Fecal Microbiota Transplantation Shows Promise for IBS in the Most Recent Randomized Controlled Trial

Monika Fischer, MD, reviewing El-Salhy M, et al. Gut 2020 May.

Alterations of the gut microbiota in irritable bowel syndrome (IBS) have been described. Observational studies on fecal microbiota transplantation (FMT) aiming to restore eubiosis have described symptomatic improvement in patients with IBS, but results from randomized controlled trials (RCTs) have been inconsistent. A meta-analysis of 4 previously published RCTs concluded that FMT was not beneficial in improving global IBS symptom scores. Subgroup analyses suggested that patients with IBS and diarrhea or mixed bowel habits might respond better to FMT than constipated patients with IBS; nasojejunal or colonoscopic delivery might be more efficacious than capsules; and finding a single “super donor” versus pooling stool from different donors might be the best option.

In this RCT from Norway, 165 patients with IBS received either 30 g or 60 g of frozen stool from a healthy super donor or autologous stool (placebo) that was delivered to the duodenum via upper endoscopy. At 3 months, a greater percentage of patients responded in both the 60-g and 30-g FMT groups than in the placebo group (89%, 77%, and 24%, respectively; P<.0001 for both). A significantly higher number of patients with any of the 3 subtypes of IBS reported improvements in abdominal symptoms and quality of life after receiving FMT compared to placebo recipients. The microbiome of the patients who underwent FMT changed; however, the dysbiosis index did not decrease significantly. Mild, self-limited adverse events (abdominal discomfort, diarrhea, constipation, nausea) occurred in up to 25% of FMT recipients.

Monika Fischer, MD, FASGE

COMMENT
To date, this is the largest RCT evaluating FMT in IBS and the third RCT with positive outcomes. Perhaps inclusion of this RCT’s data in the meta-analysis would be sufficient to swing the pendulum back in favor of FMT over placebo. This study underscores the importance of finding the super donor versus pooling stool from multiple donors in IBS, as we have seen in the ulcerative colitis-FMT studies. Interestingly, the reversal of dysbiosis was not necessary to achieve clinical improvement in IBS; this highlights the limitations of the current concept on disease-associated alterations to the gut microbiota.

Note to readers: At the time we reviewed this paper, its publisher noted that it was not in final form and that subsequent changes might be made.

CITATION(S)

El-Salhy M, Hatlebakk JG, Gilja OH, Kristoffersen AB, Hausken T. Efficacy of faecal microbiota transplantation for patients with irritable bowel syndrome in a randomised, double-blind, placebo-controlled study. Gut 2020;69:859–867. (https://doi.org/10.1136/gutjnl-2019-319630)