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NCT Number: NCT06794944

Use of Fidaxomicin Compared to Vancomycin for Decolonization of C. Difficile in Patients With Inflammatory Bowel Disease

This is a randomized, double-blind study to assess the safety and efficacy of fidaxomicin compared to vancomycin for decolonization of C. difficile in IBD patients. A total of 60 patients who meet eligibility criteria will be randomized 1:1 to either the fidaxomicin or vancomycin arm. The vancomycin arm will receive a dose of 125 mg PO q 6 hours for 10 days. The fidaxomicin arm will receive 200 mg PO BID for 10 days. In order to ensure blinding, both antibiotics will be concealed in opaque 00 capsule shells. In addition, those in the fidaxomicin arm will receive 2 placebo capsules so that all participants will receive 4 capsules daily for 10 days. Microbiome assessment and C. difficile testing will be performed at baseline, day 5, day 10, and weeks 4, 8, and 26.

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Key information

Conditions

Inflammatory Bowel Disease (IBD) Bacterial Infections Bacterial Infections and Mycoses Clostridioides Difficile Infection Clostridium Infections Colitis Colitis, Ulcerative Colonic Diseases Digestive System Diseases Gastroenteritis Gastrointestinal Diseases Gram-Positive Bacterial Infections Infections Inflammatory Bowel Diseases Intestinal Diseases

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 4

Primary location

Brigham and Women's Hospital

Boston, Massachusetts, 02115, United States

Location contact

Alexander Carlin

CONTACT

[email protected]

6175257322

About this study

This randomized, double-blind trial will assess the ability of fidaxomicin compared to vancomycin to decolonize C. difficile in the IBD patient population.

Participants who meet eligibility criteria will be randomized 1:1 to either vancomycin or fidaxomicin treatment. The vancomycin arm will receive a dose of 125 mg PO q 6 hours for 10 days. The fidaxomicin arm will receive 200 mg PO BID for 10 days. In order to ensure blinding both antibiotics will be concealed in opaque 00 capsule shells. In addition, those in the fidaxomicin arm will receive 2 placebo capsules so that all participants will receive 4 capsules daily for 10 days. Participants will end dosing after 10 days, but monitoring will continue to week 8. Both participants and study team will be blinded to treatment arm allocation.

Participants will be assessed through week 8 for the primary outcome, decolonization. Safety and tolerability outcomes will be assessed through week 8. In addition, secondary efficacy outcomes including IBD disease activity and development of CDI will be evaluated at week 8 and week 26. Participants will also be followed through week 26 for long-term safety, efficacy, and clinical outcomes. Disease activity and symptoms will be recorded from time of informed consent through to the week 26 trial visit. Stool samples for biomarker assessments and C. difficile testing will be collected at scheduled trial visits per Schedule of Assessments.

The primary outcome, decolonization of C. Difficile at week 8, will be confirmed via stool sampling. Additional C. difficile testing will be done at week 26.

Participants that experience intolerable adverse events will be withdrawn from the study and will be considered treatment failures. Additional subjects may be enrolled to obtain 60 patients with week 8 data.

The study will enroll approximately 60 adult participants at a single center.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Signed informed consent.
  • Male or female > 18 years of age.
  • IBD diagnosis (CD, UC or indeterminant Colitis will be permitted.)
  • Presenting for outpatient colonoscopy for any indication.

Exclusion criteria

  • Unable to provide consent.
  • Patients with previous colectomy, ostomy, J-pouch, or previous colon surgery (excluding appendectomy.)
  • Unable to complete study procedures.
  • Chronic use of antibiotics.
  • Inability or unwillingness to swallow capsules.
  • Allergy or sensitivity to vancomycin, fidaxomicin, or microcrystalline cellulose.

Treatment and study plan

Vancomycin (POC)

Drug

Vancomycin is glycopeptide antibiotic that has broad gram-positive coverage. Patients will receive 125mg PO every 6 hours for 10 days.

Fidaxomicin

Drug

Fidaxomicin is a macrolide antibiotic. It is narrow spectrum with potent bactericidal activity specifically against C. difficile. Patients will receive 200mg PO twice daily for 10 days.

Primary outcomes

  1. C. difficile decolonization

    Time frame: 8 weeks

    Absence of C. difficile via PCR in Week 8 stool sample

  2. Safety and tolerability

    Time frame: 8 weeks

    Subject incidence of treatment-emergent adverse events (including treatment-emergent adverse events for clinically significant changes in laboratory parameters and vital signs)

Secondary outcomes

  1. Biomass of C. difficile

    Time frame: 8 weeks

    Change in stool C. difficile biomass in patients at week 8 by quantitative culture and qPCR

  2. Long-term effect of C. difficile decolonization on IBD clinical outcomes

    Time frame: 26 weeks

    Change in IBD clinical scores from baseline at week 8 and week 26. IBD clinical scores are used to assess IBD patient symptoms. The assessments are separated between scores for Ulcerative Colitis (UC) and Crohn's Disease (CD). The Harvey Bradshaw Index (HBI) is a clinical assessment for IBD patients with Crohn's disease while Partial Mayo Score is a clinical assessment for Ulcerative Colitis. The scores will be collected at study visit in form of a survey. The HBI score can vary but a score above 8 or 9 is considered severe disease activity. The Partial Mayo Score can range from 0 to 9 and a score above 7 is considered severe disease activity. A decrease in score from baseline to follow-up timepoints is indicative of improved IBD patient symptoms. A decrease in score from baseline to follow-up timepoints is indicative of improved IBD patient symptoms.

  3. C. difficile infection surveillance

    Time frame: 26 weeks

    Incidence of patients developing CDI through Week 26

Study contacts

Contact information is provided by the study sponsor or research team.

Alexander Carlin

CONTACT

[email protected]

6175257322

Jessica Allegretti, MD, MPH

CONTACT

[email protected]

6177326389

Sponsors and collaborators

Lead sponsor

Brigham and Women's Hospital

Other

Registry information

Important dates

Study start
2026
Primary completion
2030
Study completion
2031
First posted
Jan 27, 2025
Registry last updated
Nov 3, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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