Ulcerative Colitis: Where FMT Fits Against Modern Drugs

Fecal microbiota transplantation (FMT) once looked like it might rank beside infliximab and vedolizumab for inducing ulcerative colitis remission. A 2021 network meta-analysis did place all three at the top of its probabilistic ranking. But it did not find statistically significant efficacy differences between active treatments, and the UC drug landscape has changed substantially since then.

The practical conclusion is less glamorous than an FMT-versus-biologics cage match: FMT has biological activity and deserves continued study, but current evidence does not validate it as a standalone replacement for approved biologics or JAK inhibitors in ulcerative colitis. Its results depend heavily on the donor, preparation, dosing approach, and recipient microbiome. Meanwhile, several newer therapies have accumulated trial and long-term extension data without entering the same cross-class comparison.

The 2021 ranking did not identify a proven winner

Zhou et al.'s 2021 network meta-analysis remains the broadest comparison in this group of UC induction treatments. It synthesized 16 randomized controlled trials and 21 treatment comparisons involving infliximab, vedolizumab, adalimumab, golimumab, tofacitinib, and FMT.

For clinical-remission induction, infliximab, vedolizumab, and FMT ranked highest by absolute effects and relative rank order. Adalimumab, golimumab, and tofacitinib ranked lower. This is the result that gave FMT its unusually elevated position in discussions of UC treatment.

Rankings, however, can create a false sense of a podium ceremony. The analysis found no statistically significant efficacy differences between any active treatment arms. Its abstract also does not report discrete SUCRA or P-score values. The ordering therefore reflects a probabilistic sort among estimates with overlapping credible intervals, not proof that FMT, infliximab, or vedolizumab beat every alternative.

Safety added another distinction: infliximab was the only agent associated with a statistically significant increase in adverse events versus placebo, while vedolizumab performed better than infliximab on the analysis's safety dimension. That finding does not settle an individual treatment choice, but it illustrates why remission rankings alone cannot choose a drug.

Why FMT moved down the treatment ladder

More recent work has shifted FMT from apparent co-leader to a protocol-dependent adjunct or possible rescue strategy. A 2025 systematic review and network meta-analysis of microbiome-targeted therapies frames these treatments, including FMT, as adjuvants in inflammatory bowel disease rather than primary standalone therapy.

A 2025 analysis by Pinto et al., which included a meta-analytic component covering six randomized controlled trials, describes FMT efficacy in UC as limited and reports lower response rates than FMT achieves for Clostridioides difficile infection. The study linked successful FMT outcomes with control of Prevotellaceae overgrowth. That association may help identify why some recipients respond, but it does not prove that suppressing Prevotellaceae causes remission.

FMT research has not stalled; it has become more specific about the variables that may determine whether a transplant works. A 2023 clinical study of capsulized FMT reported remission in patients with active UC alongside microbial colonization and metabolite changes. Those microbiome changes support a plausible biological pathway, but they are not a substitute for a direct comparison with a biologic.

In a 2025 randomized controlled trial, adding prebiotic fiber to FMT enhanced donor-strain engraftment in UC. Engraftment is a biomarker outcome, not clinical remission by itself, but it identifies a practical protocol variable. A separate 2025 study of oral lyophilized FMT reported remission in active UC with distinct taxonomic and functional microbiome shifts. Oral capsules and lyophilized preparations could make FMT easier to deliver and store. They do not erase the central problem: different studies use different preparations, donors, dosing schedules, and patient populations, making a single pooled efficacy claim fragile.

FMT also lacks regulatory approval as a primary UC treatment distinct from its established use in recurrent C. difficile infection. Access outside research or specialized clinical settings remains limited, and unscreened or informal stool-transplant practices carry obvious safety and quality-control concerns. Stool is not a supplement category; it is a biological material with a long list of ways to go wrong.

Newer UC therapies are missing from the old comparison

The 2021 network did not include upadacitinib, risankizumab, ozanimod, mirikizumab, or etrasimod. That omission matters because these therapies now shape real-world UC decisions, yet the evidence discussed here contains no post-2021 multi-class network meta-analysis that benchmarks them against infliximab, vedolizumab, tofacitinib, and FMT in one common framework.

Mirikizumab has the longest durability signal among these newer agents in this evidence base. In the LUCENT-3 open-label extension at 104 weeks, patients receiving continuous mirikizumab maintained clinical remission. The 152-week continuation reported sustained clinical remission through three years of continuous treatment.

Those results support mirikizumab as a long-term maintenance option, but they cannot rank it against FMT or older biologics for induction. Open-label extensions include people who responded to induction and tolerated treatment; nonresponders and early discontinuers do not contribute to the long-term responder group. This survivorship bias makes a 152-week extension result fundamentally different from an intention-to-treat induction endpoint in a randomized trial.

Guselkumab also adds to the IL-23 story. A 2025 review of the QUASAR program reports that guselkumab improved clinical remission in moderate-to-severe UC without an excess of adverse events in the trial's induction and maintenance components. Among participants enrolled throughout, clinical remission after maintenance was 45% with guselkumab and 21% with placebo: a 24-percentage-point difference. The review notes that UC still lacks a direct comparison between guselkumab and other IL-23 inhibitors.

Etrasimod, an S1P1,4,5 modulator, is another post-2021 oral option. A 2025 safety analysis examined etrasimod use alongside opioids or antidepressants in people with UC. It confirms clinical use and the relevance of medication-interaction monitoring, not superiority over biologics or JAK inhibitors.

Tofacitinib's safety profile needs UC-specific context

Tofacitinib carries warnings that can dominate the conversation, particularly around major cardiovascular events and malignancy. The UC-specific data tell a narrower story. In a 2023 integrated safety analysis spanning phase 2 and 3 trials, the OCTAVE Open extension, and RIVETING, investigators assessed 2,999.7 patient-years of tofacitinib exposure over as much as 7.8 years.

Herpes zoster was the primary differentiating safety signal. In that UC program, cardiovascular events and malignancies were characterized as broadly comparable with those seen with other UC therapies. This does not make the risk disappear, especially for a patient with substantial baseline cardiovascular risk. It does mean that the black-box warning should not be read as if it arose from an identical UC population: its strongest signal came from ORAL Surveillance, a rheumatoid arthritis study of older people with higher baseline cardiovascular risk.

What a defensible treatment hierarchy looks like now

No single study in this evidence base can tell a patient whether FMT, infliximab, vedolizumab, a JAK inhibitor, an IL-23 inhibitor, or an S1P modulator is best for them. The 2021 network meta-analysis offers a useful historical comparison, not a current league table. Its high ranking for FMT was probabilistic, lacked statistically significant differences among active therapies, and predates several drugs now used for UC.

FMT remains worth studying, especially with better donor selection, fiber co-administration, and oral formulations. The available 2025 evidence places it more credibly as an adjunct or a carefully supervised option after standard therapies fail than as a first-line substitute for approved treatment.

For someone with ulcerative colitis, the useful question is not which therapy "won" a five-year-old ranking. It is which approved option fits disease severity, prior treatment response, infection risk, cardiovascular risk, pregnancy plans, monitoring burden, and access—and whether an FMT trial belongs alongside that plan under gastroenterology supervision.

Use current clinical guidelines and a gastroenterologist to make that decision. The comparative evidence has not caught up with the treatment menu.