Clostridioides Difficile InfectionSTOP-CDINCT07120490
STOP-CDI: Efficacy of Fecal Microbiota Transplantation vs Fidaxomicin vs Vancomycin in Treating and Preventing Relapse of Clostridioides Difficile Infection
A study testing FMT (fecal microbiota transplantation), Fidaxomicin and Vancomycin (VAN) treatment in people with Clostridioides Difficile Infection and Clostridioides Difficile Infection Recurrence, run by Medical University of Warsaw.
Trial summary
The STOP-CDI study is a multicenter, randomized, open-label, three-arm clinical trial comparing the efficacy of fecal microbiota transplantation (FMT) preceded by vancomycin, fidaxomicin monotherapy, and standard-of-care vancomycin in preventing recurrence of Clostridioides difficile infection (CDI) in high-risk adult… Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Clostridioides Difficile Infection, Clostridioides Difficile Infection Recurrence, Fecal Microbiota Transplantation (FMT)
- What is being tested?
- FMT (fecal microbiota transplantation), Fidaxomicin and Vancomycin (VAN) treatment
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 424 participants
- Where
- No sites listed yet
- Study dates
- Oct 2025to 30 Apr 2027
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Individuals aged 65 years or older OR individuals aged 18 to 64 years who meet at least one of the following criteria:
- Presence of at least two comorbid chronic diseases from the groups of cardiovascular diseases, respiratory system diseases, gastrointestinal diseases, autoimmune diseases, cancers, chronic kidney and genitourinary diseases, immunodeficiencies, diabetes, and metabolic diseases,
- Previous episodes of CDI,
- Healthcare-associated CDI and/or hospitalization within the last three months,
- Concurrent use of antibiotics other than CDI treatment after CDI diagnosis,
- Use of proton pump inhibitors (PPIs) started during or after CDI diagnosis.
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- Documented Clostridioides difficile infection, defined according to ESCMID as:
- Diagnosis of diarrhea associated with C. difficile defined by:
- > 3 unformed stools (or >200 ml of unformed stool in patients with stool collection devices) within 24 hours before randomization AND
- Clinical signs consistent with CDI and microbiological evidence of free C. difficile toxins in an enzyme immunoassay (EIA) without justified evidence of another cause of diarrhea OR
- Clinical picture consistent with CDI and positive nucleic acid amplification test (NAAT; PCR) preferably with low cycle threshold (Ct) value, or positive toxigenic C. difficile culture OR
- Pseudomembranous colitis diagnosed during endoscopy or colectomy combined with a positive test for toxigenic C. difficile.
- No more than 24 hours of prior treatment with vancomycin, metronidazole, or fidaxomicin.
- Absolute neutrophil count in peripheral blood within 3 days before intervention > 500/µl.
- Ability to swallow large capsules (using test capsules) or no contraindications for FMT via nasojejunal tube, gastroscopy, colonoscopy, or rectal enema.
- Provided informed consent for participation in the clinical study.
Who cannot join
- Lack of consent to participate in the study or absence of logical contact without possibility of obtaining consent from an authorized person,
- More than 24 hours of prior treatment with vancomycin, metronidazole, or fidaxomicin,
- On the day of inclusion (up to 3 days before starting intervention) absolute neutrophil count in blood <500 cells/µl or expected drop to this level within the next 2 days,
- Diagnosed HIV infection with CD4 lymphocyte count <250 cells/µl,
- Inability to swallow large capsules (failed test capsule use) or contraindications for FMT via upper or lower gastrointestinal tract, including gastrointestinal perforation, anal atresia, discontinuity of the gastrointestinal tract, and others,
- Known presence of other pathogens in stool known to cause diarrhea,
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- Life expectancy <3 months,
- Life-threatening CDI (fulminant at diagnosis - especially with septic shock),
- Total or subtotal colectomy, ileostomy, or colostomy,
- Unwillingness or inability to comply with protocol requirements, including any condition (physical, mental, or social) that may affect the participant's ability to adhere to the protocol.
Trial locations and contacts
No sites are listed yet. Contact the study team or a site near you to ask about taking part.
Jaroslaw Bilinski, MD PhD, Assoc. Prof. contact
About this study
Official title: Multicenter, Randomized, Open-label, Three-arm Study on the Efficacy of Fecal Microbiota Transplantation vs Fidaxomicin vs Vancomycin in the Treatment and Relapse Prophylaxis of Clostridioides Difficile Infection. STOP-CDI Study
The STOP-CDI study is a multicenter, randomized, open-label, three-arm clinical trial comparing the efficacy of fecal microbiota transplantation (FMT) preceded by vancomycin, fidaxomicin monotherapy, and standard-of-care vancomycin in preventing recurrence of Clostridioides difficile infection (CDI) in high-risk adult patients.
CDI is a common healthcare-associated infection with rising incidence and high recurrence rates, particularly in elderly and immunocompromised individuals. While current guidelines recommend fidaxomicin as first-line therapy, its availability and reimbursement remain limited in some healthcare systems. FMT, although effective, is not widely implemented as first-line treatment. This study addresses the need for comparative, real-world data to inform treatment decisions for patients at high risk of severe or recurrent CDI.
Read more
Eligible participants include adults aged ≥65 years or younger patients with specific risk factors such as multiple comorbidities, prior CDI episodes, recent hospitalization, use of non-CDI antibiotics, or PPI therapy. Participants will be randomized in a 2:1:1 ratio to one of three treatment arms: (1) vancomycin plus FMT, (2) fidaxomicin, or (3) vancomycin alone. FMT is administered via capsules or, if necessary, alternative endoscopic routes.
The primary endpoint is CDI recurrence within 12 weeks following the initial treatment. Secondary endpoints include clinical cure, safety, and global cure. Exploratory analyses will assess microbiome changes and potential genomic predictors of response. A total of 424 participants will be enrolled across 10 clinical sites in Poland.
The study aims to provide robust, comparative evidence to support clinical guidelines and improve outcomes for patients with CDI, particularly in healthcare systems with limited access to novel therapies.
Read the detailed description
Clostridioides difficile infection (CDI) represents a persistent and growing challenge in modern healthcare, particularly among elderly, hospitalized, and immunocompromised patients. Despite the existence of evidence-based therapeutic guidelines, recurrence rates remain unacceptably high, often leading to cycles of reinfection and retreatment. These recurrent episodes are associated with increased morbidity, reduced quality of life, higher healthcare costs, and, in some cases, life-threatening complications.
While therapies such as fidaxomicin and fecal microbiota transplantation (FMT) have demonstrated superior efficacy in reducing recurrence compared to traditional vancomycin, access to these interventions remains inconsistent. Fidaxomicin is often restricted due to its high cost and limited reimbursement, while FMT-though highly effective-is not yet widely integrated into early-line treatment pathways, largely due to regulatory and logistical barriers, including donor screening, manufacturing infrastructure, and clinician training.
The STOP-CDI study is a multicenter, randomized, open-label, three-arm research experiment designed to directly compare the effectiveness of three therapeutic strategies in preventing recurrent CDI (rCDI) in a real-world, high-risk adult population. The project addresses key gaps identified by international societies such as ESCMID, which emphasize the need for high-quality, head-to-head comparative research in CDI management.
The primary objective is to determine which of the following approaches most effectively prevents CDI recurrence within 12 weeks after treatment completion:
- Short-course oral vancomycin followed by FMT
- Fidaxomicin monotherapy
- Standard-of-care oral vancomycin
Participants will be randomized in a 2:1:1 allocation ratio, favoring the vancomycin plus FMT group to enable robust analysis of this relatively underutilized intervention. FMT is administered either as oral capsules containing freeze-dried donor microbiota or, when oral intake is not possible, through endoscopic routes such as colonoscopy or nasoenteric tubes. All FMT materials are sourced from rigorously screened donors under standardized laboratory protocols.
The study population includes 424 adult participants across 10 clinical sites in Poland, with recruitment targeting:
Adults aged 65 years or older, or
Younger adults with clearly defined risk factors for severe or recurrent CDI, such as:
- Multiple comorbidities (e.g., diabetes, malignancy, chronic kidney disease),
- Prior CDI episodes,
- Recent hospitalization,
- Use of non-CDI antibiotics,
- Ongoing proton pump inhibitor (PPI) therapy,
- Immunosuppressive treatment.
The primary endpoint of the experiment is CDI recurrence within 12 weeks following treatment, defined by return of symptoms (e.g., diarrhea) and laboratory confirmation of C. difficile toxin. Secondary endpoints include:
- Initial clinical cure (symptom resolution at the end of therapy),
- Global cure (clinical cure without recurrence),
- Time to recurrence,
- Safety and adverse event reporting,
- Patient-reported outcomes, including quality-of-life metrics,
- Healthcare resource utilization and cost-related measures.
In addition to clinical outcomes, the study includes a comprehensive biosample collection strategy for mechanistic and exploratory analyses. Longitudinal sampling of stool, blood, urine, and saliva will allow for in-depth evaluation of:
- Microbiome composition and dynamics,
- Inflammatory and immunological markers,
- Metabolomic profiling,
- Host genetic and genomic predictors of response or recurrence.
These exploratory analyses are intended to improve understanding of host-microbiota interactions in CDI and identify potential biomarkers for personalized treatment approaches.
The sample size of 424 has been statistically powered to detect an absolute difference of at least 15 percentage points in recurrence rates between the FMT group and standard vancomycin, with 80% power and a two-sided significance level of 0.05. This allows for subgroup analyses stratified by age, comorbidities, severity of CDI, and baseline risk factors.
Although the study is open-label, outcome assessment procedures include blinded adjudication by an independent clinical review board to minimize bias. In addition, centralized data monitoring and periodic safety reviews will be conducted to ensure compliance with ethical standards and protocol fidelity.
The STOP-CDI experiment is designed not only to assess comparative efficacy but also to explore real-world feasibility, implementation barriers, and economic considerations associated with newer CDI treatments. It aims to provide decision-makers and clinicians with relevant, actionable evidence that reflects the constraints and opportunities present in everyday clinical practice-particularly in healthcare systems with limited access to novel therapies like fidaxomicin or bezlotoxumab.
Ultimately, the results of this research are expected to guide more personalized, effective, and practical strategies for managing CDI, reducing the burden of recurrence, and improving patient outcomes in diverse clinical and economic contexts.
- Conditions
- Clostridioides Difficile Infection, Clostridioides Difficile Infection Recurrence, Fecal Microbiota Transplantation (FMT), Comparative Effectiveness of CDI Treatments, Fidaxomicin, Vancomycin
- Being tested
- FMT (fecal microbiota transplantation), Fidaxomicin, Vancomycin (VAN) treatment
- Keywords
- Clostridioides difficile, CDI, Fecal microbiota transplantation, Fidaxomicin, Vancomycin, Recurrent infection
- Medical subject headings
- Clostridium Infections, Reinfection
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
FMT (fecal microbiota transplantation)Other
Also called Vancomycin short-course pretreatment
This intervention consists of a two-phase treatment for Clostridioides difficile infection in high-risk adults. First, participants receive a short-course (5 days) of oral vancomycin to reduce C. difficile bacterial load. Following antibiotic pretreatment, fecal microbiota transplantation (FMT) is administered to restore healthy gut microbiota. FMT is delivered primarily via encapsulated microbiota capsules, with alternative routes including colonoscopy, gastroscopy, nasojejunal tube, or rectal enema if capsules are contraindicated. A second FMT dose is given 7 days after the first, either as daily capsules over six days or as a single endoscopic administration. This approach aims to reduce CDI recurrence by combining targeted antibiotic reduction of pathogens with microbiome restoration.
FidaxomicinDrug
Participants receive a 10-day course of fidaxomicin administered orally at a dose of 200 mg twice daily. Fidaxomicin is a narrow-spectrum macrocyclic antibiotic specifically targeting Clostridioides difficile with minimal impact on the normal gut microbiota. This monotherapy aims to eradicate C. difficile infection while preserving the intestinal microbiome, thereby reducing the risk of recurrence. No additional interventions are provided during the treatment period. Biological samples are collected before and after treatment to evaluate clinical response, safety, and microbiome changes.
Vancomycin (VAN) treatmentDrug
Participants receive a 10-day course of oral vancomycin at a dose of 125 mg four times daily. Vancomycin is a broad-spectrum glycopeptide antibiotic commonly used as standard-of-care therapy for Clostridioides difficile infection. This monotherapy aims to eradicate C. difficile by reducing bacterial load in the colon. No additional interventions are applied during the treatment period. Biological samples are collected before and after treatment to monitor clinical outcomes, safety, and changes in the gut microbiome.
| Study group | Role | What they receive |
|---|---|---|
| FECAL MICROBIOTA TRANSPLANTATION (with vancomycin short pretreatment phase) | Experimental | Participants receive oral vancomycin (125 mg QID) for 5 days (extendable to 10 if needed), followed by FMT. On Day 6, bowel cleansing is performed (macrogol-based), and biological samples (stool, blood, urine, saliva) are collected. On Day 7, FMT is administered via preferred oral capsules or, if necessary, colonoscopy, gastroscopy, NJ tube, or rectal enema. A second FMT is given either as daily capsules on Days 9-14 or as a single dose via other routes on Day 14. Dosing: 6 jars of capsules or 200 mL suspension (≥35 kg); half for <35 kg. Supportive measures include antiemetics and fasting. Oral non-antibiotic medications continue. Post-FMT samples are collected for follow-up analyses. Receives: Other: FMT (fecal microbiota transplantation) |
| ANTIBIOTICS ONLY - FIDAXOMICIN | Experimental | Participants receive fidaxomicin 200 mg twice daily for 10 days. Biological samples (stool, blood, urine, saliva) are collected at baseline (before first antibiotic dose) for microbiome and safety analyses (PRE ATB). No additional interventions are applied. The antibiotic eradication phase ends on Day 10, after which the participant enters the follow-up phase. Post-treatment biological samples are collected (POST ATB) to assess treatment response, recurrence risk, and microbiota changes. Receives: Drug: Fidaxomicin |
| ANTIBIOTICS ONLY - VANCOMYCIN | Experimental | Participants receive vancomycin 125 mg four times daily for 10 days. Biological samples (stool, blood, urine, saliva) are collected prior to the first dose (PRE ATB) for safety and exploratory analyses. No additional therapies are administered. The eradication procedure is completed on Day 10, followed by a post-treatment sampling phase (POST ATB) for assessment of recurrence, clinical response, and microbiome status. Receives: Drug: Vancomycin (VAN) treatment |
What is being measured
The primary outcome is the main question the study is designed to answer.
Recurrence rate of Clostridioides difficile infection (CDI) within 12 weeks after treatment
Proportion of patients experiencing a new episode of CDI, defined as recurrent diarrhea with confirmed C. difficile infection, within 12 weeks (90 days) after initial clinical cure following intervention.
Measured: 12 weeks (90 days) after treatment completion
Secondary outcomes (7)
Initial Clinical Cure Rate
Proportion of patients achieving initial clinical cure, defined as resolution of diarrhea for at least 2 consecutive days during or after completion of standard antibiotic therapy.
Measured: Up to 10 days from treatment initiation
Sustained clinical cure rate at 8 weeks post-treatment
Percentage of patients with no recurrence of CDI symptoms and sustained clinical cure (no diarrhea) within 8 weeks (60 days) after completing therapy, confirmed by patient diary and clinical evaluation.
Measured: 8 weeks (60 days) after treatment completion
Recurrent CDI Rate at 8 Weeks
Proportion of patients experiencing a recurrence of Clostridioides difficile infection (CDI), defined as a new episode of diarrhea caused by C. difficile within 8 weeks (60 days) after initial clinical cure, confirmed by patient diary and clinical evaluation.
Measured: 8 weeks (60 days) after completion of therapy
Sustained Clinical Cure Rate (Complete Cure)
Proportion of patients with initial clinical cure and no recurrence of CDI symptoms for 8 weeks (60 days) after completing therapy.
Measured: 8 weeks (60 days) after treatment completion
Sustained Clinical Cure Rate (Durable Cure)
Proportion of patients with initial clinical cure and no recurrence of CDI for 12 weeks (90 days) after completing therapy.
Measured: 12 weeks (90 days) after treatment completion
Rate of Treatment-Resistant CDI
Proportion of patients with refractory CDI, defined as persistent diarrhea despite standard antibiotic therapy (vancomycin or fidaxomicin).
Measured: Up to 10 days from treatment initia
Incidence of Adverse Events
Proportion of patients experiencing adverse events during the course of treatment and follow-up period. Safety will be assessed based on clinical examination and laboratory findings.
Measured: Up to 90 days after treatment
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted13 Aug 2025
- Study startOct 2025 (estimated)
- Primary completion31 Mar 2027 (estimated)
- Study completion30 Apr 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Clostridioides Difficile InfectionStudies of the same condition, open and under way.
- More trials run by Medical University of WarsawThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- This is a multicenter, randomized, open-label, three-arm study using a parallel assignment model. Eligible participants are randomly allocated in a 2:1:1 ratio to one of three intervention groups: (1) short-course oral vancomycin followed by fecal microbiota transplantation (FMT), (2) fidaxomicin monotherapy, or (3) standard-of-care vancomycin. Each participant remains in their assigned group for the duration of the study and receives only the intervention corresponding to that group. No crossover between arms is planned. The parallel design allows for direct comparison of recurrence rates and treatment outcomes across independent, concurrently treated cohorts. Randomization is stratified by site, and outcome assessors may be blinded for certain exploratory analyses.
- Masking
- None (open label)
- Enrolment
- 424 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Medical University of Warsaw
- Sponsor type
- University, hospital or other
- Collaborators
- Human Biome S.A.
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07120490
- Sponsor's protocol ID
- STOP-CDI
- Other IDs
- 2022/ABM/03/00047
- Acronym
- STOP-CDI
- Status last verified
- Mar 2025
- First submitted
- 30 Jul 2025
- Last updated
- 13 Aug 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: Yes, individual participant data (IPD) will be shared with other researchers. Data sharing will be conducted only after the signing of a confidentiality agreement (non-disclosure agreement) to ensure the privacy and protection of participant information. Access to the data will be granted upon reasonable request and subject to approval by the study sponsor and ethics committee.
Study at a glance
From the registry record, last updated by the sponsor on 13 Aug 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Multicenter, Randomized, Open-label, Three-arm Study on the Efficacy of Fecal Microbiota Transplantation vs Fidaxomicin vs Vancomycin in the Treatment and Relapse Prophylaxis of Clostridioides Difficile Infection. STOP-CDI Study
- ClinicalTrials.gov ID
- NCT07120490
- Acronym / sponsor ID
- STOP-CDI / STOP-CDI
- Conditions
- Clostridioides Difficile Infection, Clostridioides Difficile Infection Recurrence, Fecal Microbiota Transplantation (FMT), Comparative Effectiveness of CDI Treatments, Fidaxomicin, Vancomycin
- Keywords
- Clostridioides difficile, CDI, Fecal microbiota transplantation, Fidaxomicin, Vancomycin, Recurrent infection
- Study type
- Interventional
- Recruitment status
- Not yet recruiting
- Enrolment
- 424 participants (estimated)
- Lead sponsor
- Medical University of WarsawUniversity, hospital or other
- Collaborators
- Human Biome S.A.
- Study start
- Oct 2025 (estimated)
- Primary completion
- 31 Mar 2027 (estimated)
- Study completion
- 30 Apr 2027 (estimated)
- First posted
- 13 Aug 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The STOP-CDI study is a multicenter, randomized, open-label, three-arm clinical trial comparing the efficacy of fecal microbiota transplantation (FMT) preceded by vancomycin, fidaxomicin monotherapy, and standard-of-care vancomycin in preventing recurrence of Clostridioides difficile infection (CDI) in high-risk adult patients.
CDI is a common healthcare-associated infection with rising incidence and high recurrence rates, particularly in elderly and immunocompromised individuals. While current guidelines recommend fidaxomicin as first-line therapy, its availability and reimbursement remain limited in some healthcare systems. FMT, although effective, is not widely implemented as first-line treatment. This study addresses the need for comparative, real-world data to inform treatment decisions for patients at high risk of severe or recurrent CDI.
Eligible participants include adults aged ≥65 years or younger patients with specific risk factors such as multiple comorbidities, prior CDI episodes, recent hospitalization, use of non-CDI antibiotics, or PPI therapy. Participants will be randomized in a 2:1:1 ratio to one of three treatment arms: (1) vancomycin plus FMT, (2) fidaxomicin, or (3) vancomycin alone. FMT is administered via capsules or, if necessary, alternative endoscopic routes.
The primary endpoint is CDI recurrence within 12 weeks following the initial treatment. Secondary endpoints include clinical cure, safety, and global cure. Exploratory analyses will assess microbiome changes and potential genomic predictors of response. A total of 424 participants will be enrolled across 10 clinical sites in Poland.
The study aims to provide robust, comparative evidence to support clinical guidelines and improve outcomes for patients with CDI, particularly in healthcare systems with limited access to novel therapies.
Detailed description
Clostridioides difficile infection (CDI) represents a persistent and growing challenge in modern healthcare, particularly among elderly, hospitalized, and immunocompromised patients. Despite the existence of evidence-based therapeutic guidelines, recurrence rates remain unacceptably high, often leading to cycles of reinfection and retreatment. These recurrent episodes are associated with increased morbidity, reduced quality of life, higher healthcare costs, and, in some cases, life-threatening complications.
While therapies such as fidaxomicin and fecal microbiota transplantation (FMT) have demonstrated superior efficacy in reducing recurrence compared to traditional vancomycin, access to these interventions remains inconsistent. Fidaxomicin is often restricted due to its high cost and limited reimbursement, while FMT-though highly effective-is not yet widely integrated into early-line treatment pathways, largely due to regulatory and logistical barriers, including donor screening, manufacturing infrastructure, and clinician training.
The STOP-CDI study is a multicenter, randomized, open-label, three-arm research experiment designed to directly compare the effectiveness of three therapeutic strategies in preventing recurrent CDI (rCDI) in a real-world, high-risk adult population. The project addresses key gaps identified by international societies such as ESCMID, which emphasize the need for high-quality, head-to-head comparative research in CDI management.
The primary objective is to determine which of the following approaches most effectively prevents CDI recurrence within 12 weeks after treatment completion:
- Short-course oral vancomycin followed by FMT
- Fidaxomicin monotherapy
- Standard-of-care oral vancomycin
Participants will be randomized in a 2:1:1 allocation ratio, favoring the vancomycin plus FMT group to enable robust analysis of this relatively underutilized intervention. FMT is administered either as oral capsules containing freeze-dried donor microbiota or, when oral intake is not possible, through endoscopic routes such as colonoscopy or nasoenteric tubes. All FMT materials are sourced from rigorously screened donors under standardized laboratory protocols.
The study population includes 424 adult participants across 10 clinical sites in Poland, with recruitment targeting:
Adults aged 65 years or older, or
Younger adults with clearly defined risk factors for severe or recurrent CDI, such as:
- Multiple comorbidities (e.g., diabetes, malignancy, chronic kidney disease),
- Prior CDI episodes,
- Recent hospitalization,
- Use of non-CDI antibiotics,
- Ongoing proton pump inhibitor (PPI) therapy,
- Immunosuppressive treatment.
The primary endpoint of the experiment is CDI recurrence within 12 weeks following treatment, defined by return of symptoms (e.g., diarrhea) and laboratory confirmation of C. difficile toxin. Secondary endpoints include:
- Initial clinical cure (symptom resolution at the end of therapy),
- Global cure (clinical cure without recurrence),
- Time to recurrence,
- Safety and adverse event reporting,
- Patient-reported outcomes, including quality-of-life metrics,
- Healthcare resource utilization and cost-related measures.
In addition to clinical outcomes, the study includes a comprehensive biosample collection strategy for mechanistic and exploratory analyses. Longitudinal sampling of stool, blood, urine, and saliva will allow for in-depth evaluation of:
- Microbiome composition and dynamics,
- Inflammatory and immunological markers,
- Metabolomic profiling,
- Host genetic and genomic predictors of response or recurrence.
These exploratory analyses are intended to improve understanding of host-microbiota interactions in CDI and identify potential biomarkers for personalized treatment approaches.
The sample size of 424 has been statistically powered to detect an absolute difference of at least 15 percentage points in recurrence rates between the FMT group and standard vancomycin, with 80% power and a two-sided significance level of 0.05. This allows for subgroup analyses stratified by age, comorbidities, severity of CDI, and baseline risk factors.
Although the study is open-label, outcome assessment procedures include blinded adjudication by an independent clinical review board to minimize bias. In addition, centralized data monitoring and periodic safety reviews will be conducted to ensure compliance with ethical standards and protocol fidelity.
The STOP-CDI experiment is designed not only to assess comparative efficacy but also to explore real-world feasibility, implementation barriers, and economic considerations associated with newer CDI treatments. It aims to provide decision-makers and clinicians with relevant, actionable evidence that reflects the constraints and opportunities present in everyday clinical practice-particularly in healthcare systems with limited access to novel therapies like fidaxomicin or bezlotoxumab.
Ultimately, the results of this research are expected to guide more personalized, effective, and practical strategies for managing CDI, reducing the burden of recurrence, and improving patient outcomes in diverse clinical and economic contexts.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 3
- Model description
- This is a multicenter, randomized, open-label, three-arm study using a parallel assignment model. Eligible participants are randomly allocated in a 2:1:1 ratio to one of three intervention groups: (1) short-course oral vancomycin followed by fecal microbiota transplantation (FMT), (2) fidaxomicin monotherapy, or (3) standard-of-care vancomycin. Each participant remains in their assigned group for the duration of the study and receives only the intervention corresponding to that group. No crossover between arms is planned. The parallel design allows for direct comparison of recurrence rates and treatment outcomes across independent, concurrently treated cohorts. Randomization is stratified by site, and outcome assessors may be blinded for certain exploratory analyses.
| Arm | Type | Receives |
|---|---|---|
| FECAL MICROBIOTA TRANSPLANTATION (with vancomycin short pretreatment phase) | Experimental | Other: FMT (fecal microbiota transplantation)Participants receive oral vancomycin (125 mg QID) for 5 days (extendable to 10 if needed), followed by FMT. On Day 6, bowel cleansing is performed (macrogol-based), and biological samples (stool, blood, urine, saliva) are collected. On Day 7, FMT is administered via preferred oral capsules or, if necessary, colonoscopy, gastroscopy, NJ tube, or rectal enema. A second FMT is given either as daily capsules on Days 9-14 or as a single dose via other routes on Day 14. Dosing: 6 jars of capsules or 200 mL suspension (≥35 kg); half for <35 kg. Supportive measures include antiemetics and fasting. Oral non-antibiotic medications continue. Post-FMT samples are collected for follow-up analyses. |
| ANTIBIOTICS ONLY - FIDAXOMICIN | Experimental | Drug: FidaxomicinParticipants receive fidaxomicin 200 mg twice daily for 10 days. Biological samples (stool, blood, urine, saliva) are collected at baseline (before first antibiotic dose) for microbiome and safety analyses (PRE ATB). No additional interventions are applied. The antibiotic eradication phase ends on Day 10, after which the participant enters the follow-up phase. Post-treatment biological samples are collected (POST ATB) to assess treatment response, recurrence risk, and microbiota changes. |
| ANTIBIOTICS ONLY - VANCOMYCIN | Experimental | Drug: Vancomycin (VAN) treatmentParticipants receive vancomycin 125 mg four times daily for 10 days. Biological samples (stool, blood, urine, saliva) are collected prior to the first dose (PRE ATB) for safety and exploratory analyses. No additional therapies are administered. The eradication procedure is completed on Day 10, followed by a post-treatment sampling phase (POST ATB) for assessment of recurrence, clinical response, and microbiome status. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (16 listed)
- Individuals aged 65 years or older OR individuals aged 18 to 64 years who meet at least one of the following criteria:
- Presence of at least two comorbid chronic diseases from the groups of cardiovascular diseases, respiratory system diseases, gastrointestinal diseases, autoimmune diseases, cancers, chronic kidney and genitourinary diseases, immunodeficiencies, diabetes, and metabolic diseases,
- Previous episodes of CDI,
- Healthcare-associated CDI and/or hospitalization within the last three months,
- Concurrent use of antibiotics other than CDI treatment after CDI diagnosis,
Key exclusion criteria (10 listed)
- Lack of consent to participate in the study or absence of logical contact without possibility of obtaining consent from an authorized person,
- More than 24 hours of prior treatment with vancomycin, metronidazole, or fidaxomicin,
- On the day of inclusion (up to 3 days before starting intervention) absolute neutrophil count in blood <500 cells/µl or expected drop to this level within the next 2 days,
- Diagnosed HIV infection with CD4 lymphocyte count <250 cells/µl,
- Inability to swallow large capsules (failed test capsule use) or contraindications for FMT via upper or lower gastrointestinal tract, including gastrointestinal perforation, anal atresia, discontinuity of the gastrointestinal tract, and others,
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| FMT (fecal microbiota transplantation)Also: Vancomycin short-course pretreatmentThis intervention consists of a two-phase treatment for Clostridioides difficile infection in high-risk adults. First, participants receive a short-course (5 days) of oral vancomycin to reduce C. difficile bacterial load. Following antibiotic pretreatment, fecal microbiota transplantation (FMT) is administered to restore healthy gut microbiota. FMT is delivered primarily via encapsulated microbiota capsules, with alternative routes including colonoscopy, gastroscopy, nasojejunal tube, or rectal enema if capsules are contraindicated. A second FMT dose is given 7 days after the first, either as daily capsules over six days or as a single endoscopic administration. This approach aims to reduce CDI recurrence by combining targeted antibiotic reduction of pathogens with microbiome restoration. | Other | FECAL MICROBIOTA TRANSPLANTATION (with vancomycin short pretreatment phase) |
| FidaxomicinParticipants receive a 10-day course of fidaxomicin administered orally at a dose of 200 mg twice daily. Fidaxomicin is a narrow-spectrum macrocyclic antibiotic specifically targeting Clostridioides difficile with minimal impact on the normal gut microbiota. This monotherapy aims to eradicate C. difficile infection while preserving the intestinal microbiome, thereby reducing the risk of recurrence. No additional interventions are provided during the treatment period. Biological samples are collected before and after treatment to evaluate clinical response, safety, and microbiome changes. | Drug | ANTIBIOTICS ONLY - FIDAXOMICIN |
| Vancomycin (VAN) treatmentParticipants receive a 10-day course of oral vancomycin at a dose of 125 mg four times daily. Vancomycin is a broad-spectrum glycopeptide antibiotic commonly used as standard-of-care therapy for Clostridioides difficile infection. This monotherapy aims to eradicate C. difficile by reducing bacterial load in the colon. No additional interventions are applied during the treatment period. Biological samples are collected before and after treatment to monitor clinical outcomes, safety, and changes in the gut microbiome. | Drug | ANTIBIOTICS ONLY - VANCOMYCIN |
Primary outcome
Recurrence rate of Clostridioides difficile infection (CDI) within 12 weeks after treatment
Time frame: 12 weeks (90 days) after treatment completion
Proportion of patients experiencing a new episode of CDI, defined as recurrent diarrhea with confirmed C. difficile infection, within 12 weeks (90 days) after initial clinical cure following intervention.
7 secondary outcomes
Initial Clinical Cure Rate
Time frame: Up to 10 days from treatment initiation
Sustained clinical cure rate at 8 weeks post-treatment
Time frame: 8 weeks (60 days) after treatment completion
Recurrent CDI Rate at 8 Weeks
Time frame: 8 weeks (60 days) after completion of therapy
Sustained Clinical Cure Rate (Complete Cure)
Time frame: 8 weeks (60 days) after treatment completion
Sustained Clinical Cure Rate (Durable Cure)
Time frame: 12 weeks (90 days) after treatment completion
Rate of Treatment-Resistant CDI
Time frame: Up to 10 days from treatment initia
Incidence of Adverse Events
Time frame: Up to 90 days after treatment
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 13 Aug 2025.
- Individual participant dataSharing planned: Yes. Yes, individual participant data (IPD) will be shared with other researchers. Data sharing will be conducted only after the signing of a confidentiality agreement (non-disclosure agreement) to ensure the privacy and protection of participant information. Access to the data will be granted upon reasonable request and subject to approval by the study sponsor and ethics committee.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Jaroslaw Bilinski, MD PhD, Assoc. Prof. contact
Questions about this trial
What is this clinical trial studying?
A study testing FMT (fecal microbiota transplantation), Fidaxomicin and Vancomycin (VAN) treatment in people with Clostridioides Difficile Infection and Clostridioides Difficile Infection Recurrence, run by Medical University of Warsaw.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 16 inclusion and 10 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: opening soon, as of the sponsor's last update on 13 Aug 2025. Status can change between updates, so confirm with the study contact before making plans.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Jaroslaw Bilinski, MD PhD, Assoc. Prof. (884 299 668 ext. +48, jaroslaw.bilinski@human-biome.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Recurrence rate of Clostridioides difficile infection (CDI) within 12 weeks after treatment (time frame: 12 weeks (90 days) after treatment completion). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 13 Aug 2025.