FMT Fecal Microbiota Transplantation engraftment after budesonide or placebo in patients with active ulcerative colitis using pre-selected donors: a randomized pilot study (Apr 2024, n=24) "clinical response appeared donor-dependent"

Fecal Microbiota Transplants

Michael Harrop

Active member
Jul 6, 2023


Fecal microbiota transplantation (FMT) shows some efficacy in treating patients with ulcerative colitis (UC), although variability has been observed among donors and treatment regimens. We investigated the effect of FMT using rationally selected donors after pretreatment with budesonide or placebo in active UC.

Patients ≥ 18 years old with mild to moderate active UC were randomly assigned to three weeks budesonide (9 mg) or placebo followed by four weekly infusions of a donor feces suspension. Two donors were selected based on microbiota composition, Treg induction and SCFA production in mice. The primary endpoint was engraftment of donor microbiota after FMT. In addition, clinical efficacy was assessed.

In total, 24 patients were enrolled. Pretreatment with budesonide did not increase donor microbiota engraftment (p=0.56) nor clinical response, and engraftment was not associated with clinical response. At week 14, 10/24 (42%) of patients achieved (partial) remission. Remarkably, patients treated with FMT suspensions from one donor were associated with clinical response (80% of responders, p<0.05) but had lower overall engraftment of donor microbiota. Furthermore, differences in the taxonomic composition of the donors and the engraftment of certain taxa were associated with clinical response.

In this small study, pretreatment with budesonide did not significantly influence engraftment or clinical response after FMT. However, clinical response appeared donor-dependent. Response to FMT may be related to transfer of specific strains instead of overall engraftment, demonstrating the need to characterize mechanisms of actions of strains that maximize therapeutic benefit in ulcerative colitis.

From a set of 12 eligible fecal donors, a rational selection of the 2 donors used in this study (D07 and D08) was based on microbiota community composition, ability to induce T regulatory cells (Tregs) in vivo, and capacity to produce short-chain fatty acids (SCFAs) in vivo (see supplementary appendix for a more detailed description).
These findings also suggest that selecting FMT donors based on in vitro, microbiome community, or animal model data alone may be insufficient to predict FMT clinical response in patients with IBD
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