Ongoing Clinical Trials for Clostridium difficile Infection
There are currently 4 clinical trials investigating new treatments and prevention strategies for Clostridium difficile infection (also known as: C. difficile infection, CDI, Clostridioides difficile infection). These trials are testing different approaches including live biotherapeutic products, optimized antibiotic regimens, and preventive treatments for high-risk patients across 14 European countries.
Clinical trial locations
- Belgium
- Bulgaria
- Czechia
- Denmark
- France
- Germany
- Hungary
- Ireland
- Italy
- Netherlands
- Poland
- Portugal
- Romania
- Spain
Study on EXL01 to Prevent Recurrence of C. difficile Infection in High-Risk Patients
This trial is testing a new live biotherapeutic product called EXL01 to prevent the infection from coming back in patients who have experienced multiple recurrences. The study is being conducted in France and focuses on understanding both the safety and effectiveness of this novel treatment.
Who can join: To participate, you must be over 18 years of age and have experienced at least three episodes of confirmed infection within six months. This means having three or more liquid stools per day with bacteria detected in stool tests. You should be currently taking or planning to start oral vancomycin treatment. The time between the end of your previous treatment and the new episode should be 12 weeks or less. You must be able to give informed consent and be enrolled in the French national social security scheme.
Who cannot join: The trial excludes patients who have not experienced multiple recurrences of the infection, those who have not been treated with oral vancomycin, patients who are not at high risk of recurrence, those outside the specified age range, and individuals who are part of vulnerable populations requiring special protection.
What the study aims to do: The trial has two phases. The first phase evaluates how safe and tolerable EXL01 is for patients, monitoring for any serious side effects. The second phase assesses how effectively EXL01 prevents the infection from recurring. Throughout the study, researchers will monitor your bowel movements, stool consistency, abdominal discomfort, quality of life, and the composition of gut bacteria using advanced techniques.
Treatment being tested: EXL01 is a live biotherapeutic product taken as a hard capsule. It contains live microorganisms designed to restore the natural balance of bacteria in your gut, which may help prevent harmful bacteria from causing infection again. The treatment is used alongside vancomycin, a standard antibiotic for this infection.
Study on Optimizing Antibiotic Treatment for Clostridioides Difficile Infection with Vancomycin Hydrochloride in Adult Patients
This trial in Czechia is investigating whether a shorter 5-day course of vancomycin is as effective as the standard 10-day treatment. The study aims to optimize antibiotic use while maintaining treatment effectiveness.
Who can join: You must be 18 years or older with diarrhea, meaning three or more mushy or watery stools per day that are not normal for you. Your infection must be confirmed by laboratory tests showing specific antigens and toxins in your stool. You need to be hospitalized due to the current infection at the time of joining. You must provide informed consent and, if you can have children, agree to abstain from sexual activity during the 10-day treatment phase. Those participating in an optional sub-study must also agree to provide stool samples over six months.
Who cannot join: Patients without a confirmed diagnosis of the infection, those not within the specified age range, and individuals who are part of vulnerable populations are excluded from participation.
What the study aims to do: The primary goal is to compare the effectiveness of 5-day versus 10-day vancomycin treatment. Researchers will monitor you for recovery, defined as sustained improvement for at least 48 hours with reduced stool frequency and normal stool consistency. The study also tracks infection recurrence during the 60 days following treatment and monitors for any side effects. An optional sub-study examines gut bacteria recovery and the presence of antibiotic-resistant bacteria over six months.
Treatment being tested: Vancomycin hydrochloride is a well-established antibiotic given orally as hard capsules. It works by preventing bacteria from building their cell walls, ultimately killing the bacteria causing the infection.
Study on Preventing C. difficile Infections with Oral Vancomycin in Patients Undergoing Allogeneic Stem Cell Transplantation
This French trial focuses on preventing infection in patients undergoing allogeneic hematopoietic stem cell transplantation, a procedure where blood-forming cells are replaced with those from a donor. This is a preventive study rather than a treatment study.
Who can join: You must be at least 15 years old and hospitalized for less than 72 hours to receive an allogeneic stem cell transplant. If you are a man or woman capable of having children, you must use effective birth control during the study and for one month afterward. You need to provide informed consent and have health insurance coverage.
Who cannot join: Patients not hospitalized for allogeneic stem cell transplantation, those outside the specified age ranges, and individuals who are part of vulnerable populations are excluded.
What the study aims to do: The study evaluates whether taking oral vancomycin can prevent infection from occurring in the first place. This is a double-blind trial, meaning neither you nor the researchers will know if you are receiving vancomycin or a placebo. Participants will be monitored for signs of infection, including diarrhea with more than three unformed stools per day. The treatment lasts up to five weeks, depending on your hospital stay, followed by monitoring for up to 12 weeks to observe any delayed effects. The study also assesses your intestinal bacteria composition at various points.
Treatment being tested: Oral vancomycin is used preventively in this study. It is a glycopeptide antibiotic that works by stopping bacteria from building their cell walls, thereby preventing infection.
Study on VE303 for Preventing Recurrent C. difficile Infection in Patients
This large international trial spans 14 European countries and is testing VE303, an investigational microbiome therapeutic designed to prevent infection recurrence. This is the most widely available trial geographically.
Who can join: Eligibility depends on which stage of the study you enter. For Stage 1, you must be at least 12 years old (or 18 years in some countries) with a confirmed episode of infection and at least one previous occurrence in the last six months. For Stage 2, you must either be at least 75 years old with a confirmed episode, or at least 12 years old (or 18 years in some countries) with a confirmed episode plus at least two risk factors such as being 65 or older, having kidney problems, regularly using proton pump inhibitors, having a previous infection 6-12 months ago, having a weakened immune system, or having had an organ or stem cell transplant. Your current episode must include at least three loose bowel movements daily for at least two days, with symptoms starting within four weeks before antibiotic treatment and a positive stool test. You must complete 10-21 days of antibiotics with improvement. If capable of having children, you need a negative pregnancy test and must use effective birth control. You must be able to take the first dose of study drug on the last day of antibiotics or the day after, provide written consent, and follow study procedures including taking capsules, attending visits, providing samples, and completing questionnaires.
Who cannot join: Individuals without confirmed infection, those outside the specified age range, people unable to follow study procedures, those with interfering medical conditions or medications, pregnant or breastfeeding individuals, recent participants in other trials, and those with substance abuse history are excluded.
What the study aims to do: This double-blind, placebo-controlled trial randomly assigns participants to receive either VE303 or an identical-looking placebo. The primary goal is to determine whether VE303 can reduce infection recurrence by Week 8. Participants are monitored for up to 24 weeks for recurrence and adverse events, with regular assessments including blood and stool samples, questionnaires, and study visits. The trial also examines the relationship between VE303 colonization of the gut and infection recurrence.
Treatment being tested: VE303 is an investigational microbiome therapeutic administered as oral capsules. It works by modulating the gut microbiome to restore a healthy balance of bacteria, preventing the overgrowth of harmful bacteria that cause infection. This medication is not yet approved for general use but is being actively studied in Phase 3 clinical trials.
Summary
The four ongoing clinical trials for Clostridium difficile infection represent diverse approaches to managing this challenging condition. The trials are spread across Europe, with France hosting three of the four studies, making it a major hub for research in this area. One trial extends across 14 countries, offering broad access to patients throughout Europe.
A notable focus across these studies is the prevention of recurrence, which affects many patients after their initial infection. Three trials specifically target recurrent infection, while one takes a preventive approach for high-risk patients undergoing stem cell transplantation. The investigational treatments include both novel approaches such as live biotherapeutic products (EXL01 and VE303) that aim to restore gut bacteria balance, and optimized uses of the established antibiotic vancomycin.
The trials vary in their target populations, from patients with multiple recurrences to those at high risk due to age, medical procedures, or other risk factors. This range of approaches reflects the medical community’s recognition that different patient groups may benefit from different prevention and treatment strategies. Patients interested in participating should review the specific eligibility criteria carefully and discuss options with their healthcare providers.
