Sphingosine-1-Phosphate (S1P) Receptor Modulators for the Treatment of Inflammatory Bowel Disease (IBD): Mechanisms, Clinical Evidence, and Practical Insights.

Inflammatory bowel disease commonly requires advanced therapies to induce and maintain durable remission. Sphingosine-1-phosphate receptor modulators are the latest class of orally administered small molecules that have been added to the therapeutic armamentarium for inflammatory bowel disease. These molecules reduce inflammation by sequestering lymphocytes in lymph nodes, thereby reducing immune cell trafficking to the gut. Etrasimod and ozanimod are both licensed for moderate-to-severe ulcerative colitis and have both shown superiority over placebo, with emerging data for their use in Crohn's disease. By modulating immune cell distribution, without reducing overall immune function, they offer a highly favourable safety profile. This narrative review explores the pharmacology, safety and efficacy of sphingosine-1-phosphate receptor modulators based on clinical trials and real-world evidence and offers practical guidance on their initiation and monitoring.