Clinical trial Recruiting at 95 sites Phase 2 Interventional Ages 18 and up

Preventing recurrent C. difficile infection with the AZD5148 antibody

Official title: A Phase IIb, Randomized, Double-blind, Placebo-controlled Study to Evaluate the Efficacy and Safety of AZD5148 for Prevention of Recurrence of Clostridioides Difficile Infection in Individuals 18 Years of Age and Above

Run by AstraZeneca · NCT07285213 · Data updated 2026-11-12

This will try a single dose of the antibody AZD5148 versus placebo to see if it prevents repeat C. difficile infections in adults being treated for a current infection.

Quick facts

PhasePhase 2
Study typeInterventional
Ages18 Years and up
SexAll
Enrollment230 (estimated)
SponsorAstraZeneca
Industry-sponsored
Drugs / interventionsbezlotoxumab
Locations117 sites (Phoenix, Arizona and 116 other locations)
StatusRecruiting
StartedDecember 10, 2025
Main results expectedApril 20, 2027
Study endsJanuary 18, 2028
Registry record updatedNovember 10, 2026
Trial IDNCT07285213 on ClinicalTrials.gov

Is this trial a fit for you?

Likely a good fit

Adults aged 18 or older with a positive local C. difficile toxin test on an unformed stool, receiving standard antibiotic therapy for the current episode (planned duration 10–25 days) and weighing at least 40 kg are eligible.

Probably not a fit

People with a history of inflammatory bowel disease, those with chronic non‑CDI causes of loose stools, individuals not on standard CDI antibiotic therapy, and those under 18 are unlikely to benefit from this trial.

A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.

What this trial studies

Up to 230 adults with a laboratory-confirmed C. difficile episode who are receiving standard-of-care antibiotics will be randomized 1:1 to receive a single dose of AZD5148 or placebo. The investigational product will be given by investigator choice as an intramuscular injection or an intravenous push, and randomization will be stratified by geographic region. Participants will have up to two visits for eligibility confirmation and dosing, up to seven planned visits overall with stool sample collection, weekly then monthly follow-up contacts from site staff, and electronic diary symptom reporting. Safety, tolerability, and recurrence of infection will be monitored during the follow-up period.

Why it matters

Potential benefit: If successful, AZD5148 could reduce the chance of C. difficile coming back after treatment, lowering the need for repeat antibiotics, hospital visits, and complications.

How similar studies have gone: Similar monoclonal antibody approaches (for example bezlotoxumab) have previously reduced C. difficile recurrence, so this builds on an existing, successful concept.

Who can join: the full rules

Show full inclusion / exclusion criteria
Inclusion Criteria:

Participant must be ≥ 18 years of age at the time of signing the informed consent, capable of giving signed informed consent.

Participants with a qualifying C. difficile infection episode at the time of providing informed consent defined by:

* History of 3 or more unformed stools (Bristol stool scale 6 or 7) in ≤ 24 hours for 2 consecutive calendar days, (Note: Diarrhea is not required to be present on the day of IMP administration) and
* Positive local C. difficile toxin test (eg, immune assay or CCNA) on a stool sample collected during this episode, as part of routine clinical care (Note: Toxin testing, where not part of routine clinical care, may be conducted as a pre- screening activity; if this occurs, participant consent is required), and
* Planned initiation or receipt of antibacterial drug therapy for C. difficile infection (fidaxomicin, vancomycin or metronidazole) for this episode,

Note: At the time of randomization and IMP administration, the participant must have started receiving the antibacterial drug therapy with a planned total treatment duration of at least 10 and at most 28 days at time of IMP administration. IMP can be administered at any point during the antibacterial drug therapy.

Body weight ≥ 35 kg

Exclusion Criteria:

Participants with a history of uncontrolled inflammatory bowel disease. Participants with a history of inflammatory bowel disease may be included if, in the opinion of the Investigator, their disease is clinically controlled and presenting symptoms are more likely attributable to CDI than to a flare of inflammatory bowel disease.

Participants with a non - CDI (C. difficile infection) condition such that the participant routinely passes loose stool (eg, patients with an ostomy)

Planned surgery for C. difficile infection within 24 hours of enrollment

Current toxic megacolon and/or small bowel ileus

Any history of total colectomy

Major gastrointestinal surgery as assessed by the Investigator (eg, significant bowel resection or diversion) within 90 days before enrollment (this does not include appendectomy or cholecystectomy)

Due to receive more than 28 days of antibacterial drug therapy for the qualifying C. difficile infection episode

Participants receiving a fecal microbiota transplant, fecal microbiota product, or live biotherapeutic product for the qualifying CDI episode, or planned administration during the 180 days after IMP administration.

Treatment with bezlotoxumab in the 180 days before IMP administration, are receiving or planned administration for the qualifying episode of CDI, or planned administration during the 180 days after IMP administration.

Where it's running

  • Research Site
    Sacramento, California, United States
    Recruiting
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    Torrance, California, United States
    Recruiting
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    Hamden, Connecticut, United States
    Recruiting
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    Hialeah, Florida, United States
    Recruiting
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    Homestead, Florida, United States
    Recruiting
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    Jacksonville, Florida, United States
    Recruiting
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  • Research Site
    Athens, Georgia, United States
    Recruiting
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    Atlanta, Georgia, United States
    Recruiting
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    Idaho Falls, Idaho, United States
    Recruiting
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    Burr Ridge, Illinois, United States
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    Louisville, Kentucky, United States
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    New Orleans, Louisiana, United States
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    Glen Burnie, Maryland, United States
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    Potomac, Maryland, United States
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    Boston, Massachusetts, United States
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    Boston, Massachusetts, United States
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    Detroit, Michigan, United States
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    Royal Oak, Michigan, United States
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    Columbia, Missouri, United States
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    Kansas City, Missouri, United States
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    St Louis, Missouri, United States
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    Union City, New Jersey, United States
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    Salisbury, North Carolina, United States
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    Winston-Salem, North Carolina, United States
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    Johnson City, Tennessee, United States
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    Charlottesville, Virginia, United States
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    Lynchburg, Virginia, United States
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    Roanoke, Virginia, United States
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    Seattle, Washington, United States
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    Camperdown, Australia
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    Clayton, Australia
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    Herston, Australia
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    Melbourne, Australia
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    South Brisbane, Australia
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    Vancouver, British Columbia, Canada
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    Halifax, Nova Scotia, Canada
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    London, Ontario, Canada
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    Montreal, Quebec, Canada
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    Québec, Quebec, Canada
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    Sherbrooke, Quebec, Canada
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    Aarhus N, Denmark
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    Gistrup, Denmark
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    Hvidovre, Denmark
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    København Ø, Denmark
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    Odense C, Denmark
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    Lyon, France
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    Montpellier, France
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    Nantes, France
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    Nîmes, France
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    Paris, France
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+67 more sites. See ClinicalTrials.gov for the full list.

Study contacts

Similar studies

Other studies for the same condition or treatment. Recruiting studies are listed first.

How to take part

  1. Review the eligibility criteria above with your treating physician.
  2. Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
  3. Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.
Last reviewed 2026-11-14 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.