SYK抑制剂R406产品是R406 is a potent SYK (Spleen Tyrosine Kinase) inhibitor (IC₅₀ = 41 nM). R406 strongly inhibits SYK but not Lyn, and displays 5-fold less potency towards FLT3. R406 induces apoptosis in diffuse large B-cell lymphoma cell lines. It blocks B cell receptor signaling through inhibition of SYK autophosphorylation of Y525/Y526 and SYK-dependent phosphorylation of the B-cell linker protein.