Research, trials, and evidence
If you have ulcerative colitis (UC), you've probably noticed the headlines: "breakthrough cure," "revolutionary new treatment," "game-changing therapy." Some of these stories reflect real progress. Others stretch early-stage findings into promises that won't hold up for years, if ever. The truth is somewhere in between, and it's worth understanding where things actually stand in 2026. The UC treatment landscape has shifted more in the past two years than in the previous decade, with new drug classes reaching patients, genuinely novel mechanisms entering late-stage trials, and microbiome science finally producing clinical data instead of just conference abstracts.
IL-23 Inhibitors Are Now a Standard Option
The biggest practical change for UC patients in 2025 was the expansion of IL-23 inhibitors from a promising drug class into a mainstream treatment category. Interleukin-23 (IL-23) is a protein that drives the inflammatory cascade in the gut, and blocking it has proven effective without the broad immune suppression associated with older therapies.
Guselkumab (Tremfya) received FDA approval in September 2025 for moderate-to-severe UC, becoming the first IL-23 inhibitor available in both subcutaneous and intravenous formulations. The Phase 3 ASTRO trial showed significantly more patients achieving clinical remission and endoscopic improvement compared to placebo at week 12. Around the same time, mirikizumab (Omvoh) gained approval for a simplified single-injection monthly maintenance regimen, reducing the burden of ongoing treatment.
The updated 2025 American College of Gastroenterology (ACG) guidelines now recommend guselkumab, mirikizumab, or risankizumab for inducing remission in moderate-to-severe UC. For patients who haven't responded well to TNF inhibitors or who want to avoid the cardiovascular risks associated with some other drug classes, IL-23 inhibitors now represent a well-supported alternative with a favorable safety profile.
TL1A Inhibitors: A Genuinely New Mechanism
If there's one drug class that gastroenterologists are watching most closely, it's TL1A inhibitors. Tumor necrosis factor-like ligand 1A (TL1A) is a cytokine involved in both inflammation and fibrosis, the scarring process that causes long-term bowel damage. Blocking TL1A could, in theory, address both the symptoms and the structural damage of IBD, something no current therapy does well.
Two TL1A inhibitors have posted strong Phase 2 results. Tulisokibart, developed by Merck, showed a 26% clinical remission rate compared to just 1% with placebo in a Phase 2 trial published in the New England Journal of Medicine. Merck has moved tulisokibart into Phase 3 trials (ATLAS-UC) and is also testing it in Crohn's disease and other immune-mediated conditions.
Duvakitug, co-developed by Teva and Sanofi, posted even stronger numbers in the RELIEVE UCCD Phase 2b study: 48% of patients on the higher dose achieved clinical remission at week 14, compared to 20% on placebo. Sanofi is leading the Phase 3 program.
These are still investigational drugs. Phase 3 results will determine whether TL1A inhibitors live up to their early promise, and that data is expected over the next one to two years. But the early signals, particularly the potential anti-fibrotic benefit, make this a drug class worth following closely.
Obefazimod: A Different Kind of Oral Therapy
Most UC drugs work by blocking a specific inflammatory protein. Obefazimod takes a different approach entirely. It boosts the body's production of a small RNA molecule called microRNA-124 (miR-124), which acts as a natural regulator of immune activity. By increasing miR-124 levels, obefazimod dials down inflammation through a broader regulatory pathway rather than targeting a single cytokine.
In July 2025, Abivax announced positive results from both ABTECT Phase 3 induction trials. The 50 mg once-daily dose achieved a pooled 16.4% placebo-adjusted clinical remission rate at week 8 across the two studies. The drug also met all key secondary endpoints and showed favorable tolerability with no new safety signals. Additional data presented at ECCO 2026 showed early evidence of anti-fibrotic properties, similar to the promise seen with TL1A inhibitors.
The maintenance trial results are expected in mid-2026, and if those are positive, Abivax plans to submit a New Drug Application to the FDA in the second half of 2026. As a once-daily oral pill with a novel mechanism of action, obefazimod could become an attractive option for patients who prefer to avoid injections or infusions.
Microbiome Therapies Are Producing Real Data
For years, microbiome research in UC generated more speculation than evidence. That's starting to change. Several microbiome-based therapies are now producing clinical trial data, moving the field beyond theoretical potential.
Microbiotica's MB310, an oral capsule containing eight strains of live bacteria, showed a 63% clinical remission rate compared to 30% with placebo in a Phase 1b trial. Results were announced in February 2026, and a larger Phase 2/3 trial is planned. Meanwhile, a study from the STOP-Colitis trial found that colonic fecal microbiota transplantation (FMT) produced a 75% clinical response rate compared to 25% with nasogastric delivery, suggesting that how microbiome therapies are delivered matters as much as what they contain.
Separately, researchers at Melius MicroBiomics are developing a genetically engineered bacterium that selectively colonizes inflamed gut tissue by using tetrathionate, a byproduct of gut inflammation, as its energy source. A Phase 1 safety trial is planned for 2026.
These are early-stage developments. Microbiome therapies are years away from becoming standard treatments, and the field still faces challenges around standardization, dosing, and long-term safety. But the gap between microbiome hype and microbiome evidence is narrowing.
Stem Cell Therapy: Still Experimental
Stem cell therapy for UC generates significant patient interest, but the honest assessment is that it remains experimental. Mesenchymal stem cells (MSCs) have shown the ability to modulate inflammation and promote tissue repair in small studies. One recent trial using umbilical cord-derived MSCs reported clinical response rates around 80% at two months, with evidence that the cells suppressed pro-inflammatory T lymphocyte activity.
However, large-scale randomized trials are lacking, and the field faces fundamental questions about optimal cell source, dosing, delivery method, and durability of response. A 2025 review in Clinical and Translational Discovery noted that intestinal stem cell transplantation techniques that directly rebuild the mucosal barrier have not yet been studied in UC patients. Stem cell therapy is not a treatment you can currently access outside of clinical trials, and the timeline for broader availability remains uncertain. If someone is offering stem cell therapy for UC outside of a registered clinical trial, approach that claim with significant caution.
How to Evaluate and Access Clinical Trials
With so many therapies in development, clinical trials are one way patients can access treatments before they reach the market. But understanding what a trial involves, and whether it's right for you, requires some groundwork.
General eligibility for UC trials typically requires a confirmed diagnosis of moderate-to-severe disease and, in many cases, prior treatment that didn't produce adequate results. Age requirements vary, but most adult trials enroll patients 18 and older, with some extending to adolescents. You can search for actively recruiting studies at ClinicalTrials.gov or through NIDDK's clinical trials page, and major academic medical centers like UCSF, UCLA, and Mount Sinai maintain their own searchable trial databases.
Before enrolling, understand what phase the trial is in. Phase 1 trials test safety in small groups. Phase 2 trials evaluate whether a drug works and at what dose. Phase 3 trials compare the drug against placebo or standard treatment in large populations. The later the phase, the more evidence exists about the drug's benefits and risks. Also ask whether the trial includes a placebo arm, what your chances of receiving the active drug are, and what monitoring and follow-up look like.
One practical consideration that often gets overlooked: trials require detailed baseline data about your disease activity, symptom patterns, and treatment history. Having organized, longitudinal records of your symptoms can streamline the screening process and help researchers determine whether you meet eligibility criteria.
What This Means for You
The UC treatment pipeline in 2026 is deeper and more varied than it has ever been. IL-23 inhibitors have moved from clinical trials to guideline-recommended therapies. TL1A inhibitors and obefazimod could follow the same path within the next two years. Microbiome science is finally producing clinical evidence, even if standardized treatments are still years out. Stem cell therapy, despite patient enthusiasm, remains in early research stages.
None of this constitutes a cure. UC remains a chronic condition that requires ongoing management. But the range of effective treatment options is expanding in meaningful ways, and for patients who haven't responded to existing therapies, the pipeline offers genuine reason for measured optimism.
If you're considering a clinical trial, having organized symptom data can help you meet eligibility criteria and provide a clear baseline for researchers to measure treatment effects. Tools like Aidy can help you track symptoms consistently, giving you and your care team a clearer picture of your disease activity over time.