To Understand the Safety and Effects of a C. Difficile Vaccine With New Adds-Ons That Will Be Given to Healthy Adults (NCT05805826)
A PHASE 1/2 RANDOMIZED STUDY TO EVALUATE THE SAFETY, TOLERABILITY, IMMUNOGENICITY, AND IMMUNOPERSISTENCE OF A CLOSTRIDIOIDES DIFFICILE VACCINE ADMINISTERED WITH NOVEL ADJUVANTS IN HEALTHY ADULTS
🩺 Plain-English Summary (8th-Grade Level)
An antibody is a substance your body makes to fight off infection. This study will explore the safety and antibody response of a vaccine to prevent severe diarrhea caused by a germ called Clostridoides difficile (C. diff). Three new formulations of the C. diff vaccine will be used in this study, in addition to a C. diff vaccine formulation that has been studied in previous clinical trials. 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; and 50 through 64 years of age (Cohort 4 only) * 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. A newly added cohort will evaluate the safety and effects of active C. diff vaccine formulation in participants 50 through 64 years of age. Participants will receive C. diff vaccine or placebo and will attend at least 6 study visits over a period of 18 months.
Who can join: Review the eligibility criteria below.
Location: HOPE Research Institute — Phoenix, Arizona
Age range: 50 Years
🧪 Interventions in This Study
📋 "Do I Qualify?" — 1-Minute Self Screener
Instant ChecklistFull eligibility criteria are available on the official NIH protocol. View the criteria ↗
📍 All Participating Trial Locations (23 Sites)
- HOPE Research Institute — Phoenix, Arizona
- Anaheim Clinical Trials, LLC — Anaheim, California
- Alliance for Multispecialty Research, LLC — Doral, Florida
- Indago Research & Health Center, Inc — Hialeah, Florida
- Research Centers of America — Hollywood, Florida
- Miami Clinical Research — Miami, Florida
- New Horizon Research Center — Miami, Florida
- Charisma Medical and Research Center — Miami Lakes, Florida
- Private Practice - Dr. Hector Fabregas — Pembroke Pines, Florida
- DBC Research USA — Pembroke Pines, Florida
- BRCR Medical Center Inc. — Plantation, Florida
- Clinical Research Trials of Florida — Tampa, Florida
- Great Lakes Clinical Trials - Ravenswood — Chicago, Illinois
- Alliance for Multispecialty Research, LLC — Wichita, Kansas
- Prism Research LLC dba Nucleus Network — Saint Paul, Minnesota
- Washington University School of Medicine — St Louis, Missouri
- Washington University — St Louis, Missouri
- NYU Langone Health — New York, New York
- Rochester Clinical Research, Inc. — Rochester, New York
- Qcare Site Services Inc. d/b/a Avacare — Durham, North Carolina
- CTI Clinical Research Center — Cincinnati, Ohio
- Benchmark Research — Austin, Texas
- Dynamed Clinical Research, LP d/b/a DM Clinical Research — Tomball, Texas
💰 Cost, Insurance & Patient Rights
- 100% Free Items: The investigational treatment and protocol-required procedures are supplied at zero cost by the sponsor.
- Routine Patient Care: Under federal law (ACA § 2709) and many state statutes, routine care costs are covered during participation.
- Voluntary Participation: You may withdraw at any time without affecting your standard medical care.
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💡 How to Participate
- Check the checklist above to see if you may qualify.
- Review the official NIH record below to find the coordinating site.
- Ask about the visit schedule, what is covered at no cost, and any travel support.
- Confirm with your own doctor before making a decision.