Abstract Background Etrasimod is an oral S1P-receptor modulator for ulcerative colitis (UC), demonstrating ∼25 % clinical remission at week 12 in ELEVATE.1 In the recent GLADIATOR study, remission at week 12 was observed ∼28% of more mild UC patients. Real-world evidence remains scarce, motivating this study.2 Methods Adults with active UC (endoscopic Mayo sub-score, EMS ≥2) initiating etrasimod 2mg daily between October 2024 and August 2025 were prospectively monitored. Patients with an ostomy or an IPAA were excluded. Clinical assessments were performed at week (w)4, w8 and month 6; endoscopy was repeated at w8. Non-responder imputation and last observation carried forward analysis were applied. Time-to-discontinuation to month 6 was analysed using Kaplan–Meier and log-rank tests comparing baseline moderate–severe (Modified Mayo score, MMS 6) vs mild–moderate disease (MMS ≤6). Results Twenty patients were included (Figure 1). Median follow-up was 27.1 24.0-46.2 weeks, with median exposure of 24.4 17.4-35.4 weeks. Partial modified Mayo improved from 3.0 2.0-4.3 at baseline to 2.0 0.8-3.0 at w4 (p = 0.007), with 45% and 20% of patients achieving, respectively, symptomatic response, remission. By w8, scores decreased to 1.0 0.0-3.0 (p = 0.006), with 45% of patients achieving (steroid-free) symptomatic remission (Figure 2A). Endoscopic improvement and remission at w8 were observed in, respectively, 50% and 20%. of patients. All w8 symptomatic remitters remained in steroid-free (i.e. at day of assessment) symptomatic remission through month 6. At w4, pMMS predicted outcomes: each 1-point increase reduced odds of symptomatic remission at w8 (OR 0.21 95% CI 0.05–0.82; p = 0.03), endoscopic response at w8 (0.41 0.18–0.96; p = 0.04), and symptomatic remission at month 6 (0.15 0.03–0.89; p = 0.04). A higher w4 white blood cell count predicted lower likelihood of symptomatic remission at month 6 (per 1 × 109/L 0.38 0.14–1.00; p = 0.049). Overall, 30% of patients discontinued etrasimod after a median of 12.0 10.5-11.0 weeks, mainly due PNR (n = 3). Discontinuation was more common in moderate-to-severe disease (42.9% vs 7.7%; p = 0.10). Kaplan–Meier analysis showed shorter time-to-discontinuation in this group (p = 0.03, Figure 2B). No new safety concerns emerged. Conclusion Etrasimod induced rapid symptomatic and endoscopic improvements with meaningful w8 remission and sustained steroid-free symptomatic remission to month 6. Early on, treatment disease activity, particularly w4 partial modified Mayo and WBC count, was prognostic. Discontinuation was more frequent in patients with moderate–severe UC. These real-world findings support etrasimod as an effective and well-tolerated therapy in routine clinical practice. References: 1. Sandborn et al. Lancet 2023. 2. Danese et al. UEGW 2025. Conflict of interest: Dr. Derluyn, Louis: No conflict of interest Ferrante, Marc: Research grants from AbbVie, EG Pharma, Celltrion, Janssen, Pfizer, Takeda and Viatris Consultancy fees from AbbVie, AgomAb Therapeutics, Boehringer Ingelheim, Celgene, Celltrion, Eli Lilly, Janssen-Cilag, MRM Health, Merck Sharp and Dohme, Pfizer, Takeda and ThermoFisher Speakers’ fees from AbbVie, Biogen, Boehringer Ingelheim, Dr Falk Pharma, Ferring, Janssen-Cilag, Merck Sharp and Dohme, Pfizer, Takeda, Truvion Healthcare and Viatris Guedelha Sabino, João: Speaker’s fees: Lilly, Pfizer, Abbvie, Ferring, Falk, Takeda, Janssen, Fresenius, and Galapagos. Consultancy fees: Takeda, Pfizer, Janssen, Ferring, Fresenius, Abbvie, Galapagos, Celltrion, Pharmacosmos, and Pharmanovia. Research support: Galapagos, Viatris, and Eurogenerics. JS is supported by a Senior Clinical researcher grant from the Research foundation – Flanders. Verstockt, Bram: Research support from AbbVie, Biora Therapeutics, Celltrion, Landos, Pfizer, Sanofi, Sossei Heptares/Nxera and Takeda. Speaker’s fees from Abbvie, Agomab, Alfasigma, Biogen, Bristol Myers Squibb, Celltrion, Eli Lily, Falk, Ferring, Galapagos, Materia Prima, Johnson and Johnson, Pfizer, Sandoz, Takeda, Tillots Pharma, Truvion and Viatris. Consultancy fees from Abbvie, Alfasigma, Alimentiv, Anaptys Bio, Applied Strategic, Astrazeneca, Atheneum, BenevolentAI, Biora Therapeutics, Boxer Capital, Bristol Myers Squibb, Domain Therapeutics, Eli Lily, Galapagos, Guidepont, Landos, Merck, Mirador Therapeutics, Mylan, Nxera, Inotrem, Ipsos, Johnson and Johnson, Pfizer, Sandoz, Sanofi, Santa Ana Bio, Sapphire Therapeutics, Sosei Heptares, Takeda, Tillots Pharma and Viatris. Stock options Vagustim and Thethis Pharma.
Derluyn et al. (Thu,) studied this question.