Identification of Tricyclic Agonists of Sphingosine-1-phosphate Receptor 1 (S1P) Employing Ligand-Based Drug Design.

Fingolimod (1) is the first approved oral therapy for the treatment of relapsing remitting multiple sclerosis. While the phosphorylated metabolite of fingolimod was found to be a nonselective S1P receptor agonist, agonism specifically of S1P is responsible for the peripheral blood lymphopenia believed to be key to its efficacy. Identification of modulators that maintain activity on S1P while sparing activity on other S1P receptors could offer equivalent efficacy with reduced liabilities.