Efficacy and Safety of Etrasimod in Patients With Moderately to Severely Active Ulcerative Colitis Stratified by Baseline Modified Mayo Score: A Post Hoc Analysis From the Phase 3 ELEVATE UC Clinical Program

Background: Etrasimod is an oral, once daily, selective sphingosine 1-phosphate (S1P)_1,4,5 receptor modulator for the treatment of moderately to severely active ulcerative colitis (UC). This post hoc analysis of the ELEVATE UC clinical program describes etrasimod efficacy and safety by patients’ baseline disease activity. Methods: Predefined efficacy endpoints were assessed at week 12 in patients with moderately (modified Mayo score [MMS] 5–7) or severely (MMS 8–9) active UC using pooled data from ELEVATE UC 52 and ELEVATE UC 12. Descriptive statistics with 95% CI were calculated. Results: Of 743 patients analyzed, 525 (70.7%) had moderately active and 218 (29.3%) had severely active disease at baseline. At week 12, patients treated with etrasimod showed larger mean percentage reductions (95% CI) in MMS vs placebo, regardless of baseline disease activity (−48.4% [−52.3, −44.4] vs −27.0% [−32.2, −21.7] for moderately active disease and −46.4% [−51.2, −41.5] vs −29.8% [−37.2, −22.3] for severely active disease). Similar proportions of patients with moderately or severely active disease treated with etrasimod vs placebo achieved clinical response at week 12 (61.3% vs 39.8% for moderately active disease and 64.5% vs 30.3% for severely active disease). Incidence of treatment-emergent adverse events were similar between disease activity subgroups. Conclusions: At week 12, etrasimod showed greater reductions in disease activity and higher rates of clinical response vs placebo in patients with either moderately or severely active disease at baseline. The safety profile of etrasimod was consistent with the overall trial population and was unimpacted by baseline disease activity.