Secondary Prevention of Clostridioides Difficile Using Vancomycin

Secondary Prophylaxis of Recurrent Clostridioides Difficile Infections During Systemic Antibiotics With Vancomycin: A Randomized Controlled Trial

Secondary Prevention of Clostridioides Difficile Using Vancomycin (NCT06979609) is a Phase 2 / Phase 3 interventional studying Clostridioides Difficile Infection and Clostridioides Difficile Infection Recurrence, sponsored by McGill University Health Centre/Research Institute of the McGill University Health Centre. RECRUITING as of the most recent ClinicalTrials.gov update. Talk to your doctor before contacting the trial site.

About This Trial

Re-exposure to systemic antibiotics (i.e., antibiotics absorbed into the bloodstream) is common after a Clostridioides difficile infection (CDI) and is the strongest risk factor for a recurrent episode. Oral vancomycin to prevent a recurrence during antibiotic re-exposure may reduce this risk but the data supporting this practice are limited. The aim of this trial is: 1\) Does oral vancomycin prophylaxis prevent CDI recurrences in patients with recent CDI (within 120 days) and who are re-exposed to systemic antibiotics? The trial will compare oral vancomycin to placebo. Participants will: * Take the study drug (either vancomycin or placebo) twice daily for the duration of systemic antibiotics plus once daily for 7 days after completion of systemic antibiotics. * Attend an in-person follow-up at day 56 * Respond to weekly electronic questionnaires

What Stage of Research Is This?

Phase 2 trials evaluate whether a treatment actually works against Clostridioides Difficile Infection and continue monitoring side effects. Phase 2 enrolls larger groups (typically 100–300 patients) and produces the first real efficacy signal. A successful Phase 2 readout is what unlocks the much larger Phase 3 confirmatory trials needed for FDA approval.

This trial is currently recruiting participants. The sponsor has registered the study with ClinicalTrials.gov as actively enrolling, which means new applicants who meet the eligibility criteria can be considered for screening. Trial status can change between updates — confirm current recruiting status with the study contact before traveling for a screening visit.

A target enrollment of 300 participants makes this a sizable late-stage trial. Studies in this range typically have enough power to detect clinically meaningful differences from a comparator and to characterize less-common side effects.

Who May Be Eligible (Plain English)

Who May Qualify: - Inpatient or outpatient adults (≥18 years old) treated at the participating institutions. - An episode of CDI within the preceding 120 days (rationale in 2.4), diagnosed by both a positive C. difficile assay (including PCR toxin gene detection47, toxin enzyme immunoassay, and/or cell cytotoxicity neutralization assay29) and the presence of either ≥3 unformed stools in \<24 hours with a duration \>24 hours, endoscopic/histologic evidence of pseudomembranous colitis, or ileus29. - Treatment of the qualifying CDI episode with vancomycin or fidaxomicin for ≥10 days, clinical cure (≤3 unformed stool per 24 hours in ≥2 days10) by the conclusion of therapy, and ≥1 day has elapsed since cessation of CDI treatment. - Receipt of ≤3 days of at least one oral or intravenous systemic antibiotic for the treatment of an intercurrent confirmed or suspected bacterial infection, for which therapy is planned for at least one additional consecutive day in duration. Who Should NOT Join This Trial: - Treatment of the qualifying episode of CDI with metronidazole monotherapy or intravenous immunoglobulins. - Planned treatment with or treatment of the qualifying episode of CDI with fecal microbiota transplantation (FMT), bezlotoxumab, VOWST, or REBYOTA. - Inability to take medications orally or crushed by nasogastric tube. - Prior total colectomy. - Severe intolerance or allergy to oral vancomycin. - Lack of achievement of clinical cure during the treatment of the qualifying CDI episode - Ongoing or \<1 day since receiving CDI treatment or ongoing or \<1 days since receipt of CDI-active antibiotics, including oral vancomycin, oral or intravenous metronidazole, or fidaxomicin. - The qualifying antibiotic is solely for prophylaxis (e.g., once daily trimethoprim sulfamethoxazole) or the patient is anticipated to require systemic antibiotics for \>4 weeks (e.g., lifelong suppressive therapy or for the treatment of left-sided endocarditis or a deep-seated abscess). ...See full criteria on ClinicalTrials.gov Always talk to your doctor about whether this trial is right for you.

These are translations of the protocol\'s inclusion and exclusion criteria, simplified for patients and caregivers. The original clinical text appears below. Eligibility is ultimately confirmed by the trial site\'s screening process — this summary is a starting point for a conversation with your doctor, not a final determination.

Original Eligibility Criteria

View original clinical language

Inclusion Criteria: * Inpatient or outpatient adults (≥18 years old) treated at the participating institutions. * An episode of CDI within the preceding 120 days (rationale in 2.4), diagnosed by both a positive C. difficile assay (including PCR toxin gene detection47, toxin enzyme immunoassay, and/or cell cytotoxicity neutralization assay29) and the presence of either ≥3 unformed stools in \<24 hours with a duration \>24 hours, endoscopic/histologic evidence of pseudomembranous colitis, or ileus29. * Treatment of the qualifying CDI episode with vancomycin or fidaxomicin for ≥10 days, clinical cure (≤3 unformed stool per 24 hours in ≥2 days10) by the conclusion of therapy, and ≥1 day has elapsed since cessation of CDI treatment. * Receipt of ≤3 days of at least one oral or intravenous systemic antibiotic for the treatment of an intercurrent confirmed or suspected bacterial infection, for which therapy is planned for at least one additional consecutive day in duration. Exclusion Criteria: * Treatment of the qualifying episode of CDI with metronidazole monotherapy or intravenous immunoglobulins. * Planned treatment with or treatment of the qualifying episode of CDI with fecal microbiota transplantation (FMT), bezlotoxumab, VOWST, or REBYOTA. * Inability to take medications orally or crushed by nasogastric tube. * Prior total colectomy. * Severe intolerance or allergy to oral vancomycin. * Lack of achievement of clinical cure during the treatment of the qualifying CDI episode * Ongoing or \<1 day since receiving CDI treatment or ongoing or \<1 days since receipt of CDI-active antibiotics, including oral vancomycin, oral or intravenous metronidazole, or fidaxomicin. * The qualifying antibiotic is solely for prophylaxis (e.g., once daily trimethoprim sulfamethoxazole) or the patient is anticipated to require systemic antibiotics for \>4 weeks (e.g., lifelong suppressive therapy or for the treatment of left-sided endocarditis or a deep-seated abscess). * Patients on ongoing systemic antibiotics since the completion of treatment for the qualifying episode of CDI that have not been interrupted by at least one day. * Patients admitted to a palliative care ward or is anticipated to die within 3 months of enrollment from another illness. * The qualifying antibiotic is non-systemic or is not considered a significant risk factor for CDI including: topical antibiotics, azithromycin, clarithromycin, nitrofurantoin, intravenous vancomycin, minocycline, tetracycline, doxycycline, and oral fosfomycin. * Prior enrollment in this trial. * Inability to consent without a healthcare proxy. * Lack of health insurance. * Anticipated transfer to a site not involved in this trial or to a palliative care ward. * Patient declared anticipated inability to participate in study follow-up or lack of means for contact in the outpatient setting.

Treatments Being Tested

DRUG

Oral Vancomycin Prophylaxis

125mg PO BID for the duration of antibiotic re-exposure + 125mg PO QD for 7 days

DRUG

Placebo

2 capsules PO BID for the duration of antibiotic re-exposure + 1 capsule PO QD x 7 days

Locations (1)

Trial sites listed on ClinicalTrials.gov for this study. Site activation status can vary — confirm with the specific site before traveling for a screening visit.

McGill University Health Centre

Montreal, Quebec, Canada

How to Talk to Your Doctor About This Trial

Bring the printable summary of this trial — including the NCT ID (NCT06979609), the sponsor (McGill University Health Centre/Research Institute of the McGill University Health Centre), and the key eligibility criteria — to your next appointment. Your doctor can review the inclusion and exclusion criteria against your medical history, lab values, and current treatments to assess whether you are likely to qualify. They can also help you weigh whether trial participation makes sense alongside your existing care plan.

Useful questions to walk through together: What does the trial protocol require beyond standard care? How long is the active treatment phase, and how long is follow-up? Are there study visits at sites I can reach? Who pays for the trial-specific procedures, and who pays for standard-of-care portions? See our 25 questions to ask about clinical trials guide for a more complete checklist.

Authoritative Sources

The official record for this trial lives on ClinicalTrials.gov — the federal registry maintained by the National Library of Medicine at NIH. For background on how this trial fits into the FDA approval pathway, see the FDA drug approval process. For oncology-specific guidance for patients considering trials, the National Cancer Institute publishes patient-oriented overviews. International trial registries are aggregated by the WHO ICTRP.

Frequently Asked Questions

What is the NCT06979609 clinical trial studying?

Re-exposure to systemic antibiotics (i.e., antibiotics absorbed into the bloodstream) is common after a Clostridioides difficile infection (CDI) and is the strongest risk factor for a recurrent episode. Oral vancomycin to prevent a recurrence during antibiotic re-exposure may reduce this risk but the data supporting this practice are limited. The aim of this trial is: 1\) Does oral vancomycin prophylaxis prevent CDI recurrences in patients with recent CDI (within 120 days) and who are re-exposed to systemic antibiotics? The trial will compare oral vancomycin to placebo. Participants will: … The full protocol is registered on ClinicalTrials.gov and includes the primary outcome measures, eligibility criteria, and study endpoints.

Who can participate in NCT06979609?

Eligibility for this trial depends on the specific inclusion and exclusion criteria set by the sponsor. The plain-English summary above translates the most important criteria into accessible language; the official clinical text is preserved in the collapsible section underneath. Whether you fit any specific trial is a medical decision your doctor needs to confirm — bring the trial information to your treating physician for a full review against your medical history.

How do I contact the trial site for NCT06979609?

Contact information registered with ClinicalTrials.gov is shown in the sidebar of this page. Before reaching out, confirm with your treating physician that this trial is appropriate for your situation. The trial site will then walk you through the screening process to determine final eligibility.

Is participating in a clinical trial safe?

Clinical trials in the United States are regulated by the FDA and overseen by Institutional Review Boards (IRBs) that review the protocol for safety. Risk varies by trial — Phase 1 studies test new treatments in humans for the first time, while Phase 3 trials use treatments that have already passed earlier safety screening. The informed consent document for any specific trial details the known risks and what to expect. Discuss those risks with your physician before deciding whether to participate.

Where can I verify the data on this page?

Every detail on this page comes directly from the ClinicalTrials.gov API. Click "View on ClinicalTrials.gov" in the sidebar to see the official, unmodified record. The federal record is always authoritative; this page is a structured presentation with a plain-English eligibility translation. For background on how clinical trials are regulated, see the FDA drug approval process documentation.

How This Page Is Built

Every field on this page is pulled directly from the ClinicalTrials.gov API v2 — no estimates, no proxies. The plain-English eligibility translation is generated from the original protocol text and reviewed for fidelity to the underlying clinical criteria. The original clinical text remains visible in the collapsible section above so users and clinicians can verify the translation. Read the full methodology for the data pipeline and known limitations.

Source: ClinicalTrials.gov API v2 record for NCT06979609. Maintained by the National Library of Medicine at NIH. Public domain. Cite as: "TrialFinderData. NCT06979609. Data: ClinicalTrials.gov."

Medical disclaimer: This page is informational, not medical advice. Talk to your doctor about whether a clinical trial is right for you.

Last updated 2026-05-08 · Data from ClinicalTrials.gov.