A recent systematic review and meta-analysis published in American Journal of gastroenterology and reported by AusDoc (Clair Pain) discussed the lack of benefit seen at 12 weeks after a Faecal transplant for irritable bowel syndrome however the route of administration may play a part.

Pooling data from four randomised controlled trials with 254 participants, the US authors found no difference between people given a faecal microbiota transplant (FMT) and those given placebo. At 12 weeks after transplant, 49% of those receiving donor faecal material reported an improvement of global IBS symptoms, compared with 51% of those assigned to placebo, the authors wrote in the American Journal of Gastroenterology.

The four studies had different approaches to treatment administration: two used donor faeces and a placebo consisting of the patient’s own faeces, delivered either via colonscopy or nasojejunal tube. The other two studies delivered donor faeces via oral capsules — either 75 capsules over three days or 300 over 12 days. The placebo capsules in the latter studies contained only excipients and in one study, brown colouring.

After drawing a blank looking at the data for all the studies pooled together, the researchers then analysed data for the tubal and oral studies separately.

The faecal transplants appeared to be effective in the tubal studies. Patients given donor faeces in this way were 60% more likely to report improvement in their global IBS symptom score than those given a placebo consisting of their own faeces.

In contrast, pooled data from the two studies that employed oral capsules to administer the treatments showed that placebo was better at reducing IBS global symptoms than the faecal capsules.

“The benefit or harm of FMT seems to be associated with the methodology of FMT and placebo because the two randomised controlled trials using single-dose FMT through colonoscopy and nasojejunal tubes demonstrated a clinically significant improvement in global IBS symptoms in comparison with autologous FMT, whereas the two multiple-dose oral capsule FMT studies showed not just lack of benefit, but potential harm to the subjects when compared with capsule excipients only.”

The apparent effectiveness of non-oral FMT in IBS “contrasted starkly” with studies on transplant for Clostridium difficile where capsule FMT was “highly effective and not inferior to non-oral FMT”, they added. However, their conclusions were based on only a few small trials and more randomised trials were needed, they said.

More information: American Journal of Gastroenterology 2019