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C.difficile vaccine

Phase 3

Clostridoides Difficile Associated Disease | Monoclonal antibody | Infectious Disease |Pfizer, Inc.|Last Updated: Aug 14, 2026

Target and mechanism

ModalityMonoclonal antibody

Also known as C. difficile vaccine (previously studied formulation)., C. difficile vaccine

Success Probability

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Market & Valuation

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Trial Design

RandomizedDouble-BlindCONTROLLEDDMC
Total Trials1
Total Enrollment32,500

FDA Designations

No designations recorded

Clinical trial landscape

C.difficile vaccine · 1 trial · 1 indication

Phase 3 1
NCT07282665A Study to Learn About a Clostridioides Difficile Vaccine in People 65 Years of Age and OlderClostridoides Difficile Associated Disease
RECRUITING32,500 Analytics
PHASE3RECRUITING
A Study to Learn About a Clostridioides Difficile Vaccine in People 65 Years of Age and Older
Clostridoides Difficile Associated DiseaseUnlock trial analytics

Study Endpoints

Primary Endpoints

The percentage of participants reporting local reactions
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
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
From each vaccination through 1 month after each vaccination

As elicited by investigator site staff

Percentage of participants reporting serious adverse events
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)
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
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
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 Endpoints

The incidence of antibiotic use in the treatment of a first episode of the primary CDI
from 14 days after Vaccination 2 to the end of the surveillance period (up to approximately 3.5 years)
The incidence of severe or fulminant primary CDI
from 14 days after Vaccination 2 to the end of the surveillance period (up to approximately 3.5 years)
The incidence of a first episode of primary CDI (any severity)
from 14 days after Vaccination 2 to the end of the surveillance period (up to approximately 3.5 years)
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Study Design & Arms

AllocationRANDOMIZED
MaskingQUADRUPLE
ModelPARALLEL
PurposePREVENTION

Treatment Arms

ArmTypeDescription
C.difficile vaccineEXPERIMENTALNovel vaccine formulation
Saline PlaceboOTHER -

Interventions

NameTypeDescription
C.difficile vaccineBIOLOGICALC.difficile vaccine given as an intramuscular injection
Saline PlaceboOTHER0.9% sodium chloride solution given as a intramuscular injection
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Eligibility Criteria

Age Range65 Years to N/A
SexALL
Healthy VolunteersYes
Study Sites183

Who Can Join the Study (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 ...

Countries:United StatesArgentinaJapanUnited Kingdom
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Recent Changes (Last 90 Days)

MEDIUMAug 14, 2026NCT07282665Enrollment: 32000 → 32500
MEDIUMAug 14, 2026NCT07282665Enrollment: 32000 → 32500

Frequently asked questions about C.difficile vaccine

What is C. difficile vaccine used for?

C. difficile vaccine is an investigational vaccine being developed to prevent Clostridium difficile associated disease, also referred to as Clostridioides difficile associated disease. It is intended for use in adults, with clinical studies evaluating regimens in healthy adults aged 50 to 85 years and in people 65 years of age and older.

Who makes C. difficile vaccine?

C. difficile vaccine is being developed by Pfizer, Inc., a biopharmaceutical company traded on the New York Stock Exchange under the ticker symbol PFE. The vaccine is currently in clinical development and has not been approved by regulatory authorities.

What phase is C. difficile vaccine in?

C. difficile vaccine is in Phase 1 clinical development. Early-stage trials have been completed, and a Phase 3 study is currently recruiting participants. The vaccine remains investigational and is not yet approved for commercial use.

What clinical trials is C. difficile vaccine in?

C. difficile vaccine has been studied in several clinical trials. Completed Phase 1 trials include NCT01706367 and NCT02052726, which evaluated 3-dose regimens in healthy adults aged 50 to 85 years. A Phase 3 trial, NCT07282665, is currently recruiting 32,500 participants aged 65 years and older.

Is C. difficile vaccine the same as C.difficile vaccine?

Yes, C. difficile vaccine is also known as C.difficile vaccine. The alternative name refers to the same investigational vaccine developed by Pfizer, Inc. for the prevention of Clostridium difficile associated disease.