A Study to Learn About a Clostridioides Difficile Vaccine in People 65 Years of Age and Older

A PHASE 3, PLACEBO-CONTROLLED, DOUBLE-BLINDED, RANDOMIZED STUDY TO EVALUATE THE EFFICACY, SAFETY, AND TOLERABILITY OF A CLOSTRIDIOIDES DIFFICILE VACCINE IN ADULTS 65 YEARS OF AGE AND OLDER - BEETHOVEN

Status

Recruiting

Phases

Phase 3

Study type

Interventional

Source

JPRN

Registry ID

JPRN-jRCT2031260066

Enrollment

32000

Registered

2026-04-20

Start date

2026-05-20

Completion date

Unknown

Last updated

2026-05-25

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

* Clostridioides Difficile Associated Disease

Interventions

* Biological: C.difficile vaccine - C.difficile vaccine given as an intramuscular injection * Other: Saline Placebo - 0.9% sodium chloride solution given as a intramuscular injection

Eligibility

Sex/Gender

All

Inclusion criteria

Inclusion criteria: Who Can Join the Study (Inclusion Criteria): * People with recent or future planned contact with healthcare systems or who have recently received antibiotics.

Exclusion criteria

Exclusion criteria: 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, kidney failure, or another serious health problem.

Design outcomes

Primary

Measure	Time frame
* The percentage of participants reporting local reactions [Time Frame: For 7 days after each vaccination] - Injection site pain, redness, and swelling as self-reported in electronic diaries * The percentage of participants reporting systemic events [Time Frame: For 7 days after each vaccination] - Fever, vomiting, fatigue, headache, muscle pain, and joint pain as self-reported in electronic diaries * Percentage of participants reporting adverse events [Time Frame: From each vaccination through 1 month after each vaccination] - As elicited by investigator site staff * Percentage of participants reporting serious adverse events [Time Frame: From Vaccination 1 (Day 1) through 12 months after Vaccination 2 (last dose) (18 months)] - As elicited by investigator site staff * The incidence of the first episode of medically attended and clinically meaningful primary Clostridioides difficile infection (CDI) [Time Frame: from 14 days after Vaccination 2 to the end of the surveillance period (up to approximately 3.5 years)] - First episode of medically attended and clinically meaningful primary CDI incidence per 1000 person- years of follow- up * The incidence of the first episode of medically attended primary CDI [Time Frame: from 14 days after Vaccination 2 to the end of the surveillance period (up to approximately 3.5 years)] - First episode of medically attended primary CDI incidence per 1000 person- years of follow- up * The incidence of the first episode of clinically meaningful primary CDI [Time Frame: from 14 days after Vaccination 2 to the end of the surveillance period (up to approximately 3.5 years)] - First episode of clinically meaningful primary CDI incidence per 1000 person- years of follow- up	—

Measure

Time frame

* The percentage of participants reporting local reactions [Time Frame: For 7 days after each vaccination] - Injection site pain, redness, and swelling as self-reported in electronic diaries * The percentage of participants reporting systemic events [Time Frame: For 7 days after each vaccination] - Fever, vomiting, fatigue, headache, muscle pain, and joint pain as self-reported in electronic diaries * Percentage of participants reporting adverse events [Time Frame: From each vaccination through 1 month after each vaccination] - As elicited by investigator site staff * Percentage of participants reporting serious adverse events [Time Frame: From Vaccination 1 (Day 1) through 12 months after Vaccination 2 (last dose) (18 months)] - As elicited by investigator site staff * The incidence of the first episode of medically attended and clinically meaningful primary Clostridioides difficile infection (CDI) [Time Frame: from 14 days after Vaccination 2 to the end of the surveillance period (up to approximately 3.5 years)] - First episode of medically attended and clinically meaningful primary CDI incidence per 1000 person- years of follow- up * The incidence of the first episode of medically attended primary CDI [Time Frame: from 14 days after Vaccination 2 to the end of the surveillance period (up to approximately 3.5 years)] - First episode of medically attended primary CDI incidence per 1000 person- years of follow- up * The incidence of the first episode of clinically meaningful primary CDI [Time Frame: from 14 days after Vaccination 2 to the end of the surveillance period (up to approximately 3.5 years)] - First episode of clinically meaningful primary CDI incidence per 1000 person- years of follow- up

—

Secondary

Measure	Time frame
* The incidence of antibiotic use in the treatment of a first episode of the primary CDI [Time Frame: from 14 days after Vaccination 2 to the end of the surveillance period (up to approximately 3.5 years)] - First episode of primary CDI with antibiotic use incidence per 1000 person- years of follow- up * The incidence of severe primary CDI as defined by Infectious Diseases Society of America (IDSA)/ Society for Healthcare Epidemiology of America (SHEA) [Time Frame: from 14 days after Vaccination 2 to the end of the surveillance period (up to approximately 3.5 years)] - First episode of severe or fulminant primary CDI incidence per 1000 person- years of follow- up * The incidence of a first episode of primary CDI (any severity) [Time Frame: from 14 days after Vaccination 2 to the end of the surveillance period (up to approximately 3.5 years)] - First episode of primary CDI incidence per 1000 person- years of follow- up * The incidence of all CDI (primary and recurrent) [Time Frame: from 14 days after Vaccination 2 to the end of the surveillance period (up to approximately 3.5 years)] - Time to all C.difficile infection cases	—

Measure

Time frame

* The incidence of antibiotic use in the treatment of a first episode of the primary CDI [Time Frame: from 14 days after Vaccination 2 to the end of the surveillance period (up to approximately 3.5 years)] - First episode of primary CDI with antibiotic use incidence per 1000 person- years of follow- up * The incidence of severe primary CDI as defined by Infectious Diseases Society of America (IDSA)/ Society for Healthcare Epidemiology of America (SHEA) [Time Frame: from 14 days after Vaccination 2 to the end of the surveillance period (up to approximately 3.5 years)] - First episode of severe or fulminant primary CDI incidence per 1000 person- years of follow- up * The incidence of a first episode of primary CDI (any severity) [Time Frame: from 14 days after Vaccination 2 to the end of the surveillance period (up to approximately 3.5 years)] - First episode of primary CDI incidence per 1000 person- years of follow- up * The incidence of all CDI (primary and recurrent) [Time Frame: from 14 days after Vaccination 2 to the end of the surveillance period (up to approximately 3.5 years)] - Time to all C.difficile infection cases

—

Countries

Argentina, Japan, United Kingdom, United States

Contacts

Public ContactClinical Trials Information Desk

Pfizer R&D Japan G.K.

clinical-trials@pfizer.com+81-3-5309-7000

Outcome results

None listed

Source: JPRN (via WHO ICTRP) · Data processed: May 30, 2026