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Purpose

The purpose of the study is to learn about how effective, safe, and tolerable the Clostridioides difficile (C. difficile) vaccine is in decreasing the number of C. difficile infections (pCDI) in adults 65 years of age or older. The participants will receive either the C. difficile vaccine or placebo (saline). A placebo does not contain any active ingredients. The vaccines will be given as a shot into the upper arm muscle. This study looks at the number of diarrhea (loose stools) events related to a C. difficile infection, so the length of the study can change. If these events happen quickly, the study may finish sooner; if they happen slowly, it could take longer. Sometimes, the study might stop early if the vaccine clearly does not work. Participants will stay in the study until enough events have occurred to answer the main question. On average, each person is expected to take part for up to about three and a half years. During this time, participants will have 3 planned clinic visits and 3 planned phone visits. After these visits, more scheduled clinic visits will happen every year until the end of study. Besides the scheduled study visits, if at any time during the study a participant has 3 or more loose stools in 24 hours, they will be asked to save the next one (the fourth or later) and contact the study site. The study site will check to see if it could be a C. difficile infection. This check may happen at the clinic or through a phone or video call.

Condition

Eligibility

Eligible Ages
Over 65 Years
Eligible Sex
All
Accepts Healthy Volunteers
Yes

Inclusion Criteria

): • People with recent or future planned contact with healthcare systems, recent antibiotic exposure, or a diagnosis of certain chronic medical conditions. Who Cannot Join the Study (

Exclusion Criteria

): - Anyone who has had CDI before. - Anyone who has had surgery to remove part of their small or large intestine. - Anyone who often has diarrhea (meaning three or more loose stools in a day, more than once a month). - Anyone who has already received a vaccine or special antibody treatment for C. difficile. - Anyone who has had a serious allergic reaction to a vaccine or to any part of the study vaccines. - Anyone who might not respond well to the vaccine because their immune system is weak (either from a disease or from treatment). - Anyone with cancer that has spread or another serious health problem.

Study Design

Phase
Phase 3
Study Type
Interventional
Allocation
Randomized
Intervention Model
Parallel Assignment
Primary Purpose
Prevention
Masking
Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)

Arm Groups

ArmDescriptionAssigned Intervention
Experimental
C.difficile vaccine 		Novel vaccine formulation
  • Biological: C.difficile vaccine
    C.difficile vaccine given as an intramuscular injection
Other
Saline Placebo
  • Other: Saline Placebo
    0.9% sodium chloride solution given as a intramuscular injection

Recruiting Locations

Memorial Hermann Hospital - TMC
Houston, Texas 77030

The University of Texas Health Science Center at Houston
Houston, Texas 77030

More Details

Status
Recruiting
Sponsor
Pfizer

Study Contact

Pfizer CT.gov Call Center
1-800-718-1021
ClinicalTrials.gov_Inquiries@pfizer.com

Notice

Study information shown on this site is derived from ClinicalTrials.gov (a public registry operated by the National Institutes of Health). The listing of studies provided is not certain to be all studies for which you might be eligible. Furthermore, study eligibility requirements can be difficult to understand and may change over time, so it is wise to speak with your medical care provider and individual research study teams when making decisions related to participation.