Purity >98%. FTY720 is a derivative of ISP-1 (myriocin), a fungal metabolite of the Chinese herb Iscaria sinclarii as well as a structural analog of sphingosine. It is a novel immune modulator that prolongs allograft transplant survival in numerous models by inhibiting lymphocyte emigration from lymphoid organs. In vivo, FTY720 is phosphorylated by sphingosine kinase to the physiologically active phosphoric acid ester. FTY720 phosphate acts as a potent agonist at four of the sphingosine-1-phosphate (S1P) receptors (S1P1, S1P3, S1P4, and S1P5 ), with IC50 values of 0.2-6 nM.