Fostamatinib (R788), a prodrug of the active metabolite R406, is a Syk inhibitor with IC50 of 41 nM, strongly inhibits Syk but not Lyn, 5-fold less potent to Flt3. Phase 3.
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Moligand™
Product Description
Information
Fostamatinib (R788) Fostamatinib (R788), a prodrug of the active metabolite R406, is a Syk inhibitor with IC50 of 41 nM, strongly inhibits Syk but not Lyn, 5-fold less potent to Flt3. Phase 3. In vitro
R788 is a prodrug of the spleen tyrosine kinase (Syk) inhibitor R406. R788 is a competitive inhibitor for ATP binding with a Ki of 30 nM. R788 dose-dependently inhibits anti-IgE-mediated CHMC degranulation with an EC50 of 56 nM. R788 also inhibits the anti-IgE-induced production and release of LTC4 and cytokines and chemokines, including TNFα, IL-8, and GM-CSF. Inhibition of Syk by R788 results in inhibition of all phosphorylation events downstream of Syk signaling. Next to FcϵRI signaling in CHMC, R788 most potently inhibits the signaling of IL-4 and IL-2 receptors. R788 specifically inhibits FcγR signaling in human mast cells, macrophages, and neutrophils. R788 can inhibit local inflammatory injury mediated by immune complexes. R788 induces apoptosis of the majority of examined DLBCL cell lines. In R788-sensitive DLBCL cell lines, R788 specifically inhibits both tonic- and ligand-induced BCR signaling (autophosphorylation of SYK525/526 and SYK-dependent phosphorylation of the B-cell linker protein [BLNK]).
In vivo
Oral administration of R788 to mice reduces immune complex-mediated inflammation in a reverse-passive Arthus reaction and two antibody-induced arthritis models. In another study, R788 effectively inhibits BCR signaling in vivo, resulting in reduced proliferation and survival of the malignant B cells and significantly prolongs survival of the treated animals. R788 demonstrates a significant reduction in major inflammatory mediators such as TNFalpha, IL-1, IL-6 and IL-18, leading to reduced inflammation and bone degradation in models of rheumatoid arthritis. Cell Data
