FTY720 is a structural analog of sphingosine as well as a substrate for sphingosine kinase. The phosphorylated FTY720 acts as a potent agonist at four of the sphingosine-1-phosphate (S1P) receptors (S1P₁, S1P₃, S1P₄, and S1P₅). It is a novel immune modulator that prolongs allograft transplant survival in numerous models by inhibiting lymphocyte emigration from lymphoid organs. Animal studies suggest that FTY720 can effectively treat several autoimmune diseases and can be used in relapsing-remitting multiple sclerosis therapy.