A Phase 2 interventional study of Vancomycin and Placebo in Recurrent Clostridium Difficile Infection, Clostridium Difficile Infection and CDI, sponsored by University of Wisconsin, Madison. Completed at 2 sites in United States. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2025-05-25.
Sponsored by University of Wisconsin, Madison · Phase 2, Interventional, and Prevention
This study evaluates the efficacy of prophylaxis with oral vancomycin for preventing recurrent Clostridium difficile Infection (CDI) in patients who have experienced at least one CDI episode in the last 180 days and are receiving antibiotics for a non CDI condition. Participants will be randomized to receive either placebo or oral vancomycin in addition to their prescribed antibiotic therapy.
Many patients who have a CDI experience recurrent or relapsing symptoms. The investigators are studying whether vancomycin in low doses will help prevent further CDI episodes and how this therapy impacts patients' gastrointestinal microbiome and composition.
Patients with a history of past CDI who are receiving antibiotics for a non-CDI condition will be invited to participate. Approximately half of the participants will receive a low-dose capsule of vancomycin and half will receive a placebo. Participants will continue taking the vancomycin/placebo for 5 days after their prescribed antibiotics end.
251 studies on the registry are indexed under Clostridium Infections; 51 are open to participants now.
This study's enrollment of 79 is above the median of 64 across 185 interventional studies indexed under Clostridium Infections.
Browse Clostridium Infections studies →University of Wisconsin, Madison is the lead sponsor of 1,188 studies on the registry; 181 are open to participants now.
Of its 157 completed or terminated interventional studies of FDA-regulated products, 118 (75%) have results posted.
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Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
The study doctor’s estimate of how long someone is likely to live. Criteria use it so that people can stay in the study long enough for it to answer its question.
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Childbearing potential
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hypersensitivity
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Life expectancy
The study doctor’s estimate of how long someone is likely to live. Criteria use it so that people can stay in the study long enough for it to answer its question.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Investigational drug or device
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
125 mg, oral capsule by mouth, once daily, for the duration of standard-of-care antibiotic therapy plus 5 days
Drug: Vancomycin
125 mg placebo capsule by mouth, once daily, for the duration of standard-of-care antibiotic therapy plus 5 days
Drug: Placebo
Vancomycin capsule, 125 mg
Also known as: Vancomycin Hydrochloride, Vancocin
Capsule containing inert (nonactive) material to mimic 125 mg vancomycin capsule
Recurrent Clostridium Difficile Infection (CDI)
Determine whether CDI recurrence is decreased in patients taking oral vancomycin as prophylactic therapy in addition to standard-of-care antibiotics that patients are taking for non-CDI reasons.
Time frame: 8 weeks
Gut Microbiome Composition
Study how the gut microbiome is altered in patients receiving vancomycin treatment compared to placebo.
Time frame: 8 weeks
Vancomycin-resistant Enterococcus (VRE) Colonization in Stool Samples of Patients Receiving Vancomycin vs. Patients Receiving Placebo
Low-dose exposure to vancomycin and VRE infection has not been studied. We will examine the incidence of VRE colonization in stool samples of all patients and determine whether oral vancomycin increases the VRE colonization rate, which has a negative impact on the overall health of patients being treated with vancomycin for C. difficile infection.
Time frame: 8 weeks
Determine Whether Clostridium Difficile Positivity on Any Stool Sample is a Predictor of CDI Recurrence.
Stool samples will be tested at baseline, at the last dose date of vancomycin or placebo, at approximately 8 weeks following the last dose of vancomycin or placebo, and as indicated for diarrhea symptoms. Samples will be collected and tested for the presence of Clostridium difficile.
Time frame: 8 weeks
| Milestone | Vancomycin | Placebo |
|---|---|---|
| Started | 37 | 42 |
| Completed | 30 | 29 |
| Not completed | 7 | 13 |
| Withdrew: Death | 1 | 0 |
| Withdrew: Lack of efficacy | 2 | 4 |
| Withdrew: Lost to follow-up | 1 | 3 |
| Withdrew: Unable to complete doses of study drug/placebo | 0 | 3 |
| Withdrew: Withdrawal by subject | 3 | 2 |
| Withdrew: Unable to obtain stool samples at visit | 0 | 1 |
Determine whether CDI recurrence is decreased in patients taking oral vancomycin as prophylactic therapy in addition to standard-of-care antibiotics that patients are taking for non-CDI reasons.
| Participants | Vancomycin | Placebo |
|---|---|---|
| Recurrent Clostridium Difficile Infection (CDI) | 17 | 24 |
Study how the gut microbiome is altered in patients receiving vancomycin treatment compared to placebo.
| stool samples | Vancomycin | Placebo |
|---|---|---|
| Gut Microbiome Composition | NA | NA |
Low-dose exposure to vancomycin and VRE infection has not been studied. We will examine the incidence of VRE colonization in stool samples of all patients and determine whether oral vancomycin increases the VRE colonization rate, which has a negative impact on the overall health of patients being treated with vancomycin for C. difficile infection.
| Participants | Vancomycin | Placebo |
|---|---|---|
| Vancomycin-resistant Enterococcus (VRE) Colonization in Stool Samples of Patients Receiving Vancomycin vs. Patients Receiving Placebo | 15 | 6 |
Stool samples will be tested at baseline, at the last dose date of vancomycin or placebo, at approximately 8 weeks following the last dose of vancomycin or placebo, and as indicated for diarrhea symptoms. Samples will be collected and tested for the presence of Clostridium difficile.
| stool samples | Vancomycin | Placebo |
|---|---|---|
| Determine Whether Clostridium Difficile Positivity on Any Stool Sample is a Predictor of CDI Recurrence. | NA | NA |
Collected over 8 weeks. Non-serious events are listed at a 5% frequency threshold.
| Group | Deaths | Serious | Other |
|---|---|---|---|
| Vancomycin | 1/37 (2.7%) | 9/37 (24.3%) | 37/37 (100%) |
| Placebo | 2/42 (4.8%) | 10/42 (23.8%) | 42/42 (100%) |
| Event | Vancomycin | Placebo |
|---|---|---|
| Bacteremia/SepsisInfections and infestations | 0/37 | 2/42 |
| Elevated liver function tests due to transplantGastrointestinal disorders | 1/37 | 0/42 |
| Recurrent C difficile Infection (rCDI)Gastrointestinal disorders | 1/37 | 1/42 |
| DiarrheaGastrointestinal disorders | 1/37 | 0/42 |
| Sickle Cell Pain CrisisBlood and lymphatic system disorders | 1/37 | 0/42 |
| VomitingGastrointestinal disorders | 1/37 | 1/42 |
| CellulitisInfections and infestations | 1/37 | 1/42 |
| Congestive Heart Failure ExacerbationCardiac disorders | 1/37 | 0/42 |
| Whipple ProcedureSurgical and medical procedures | 1/37 | 0/42 |
| Toe InfectionInfections and infestations | 1/37 | 0/42 |
| Event | Vancomycin | Placebo |
|---|---|---|
| Abdominal Pain/DiscomfortGastrointestinal disorders | 9/37 | 9/42 |
| Nausea/VomitingGastrointestinal disorders | 9/37 | 5/42 |
| Gastrointestinal disordersGastrointestinal disorders | 6/37 | 10/42 |
| ConstipationGastrointestinal disorders | 4/37 | 8/42 |
| Bloating/flatulenceGastrointestinal disorders | 4/37 | 7/42 |
| InfectionsInfections and infestations | 4/37 | 3/42 |
| Joint pain and swellingMusculoskeletal and connective tissue disorders | 4/37 | 1/42 |
| Bloody stool/loose stoolGastrointestinal disorders | 4/37 | 1/42 |
| Fever/Flu-Like SymptomsGeneral disorders | 3/37 | 2/42 |
| UTIInfections and infestations | 3/37 | 1/42 |
Adults age 18 or older with a diagnosis of recurrent Clostridioides diffcile infection
| Age, Continuous(years) | Vancomycin | Placebo | Total |
|---|---|---|---|
| Mean | 58.89 ± 15 | 58.40 ± 13 | 58.65 ± 14 |
| Sex: Female, Male(Participants) | Vancomycin | Placebo | Total |
|---|---|---|---|
| Female | 24 | 25 | 49 |
| Male | 13 | 17 | 30 |
| Ethnicity (NIH/OMB)(Participants) | Vancomycin | Placebo | Total |
|---|---|---|---|
| Hispanic or Latino | 1 | 1 | 2 |
| Not Hispanic or Latino | 36 | 40 | 76 |
| Unknown or Not Reported | 0 | 1 | 1 |
| Race (NIH/OMB)(Participants) | Vancomycin | Placebo | Total |
|---|---|---|---|
| American Indian or Alaska Native | 0 | 1 | 1 |
| Asian | 0 | 0 | 0 |
| Native Hawaiian or Other Pacific Islander | 0 | 0 | 0 |
| Black or African American | 3 | 6 | 9 |
| White | 33 | 34 | 67 |
| More than one race | 0 | 0 | 0 |
| Unknown or Not Reported | 1 | 1 | 2 |
| Region of Enrollment(Participants) | Vancomycin | Placebo | Total |
|---|---|---|---|
| United States | 37 | 42 | 79 |
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This study is completed, as verified in May 2025. You cannot join it, but the record below documents what was studied.
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Studies of the drug tested here: Vancomycin
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