Efficacy and Mechanism Evaluation (Aug 2024)
Determining the optimal route of faecal microbiota transplant in patients with ulcerative colitis: the STOP-Colitis pilot RCT
Abstract
Background Ulcerative colitis is an autoimmune reaction to imbalanced colonic microbiome in genetically predisposed patients. There have been four published randomised controlled trials of faecal microbiota transplant versus placebo in ulcerative colitis; three being positive. However, the methodology used varied and mechanistic data were sparse. Objective To identify an optimal faecal microbiota transplant delivery route to test in a future efficacy-powered randomised controlled trial. Design Prospective, multicentre, open-label, parallel-group, randomised pilot study. Participants were randomised in a 1 : 1 ratio to faecal microbiota transplant by nasogastric or by colonoscopy, minimised by partial Mayo score and current smoking status. Setting Three secondary care hospitals in the United Kingdom. Participants Thirty adult patients with mild to moderately active ulcerative colitis (partial Mayo score of ≥4 and ≤8). Interventions Faecal microbiota transplant samples were prepared at the University of Birmingham Microbiome Treatment Centre and administered to participants either via a nasogastric tube on 4 consecutive days repeated after a month (nasogastric) or by colonoscopy followed by 7 weekly enemas (COLON). Each treatment course was from a single matched donor. Participants and researchers underwent qualitative interviews regarding the faecal microbiota transplant experience. Main outcome measure Composite assessment of qualitative and quantitative data based on efficacy, acceptability and safety. Clinical response (primary measure of efficacy) was defined as a ≥3 point and ≥30% reduction in full Mayo score from randomisation to week 8 and a ≥1 point reduction in rectal bleeding subscore or absolute rectal bleeding subscore of 0 or 1. Results Thirty ulcerative colitis patients were randomised: 16 to nasogastric; 14 to COLON. Seven participants in the nasogastric arm and two in the COLON arm withdrew from treatment and clinical follow-up. Eight of 16 (50%) nasogastric participants were adherent compared to 12/14 (86%) COLON participants. Clinical response data were available for 20 of 30 randomised participants. Clinical response was seen in 2/8 (25%) nasogastric participants versus 9/12 (75%) COLON participants: adjusted risk ratio 2.94 (95% CI 0.84 to 10.30). Adverse events were reported in 11/16 (69%) nasogastric participants versus 11/14 (79%) COLON participants. There were three serious adverse events in two nasogastric participants. Faecal microbiota transplant was deemed an acceptable treatment for ulcerative colitis, with greater participant and clinician acceptability for the COLON route. Faecal microbiota transplant responders had a greater reduction in faecal calprotectin compared to non-responders (t-test p = 0.03) and increase in faecal microbiome diversity (Shannon diversity p < 0.01). In the whole cohort, a negative association between faecal calprotectin and diversity was seen (Kendall’s tau z = −2.8231, p = 0.004757). There were increases in faecal acetate (p = 0.05) and butyrate (p = 0.03) after faecal microbiota transplant intervention, but these were not associated with clinical response. A limitation was that this was an open-label pilot study, which was not powered to assess for efficacy of faecal microbiota transplant. Conclusions Faecal microbiota transplant delivered by the colonic route was considered safe and better tolerated than the nasogastric route. The colonic route was preferred by both participants and clinicians. Mechanistic signals indicated reduction in colonic inflammation and increased microbiome diversity in faecal microbiota transplant responders. Future work An efficacy-powered randomised controlled trial. Trial registration This trial is registered as ISRCTN74072945 and EudraCT 2015-005753-12. Funding This award was funded by the National Institute for Health and Care Research (NIHR) Efficacy and Mechanism Evaluation (EME) programme (NIHR award ref: 13/179/01) and is published in full in Efficacy and Mechanism Evaluation; Vol. 11, No. 14. See the NIHR Funding and Awards website for further award information. Plain language summary Ulcerative colitis, a chronic inflammatory condition affecting the colon, results from the body’s immune response to imbalance in colonic microbes (microbiota). Faecal microbiota transplantation involves transferring processed donated stool samples from carefully screened healthy donors to ulcerative colitis patients aiming to correct the imbalance and reduce inflammation. There have been four trials comparing faecal microbiota transplant with placebo (dummy no treatment) to treat ulcerative colitis, and one which investigated faecal microbiota transplant with dietary intervention. Three of these studies showed encouraging benefit for faecal microbiota transplant. However, these studies varied in the methods used, with faecal microbiota transplant delivered either to the stomach or colon, or both. The aim of this study was to identify the best route of faecal microbiota transplant administration before undertaking a large-scale trial comparing faecal microbiota transplant with placebo. Between March 2018 and 30 April 2019 ulcerative colitis patients from three hospitals were randomly allocated to receive faecal microbiota transplant via either a tube inserted through the nose into the stomach on 4 consecutive days repeated after a month (nasogastric group; 16 participants) or by colonoscopy followed by 7 weekly enemas (COLON group; 14 participants). Faecal microbiota transplant was well accepted, with both patients with ulcerative colitis and healthcare staff stating a preference for the colonic route. Only 8 of 16 in the nasogastric group completed the study compared to 12 of 14 in the COLON group. Altogether, 9/12 (75%) in the COLON group improved compared with 2/8 (25%) in the nasogastric group. The majority of participants [11/14 (79%) COLON vs. 11/16 (69%) nasogastric] had mild, short-lived side effects following faecal microbiota transplant. There were three serious adverse events. Faecal calprotectin (indicating colonic inflammation) fell in responders and stool samples showed an increase in the number of microbial species after faecal microbiota transplant. At the end of the study, a recommendation was made by the Independent Oversight Committee to proceed to a large placebo-controlled randomised trial using the colonic route. Scientific summary Background Ulcerative colitis (UC) results from an exaggerated immune response to an imbalanced (dysbiotic) colonic microbiome in genetically predisposed patients. At the inception of this study, there had been four published randomised controlled trials (RCTs) comparing faecal microbiota transplantation (FMT) with placebo to treat UC in adults. Of these four seminal studies, three involved delivery of FMT via the colonic route and one a combination of delivery to the foregut and colon. This latter study was the only one of the four not to show a difference in efficacy compared to placebo. Foregut-delivered FMT is extensively and successfully used in clinical practice to treat Clostridioides difficile infection (CDI). From the results of the UC trials, FMT appeared to have therapeutic potential for UC. However, the methodology employed in these studies was varied and, taking into account the efficacy of FMT delivered to the foregut to treat CDI, there was uncertainty regarding the best route of delivery in the context of UC. Objectives The aims of this pilot study were as follows: to determine which FMT administration route [nasogastric (NG) or colonic (COLON)] should be investigated in a randomised double-blind, placebo-controlled trial to determine whether a full-scale RCT was feasible. In order to achieve these aims, the pilot study had the following clinical objectives. To assess the following: whether FMT by the NG route induces clinical response in patients with active UC whether FMT by the COLON route induces clinical response in patients with active UC tolerability and safety which route of FMT delivery (if any) was suitable to investigate in a full-scale RCT. The aims of the qualitative research were to assess the following: patient and clinician acceptability of FMT (NG route) patient and clinician acceptability of FMT (COLON route). The aims of the nested-mechanistic substudy were to assess the following: whether FMT by either route is associated with a change in faecal calprotectin as a surrogate marker of colonic inflammation changes in the colonic microbiome induced by FMT via each route changes in the metabolome [short-chain fatty acids (SCFAs)] induced by FMT via each route effect of diet (donors) time from stool donation to treatment. Methods In this prospective, multicentre, open-label, parallel group, randomised pilot study, adult patients with mild to moderate active UC (partial Mayo score of ≥4 and ≤8) were recruited from three centres in the UK (Birmingham, Glasgow and St Mark’s, London). Patients were randomised to receive FMT delivered either via a NG tube for delivery to the stomach (foregut-NG) on 4 consecutive days repeated after a month or by a combination of delivery through a colonoscope followed by 7 weekly enemas (hindgut-COLON). All participants underwent a treatment schedule using FMT derived, in each case, from a single donor. The primary outcome was a composite assessment of both qualitative and quantitative data based on efficacy, acceptability and safety. Clinical response (primary measure of efficacy) was defined as a ≥3 point and a ≥30% reduction in full Mayo score from randomisation to week 8 and a ≥1 point reduction in the rectal bleeding subscore or an absolute rectal bleeding subscore of 0 or 1. Patient and clinician acceptability of FMT and preference of treatment route was assessed through semi-structured qualitative research interviews. Interviews also explored reasons for adherence to treatment allocation and patients’ perspectives on FMT and trial experience. Participants were interviewed face to face or by telephone at two time points, first following the screening visit and prior to randomisation, and second after the 12-week follow-up period. Safety was assessed by the number of participants experiencing adverse events (AEs) and serious adverse events (SAEs). For the translational research, stool samples were taken from participants at baseline and then at 2 weekly intervals throughout the study to assess microbiome diversity (by 16S rRNA sequencing) and to examine the effect of FMT on faecal calprotectin. Donor stool samples were also analysed by 16S rRNA sequencing. Biopsy samples were taken from the colon at the time of endoscopy (baseline and week 8) to analyse mucosa-associated microbiome by 16S rRNA sequencing. SCFA levels in stool samples were also measured throughout the study and blood was taken from participants to look for changes in C-reactive protein (CRP) in response to FMT. Donors were asked to fill in a dietary questionnaire in order to look for associations between dietary components in their habitual diet and the efficacy of their donated FMT samples. Results Thirty patients with UC were randomised between March 2018 and April 2019; 16 to NG; 14 to COLON route. Seven participants in the NG arm and two participants in the colonic arm withdrew from the study. Clinical response was achieved in a higher proportion of participants in the colonic arm [9/12 (75%)] compared with the NG arm [2/8 (25%)]; [adjusted risk ratio 2.94 (95% confidence interval, 0.84 to 10.30)]. In the colonic arm, 12/14 (86%) participants were considered adherent compared with 8/16 (50%) in the NG arm. AEs were reported in 11/14 (79%) participants in the colonic arm and 11/16 (69%) in the NG arm. There were three SAEs in two participants in the NG arm, and none in the colonic arm. Qualitative research found a high level of enthusiasm for the trial among both patients and staff. Patients were more positive about the colonic treatment route than the NG route, both before randomisation and after the patients had been through the study. Lower calprotectin levels, implying reduced colonic inflammation, averaged over the last half of the treatment course (weeks 4, 6 and 8), were seen in the responders (N = 11, mean 508.6 mg/kg) versus the non-responders (N = 9, mean 853.6 mg/kg) (p = 0.03). Furthermore, there was a negative association between faecal microbiome alpha diversity [rarefied total operational taxonomic unit (OTU) richness] and calprotectin levels (p < 0.01). This is the first time that change in faecal calprotectin, a widely used clinical inflammatory biomarker in UC, has been reported in response to FMT in inflammatory bowel disease (IBD). With respect to SCFAs, there were significant and large increases observed in the concentration of acetate (45% increase, p = 0.05) and butyrate (57% increase, p = 0.03) across all participants (N = 19) from baseline to week 2 following FMT treatment. This effect was also observed over the course of the entire FMT treatment period from baseline to 8 weeks (N = 16, acetate 21% increase, p = 0.02; butyrate 39% increase, p = 0.08). Significant changes were not observed for the other SCFAs measured, notably propionate (2 weeks p = 0.46, 8 weeks p = 0.36). The observed increase in acetate and butyrate was not associated with clinical response, and in fact when restricted to the responder group (N = 9) changes at both 2 and 8 weeks were no longer significant, although increases were still observed. Across all participants that completed FMT to day 56, and for whom baseline and week 8 DNA was available (N = 13), there was no significant change in faecal microbiome alpha diversity, as measured by rarefied Shannon diversity of 3% OTUs (p = 0.43). However, when restricted to the colonic arm only (N = 8), there was a significant increase in alpha diversity (p = 0.01) observed after FMT. Again, for those participants in the colonic arm that responded to FMT, there was a significant increase in alpha diversity (rarefied Shannon diversity, p < 0.01) compared to those who did not. No differences were seen in alpha diversity of mucosa-associated bacteria pre and post treatment. Donor microbiome diversity, as measured by rarefied 16S rRNA gene Shannon diversity, varied substantially between donors. There was a non-significant positive association between clinical response and donor diversity (p = 0.19) with the treatment arm taken into account. In this pilot study, CRP values were lower at baseline in the colonic arm (4.2 mg/l) compared with the NG arm (11.3 mg/l). Similarly, CRP values at weeks 4, 6 and 8 were also lower in the colonic arm than in the NG arm. With regard to data derived from diet questionnaires administered to donors, higher milk and milk product intakes were associated with higher alpha diversity, but this was not statistically significant. The mean number of days from stool donation to FMT treatment was similar in participants who achieved a clinical response compared with those who did not achieve a clinical response. There was no association between time from stool donation and treatment, and clinical response when added to the primary intention-to-treat analysis model. Conclusion This pilot study suggests that in patients with active UC, FMT delivered via the colonic route appears to be safe and better tolerated with signals suggesting greater efficacy compared to the NG route. The pilot study was welcomed by patients and clinicians, and FMT appears, at least in the short term, to be safe and well tolerated. On review of these data, the Independent Oversight Committee recommended progressing to the planned placebo-controlled randomised trial, which would be powered to assess efficacy, and would have enabled more detailed mechanistic studies to assess for strains engrafting from donors to recipients, which are associated with clinical response. Patients remain very interested in FMT as a potential treatment for UC as this microbiome manipulation affords an alternative therapy to immune system suppression as a means to treat UC. The trial management group involved in this pilot believe that further studies to assess the efficacy of FMT in UC with a focus on understanding mechanisms are warranted as the first step towards developing precision live biotherapeutics for IBD. Trial registration This trial is registered as ISRCTN74072945 and EudraCT 2015-005753-12. Funding This award was funded by the National Institute for Health and Care Research (NIHR) Efficacy and Mechanism Evaluation (EME) programme (NIHR award ref: 13/179/01) and is published in full in Efficacy and Mechanism Evaluation; Vol. 11, No. 14. See the NIHR Funding and Awards website for further award information.
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