TC-SP 14, also known as compound 14, is a highly active and potent S1P1 agonist with oral bioavailability. It exhibits an EC50 value of 0.042 μM, indicating its strong binding affinity to the S1P1 receptor. Notably, its interaction with the S1P3 receptor is minimal, as evidenced by an EC50 value of 3.47 μM. TC-SP 14 demonstrates significant pharmacological effects, including a marked reduction in blood lymphocyte counts and the attenuation of delayed type hypersensitivity response to antigen challenge [1].