Dosing regimen for a selective s1p1 receptor agonist

A method of treating a disease or disorder associated with an activated immune systems comprising administering (R)-5-[3-Chloro-4-(2,3-dihydroxy-propoxy)-benz[Z]ylidene]-2-([Z]-propylimino)-3-o-tolyl-thiazolidin-4-one (Compound 1), or a pharmaceutically acceptable salt thereof, to a subject in need thereof, for use in the treatment of a disease or disorder associated with an activated immune system, wherein during initiation of treatment, or upon re-initiation of treatment after drug discontinuation, Compound 1, or a pharmaceutically acceptable salt thereof, is to be administered to a human subject orally once daily as follows:

• 2 mg of Compound 1 on days 1 and 2;
• 3 mg of Compound 1 on days 3 and 4;
• 4 mg of Compound 1 on days 5 and 6;
• 5 mg of Compound 1 on day 7;
• 6 mg of Compound 1 on day 8;
• 7 mg of Compound 1 on day 9;
• 8 mg of Compound 1 on day 10;
• and 9 mg of Compound 1 on day 11;
• followed by (a) the maintenance dose of 10 mg of Compound 1 to be administered orally once daily from day 12 onwards;
• or (b) 10 mg of Compound 1 to be administered orally once daily for 2, 3 or 4 days, followed by the maintenance dose of 20 mg of Compound 1 to be administered orally once daily.