Preclinical evaluation of a new immunosuppressive agent, FTY720

FTY720 is a synthetic analog of a fungal metabolite that shows potent immunosuppressive activity in vitro and in vivo with little apparent toxicity. The drug displays marked synergistic effects in vivo with CsA and/or rapamycin. Therefore, this drug may improve the therapeutic window of agents that target cytokine synthesis or signal transduction. Because of these promising findings, the agent is likely to be tested in humans as an adjunct to clinical immunosuppressive regimens.