Evaluating rifaximin's effect on gut microbiota in SIBO patients

Evaluating the Effect of Rifaximin on the Regional Composition of the Gut Microbiota and Metabolic Profiles of Subjects With SIBO Using the CapScan® Collection Capsule

Phase 1 Interventional Envivo Bio Inc · NCT06298409

This study is testing how the antibiotic rifaximin affects the gut bacteria and metabolism in people with Small Intestinal Bacterial Overgrowth (SIBO) before they start treatment.

Quick facts

PhasePhase 1
Study typeInterventional
Enrollment34 (estimated)
Ages18 Years to 80 Years
SexAll
SponsorEnvivo Bio Inc Industry-sponsored
Locations1 site (Mountain View, California)
Trial IDNCT06298409 on ClinicalTrials.gov

What this trial studies

This study aims to assess how the antibiotic rifaximin influences the gut microbiota and metabolic profiles in patients diagnosed with Small Intestinal Bacterial Overgrowth (SIBO). It employs a microbiome sampling capsule, CapScan, to collect intestinal microbiota samples from participants. The study is designed as a prospective, open-label, single-arm, non-randomized, multi-center approach, focusing on individuals who have been prescribed rifaximin but have not yet started treatment.

Who should consider this trial

Good fit: Ideal candidates are adults aged 18 to 80 who have been diagnosed with SIBO and are about to start treatment with rifaximin.

Not a fit: Patients with a history of gastric or esophageal surgery or bowel obstruction may not benefit from this study.

Why it matters

Potential benefit: If successful, this study could lead to improved understanding and treatment options for patients suffering from SIBO.

How similar studies have performed: While there have been studies on rifaximin for SIBO, this specific approach using the CapScan capsule is relatively novel.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Males or females 18 years of age or older and 80 years of age or younger at the time of the first Screening Visit.
* ASA Classification 1 or 2.
* For women of childbearing potential, negative urine pregnancy test within 7 days of Screening Visit.
* Willingness to use highly effective contraception during the entire study period (e.g.: implants, injectables, oral contraceptives, intra-uterine device or declared abstinence).
* Subject is fluent in English and understands the study protocol and informed consent and is willing and able to comply with study requirements and sign the informed consent form.
* Positive for at least one clinical symptom consistent with SIBO.
* Positive lactulose breath test for SIBO, by Hydrogen (H2) criteria.
* Prescribed, but has not started, a two-week course of Rifaximin for SIBO.

Exclusion Criteria:

* History of any of the following: Prior gastric or esophageal surgery, including lap banding or bariatric surgery, bowel obstruction, gastric outlet obstruction, diverticulitis, inflammatory bowel disease, ileostomy or colostomy, gastric or esophageal cancer, achalasia, esophageal diverticulum, active dysphagia or odynophagia.
* Actively taking a proton-pump-inhibitor medication within 30 days of enrollment
* Pregnancy or planned pregnancy within 30 days from Screening Visit, or breast-feeding
* Any form of active substance abuse or dependence (including drug or alcohol abuse), unstable medical or psychiatric disorder, or any chronic condition susceptible, in the opinion of the investigator, to interfere with the conduct of the study
* A clinical condition that, in the judgment of the investigator, could potentially pose a health risk to the subject while involved in the study

Where this trial is running

Mountain View, California

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Small Intestinal Bacterial Overgrowth
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.