Fostamatinib sodium

    WARNING: This product is for research use only, not for human or veterinary use.

MedKoo CAT#: 200393

CAS#: 1025687-58-4 (sodium)

Description: Fostamatinib, also known as R 788 and R-935788, is an orally active, potent and selective Syk kinase inhibitor with potential anti-inflammatory and immunomodulating activities. Fostamatinib is also a pro-drug of R-406. Fostamatinib inhibits Syk kinase-mediated IgG Fc gamma receptor signaling, resulting in inhibition of the activation of mast cells, macrophages, and B-cells and related inflammatory responses and tissue damage.

Price and Availability


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Fostamatinib sodium, purity > 98%, is in stock. Current shipping out time is about 2 weeks after order is received. CoA, QC data and MSDS documents are available in one week after order is received.

Chemical Structure


Theoretical Analysis

MedKoo Cat#: 200393
Name: Fostamatinib sodium
CAS#: 1025687-58-4 (sodium)
Chemical Formula: C23H24FN6Na2O9P
Exact Mass:
Molecular Weight: 624.42
Elemental Analysis: C, 44.24; H, 3.87; F, 3.04; N, 13.46; Na, 7.36; O, 23.06; P, 4.96

Related CAS #: 1025687-58-4 (sodium)   901119-35-5 (free acid)    

Synonym: R935788; R-935788; R 935788; 788; R 788; R788 sodium. R935788 sodium. Fostamatinib sodium, prodrug of R-406.

IUPAC/Chemical Name: sodium (6-((5-fluoro-2-((3,4,5-trimethoxyphenyl)amino)pyrimidin-4-yl)amino)-2,2-dimethyl-3-oxo-2H-pyrido[3,2-b][1,4]oxazin-4(3H)-yl)methyl phosphate


InChi Code: InChI=1S/C23H26FN6O9P.2Na/c1-23(2)21(31)30(11-38-40(32,33)34)20-14(39-23)6-7-17(28-20)27-19-13(24)10-25-22(29-19)26-12-8-15(35-3)18(37-5)16(9-12)36-4;;/h6-10H,11H2,1-5H3,(H2,32,33,34)(H2,25,26,27,28,29);;/q;2*+1/p-2

SMILES Code: O=P([O-])([O-])OCN1C2=NC(NC3=NC(NC4=CC(OC)=C(OC)C(OC)=C4)=NC=C3F)=CC=C2OC(C)(C)C1=O.[Na+].[Na+]

Technical Data

white solid powder

>98% (or refer to the Certificate of Analysis)

Certificate of Analysis:

Safety Data Sheet (MSDS):

Shipping Condition:
Shipped under ambient temperature as non-hazardous chemical. This product is stable enough for a few weeks during ordinary shipping and time spent in Customs.

Storage Condition:
Dry, dark and at 0 - 4 C for short term (days to weeks) or -20 C for long term (months to years).

Soluble in DMSO, not in water

Shelf Life:
>2 years if stored properly

Drug Formulation:
This drug may be formulated in DMSO

Stock Solution Storage:
0 - 4 C for short term (days to weeks), or -20 C for long term (months).

Harmonized System Code:

Additional Information

Fostamatinib is an experimental drug candidate for the treatment of a variety of diseases. It is in Phase III clinical trials for rheumatoid arthritis and Phase II trials for autoimmune thrombocytopenia and lymphoma.  The oral drug is used as its disodium salt and it is a prodrug of the active compound tamatinib (R-406), which is an inhibitor of the enzyme spleen tyrosine kinase (Syk) (source:


1: Skinner M, Philp K, Lengel D, Coverley L, Lamm Bergström E, Glaves P, Musgrove H, Prior H, Braddock M, Huby R, Curwen J, Duffy P, Harmer A. The Contribution of Vegf Signalling to Fostamatinib-Induced Blood Pressure Elevation. Br J Pharmacol. 2013 Dec 16. doi: 10.1111/bph.12559. [Epub ahead of print] PubMed PMID: 24329544.

2: Park SR, Speranza G, Piekarz R, Wright JJ, Kinders RJ, Wang L, Pfister T, Trepel JB, Lee MJ, Alarcon S, Steinberg SM, Collins J, Doroshow JH, Kummar S. A multi-histology trial of fostamatinib in patients with advanced colorectal, non-small cell lung, head and neck, thyroid, and renal cell carcinomas, and pheochromocytomas. Cancer Chemother Pharmacol. 2013 Apr;71(4):981-90. doi: 10.1007/s00280-013-2091-3. Epub 2013 Feb 13. PubMed PMID: 23404627.

3: Herman SE, Barr PM, McAuley EM, Liu D, Wiestner A, Friedberg JW. Fostamatinib inhibits B-cell receptor signaling, cellular activation and tumor proliferation in patients with relapsed and refractory chronic lymphocytic leukemia. Leukemia. 2013 Aug;27(8):1769-73. doi: 10.1038/leu.2013.37. Epub 2013 Feb 6. PubMed PMID: 23385377.

4: Weinblatt ME, Kavanaugh A, Genovese MC, Jones DA, Musser TK, Grossbard EB, Magilavy DB. Effects of fostamatinib (R788), an oral spleen tyrosine kinase inhibitor, on health-related quality of life in patients with active rheumatoid arthritis: analyses of patient-reported outcomes from a randomized, double-blind, placebo-controlled trial. J Rheumatol. 2013 Apr;40(4):369-78. doi: 10.3899/jrheum.120923. Epub 2013 Feb 1. PubMed PMID: 23378467.

5: Baluom M, Grossbard EB, Mant T, Lau DT. Pharmacokinetics of fostamatinib, a spleen tyrosine kinase (SYK) inhibitor, in healthy human subjects following single and multiple oral dosing in three phase I studies. Br J Clin Pharmacol. 2013 Jul;76(1):78-88. doi: 10.1111/bcp.12048. PubMed PMID: 23190017; PubMed Central PMCID: PMC3703230.

6: Morales-Torres J. The status of fostamatinib in the treatment of rheumatoid arthritis. Expert Rev Clin Immunol. 2012 Sep;8(7):609-15. doi: 10.1586/eci.12.63. PubMed PMID: 23078058.

7: Barr PM, Wei C, Roger J, Schaefer-Cutillo J, Kelly JL, Rosenberg AF, Jung J, Sanz I, Friedberg JW. Syk inhibition with fostamatinib leads to transitional B lymphocyte depletion. Clin Immunol. 2012 Mar;142(3):237-42. doi: 10.1016/j.clim.2011.12.012. Epub 2012 Jan 5. PubMed PMID: 22284392; PubMed Central PMCID: PMC3288165.

8: Hilgendorf I, Eisele S, Remer I, Schmitz J, Zeschky K, Colberg C, Stachon P, Wolf D, Willecke F, Buchner M, Zirlik K, Ortiz-Rodriguez A, Lozhkin A, Hoppe N, von zur Muhlen C, zur Hausen A, Bode C, Zirlik A. The oral spleen tyrosine kinase inhibitor fostamatinib attenuates inflammation and atherogenesis in low-density lipoprotein receptor-deficient mice. Arterioscler Thromb Vasc Biol. 2011 Sep;31(9):1991-9. doi: 10.1161/ATVBAHA.111.230847. Epub 2011 Jun 23. PubMed PMID: 21700926.

9: Baluom M, Samara E, Grossbard EB, Lau DT. Fostamatinib, a Syk-kinase inhibitor, does not affect methotrexate pharmacokinetics in patients with rheumatoid arthritis. J Clin Pharmacol. 2011 Sep;51(9):1310-8. doi: 10.1177/0091270010381496. Epub 2011 Jan 5. PubMed PMID: 21209239.

10: McAdoo SP, Tam FW. Fostamatinib Disodium. Drugs Future. 2011;36(4):273. PubMed PMID: 23284223; PubMed Central PMCID: PMC3533134.