Overview

This trial is active, not recruiting.

Condition clostridium difficile associated disease
Treatments clostridium difficile vaccine, placebo
Phase phase 2
Sponsor Pfizer
Start date July 2015
End date March 2017
Trial size 854 participants
Trial identifier NCT02561195, B5091009

Summary

This study will investigate a Clostridium difficile vaccine in healthy adults aged 65-85 years. Each subject will initially receive 3 doses of vaccine on 1 of 2 vaccination schedules. The study will assess the safety and tolerability of the vaccine as well as the subjects' immune response to the vaccine. One year after the third dose subjects that did not receive placebo will be randomized to receive a fourth dose. Subjects will be followed for up to 4 years after their third vaccination.

United States No locations recruiting
Other countries No locations recruiting

Study Design

Allocation randomized
Intervention model parallel assignment
Primary purpose prevention
Masking participant, investigator, outcomes assessor
Arm
(Experimental)
clostridium difficile vaccine
0.5 mL intramuscular injection.
(Experimental)
clostridium difficile vaccine
0.5 mL intramuscular injection.
(Placebo Comparator)
placebo
0.5 mL intramuscular injection
(Experimental)
clostridium difficile vaccine
0.5 mL intramuscular injection.
(Experimental)
clostridium difficile vaccine
0.5 mL intramuscular injection.
(Placebo Comparator)
placebo
0.5 mL intramuscular injection

Primary Outcomes

Measure
Proportions of subjects in each vaccine group with toxin A- specific neutralizing antibody level greater than or equal to the specified threshold for toxin A.
time frame: 7 days or 1 month after dose 3
Proportions of subjects in each vaccine group with toxin B- specific neutralizing antibody level greater than or equal to the specified threshold for toxin B.
time frame: 7 days or 1 month after dose 3
Proportions of subjects in each vaccine group with both toxin A- toxin B- specific neutralizing antibody level greater than or equal to the specified threshold for toxin A- and toxin B, respectively.
time frame: 7 days or 1 month after dose 3
Proportions of subjects reporting local reactions (pain, erythema, and induration) and their severity, as self-reported on e-diaries.
time frame: Up to 14 days after vaccinations 1, 2, and 3
Proportions of subjects reporting systemic events (fever, vomiting, diarrhea, headache, fatigue, new or worsening muscle pain and new or worsening joint pain) and their severity, as self-reported on e-diaries.
time frame: Up to 14 days after vaccinations 1, 2, and 3
Proportions of subjects reporting AEs (categorized according to the Medical Dictionary for Regulatory Activities [MedDRA]).
time frame: From the first vaccination up to 28 days after the third vaccination.
Proportions of subjects reporting SAEs (categorized according to the Medical Dictionary for Regulatory Activities [MedDRA]).
time frame: From the first vaccination until 6 months after the third vaccination.

Secondary Outcomes

Measure
Toxin A- and toxin B-specific neutralizing antibody levels, expressed as geometric mean concentrations.
time frame: At multiple timepoints during the study up to 36 months after dose 4
Geometric mean fold rises in toxin A-specific neutralizing antibody levels.
time frame: At multiple timepoints during the study up to 36 months after dose 4
Geometric mean fold rises in toxin B-specific neutralizing antibody levels.
time frame: At multiple timepoints during the study up to 36 months after dose 4
Geometric mean fold rises in both toxin A- and toxin B-specific neutralizing antibody levels.
time frame: At multiple timepoints during the study up to 36 months after dose 4
Proportions of subjects in each vaccine group with fold rises in toxin A-specific neutralizing antibody levels.
time frame: At multiple timepoints during the study up to 36 months after dose 4
Proportions of subjects in each vaccine group with fold rises in toxin B-specific neutralizing antibody levels.
time frame: At multiple timepoints during the study up to 36 months after dose 4
Proportions of subjects in each vaccine group with fold rises in both toxin A- and toxin B-specific neutralizing antibody levels.
time frame: At multiple timepoints during the study up to 36 months after dose 4
Proportions of subjects in each vaccine group with toxin A- specific neutralizing antibody level greater than or equal to the specified threshold for toxin A.
time frame: At multiple timepoints during the study up to 36 months after dose 4
Proportions of subjects in each vaccine group with toxin B- specific neutralizing antibody level greater than or equal to the specified threshold for toxin B.
time frame: At multiple timepoints during the study up to 36 months after dose 4
Proportions of subjects in each vaccine group with both toxin A- toxin B- specific neutralizing antibody level greater than or equal to the specified threshold for toxin A- and toxin B, respectively.
time frame: At multiple timepoints during the study up to 36 months after dose 4
Proportions of subjects reporting local reactions (pain, erythema, and induration) and their severity, as self-reported on e-diaries.
time frame: Up to 14 days after vaccination 4
Proportions of subjects reporting systemic events (fever, vomiting, diarrhea, headache, fatigue, new or worsening muscle pain and new or worsening joint pain) and their severity, as self-reported on e-diaries.
time frame: Up to 14 days after vaccination 4
Proportions of subjects reporting AEs (categorized according to the Medical Dictionary for Regulatory Activities [MedDRA]).
time frame: From the fourth vaccination up to 28 days after it.
Proportions of subjects reporting SAEs (categorized according to the Medical Dictionary for Regulatory Activities [MedDRA]).
time frame: From the fourth vaccination until 6 months after it

Eligibility Criteria

All participants from 65 years up to 85 years old.

Inclusion Criteria: - Healthy male and female subjects - Aged 65 to 85 years Additional Inclusion Criteria for the extension Stage: - Receipt of all 3 doses of C difficile vaccine (100 µg or 200 µg antigen dose level) in the original portion of the study. Exclusion Criteria: - Proven or suspected prior episode of Clostridium difficile associated diarrhea - Unstable chronic medical condition - Disease requiring significant change in therapy or hospitalization for worsening disease within 8 weeks before receipt of study vaccine - Serious chronic disorders - Congenital or acquired immunodeficiency disorders - Rheumatologic disorders or other illnesses requiring chronic treatment with known immunosuppressant medications. - Active or treated leukemia or lymphoma or bone marrow disorder - Any contraindication to vaccination or vaccine components including previous anaphylactic reaction to any vaccine or vaccine-related components Additional Exclusion Criteria for the Extension Stage: - Subjects originally randomized to placebo during the original portion of the study. - Subjects who have already completed Visit 9 prior to study unblinding.

Additional Information

Official title A Phase 2, Placebo-controlled, Randomized, Observer-blinded Study To Evaluate The Safety, Tolerability, And Immunogenicity Of Two 3-dose Regimens Of A Clostridium Difficile Vaccine In Healthy Adults Aged 65 To 85 Years
Trial information was received from ClinicalTrials.gov and was last updated in March 2017.
Information provided to ClinicalTrials.gov by Pfizer.