Amiselimod is a selective sphingosine 1-phosphate receptor modulator in development for inflammatory bowel disease. It is converted to its active metabolite, amiselimod phosphate (amiselimod-P), and has a long half-life and slow accumulation to steady state. We evaluated a multiple-dose titration regimen to determine the plasma pharmacokinetic (PK) profile of amiselimod and amiselimod-P at steady state for the 0.4 mg QD therapeutic dose on day 13 and for the 0.8 mg QD supratherapeutic dose on day 26.