To Understand the Safety and Effects of a C. Difficile Vaccine With New Adds-Ons That Will Be Given to Healthy Adults
NCT ID: NCT05805826
Last Updated: 2025-11-12
Study Results
The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.
Basic Information
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ACTIVE_NOT_RECRUITING
PHASE1/PHASE2
779 participants
INTERVENTIONAL
2023-03-23
2031-06-19
Brief Summary
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The purpose of this study is to understand if giving the new C. diff vaccine formulations helps people make as many antibodies as giving the previously studied C. diff vaccine formulation.
The study is divided into 2 phases.
Phase 1 will evaluate 3 new formulations of the C. diff vaccine and 2 dosing schedules spread out over 2 months or 6 months.
The Phase 1 portion of the study is seeking participants:
* who are healthy adults of 65 to 84 years of age
* who have not had a C. diff infection before
* who have not received a C. diff vaccine or C. diff monoclonal antibody therapy before.
All participants in Phase 1 will receive study injections with active vaccine or placebo at each vaccination visit, depending on the vaccine group to which they are assigned. A placebo does not contain any active ingredients. Participants in Phase 1 will attend at least 9 study visits and will take part in the study for approximately 18 months. Based on the results of Phase 1, 1 or 2 of the new C. diff vaccine formulations will be chosen for further study in Phase 2.
Phase 2 will evaluate the safety and effects of the new C. diff vaccine formulation(s) chosen in Phase 1.
The Phase 2 portion of the study is seeking participants:
* who are healthy adults ≥65 years of age
* who have not had a C. diff infection before
* who have not received a C. diff vaccine or C. diff monoclonal antibody therapy before.
Phase 2 participants will receive active C. diff vaccine or placebo at each vaccination visit. Participants in Phase 2 will attend at least 6 and up to 12 study visits and will take part in the study for up to 4 years.
A booster stage for selected participants in Phase 2 will have participants receive active C. diff vaccine or placebo to examine immune persistence. The booster stage participants will attend at least 10 additional study visits and will take part in the study for 6 years.
Detailed Description
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Conditions
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Keywords
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Study Design
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RANDOMIZED
PARALLEL
PREVENTION
TRIPLE
Study Groups
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C. difficile vaccine formulation 1, Schedule 2 (Phase 1)
Novel vaccine formulation 1
C. difficile vaccine formulation 1.
C. difficile vaccine formulation 1 given as an intramuscular injection
Saline Placebo.
0.9% sodium chloride solution given as an intramuscular injection
C. difficile vaccine formulation 2, Schedule 3 (Phase 1)
Novel vaccine formulation 2
C. difficile vaccine formulation 2.
C. difficile vaccine formulation 2 given as an intramuscular injection
Saline Placebo.
0.9% sodium chloride solution given as an intramuscular injection
C. difficile vaccine formulation 3, Schedule 2 (Phase 1)
Novel vaccine formulation 3
C. difficile vaccine formulation 3.
C. difficile vaccine formulation 3 given as an intramuscular injection
Saline Placebo.
0.9% sodium chloride solution given as an intramuscular injection
C. difficile vaccine formulation 1, Schedule 4 (Phase 1)
Novel vaccine formulation 1
Saline Placebo.
0.9% sodium chloride solution given as an intramuscular injection
C. difficile vaccine formulation 2, Schedule 4 (Phase 1)
Novel vaccine formulation 2
C. difficile vaccine formulation 2.
C. difficile vaccine formulation 2 given as an intramuscular injection
Saline Placebo.
0.9% sodium chloride solution given as an intramuscular injection
C. difficile vaccine formulation 3, Schedule 4 (Phase 1)
Novel vaccine formulation 3
C. difficile vaccine formulation 3.
C. difficile vaccine formulation 3 given as an intramuscular injection
Saline Placebo.
0.9% sodium chloride solution given as an intramuscular injection
C. difficile vaccine (previously studied formulation) Schedule 1 (Phase 1)
Previously studied C. difficile vaccine formulation
C. difficile vaccine (previously studied formulation).
Toxoid based Clostridioides difficile vaccine (previously studied formulation) given as an intramuscular injection
Saline Placebo.
0.9% sodium chloride solution given as an intramuscular injection
C difficile vaccine formulation 2, Schedule 1 (Phase 2)
Novel vaccine formulation 2
C. difficile vaccine formulation 2.
C. difficile vaccine formulation 2 given as an intramuscular injection
Saline Placebo.
0.9% sodium chloride solution given as an intramuscular injection
C. difficile vaccine formulation 2, Schedule 4 (Phase 2)
Novel vaccine formulation 2
C. difficile vaccine formulation 2.
C. difficile vaccine formulation 2 given as an intramuscular injection
Saline Placebo.
0.9% sodium chloride solution given as an intramuscular injection
C. difficile vaccine formulation 2, Schedule 5 (Phase 2)
Novel vaccine formulation 2
C. difficile vaccine formulation 2.
C. difficile vaccine formulation 2 given as an intramuscular injection
Saline Placebo.
0.9% sodium chloride solution given as an intramuscular injection
C. difficile vaccine formulation 2, Schedule 6 (Phase 2)
Novel vaccine formulation 2
C. difficile vaccine formulation 2.
C. difficile vaccine formulation 2 given as an intramuscular injection
C. difficile vaccine (previously studied formulation) , Schedule 1 (Phase 2)
Previously studied C. difficile vaccine formulation
C. difficile vaccine (previously studied formulation).
Toxoid based Clostridioides difficile vaccine (previously studied formulation) given as an intramuscular injection
Saline Placebo.
0.9% sodium chloride solution given as an intramuscular injection
C. difficile vaccine formulation 2, Schedule 7 (Phase 2)
Novel vaccine formulation 2
C. difficile vaccine formulation 2.
C. difficile vaccine formulation 2 given as an intramuscular injection
Saline Placebo.
0.9% sodium chloride solution given as an intramuscular injection
C. difficile vaccine formulation 2, Schedule 1, (Phase 2)
Novel vaccine formulation 2
C. difficile vaccine formulation 2.
C. difficile vaccine formulation 2 given as an intramuscular injection
C. difficile vaccine formulation 2, Schedule 4, (Phase 2)
Novel vaccine formulation 2
C. difficile vaccine formulation 2.
C. difficile vaccine formulation 2 given as an intramuscular injection
Saline Placebo.
0.9% sodium chloride solution given as an intramuscular injection
C. difficile vaccine formulation 2, Schedule 8, (Phase 2)
Novel vaccine formulation 2
C. difficile vaccine formulation 2.
C. difficile vaccine formulation 2 given as an intramuscular injection
Saline Placebo.
0.9% sodium chloride solution given as an intramuscular injection
C. difficile vaccine formulation 2, Schedule 9, (Phase 2)
Novel vaccine formulation 2
C. difficile vaccine formulation 2.
C. difficile vaccine formulation 2 given as an intramuscular injection
Saline Placebo.
0.9% sodium chloride solution given as an intramuscular injection
Interventions
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C. difficile vaccine (previously studied formulation).
Toxoid based Clostridioides difficile vaccine (previously studied formulation) given as an intramuscular injection
C. difficile vaccine formulation 1.
C. difficile vaccine formulation 1 given as an intramuscular injection
C. difficile vaccine formulation 2.
C. difficile vaccine formulation 2 given as an intramuscular injection
C. difficile vaccine formulation 3.
C. difficile vaccine formulation 3 given as an intramuscular injection
Saline Placebo.
0.9% sodium chloride solution given as an intramuscular injection
Eligibility Criteria
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Inclusion Criteria
Phase 1: Participants ≥65 to \<85 years of age; Phase 2: Participants ≥65 years of age.
2. Healthy participants as determined by medical history, clinical assessment, and the judgment of the investigator.
3. Participants who are willing and able to comply with all scheduled visits, investigational plan, laboratory tests, lifestyle considerations, and other study procedures.
4. Capable of giving personally signed informed consent, which includes compliance with the requirements and restrictions listed in the ICD and in this protocol.
Exclusion Criteria
2. Serious chronic disorder, including history of metastatic malignancy, severe COPD requiring supplemental oxygen, end-stage renal disease with or without dialysis, cirrhosis of the liver, clinically unstable cardiac disease, or any other disorder that, in the investigator's opinion, would make the participant inappropriate for entry into the study.
3. Any contraindication to vaccination or vaccine components, including previous hypersensitivity or anaphylactic reaction to any vaccine or vaccine-related components.
4. Prior episode of CDI, confirmed by either laboratory test or diagnosis of pseudomembranous colitis at colonoscopy, at surgery, or histopathologically.
5. Any bleeding disorder or anticoagulant therapy that would contraindicate intramuscular injection.
6. Known or suspected immunodeficiency or other conditions associated with immunosuppression, including, but not limited to, leukocyte, lymphocyte, or immunoglobulin class/subclass deficiencies or abnormalities, generalized malignancy, HIV infection, leukemia, lymphoma, or organ or bone marrow transplant.
7. Other medical or psychiatric condition including recent (within the past year) or active suicidal ideation/behavior or laboratory abnormality that may increase the risk of study participation or, in the investigator's judgment, make the participant inappropriate for the study.
8. Previous receipt of an investigational C difficile vaccine or C difficile mAb therapy.
9. Receipt of blood product or immunoglobulin within 6 months before enrollment.
10. Currently receives treatment with immunosuppressive therapy, including cytotoxic agents or systemic corticosteroids, or planned receipt throughout the study. Participants may not be enrolled if corticosteroids were administered within 28 days before study intervention administration.
11. Participation in other studies involving investigational drugs, investigational vaccines, or investigational devices within 28 days prior to study entry through 12 months after the last dose of study intervention.
12. Phase 1 only: Any screening hematology and/or blood chemistry laboratory value that meets the definition of a ≥ Grade 1 abnormality.
13. Investigator site staff directly involved in the conduct of the study and their family members, site staff otherwise supervised by the investigator, and sponsor and sponsor delegate employees directly involved in the conduct of the study and their family members.
65 Years
ALL
Yes
Sponsors
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Pfizer
INDUSTRY
Responsible Party
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Principal Investigators
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Pfizer CT.gov Call Center
Role: STUDY_DIRECTOR
Pfizer
Locations
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HOPE Research Institute
Phoenix, Arizona, United States
Anaheim Clinical Trials, LLC
Anaheim, California, United States
Alliance for Multispecialty Research, LLC
Doral, Florida, United States
Indago Research & Health Center, Inc
Hialeah, Florida, United States
Research Centers of America
Hollywood, Florida, United States
Miami Clinical Research
Miami, Florida, United States
New Horizon Research Center
Miami, Florida, United States
Charisma Medical and Research Center
Miami Lakes, Florida, United States
Private Practice - Dr. Hector Fabregas
Pembroke Pines, Florida, United States
DBC Research USA
Pembroke Pines, Florida, United States
BRCR Medical Center Inc.
Plantation, Florida, United States
Clinical Research Trials of Florida
Tampa, Florida, United States
Great Lakes Clinical Trials - Ravenswood
Chicago, Illinois, United States
Great Lakes Clinical Trials - Gurnee
Gurnee, Illinois, United States
AMR Clinical
Wichita, Kansas, United States
Prism Research LLC dba Nucleus Network
Saint Paul, Minnesota, United States
Washington University
St Louis, Missouri, United States
NYU Langone Health
New York, New York, United States
Rochester Clinical Research, LLC
Rochester, New York, United States
CTI Clinical Research Center
Cincinnati, Ohio, United States
Benchmark Research
Austin, Texas, United States
Dynamed Clinical Research, LP d/b/a DM Clinical Research
Tomball, Texas, United States
Countries
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Related Links
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To obtain contact information for a study center near you, click here.
Other Identifiers
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NCT05805826
Identifier Type: REGISTRY
Identifier Source: secondary_id
C4771001
Identifier Type: -
Identifier Source: org_study_id