---|
| Solubility (In Vivo) |
Note: Listed below are some common formulations that may be used to formulate products with low water solubility (e.g. < 1 mg/mL), you may test these formulations using a minute amount of products to avoid loss of samples.
Injection Formulations
Injection Formulation 1: DMSO : Tween 80： Saline = 10 : 5 : 85 (i.e. 100 μL DMSO stock solution → 50 μL Tween 80 → 850 μL Saline)(e.g. IP/IV/IM/SC) *Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH ₂ O to obtain a clear solution. Injection Formulation 2: DMSO : PEG300 ：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL DMSO → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline) Injection Formulation 3: DMSO : Corn oil = 10 : 90 (i.e. 100 μL DMSO → 900 μL Corn oil) Example: Take the Injection Formulation 3 (DMSO : Corn oil = 10 : 90) as an example, if 1 mL of 2.5 mg/mL working solution is to be prepared, you can take 100 μL 25 mg/mL DMSO stock solution and add to 900 μL corn oil, mix well to obtain a clear or suspension solution (2.5 mg/mL, ready for use in animals). View More
Injection Formulation 4: DMSO : 20% SBE-β-CD in saline = 10 : 90 [i.e. 100 μL DMSO → 900 μL (20% SBE-β-CD in saline)] Oral Formulations
Oral Formulation 1: Suspend in 0.5% CMC Na (carboxymethylcellulose sodium) Oral Formulation 2: Suspend in 0.5% Carboxymethyl cellulose Example: Take the Oral Formulation 1 (Suspend in 0.5% CMC Na) as an example, if 100 mL of 2.5 mg/mL working solution is to be prepared, you can first prepare 0.5% CMC Na solution by measuring 0.5 g CMC Na and dissolve it in 100 mL ddH2O to obtain a clear solution; then add 250 mg of the product to 100 mL 0.5% CMC Na solution, to make the suspension solution (2.5 mg/mL, ready for use in animals). View More
Oral Formulation 3: Dissolved in PEG400 (Please use freshly prepared in vivo formulations for optimal results.) |
| Preparing Stock Solutions | 1 mg | 5 mg | 10 mg | |
| 1 mM | 0.5845 mL | 2.9223 mL | 5.8446 mL | |
| 5 mM | 0.1169 mL | 0.5845 mL | 1.1689 mL | |
| 10 mM | 0.0584 mL | 0.2922 mL | 0.5845 mL |
*Note: Please select an appropriate solvent for the preparation of stock solution based on your experiment needs. For most products, DMSO can be used for preparing stock solutions (e.g. 5 mM, 10 mM, or 20 mM concentration); some products with high aqueous solubility may be dissolved in water directly. Solubility information is available at the above Solubility Data section. Once the stock solution is prepared, aliquot it to routine usage volumes and store at -20°C or -80°C. Avoid repeated freeze and thaw cycles.
Calculation results
Working concentration： mg/mL；
Method for preparing DMSO stock solution： mg drug pre-dissolved in μL DMSO (stock solution concentration mg/mL). Please contact us first if the concentration exceeds the DMSO solubility of the batch of drug.
Method for preparing in vivo formulation:：Take μL DMSO stock solution, next add μL PEG300, mix and clarify, next addμL Tween 80, mix and clarify, next add μL ddH2O，mix and clarify.
(1) Please be sure that the solution is clear before the addition of next solvent. Dissolution methods like vortex, ultrasound or warming and heat may be used to aid dissolving.
(2) Be sure to add the solvent(s) in order.
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