miR-124 upregulation as a new therapeutic strategy: The evolving role of obefazimod in ulcerative colitis

Ulcerative colitis (UC) remains difficult to manage, with many patients failing to achieve durable, steroid-free remission despite available biologics and small molecules. Obefazimod (ABX464) is a first-in-class, oral small molecule that enhances microRNA-124 (miR-124) biogenesis, suppressing STAT3 and CCL2 signaling, reducing Th17 polarization and macrophage activation. This inflammation-dependent mechanism enables targeted immune modulation without broad immunosuppression. In Phase IIa and IIb trials, obefazimod significantly improved clinical remission, clinical response, and endoscopic outcomes versus placebo, with durable efficacy maintained in a 96-week maintenance study. The pivotal Phase III ABTECT-1 and ABTECT-2 trials (n = 1275) confirmed these findings, achieving a pooled placebo-adjusted clinical remission rate of 16.4% at week 8 and meeting all key secondary endpoints, with symptomatic improvement reported as early as week 1. Across studies, obefazimod showed a consistent, reassuring safety profile, with most adverse events mild to moderate, low discontinuation rates, and no new safety signals during long-term exposure. Obefazimod represents a promising addition to the therapeutic landscape for moderate-to-severe UC. Key questions remain regarding its optimal positioning, real-world effectiveness, and potential role in rational combination regimens to further improve remission depth and durability.