A phase II, Multicentre, Randomised, Double-Blind, Placebo-controlled Study to Evaluate Safety, Tolerability, and Efficacy of Amiselimod in Patients with Moderate to Severe Active Crohn's Disease

Background and Aims Amiselimod is an oral selective S1P(1) receptor modulator with potentially fewer adverse effects than fingolimod. We evaluated the safety, tolerability, and clinical efficacy of amiselimod in participants with moderate to severe active Crohn's disease. Methods This was a phase IIa, multicentre, randomised, double-blind, parallel group, placebo-controlled study comparing amiselimod 0.4 mg with placebo over a 14-Week treatment period. The primary endpoint of the study was the proportion of participants with clinical response (Crohn's Disease activity Index [CDAI] 100) from baseline at Week 12. Results A total of 180 patients were screened and 78 were randomised [40 to amiselimod 0.4 mg and 38 to placebo]. There was no significant difference in the proportion of patients achieving CDAI 100 at Week 12 on amiselimod 0.4 mg and on placebo [48.7% vs. 54.1%, respectively] (odds ratio [OR] [95% confidence interval]: 0.79 [0.31, 1.98]). The results from the secondary endpoint analyses supported the results of the primary endpoint analysis. Treatment with amiselimod 0.4 mg was generally well tolerated, with 71.8% of participants completing the 14-week treatment period. Seven participants had serious adverse events and four discontinued treatment in the amiselimod group. Conclusions Amiselimod 0.4 mg for 12 weeks was not superior to placebo for the induction of clinical response [CDAI 100] in Crohn's disease. Treatment with amiselimod 0.4 mg was generally well tolerated and no new safety concerns related to amiselimod were reported in this study.