Use of A Complex Gut Bacterial Consortium (MITI 001) for the Treatment of Irritable Bowel Syndrome With Diarrhea

Trial details

Who runs it

Stanford University

Trial code

NCT07238790

Record updated

20 November 2025

Original description

While the pathophysiology of diarrhea-predominant irritable bowel syndrome (IBS-D) is complex and heterogeneous, dysbiosis of the gut microbiome is frequently observed, suggesting that a substantial subset of patients with irritable bowel syndrome (IBS) have symptoms that are initiated and/or perpetuated by a microbiome dysfunction. Successful randomized controlled trials (RCT) for IBS-D (Ford 2018; Black 2022) leveraging microbiome-targeted therapies (antibiotics or low microbiome fermentation diets) suggest the gut microbiome is at least partially involved in IBS symptoms. Furthermore, fecal microbiota transplantation (FMT) for patients with IBS-D has demonstrated promising results (El-Salhy 2020), supporting the possibility that altering the microbiome composition could ameliorate IBS-D symptoms.Read full original descriptionShow less

A Phase 1 Study to Evaluate the Safety of a Complex Gut Bacterial Consortium (MITI 001) for the Treatment of Irritable Bowel Syndrome With Diarrhea

While the pathophysiology of diarrhea-predominant irritable bowel syndrome (IBS-D) is complex and heterogeneous, dysbiosis of the gut microbiome is frequently observed, suggesting that a substantial subset of patients with irritable bowel syndrome (IBS) have symptoms that are initiated and/or perpetuated by a microbiome dysfunction. Successful randomized controlled trials (RCT) for IBS-D (Ford 2018; Black 2022) leveraging microbiome-targeted therapies (antibiotics or low microbiome fermentation diets) suggest the gut microbiome is at least partially involved in IBS symptoms. Furthermore, fecal microbiota transplantation (FMT) for patients with IBS-D has demonstrated promising results (El-Salhy 2020), supporting the possibility that altering the microbiome composition could ameliorate IBS-D symptoms.

MITI-001 is a transplantable gut bacterial community composed of 157 live bacterial strains, encompassing 79 genera of commensal bacteria, that have been isolated from healthy donor stool, purified, and banked. The hypothesis of the proposed research is that MITI-001 can target the pathophysiologic lesion in a subset of IBS-D patients, restore the altered microbial metabolic process, and thus alleviate IBS-D symptoms.

Inclusion: Age 18 to 65 years inclusive at the time of signing the informed consent; Diagnosis of IBS-D according to the Rome IV criteria (Lacy 2017); At least 1 of the following measures of microbiome dysfunction:; Primary bile acid proportion ≥ 12% in stool samples, or; Positive hydrogen breath test (with either glucose or lactulose substrate) (Rezaie 2017); Normal C-reactive protein level; Gallbladder intact; Willing to use appropriate contraception during the treatment period and for one week after the last study visit; Male participants with partners who are women of childbearing potential (WOCBP): Appropriate contraception includes condoms or other means considered adequate by the responsible Investigator; Female participants who are WOCBP: Appropriate contraception includes condoms, an intrauterine device, hormonal contraception, or other means considered adequate by the responsible Investigator; Capable of giving signed informed consent as described in Appendix 1, which includes compliance with the requirements and restrictions listed in the informed consent form and in this protocol; Able to tolerate the planned course of antibiotics, EGD, and colonoscopy with bowel lavage.

Exclusion: Severe immunodeficiency, inherited or acquired (e.g., human immunodeficiency virus, active chemotherapy or immunosuppressive medications [including steroids, biologic therapy, or bone marrow suppressive agent], or radiation therapy); Active treatment with high levels of immunosuppressive therapies (active chemotherapy or immunosuppressive medications [including steroids, biologic therapies, or bone marrow suppressive agents], or radiation therapy); Active anticoagulant or antiplatelet therapy, or use of other medications associated with a high risk of bleeding within 48 hours prior to endoscopy on Day 1; Use of a probiotic within one month prior to dosing of MITI-001 on Day 1; Inflammatory bowel disease; Untreated enteric infections; History of gastrointestinal (GI) surgery: All participants with GI surgeries below the pylorus will be excluded from this study. This includes participants with a history of colectomy, segmental colonic resection, and small bowel resections; History of recurrent aspiration episodes; Any conditions associated with a high risk of bleeding, including but not limited to coagulopathy/bleeding disorder, severe liver disease, active or recent GI bleeding, or recent abdominal or other GI surgery; Active diagnosis of major depressive disorder; Any other significant medical condition that could confound or interfere with evaluation of safety or tolerability or prevent compliance with the study protocol at the discretion of the Investigator; Renal insufficiency (estimated glomerular filtration rate < 50 mL/min); Active drug or alcohol use disorder; Known allergy or anaphylaxis to vancomycin, metronidazole, ciprofloxacin, or polyethylene glycol; Absolute neutrophil count < 1000 μL, platelet count < 50 × 109/L, or hemoglobin level < 6.5 g/dL; Documented severe gastroparesis; Active intestinal obstruction; Dysphagia (oropharyngeal, esophageal, functional, or neuromuscular); Active antibiotic use (except protocol-specified antibiotics); Simultaneous participation in another interventional clinical trial; Pregnant, breastfeeding, or planning pregnancy during the study period; Inability to comply with research requirements.

ClinicalTrials.gov NCT07238790