S1687 Long-Term Efficacy of Etrasimod in Patients With Ulcerative Colitis: Two-Year Outcomes From the ELEVATE Open-Label Extension

Introduction: Etrasimod is an oral, once-daily (QD), selective sphingosine 1-phosphate (S1P)1,4,5 receptor modulator for the treatment of moderately to severely active ulcerative colitis (UC). The efficacy and safety of etrasimod were demonstrated in the phase 3 ELEVATE UC clinical program. This is the first report of the long-term efficacy of etrasimod 2 mg QD from the ongoing phase 3 open-label extension (OLE) study, ELEVATE UC OLE (NCT03950232). Pooled safety data up to 4 years from the global clinical program have been previously reported Methods: Patients (pts) entered the OLE from qualifying UC parent studies if they completed the parent studies or experienced disease worsening during the maintenance period of the parent study. Efficacy endpoints included blinded centrally-read endoscopy, performed at Week (Wk) 52 and Wk 104 of the OLE. Endpoints were assessed among pts who entered the OLE as clinical responders to etrasimod 2 mg QD in the parent studies (data cut-off: June 20, 2024). Data are reported using observed cases with corresponding modified nonresponder imputation (mNRI) rates. Results: A total of 296 pts were included, with a mean (standard deviation) etrasimod exposure of 120.0 (50.3; range: 3.0–218.3) wks. Most pts (n = 252; 85.1%) received ≥52 wks and 207 (69.9%) received ≥104 wks of open-label treatment. For this analysis, treatment was ongoing in 186 (62.8%) pts, while 109 (36.8%) had discontinued; reasons for discontinuation included pt withdrawal (n = 38; 12.8%), adverse events (n = 38; 12.8%), and lack of efficacy (n = 20; 6.8%). In the OLE, clinical response was observed in 89.3% (mNRI: 74.4%) and 87.6% (61.8%) of pts at Wks 52 and 104, respectively. At Wk 52 and Wk 104, clinical remission rates were 56.6% (47.1%) and 55.2% (38.9%), respectively. Endoscopic improvement was observed in ∼65% of pts at both timepoints (Wk 52: 53.2%; Wk 104: 43.9%). Symptomatic response and symptomatic remission were observed in ∼ 95% (Wk 52: 78.5%; Wk 104: 66.0%) and ∼80% (Wk 52: 66.9%; Wk 104: 54.7%) of pts, respectively, through Wk 104. Conclusion: Etrasimod efficacy was maintained through an additional 2 years of continuous treatment across clinical, endoscopic, and symptomatic outcomes, supporting long-term durable efficacy with etrasimod treatment. This study is ongoing with future expected readouts.