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Clostridium Difficile Associated DiseasePhase 2NCT02561195

A Study To Investigate Two 3-dose Schedules Of A Clostridium Difficile Vaccine In Healthy Adults Aged 65 to 85 Years

A Phase 2 study testing Clostridium difficile Vaccine in people with Clostridium Difficile Associated Disease, run by Pfizer at 17 sites in United States.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record
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Trial 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. Read more about this study

Who is it for?
Ages 65 to 85 yearsHealthy volunteers can take part
Conditions the study is for
Clostridium Difficile Associated Disease
What is being tested?
Clostridium difficile Vaccine
Could I receive a placebo?
Yes, some participants may receive a placebo
How many people
300 participants
Where
17 sitesUnited States
Study dates
16 Jul 2015to 13 Feb 2020
Phase
Phase 2
Are there results?
Yes, posted in the registrySummary in the doctors' view

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 65 to 85 years
  • All sexes
  • Healthy volunteers accepted
  • Older adult

Who may be able to join

  • 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.

Who cannot join

  • 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.
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  • 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.

Trial locations and contacts

17 sites in 1 country.

17 sites in 1 country

United States17 sites
  • Benchmark Research

    Austin, Texas, 78705

  • Cincinnati Childrens Hospital Medical Center

    Cincinnati, Ohio, 45206

  • Cincinnati Childrens Hospital Medical Center

    Cincinnati, Ohio, 45229

  • Avail Clinical Research, LLC

    DeLand, Florida, 32720

  • QPS-MRA, LLC (Broward Research Group)

    Hollywood, Florida, 33024

  • East-West Medical Research Institute

    Honolulu, Hawaii, 96814

  • Texas Center For Drug Development, Inc.

    Houston, Texas, 77081

  • Clinical Research Center of Nevada LLC

    Las Vegas, Nevada, 89104

  • Meridian Clinical Research, LLC

    Omaha, Nebraska, 68134

  • Vince & Associates Clinical Research, Inc.

    Overland Park, Kansas, 66212

  • Vince & Associates Clinical Research, Inc

    Overland Park, Kansas, 66212

  • Wake Research Associates, LLC

    Raleigh, North Carolina, 27612

  • J. Lewis Research, Inc. / Foothill Family Clinic

    Salt Lake City, Utah, 84109

  • J. Lewis Research, Inc. / Foothill Family Clinic South

    Salt Lake City, Utah, 84121

  • Clinical Trials of Texas, Inc.

    San Antonio, Texas, 78229

  • QPS-MRA, LLC (Miami Research Associates)

    South Miami, Florida, 33143

  • PMG Research of Wilmington, LLC

    Wilmington, North Carolina, 28401

Other trials in United States

About this study

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

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.

Being tested
Clostridium difficile Vaccine, Placebo
Keywords
Clostridium difficile, Vaccine.

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • Clostridium difficile VaccineBiological

    0.5 mL intramuscular injection.

  • PlaceboBiological

    0.5 mL intramuscular injection

Study groups in NCT02561195
Study groupRoleWhat they receive
Low-dose C. difficile Vaccine (accelerated schedule)ExperimentalNot described
Receives: Biological: Clostridium difficile Vaccine
High-dose C. difficile Vaccine (accelerated schedule)ExperimentalNot described
Receives: Biological: Clostridium difficile Vaccine
Placebo (accelerated schedule)Placebo comparatorNot described
Receives: Biological: Placebo
Low-dose C. difficile Vaccine (non-accelerated schedule)ExperimentalNot described
Receives: Biological: Clostridium difficile Vaccine
High-Dose C. difficile Vaccine (non-accelerated schedule)ExperimentalNot described
Receives: Biological: Clostridium difficile Vaccine
Placebo (non-accelerated schedule)Placebo comparatorNot described
Receives: Biological: Placebo

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Day 1, 8 and 30 Regimen: Percentage of Participants Achieving Prespecified Antibody Titer Level for Toxin A at Day 37

    Toxin A antibodies (threshold >= 219 neutralization units/mL) were measured using neutralization assay.

    Measured: Day 37 (7 days after Vaccination 3 of Day 1, 8 and 30 regimen)

  2. Month 0, 1 and 6 Regimen: Percentage of Participants Achieving Prespecified Antibody Titer Level for Toxin A at Month 7

    Toxin A antibodies (threshold >= 219 neutralization units/mL) were measured using neutralization assay.

    Measured: Month 7 (1 month after Vaccination 3 of Month 0, 1 and 6 regimen)

  3. Day 1, 8 and 30 Regimen: Percentage of Participants Achieving Prespecified Antibody Titer Level for Toxin B at Day 37

    Toxin B antibodies (threshold >= 2586 neutralization units/mL) were measured using neutralization assay.

    Measured: Day 37 (7 days after Vaccination 3 of Day 1, 8 and 30 regimen)

  4. Month 0, 1 and 6 Regimen: Percentage of Participants Achieving Prespecified Antibody Titer Level for Toxin B at Month 7

    Toxin B antibodies (threshold >= 2586 neutralization units/mL) were measured using neutralization assay.

    Measured: Month 7 (1 month after Vaccination 3 of Month 0, 1 and 6 regimen)

  5. Day 1, 8 and 30 Regimen: Percentage of Participants Achieving Prespecified Antibody Titer Level for Both Toxin A and Toxin B at Day 37

    Toxin A and B antibodies (threshold >= 219 and 2586 neutralization units/mL) were measured using neutralization assay.

    Measured: Day 37 (7 days after Vaccination 3 of Day 1, 8 and 30 regimen)

  6. Month 0, 1 and 6 Regimen: Percentage of Participants Achieving Prespecified Antibody Titer Level for Both Toxin A and Toxin B at Month 7

    Toxin A and B antibodies (threshold >= 219 and 2586 neutralization units/mL) were measured using neutralization assay.

    Measured: Month 7 (1 month after Vaccination 3 of Month 0, 1 and 6 regimen)

  7. Day 1, 8 and 30 Regimen: Percentage of Participants With Local Reactions by Severity Within 7 Days After Vaccination 1

    Local reactions included pain at injection site, swelling and redness collected by using an electronic diary (e-diary). Pain was graded as: mild (grade 1) (did not interfere with activity), moderate (grade 2)(interfered with activity), severe (grade 3) (prevented daily activity) and grade 4 (emergency room visit or hospitalization). Redness and swelling were graded as: mild (2.5-5.0 centimeter [cm]), moderate (>5.0 to 10.0 cm), severe (>10.0 cm) and grade 4 (necrosis).

    Measured: within 7 days After Vaccination 1

  8. Month 0, 1 and 6 Regimen: Percentage of Participants With Local Reactions by Severity Within 14 Days After Vaccination 1

    Local reactions included pain at injection site, swelling and redness collected by using an electronic diary (e-diary). Pain was graded as: mild (did not interfere with activity), moderate (interfered with activity), severe (prevented daily activity) and grade 4 (emergency room visit or hospitalization). Redness and swelling were graded as: mild (2.5-5.0 cm), moderate (>5.0 to 10.0 cm), severe (>10.0 cm) and grade 4 (necrosis).

    Measured: within 14 days After Vaccination 1

  9. Day 1, 8 and 30 Regimen: Percentage of Participants With Local Reactions by Severity Within 14 Days After Vaccination 2

    Local reactions included pain at injection site, swelling and redness collected by using an electronic diary (e-diary). Pain was graded as: mild (did not interfere with activity), moderate (interfered with activity), severe (prevented daily activity) and grade 4 (emergency room visit or hospitalization). Redness and swelling were graded as: mild (2.5-5.0 cm), moderate (>5.0 to 10.0 cm), severe (>10.0 cm) and grade 4 (necrosis).

    Measured: within 14 days After Vaccination 2

  10. Month 0, 1 and 6 Regimen: Percentage of Participants With Local Reactions by Severity Within 14 Days After Vaccination 2

    Local reactions included pain at injection site, swelling and redness collected by using an electronic diary (e-diary). Pain was graded as: mild (did not interfere with activity), moderate (interfered with activity), severe (prevented daily activity) and grade 4 (emergency room visit or hospitalization). Redness and swelling were graded as: mild (2.5-5.0 cm), moderate (>5.0 to 10.0 cm), severe (>10.0 cm) and grade 4 (necrosis).

    Measured: within 14 days after Vaccination 2

  11. Day 1, 8 and 30 Regimen: Percentage of Participants With Local Reactions by Severity Within 14 Days After Vaccination 3

    Local reactions included pain at injection site, swelling and redness collected by using an electronic diary (e-diary). Pain was graded as: mild (did not interfere with activity), moderate (interfered with activity), severe (prevented daily activity) and grade 4 (emergency room visit or hospitalization). Redness and swelling were graded as: mild (2.5-5.0 cm), moderate (>5.0 to 10.0 cm), severe (>10.0 cm) and grade 4 (necrosis).

    Measured: within 14 days after Vaccination 3

  12. Month 0, 1 and 6 Regimen: Percentage of Participants With Local Reactions by Severity Within 14 Days After Vaccination 3

    Local reactions included pain at injection site, swelling and redness collected by using an electronic diary (e-diary). Pain was graded as: mild (did not interfere with activity), moderate (interfered with activity), severe (prevented daily activity) and grade 4 (emergency room visit or hospitalization). Redness and swelling were graded as: mild (2.5-5.0 cm), moderate (>5.0 to 10.0 cm), severe (>10.0 cm) and grade 4 (necrosis).

    Measured: within 14 days after Vaccination 3

  13. Day 1, 8 and 30 Regimen: Percentage of Participants With Systemic Events by Severity Within 7 Days After Vaccination 1

    Systemic events included fever, vomiting, diarrhea, headache, fatigue, new or worsening muscle pain, new or worsening joint pain and were recorded by using an e-diary. Fever was graded as mild (38.0 to 38.4 degree Celsius (C)), moderate (38.5 to 38.9 degree C), severe (39.0 to 40.0 degree C), grade 4 (>40.0 degree C). Vomiting was graded as mild (1-2 times in 24 hours), moderate (>2 times in 24 hours), severe (required intravenous hydration) and grade 4 (hospitalization for hypotensive shock). Diarrhea was graded as mild (2-3 loose stools in 24 hours), moderate (4-5 loose stools in 24 hours), severe (>=6 stools in 24 hours) and grade 4 (hospitalization). Headache, fatigue, new or worsening muscle pain and new or worsening joint pain was graded as mild (no interference with activity), moderate (some interference with activity), severe (prevents daily activity) and grade 4 (hospitalization).

    Measured: within 7 days after Vaccination 1

  14. Month 0, 1 and 6 Regimen: Percentage of Participants With Systemic Events by Severity Within 14 Days After Vaccination 1

    Systemic events included fever, vomiting, diarrhea, headache, fatigue, new or worsening muscle pain, new or worsening joint pain and were recorded by using an e-diary. Fever was graded as mild (38.0 to 38.4 C), moderate (38.5 to 38.9 degree C), severe (39.0 to 40.0 degree C), grade 4 (>40.0 degree C). Vomiting was graded as mild (1-2 times in 24 hours), moderate (>2 times in 24 hours), severe (required intravenous hydration) and grade 4 (hospitalization for hypotensive shock). Diarrhea was graded as mild (2-3 loose stools in 24 hours), moderate (4-5 loose stools in 24 hours), severe (>=6 stools in 24 hours) and grade 4 (hospitalization). Headache, fatigue, new or worsening muscle pain and new or worsening joint pain was graded as mild (no interference with activity), moderate (some interference with activity), severe (prevents daily activity) and grade 4 (hospitalization).

    Measured: within 14 days after Vaccination 1

  15. Day 1, 8 and 30 Regimen: Percentage of Participants With Systemic Events by Severity Within 14 Days After Vaccination 2

    Systemic events included fever, vomiting, diarrhea, headache, fatigue, new or worsening muscle pain, new or worsening joint pain and were recorded by using an e-diary. Fever was graded as mild (38.0 to 38.4 C), moderate (38.5 to 38.9 degree C), severe (39.0 to 40.0 degree C), grade 4 (>40.0 degree C). Vomiting was graded as mild (1-2 times in 24 hours), moderate (>2 times in 24 hours), severe (required intravenous hydration) and grade 4 (hospitalization for hypotensive shock). Diarrhea was graded as mild (2-3 loose stools in 24 hours), moderate (4-5 loose stools in 24 hours), severe (>=6 stools in 24 hours) and grade 4 (hospitalization). Headache, fatigue, new or worsening muscle pain and new or worsening joint pain was graded as mild (no interference with activity), moderate (some interference with activity), severe (prevents daily activity) and grade 4 (hospitalization).

    Measured: within 14 days after Vaccination 2

  16. Month 0, 1 and 6 Regimen: Percentage of Participants With Systemic Events by Severity Within 14 Days After Vaccination 2

    Systemic events included fever, vomiting, diarrhea, headache, fatigue, new or worsening muscle pain, new or worsening joint pain and were recorded by using an e-diary. Fever was graded as mild (38.0 to 38.4 C), moderate (38.5 to 38.9 degree C), severe (39.0 to 40.0 degree C), grade 4 (>40.0 degree C). Vomiting was graded as mild (1-2 times in 24 hours), moderate (>2 times in 24 hours), severe (required intravenous hydration) and grade 4 (hospitalization for hypotensive shock). Diarrhea was graded as mild (2-3 loose stools in 24 hours), moderate (4-5 loose stools in 24 hours), severe (>=6 stools in 24 hours) and grade 4 (hospitalization). Headache, fatigue, new or worsening muscle pain and new or worsening joint pain was graded as mild (no interference with activity), moderate (some interference with activity), severe (prevents daily activity) and grade 4 (hospitalization).

    Measured: within 14 days after Vaccination 2

  17. Day 1, 8 and 30 Regimen: Percentage of Participants With Systemic Events by Severity Within 14 Days After Vaccination 3

    Systemic events included fever, vomiting, diarrhea, headache, fatigue, new or worsening muscle pain, new or worsening joint pain and were recorded by using an e-diary. Fever was graded as mild (38.0 to 38.4 C), moderate (38.5 to 38.9 degree C), severe (39.0 to 40.0 degree C), grade 4 (>40.0 degree C). Vomiting was graded as mild (1-2 times in 24 hours), moderate (>2 times in 24 hours), severe (required intravenous hydration) and grade 4 (hospitalization for hypotensive shock). Diarrhea was graded as mild (2-3 loose stools in 24 hours), moderate (4-5 loose stools in 24 hours), severe (>=6 stools in 24 hours) and grade 4 (hospitalization). Headache, fatigue, new or worsening muscle pain and new or worsening joint pain was graded as mild (no interference with activity), moderate (some interference with activity), severe (prevents daily activity) and grade 4 (hospitalization).

    Measured: within 14 days after Vaccination 3

  18. Month 0, 1 and 6 Regimen: Percentage of Participants With Systemic Events by Severity Within 14 Days After Vaccination 3

    Systemic events included fever, vomiting, diarrhea, headache, fatigue, new or worsening muscle pain, new or worsening joint pain and were recorded by using an e-diary. Fever was graded as mild (38.0 to 38.4 C), moderate (38.5 to 38.9 degree C), severe (39.0 to 40.0 degree C), grade 4 (>40.0 degree C). Vomiting was graded as mild (1-2 times in 24 hours), moderate (>2 times in 24 hours), severe (required intravenous hydration) and grade 4 (hospitalization for hypotensive shock). Diarrhea was graded as mild (2-3 loose stools in 24 hours), moderate (4-5 loose stools in 24 hours), severe (>=6 stools in 24 hours) and grade 4 (hospitalization). Headache, fatigue, new or worsening muscle pain and new or worsening joint pain was graded as mild (no interference with activity), moderate (some interference with activity), severe (prevents daily activity) and grade 4 (hospitalization).

    Measured: within 14 days after Vaccination 3

  19. Day 1, 8 and 30 Regimen: Percentage of Participants With Treatment Emergent Adverse Events (AEs)

    An AE was any untoward medical occurrence in a participant who received investigational product without regard to possibility of causal relationship. Treatment-emergent are events between first dose of study drug and up to 28 days after last dose of study drug that were absent before treatment or that worsened relative to pretreatment state.

    Measured: From Vaccination 1 up to 28 days after Vaccination 3 (Day 58)

  20. Month 0, 1 and 6 Regimen: Percentage of Participants With Treatment Emergent Adverse Events (AEs)

    An AE was any untoward medical occurrence in a participant who received investigational product without regard to possibility of causal relationship. Treatment-emergent are events between first dose of study drug and up to 28 days after last dose of study drug that were absent before treatment or that worsened relative to pretreatment state.

    Measured: From Vaccination 1 up to 28 days after Vaccination 3 (Day 208)

  21. Day 1, 8 and 30 Regimen: Percentage of Participants With Treatment Emergent Serious Adverse Events (SAEs)

    An AE was any untoward medical occurrence in a participant who received investigational product without regard to possibility of causal relationship. SAE was an AE resulting in any of the following outcomes or deemed significant for any other reason: death; initial or prolonged inpatient hospitalization; life-threatening experience (immediate risk of dying); persistent or significant disability/incapacity; congenital anomaly; lack of efficacy in an approved indication. Treatment-emergent serious adverse events are events between first dose of study drug and up to 6 months after last dose of study drug that were absent before treatment or that worsened relative to pretreatment state.

    Measured: From Vaccination 1 up to 6 months after Vaccination 3 (Month 7)

  22. Month 0, 1 and 6 Regimen: Percentage of Participants With Treatment Emergent Serious Adverse Events (SAEs)

    An AE was any untoward medical occurrence in a participant who received investigational product without regard to possibility of causal relationship. SAE was an AE resulting in any of the following outcomes or deemed significant for any other reason: death; initial or prolonged inpatient hospitalization; life-threatening experience (immediate risk of dying); persistent or significant disability/incapacity; congenital anomaly; lack of efficacy in an approved indication. Treatment-emergent serious adverse events are events between first dose of study drug and up to 6 months after last dose of study drug that were absent before treatment or that worsened relative to pretreatment state.

    Measured: From Vaccination 1 up to 6 months after Vaccination 3 (Month 12)

Secondary outcomes (48)
  1. Day 1, 8 and 30 Regimen: Percentage of Participants Achieving Prespecified Antibody Titer Level for Toxin A at Day 1, 8, 15, 30, and Month 2, 4, 7, 13

    Toxin A antibodies were measured using neutralization assay.

    Measured: Day 1, 8, 15, 30 and Month 2, 4, 7, 13

  2. Day 1, 8 and 30 Regimen: Percentage of Participants Achieving Prespecified Antibody Titer Level for Toxin B at Day 1, 8, 15, 30 and Month 2, 4, 7, 13

    Toxin B antibodies were measured using neutralization assay.

    Measured: Day 1, 8, 15, 30 and Month 2, 4, 7, 13

  3. Day 1, 8 and 30 Regimen: Percentage of Participants Achieving Prespecified Antibody Titer Level for Both Toxin A and Toxin B at Day 1, 8, 15, 30 and Month 2, 4, 7, 13

    Toxin A and toxin B antibodies were measured using neutralization assay.

    Measured: Day 1, 8, 15, 30 and Month 2, 4, 7, 13

  4. Month 0, 1 and 6 Regimen: Percentage of Participants Achieving Prespecified Antibody Titer Level for Toxin A at Day 1, 30, 37, 187 and Month 2, 6, 12, 18

    Toxin A antibodies were measured using neutralization assay.

    Measured: Day 1, 30, 37, 187 and Month 2, 6, 12, 18

  5. Month 0, 1 and 6 Regimen: Percentage of Participants Achieving Prespecified Antibody Titer Level for for Toxin B at Day 1, 30, 37, 187 and Month 2, 6, 12, 18

    Toxin B antibodies were measured using neutralization assay.

    Measured: Day 1, 30, 37, 187 and Month 2, 6, 12, 18

  6. Month 0, 1 and 6 Regimen: Percentage of Participants Achieving Prespecified Antibody Titer Level for Both Toxin A and Toxin B at Day 1, 30, 37, 187 and Month 2, 6, 12, 18

    Toxin A and toxin B antibodies were measured using neutralization assay.

    Measured: Day 1, 30, 37, 187 and Month 2, 6, 12, 18

  7. Day 1, 8 and 30 Regimen: Geometric Mean Concentration of Toxin A Specific Neutralizing Antibody Levels at Day 1, 8, 15, 30, 37 and Month 2, 4, 7, 13

    Geometric mean concentration (GMC) of toxin A specific antibody levels was calculated using back transformations of the logarithmically transformed means of assay results. Confidence interval (CI) for GMC were back transformations of a CI based on the Student t distribution for the mean logarithm of concentrations.

    Measured: Day 1, 8, 15, 30, 37 and Month 2, 4, 7, 13

  8. Day 1, 8 and 30 Regimen: Geometric Mean Concentration of Toxin B Specific Neutralizing Antibody Levels at Day 1, 8, 15, 30, 37 and Month 2, 4, 7, 13

    GMC of toxin B specific antibody levels was calculated using back transformations of the logarithmically transformed means of assay results. CI for GMC were back transformations of a CI based on the Student t distribution for the mean logarithm of concentrations.

    Measured: Day 1, 8, 15, 30, 37 and Month 2, 4, 7, 13

  9. Month 0, 1 and 6 Regimen: Geometric Mean Concentration of Toxin A Specific Neutralizing Antibody Levels at Day 1, 30, 37, 187 and Month 2, 6, 7, 12, 18

    GMC of toxin A specific antibody levels was calculated using back transformations of the logarithmically transformed means of assay results. CI for GMC were back transformations of a CI based on the Student t distribution for the mean logarithm of concentrations.

    Measured: Day 1, 30, 37, 187 and Month 2, 6, 7, 12, 18

  10. Month 0, 1 and 6 Regimen: Geometric Mean Concentration of Toxin B Specific Neutralizing Antibody Levels at Day 1, 30, 37, 187 and Month 2, 6, 7, 12, 18

    GMC of toxin B specific antibody levels was calculated using back transformations of the logarithmically transformed means of assay results. CI for GMC were back transformations of a CI based on the Student t distribution for the mean logarithm of concentrations.

    Measured: Day 1, 30, 37, 187 and Month 2, 6, 7, 12, 18

  11. Day 1, 8 and 30 Regimen: Geometric Mean Fold Rise in Toxin A Specific Neutralizing Antibody Levels From Baseline at Day 8, 15, 30, 37 and Month 2, 4, 7, 13

    Geometric mean fold rise (GMFR) in toxin A specific antibody levels was calculated using back transformations of the logarithmically transformed means of fold rise from baseline with assay results. CI for GMFR were back transformations of a CI based on the Student t distribution for the mean logarithm of the mean fold rise.

    Measured: Day 8, 15, 30, 37 and Month 2, 4, 7, 13

  12. Day 1, 8 and 30 Regimen: Geometric Mean Fold Rise in Toxin B Specific Neutralizing Antibody Levels From Baseline at Day 8, 15, 30, 37 and Month 2, 4, 7, 13

    GMFR in toxin B specific antibody levels was calculated using back transformations of the logarithmically transformed means of fold rise from baseline with assay results. CI for GMFR were back transformations of a CI based on the Student t distribution for the mean logarithm of the mean fold rise.

    Measured: Day 8, 15, 30, 37 and Month 2, 4, 7, 13

  13. Month 0, 1 and 6 Regimen: Geometric Mean Fold Rise in Toxin A Specific Neutralizing Antibody Levels From Baseline at Day 30, 37, 187 and Month 2, 6, 7, 12, 18

    GMFR in toxin A specific antibody levels was calculated using back transformations of the logarithmically transformed means of fold rise from baseline with assay results. CI for GMFR were back transformations of a CI based on the Student t distribution for the mean logarithm of the mean fold rise.

    Measured: Day 30, 37, 187 and Month 2, 6, 7, 12, 18

  14. Month 0, 1 and 6 Regimen: Geometric Mean Fold Rise in Toxin B Specific Neutralizing Antibody Levels From Baseline at Day 30, 37, 187 and Month 2, 6, 7, 12, 18

    GMFR for toxin B specific antibody levels was calculated using back transformations of the logarithmically transformed means of fold rise from baseline with assay results. CI for GMFR were back transformations of a CI based on the Student t distribution for the mean logarithm of the mean fold rise.

    Measured: Day 30, 37, 187 and Month 2, 6, 7, 12, 18

  15. Day 1, 8 and 30 Regimen: Percentage of Participants Achieving >=4, >=8, >=16 and >=32 Fold Rise From Baseline in Toxin A Specific Antibody Levels at Day 8, 15, 30, 37 and Month 2, 4, 7, 13

    Toxin A antibodies were measured using neutralization assay.

    Measured: Day 8, 15, 30, 37 and Month 2, 4, 7, 13

  16. Day 1, 8 and 30 Regimen: Percentage of Participants Achieving >=4, >=8, >=16 and >=32 Fold Rise From Baseline in Toxin B Specific Antibody Levels at Day 8, 15, 30, 37 and Month 2, 4, 7, 13

    Toxin B antibodies were measured using neutralization assay.

    Measured: Day 8, 15, 30, 37 and Month 2, 4, 7, 13

  17. Day 1, 8 and 30 Regimen: Percentage of Participants Achieving>=4,>=8,>=16,>=32 Fold Rise From Baseline in Both Toxin A and Toxin B Specific Antibody Levels at Day 8, 15, 30, 37 and Month 2, 4, 7, 13

    Toxin A and toxin B antibodies were measured using neutralization assay.

    Measured: Day 8, 15, 30, 37 and Month 2, 4, 7, 13

  18. Month 0, 1 and 6 Regimen: Percentage of Participants Achieving >=4, >=8, >=16 and >=32 Fold Rise From Baseline in Toxin A Specific Antibody Levels at Day 30, 37, 187 and Month 2, 6, 7, 12, 18

    Toxin A antibodies were measured using neutralization assay.

    Measured: Day 30, 37, 187 and Month 2, 6, 7, 12, 18

  19. Month 0, 1 and 6 Regimen: Percentage of Participants Achieving >=4, >=8, >=16 and >=32 Fold Rise From Baseline in Toxin B Specific Antibody Levels at Day 30, 37, 187 and Month 2, 6, 7, 12, 18

    Toxin A antibodies were measured using neutralization assay.

    Measured: Day 30, 37, 187 and Month 2, 6, 7, 12, 18

  20. Month 0, 1 and 6 Regimen: Percentage of Participants Achieving>=4,>=8,>=16,>=32 Fold Rise From Baseline in Both Toxin A and Toxin B Antibody Levels at Day 30, 37, 187 and Month 2, 6, 7, 12, 18

    Toxin A and toxin B antibodies were measured using neutralization assay.

    Measured: Day 30, 37, 187 and Month 2, 6, 7, 12, 18

  21. Extension Stage Day 1, 8 and 30 Regimen: Percentage of Participants Achieving Prespecified Antibody Titer Level for Toxin A at Days 1, 8, 30 and Months 6, 12, 18, 24, 30, 36

    Toxin A antibodies (threshold >= 219 neutralization units/mL) were measured using neutralization assay.

    Measured: Days 1, 8, 30 and Months 6, 12, 18, 24, 30, 36 after Vaccination 4

  22. Extension Stage Day 1, 8 and 30 Regimen: Percentage of Participants Achieving Prespecified Antibody Titer Level for Toxin B at Days 1, 8, 30 and Months 6, 12, 18, 24, 30, 36

    Toxin B antibodies (threshold >= 2586 neutralization units/mL) were measured using neutralization assay.

    Measured: Days 1, 8, 30 and Months 6, 12, 18, 24, 30, 36 after Vaccination 4

  23. Extension Stage Day 1, 8 and 30 Regimen: Percentage of Participants Achieving Prespecified Antibody Titer Level for Both Toxin A and Toxin B at Days 1, 8, 30 and Months 6, 12, 18, 24, 30, 36

    Toxin A and B antibodies (threshold >= 219 and 2586 neutralization units/mL) were measured using neutralization assay.

    Measured: Days 1, 8, 30 and Months 6, 12, 18, 24, 30, 36 after Vaccination 4

  24. Extension Stage Month 0, 1 and 6 Regimen: Percentage of Participants Achieving Prespecified Antibody Titer Level for Toxin A at Days 1, 8, 30 and Months 6, 12, 18, 24, 30, 36

    Toxin A antibodies (threshold >= 219 neutralization units/mL) were measured using neutralization assay.

    Measured: Days 1, 8, 30 and Months 6, 12, 18, 24, 30, 36 after Vaccination 4

  25. Extension Stage Month 0, 1 and 6 Regimen: Percentage of Participants Achieving Prespecified Antibody Titer Level for Toxin B at Days 1, 8, 30 and Months 6, 12, 18, 24, 30, 36

    Toxin B antibodies (threshold >= 2586 neutralization units/mL) were measured using neutralization assay.

    Measured: Days 1, 8, 30 and Months 6, 12, 18, 24, 30, 36 after Vaccination 4

  26. Extension Stage Month 0, 1 and 6 Regimen: Percentage of Participants Achieving Prespecified Antibody Titer Level for Both Toxin A and Toxin B at Days 1, 8, 30 and Months 6, 12, 18, 24, 30, 36

    Toxin A and B antibodies (threshold >= 219 and 2586 neutralization units/mL) were measured using neutralization assay.

    Measured: Days 1, 8, 30 and Months 6, 12, 18, 24, 30, 36 after Vaccination 4

  27. Extension Stage Day 1, 8 and 30 Regimen: Geometric Mean Concentration for Toxin A Specific Neutralizing Antibody Levels at Days 1, 8, 30 and Months 6, 12, 18, 24, 30, 36

    GMC of toxin A specific antibody levels was calculated using back transformations of the logarithmically transformed means of assay results. CI for GMC were back transformations of a CI based on the Student t distribution for the mean logarithm of concentrations.

    Measured: Days 1, 8, 30 and Months 6, 12, 18, 24, 30, 36 after Vaccination 4

  28. Extension Stage Day 1, 8 and 30 Regimen: Geometric Mean Concentration for Toxin B Specific Neutralizing Antibody Levels at Days 1, 8, 30 and Months 6, 12, 18, 24, 30, 36

    GMC of toxin B specific antibody levels was calculated using back transformations of the logarithmically transformed means of assay results. CI for GMC were back transformations of a CI based on the Student t distribution for the mean logarithm of concentrations.

    Measured: Extension Stage Days 1, 8, 30 and Months 6, 12, 18, 24, 30, 36 after Vaccination 4

  29. Extension Stage Month 0, 1 and 6 Regimen: Geometric Mean Concentration for Toxin A Specific Neutralizing Antibody Levels at Days 1, 8, 30 and Months 6, 12, 18, 24, 30, 36

    GMC of toxin A specific antibody levels was calculated using back transformations of the logarithmically transformed means of assay results. CI for GMC were back transformations of a CI based on the Student t distribution for the mean logarithm of concentrations.

    Measured: Days 1, 8, 30 and Months 6, 12, 18, 24, 30, 36 after Vaccination 4

  30. Extension Stage Month 0, 1 and 6 Regimen: Geometric Mean Concentration for Toxin B Specific Neutralizing Antibody Levels at Days 1, 8, 30 and Months 6, 12, 18, 24, 30, 36

    GMC of toxin B specific antibody levels was calculated using back transformations of the logarithmically transformed means of assay results. CI for GMC were back transformations of a CI based on the Student t distribution for the mean logarithm of concentrations.

    Measured: Days 1, 8, 30 and Months 6, 12, 18, 24, 30, 36 after Vaccination 4

  31. Extension Stage Day 1, 8 and 30 Regimen: Geometric Mean Fold Rise in Toxin A Specific Neutralizing Antibody Levels From Baseline at Days 8, 30 and Months 6, 12, 18, 24, 30, 36

    GMFR in toxin A specific antibody levels was calculated using back transformations of the logarithmically transformed means of fold rise from baseline with assay results. CI for GMFR were back transformations of a CI based on the Student t distribution for the mean logarithm of the mean fold rise.

    Measured: Days 8, 30 and Months 6, 12, 18, 24, 30, 36 after Vaccination 4

  32. Extension Stage Day 1, 8 and 30 Regimen: Geometric Mean Fold Rise in Toxin B Specific Neutralizing Antibody Levels From Baseline at Day 8, 30 and Months 6, 12, 18, 24, 30, 36

    GMFR in toxin B specific antibody levels was calculated using back transformations of the logarithmically transformed means of fold rise from baseline with assay results. CI for GMFR were back transformations of a CI based on the Student t distribution for the mean logarithm of the mean fold rise.

    Measured: Days 8, 30 and Months 6, 12, 18, 24, 30, 36 after Vaccination 4

  33. Extension Stage Month 0, 1 and 6 Regimen: Geometric Mean Fold Rise in Toxin A Specific Neutralizing Antibody Levels From Baseline at Days 8, 30 and Months 6, 12, 18, 24, 30, 36

    GMFR in toxin A specific antibody levels was calculated using back transformations of the logarithmically transformed means of fold rise from baseline with assay results. CI for GMFR were back transformations of a CI based on the Student t distribution for the mean logarithm of the mean fold rise.

    Measured: Days 8, 30 and Months 6, 12, 18, 24, 30, 36 after Vaccination 4

  34. Extension Stage Month 0, 1 and 6 Regimen: Geometric Mean Fold Rise in Toxin B Specific Neutralizing Antibody Levels From Baseline at Days 8, 30 and Months 6, 12, 18, 24, 30, 36

    GMFR in toxin B specific antibody levels was calculated using back transformations of the logarithmically transformed means of fold rise from baseline with assay results. CI for GMFR were back transformations of a CI based on the Student t distribution for the mean logarithm of the mean fold rise.

    Measured: Days 8, 30 and Months 6, 12, 18, 24, 30, 36 after Vaccination 4

  35. Extension Stage Day 1, 8 and 30 Regimen: Percentage of Participants Achieving >=4, >=8, >=16 and >=32 Fold Rise From Baseline in Toxin A Specific Antibody Levels at Days 8, 30 and Months 6, 12, 18, 24, 30, 36

    Toxin A antibodies were measured using neutralization assay.

    Measured: Days 8, 30 and Months 6, 12, 18, 24, 30, 36 after Vaccination 4

  36. Extension Stage Day 1, 8 and 30 Regimen: Percentage of Participants Achieving >=4, >=8, >=16 and >=32 Fold Rise From Baseline in Toxin B Specific Antibody Levels at Days 8, 30 and Months 6, 12, 18, 24, 30, 36

    Toxin B antibodies were measured using neutralization assay.

    Measured: Days 8, 30 and Months 6, 12, 18, 24, 30, 36 after Vaccination 4

  37. Extension Stage Day 1, 8 and 30 Regimen: Percentage of Participants Achieving >=4, >=8, >=16 and >=32 Fold Rise From Baseline in Both Toxin A and Toxin B Specific Antibody Levels at Days 8, 30 and Months 6, 12, 18, 24, 30, 36

    Toxin A and B antibodies were measured using neutralization assay.

    Measured: Days 8, 30 and Months 6, 12, 18, 24, 30, 36 after Vaccination 4

  38. Extension Stage Month 0, 1 and 6 Regimen: Percentage of Participants Achieving >=4, >=8, >=16 and >=32 Fold Rise From Baseline in Toxin A Specific Antibody Levels at Days 8, 30 and Months 6, 12, 18, 24, 30, 36

    Toxin A antibodies were measured using neutralization assay.

    Measured: Days 8, 30 and Months 6, 12, 18, 24, 30, 36 after Vaccination 4

  39. Extension Stage Month 0, 1 and 6 Regimen: Percentage of Participants Achieving >=4, >=8, >=16 and >=32 Fold Rise From Baseline in Toxin B Specific Antibody Levels at Days 8, 30 and Months 6, 12, 18, 24, 30, 36

    Toxin B antibodies were measured using neutralization assay.

    Measured: Days 8, 30 and Months 6, 12, 18, 24, 30, 36 after Vaccination 4

  40. Extension Stage Month 0, 1 and 6 Regimen: Percentage of Participants Achieving >=4, >=8, >=16 and >=32 Fold Rise From Baseline in Both Toxin A and Toxin B Specific Antibody Levels at Days 8, 30 and Months 6, 12, 18, 24, 30, 36

    Toxin A and B antibodies were measured using neutralization assay.

    Measured: Days 8, 30 and Months 6, 12, 18, 24, 30, 36 after Vaccination 4

  41. Extension Stage Day 1, 8 and 30 Regimen: Percentage of Participants With Local Reactions by Severity Within 14 Days After Vaccination 4

    Local reactions included pain at injection site, swelling and redness collected by using an electronic diary (e-diary). Pain was graded as: mild (grade 1) (did not interfere with activity), moderate (grade 2) (interfered with activity), severe (grade 3) (prevented daily activity) and grade 4 (emergency room visit or hospitalization). Redness and swelling were graded as: mild (2.5-5.0 cm), moderate (>5.0 to 10.0 cm), severe (>10.0 cm) and grade 4 (necrosis). Any local reaction referred to any injection site pain, any swelling, or any redness.

    Measured: Within 14 days after Vaccination 4

  42. Extension Stage Month 0, 1 and 6 Regimen: Percentage of Participants With Local Reactions by Severity Within 14 Days After Vaccination 4

    Local reactions included pain at injection site, swelling and redness collected by using an electronic diary (e-diary). Pain was graded as: mild (grade 1) (did not interfere with activity), moderate (grade 2) (interfered with activity), severe (grade 3) (prevented daily activity) and grade 4 (emergency room visit or hospitalization). Redness and swelling were graded as: mild (2.5-5.0 cm), moderate (>5.0 to 10.0 cm), severe (>10.0 cm) and grade 4 (necrosis). Any local reaction referred to any injection site pain, any swelling, or any redness.

    Measured: Within 14 days after Vaccination 4

  43. Extension Stage Day 1, 8 and 30 Regimen: Percentage of Participants With Systemic Events by Severity Within 14 Days After Vaccination 4

    Systemic events included following events: Fever was graded as mild (38.0 to 38.4 degree C), moderate (38.5 to 38.9 degree C), severe (39.0 to 40.0 degree C), grade (G) 4 (>40.0 degree C). Vomiting was graded as mild (1-2 times in 24 hours), moderate (>2 times in 24 hours), severe (required intravenous hydration)/grade 4 (hospitalization for hypotensive shock). Diarrhea was graded as mild (2-3 loose stools in 24 hours), moderate (4-5 loose stools in 24 hours), severe (>=6 stools in 24 hours) and G4 (hospitalization). Headache, fatigue, new/worsening muscle pain and new/worsening joint pain was graded as mild (no interference with activity), moderate (some interference with activity), severe (prevents daily activity) and G4 (hospitalization). Any systemic event referred to any fever >= 38.0 degree C, any vomiting, any diarrhea, any headache, any fatigue, any new/worsening muscle pain, or any new or worsening joint pain.

    Measured: Within 14 days after Vaccination 4

  44. Extension Stage Month 0, 1 and 6 Regimen: Percentage of Participants With Systemic Events by Severity Within 14 Days After Vaccination 4

    Systemic events included following events: Fever was graded as mild (38.0 to 38.4 degree C), moderate (38.5 to 38.9 degree C), severe (39.0 to 40.0 degree C), grade (G) 4 (>40.0 degree C). Vomiting was graded as mild (1-2 times in 24 hours), moderate (>2 times in 24 hours), severe (required intravenous hydration)/grade 4 (hospitalization for hypotensive shock). Diarrhea was graded as mild (2-3 loose stools in 24 hours), moderate (4-5 loose stools in 24 hours), severe (>=6 stools in 24 hours) and G4 (hospitalization). Headache, fatigue, new/worsening muscle pain and new/worsening joint pain was graded as mild (no interference with activity), moderate (some interference with activity), severe (prevents daily activity) and G4 (hospitalization). Any systemic event referred to any fever >= 38.0 degree C, any vomiting, any diarrhea, any headache, any fatigue, any new/worsening muscle pain, or any new or worsening joint pain.

    Measured: within 14 days after Vaccination 4

  45. Extension Stage Day 1, 8 and 30 Regimen: Number of Participants With Treatment Emergent Adverse Events (AEs)

    An AE was any untoward medical occurrence in a participant who received investigational product without regard to possibility of causal relationship. Treatment-emergent adverse events are events from dose 4 of study drug to 28 days after dose 4 of study drug that were absent before treatment or that worsened relative to pretreatment state.

    Measured: From Vaccination 4 up to 28 days after Vaccination 4

  46. Extension Stage Month 0, 1 and 6 Regimen: Number of Participants With Treatment Emergent Adverse Events (AEs)

    An AE was any untoward medical occurrence in a participant who received investigational product without regard to possibility of causal relationship. Treatment-emergent adverse events are events from dose 4 of study drug to 28 days after dose 4 of study drug that were absent before treatment or that worsened relative to pretreatment state.

    Measured: From Vaccination 4 up to 28 days after Vaccination 4

  47. Extension Stage Day 1, 8 and 30 Regimen: Number of Participants With Treatment Emergent Serious Adverse Events (SAEs)

    An AE was any untoward medical occurrence in a participant who received investigational product without regard to possibility of causal relationship. SAE was an AE resulting in any of the following outcomes or deemed significant for any other reason: death; initial or prolonged inpatient hospitalization; life-threatening experience (immediate risk of dying); persistent or significant disability/incapacity; congenital anomaly; lack of efficacy in an approved indication. Treatment-emergent serious adverse events are events from dose 4 of study drug to 6 months after dose 4 of study drug that were absent before treatment or that worsened relative to pretreatment state.

    Measured: From Vaccination 4 up to 6 months after Vaccination 4

  48. Extension Stage Month 0, 1 and 6 Regimen: Number of Participants With Treatment Emergent Serious Adverse Events (SAEs)

    An AE was any untoward medical occurrence in a participant who received investigational product without regard to possibility of causal relationship. SAE was an AE resulting in any of the following outcomes or deemed significant for any other reason: death; initial or prolonged inpatient hospitalization; life-threatening experience (immediate risk of dying); persistent or significant disability/incapacity; congenital anomaly; lack of efficacy in an approved indication. Treatment-emergent serious adverse events are events from dose 4 of study drug to 6 months after dose 4 of study drug that were absent before treatment or that worsened relative to pretreatment state.

    Measured: From Vaccination 4 up to 6 months after Vaccination 4

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted25 Sep 2015 (estimated)
  2. Study start16 Jul 2015
  3. Primary completion7 Mar 2017
  4. Study completion13 Feb 2020

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase 2
Primary purpose
Prevention
Allocation
Randomised
Intervention model
Parallel groups
Masking
Triple blind
Who is masked
Participant, Investigator, Outcomes assessor
Enrolment
300 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT02561195
Sponsor's protocol ID
B5091009
Status last verified
Feb 2021
First submitted
9 Jul 2015
Last updated
8 Mar 2021
Data monitoring committee
Yes
FDA-regulated drug
Yes
FDA-regulated device
No
Individual data sharing
Yes: Pfizer will provide access to individual de-identified participant data and related study documents (e.g. protocol, Statistical Analysis Plan (SAP), Clinical Study Report (CSR)) upon request from qualified researchers, and subject to certain criteria, conditions, and exceptions. Further details on Pfizer's data sharing criteria and process for requesting access can be found at: https://www.pfizer.com/science/clinical\_trials/trial\_data\_and\_results/data\_requests.

Publications

  • Remich S, Kitchin N, Peterson J, Li P, Pride MW, Brock L, Anderson AS, Gruber WC, Jansen KU, Lockhart SP, Webber C. A Phase 2 Extension Study Evaluating the Immunogenicity, Safety, and Tolerability of 3 or 4 Doses of a Clostridioides difficile Vaccine in Healthy US Adults Aged 65 to 85 Years. J Infect Dis. 2024 Feb 14;229(2):367-375. doi: 10.1093/infdis/jiad307.

    PubMed 37531657
  • Kitchin N, Remich SA, Peterson J, Peng Y, Gruber WC, Jansen KU, Pride MW, Anderson AS, Knirsch C, Webber C. A Phase 2 Study Evaluating the Safety, Tolerability, and Immunogenicity of Two 3-Dose Regimens of a Clostridium difficile Vaccine in Healthy US Adults Aged 65 to 85 Years. Clin Infect Dis. 2020 Jan 1;70(1):1-10. doi: 10.1093/cid/ciz153.

    PubMed 31125055

Questions about this trial

What is this clinical trial studying?

A Phase 2 study testing Clostridium difficile Vaccine in people with Clostridium Difficile Associated Disease, run by Pfizer at 17 sites in United States.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 4 inclusion and 11 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: finished, as of the sponsor's last update on 8 Mar 2021. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 17 sites in United States. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this phase mean?

Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

Yes. Results are posted in the registry (first posted 30 Mar 2018). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Day 1, 8 and 30 Regimen: Percentage of Participants Achieving Prespecified Antibody Titer Level for Toxin A at Day 37 (time frame: Day 37 (7 days after Vaccination 3 of Day 1, 8 and 30 regimen)). The study lists 22 primary outcomes in all. It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT02561195, which also lists 2 linked publications.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 8 Mar 2021.

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