Clostridium Difficile Infection
Conditions
Keywords
Clostridium difficile Toxoid Vaccine, Clostridium difficile infection, Cdiffense
Brief summary
The aim of this study was to evaluate the efficacy of the Clostridium difficile vaccine to prevent primary symptomatic C. difficile infection (CDI) in participants at risk for CDI where there is a substantial unmet medical need. Primary objective: * To assess the efficacy of the C. difficile vaccine in preventing the onset of symptomatic primary CDI confirmed by polymerase chain reaction (PCR) in adult participants aged \>= 50 years who are at risk for CDI and have received at least 1 injection. Secondary Objectives: Efficacy: * To assess prevention of symptomatic PCR-confirmed primary CDI cases after 3 injections administered at 0, 7, and 30 days. * To assess prevention of symptomatic PCR-confirmed primary CDI cases after completion of at least 2 injections. Immunogenicity: * To describe the immunogenicity to toxin A and toxin B at specific time points in a subset of participant and in participants with CDI at Day 0 and Day 60. Safety: * To describe the safety profile of all participants who received at least 1 injection.
Detailed description
The study was designed as an event-driven group sequential protocol with 4 interim analyses at defined information milestones and a final analysis when a specific number of clinical endpoints are reached. Analyses of trial futility (non-efficacy) were to be performed at the first 2 interim analyses, and the study was to be stopped if either of those analyses provided robust and compelling evidence that meaningful levels of vaccine efficacy (VE) would not be demonstrated. Following completion of the first interim analysis (50 cases of confirmed CDI observed), the futility criterion was met and in accordance with IDMC recommendation, enrollment and further vaccination ceased in November 2017. Due to the early termination of the study, some of the planned secondary efficacy endpoints could not be analyzed as all planned data were not collected. Participants were randomized to receive either the candidate vaccine or a placebo that was to be administered in a 3-dose schedule. At the time of group assignment, 928 participants (10% of total enrollment) were randomized to an immunogenicity subset; and 1859 participants (20% of total enrollment) were randomized to a reactogenicity subset. Safety was assessed in all participants in terms of unsolicited adverse events from Day 0 to Day 60, as well as serious adverse events (SAEs) throughout the study. Solicited adverse reactions were collected for 6 days following each injection in the reactogenicity subset.
Interventions
BIOLOGICALC. difficile Toxoid Vaccine
0.5 mL, Intramuscular
BIOLOGICALPlacebo: 0.9% normal saline
0.5 mL, Intramuscular
Sponsors
Sanofi Pasteur, a Sanofi Company
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
PREVENTION
Masking
TRIPLE (Subject, Investigator, Outcomes Assessor)
Intervention model description
This study was observer-blind. The vaccine preparer and administrator may have been unblinded to treatment assignment due to the steps necessary for vaccine preparation. However, the participant, the Investigator, and study staff members who collected the safety data and laboratory personnel who analyzed the blood and stool samples were all blinded to the group assignment.
Eligibility
Sex/Gender
ALL
Age
50 Years to No maximum
Healthy volunteers
Yes
Inclusion criteria
* Aged \>= 50 years on the day of inclusion * Informed consent form had been signed and dated. * Attended all scheduled visits and complied with all trial procedures. * Covered by health insurance (if required). * Must fulfill at least 1 of the following criteria Risk Stratum 1: * Had at least 2 hospital stays, each lasting at least \>= 24 hours, in the 12 months before enrollment, and * Had received systemic (not topical) antibiotics in the 12 months before enrollment, or Risk Stratum 2: * Was anticipated to have an in-patient hospitalization for a planned surgical procedure within 60 days of enrollment. The impending hospital stay was planned to be \>= 72 hours for a surgery involving 1 of the following: * Kidney/bladder/urinary system * Musculoskeletal system * Respiratory system * Circulatory system * Central nervous system.
Exclusion criteria
* Participant was pregnant, or lactating, or of childbearing potential (to be considered of non-childbearing potential, a female must be post-menopausal for at least 1 year, surgically sterile, or using an effective method of contraception or abstinence from at least 4 weeks prior to the first vaccination and until at least 4 weeks after the last vaccination). * Participation in the 4 weeks preceding the first trial vaccination or participation during the present trial period in another clinical trial investigating a vaccine, drug, medical device, or medical procedure. * Receipt of any vaccine in the 4 weeks preceding the first trial vaccination except for influenza (seasonal or pandemic) and pneumococcal vaccines. This exception includes monovalent pandemic influenza vaccines and multivalent influenza vaccines. * Previous vaccination against C. difficile with either the trial vaccine, another vaccine, or monoclonal antibodies. * Diarrhea on day of enrollment. * Self-reported current or prior CDI episode. * Anticipated or current receipt of kidney dialysis treatment. * History of gastrointestinal surgery for gastrointestinal malignancy (Note: Colonoscopy, polypectomy, and appendectomy are not
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Number of Participants With Symptomatic Polymerase Chain Reaction (PCR)-Confirmed Primary C. Difficile Infection (CDI) Cases | Up to 3 years post injection 1 | Symptomatic PCR-confirmed CDI cases were defined as the number of participants with combination of clinical and laboratory findings. Clinical components were: \>= 3 loose stools in \<= 24 hours, loose stools (defined as type 6 \[fluffy pieces with ragged edges, mushy\] or type 7 \[watery, no solid pieces\] according to the Bristol Stool Chart) lasting \>= 24 hours. Laboratory findings were: stool sample positive for C. difficile Toxin B by PCR at central laboratory or diagnosis of pseudomembranous colitis visualized at colonoscopy. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Number of Participants With Loose Stool Episodes | Up to 3 years post injection 1 | Loose stools were defined as type 6 (fluffy pieces with ragged edges, mushy) or type 7 (watery, no solid pieces) according to the Bristol Stool Chart. In this outcome measure, participants with number of loose stool episodes (categorized as: loose stool episodes less than 3, 3 to 6, 7 to 10, 11 to 15 and greater than 15) were reported. |
| Number of Participants With Symptomatic PCR Confirmed CDI Cases: Per-Protocol Population | Up to 3 years post injection 1 | Symptomatic PCR confirmed CDI cases were defined as the number of participants with combination of clinical and laboratory findings. Clinical components were: \>= 3 loose stools in \<= 24 hours, loose stools (defined as type 6 \[fluffy pieces with ragged edges, mushy\] or type 7 \[watery, no solid pieces\] according to the Bristol Stool Chart) lasting \>= 24 hours. Laboratory findings were: stool sample positive for C. difficile Toxin B by PCR at central laboratory or diagnosis of pseudomembranous colitis visualized at colonoscopy. Analysis was performed on per-protocol efficacy analysis set (PPEAS). |
| Percentage of Participants With >= 2 and 4-Fold Rise in Serum Antibody Concentrations From Baseline Against Toxins A and B Measured by ELISA | Day 60 | Percentage of Participants with \>= 2 and 4-fold rise in serum antibody concentrations against toxins A and B were measured by ELISA. The 2-sided 95% Cl of the percentage was based on Exact method calculations. |
| Serum Antibody Concentrations Against Toxins A and B Measured by Enzyme-Linked Immunosorbent Assay (ELISA) | Day 0, Day 14, Day 30, Day 60, Day 210, Day 390, Day 570, Day 750, Day 930, and Day 1110 | Serum antibody concentrations against toxins A and B were measured by ELISA and expressed as geometric mean concentration (GMC). The 2-sided 95% Confidence Interval (CI) of GMC was based on the Student t-distribution. Analysis was performed on Per Protocol Immunogenicity Analysis Set, which included participants who had at least 1 injection, no relevant protocol deviations (not met inclusion criteria/ met exclusion criteria, not received vaccine/ not received in proper time window, received different vaccine than randomized, preparation and/ or administration of vaccine not per protocol, protocol-restricted therapy, not provided post-dose serology sample/serology sample did not produced a valid test result). |
| Number of Participants With Severe PCR-Confirmed Primary CDI Cases | Up to 3 years post injection 1 | Severe CDI cases were defined as number of participants with at least one of the following symptoms: fever \>= 38.5 degree Celsius (°C), white blood cell count \>= 15,000 cells/mm\^3, ileus, pseudomembranous colitis, serum albumin \<3 gram per deciliter, abdominal distension, abdominal tenderness, or admission to the intensive care unit within 7 days of CDI diagnosis. |
| Serum Antibody Concentrations Against Toxins A and B Measured by Toxin Neutralization Assay (TNA) | Day 0, Day 14, Day 30, Day 60, Day 210, Day 390, Day 570, Day 750, Day 930, and Day 1110 | Serum antibody concentrations against toxins A and B were measured by TNA and expressed as geometric mean titer (GMT). The 2-sided 95% Cl of GMT was based on the Student t-distribution. |
| Percentage of Participants With >= 2 and 4-Fold Rise in Serum Antibody Concentrations From Baseline Against Toxins A and B Measured by TNA | Day 60 | Percentage of Participants with \>= 2 and 4-fold rise in serum antibody concentrations against toxins A and B were measured by TNA. The 2-sided 95% CI of the percentage was based on Exact method calculations. |
| Serum Antibody Concentrations Against Toxins A and B Measured by TNA in Participants With CDI | Day 0 and Day 60 | Serum antibody concentrations against toxins A and B were measured by TNA and were expressed as GMT. The 2-sided 95% CI GMC was based on the Student t-distribution. Symptomatic PCR confirmed CDI cases were defined as the number of participants with combination of clinical and laboratory findings. Clinical components were: \>= 3 loose stools in \<= 24 hours, loose stools (defined as type 6 \[fluffy pieces with ragged edges, mushy\] or type 7 \[watery, no solid pieces\] according to the Bristol Stool Chart) lasting \>= 24 hours. Laboratory findings were: stool sample positive for C. difficile Toxin B by PCR at central laboratory or diagnosis of pseudomembranous colitis visualized at colonoscopy. |
| Percentage of Participants Reporting Solicited Injection Site and Systemic Reactions | Day 0 to Day 6 after any vaccination | Solicited injection site reactions: pain, erythema, and swelling. Pain: Grade 1: no interference with activity, Grade 2: some interference with activity, Grade 3: significant; prevents daily activity; Erythema and swelling: Grade 1: \>= 25 to \<=50 mm, Grade 2: \>51 to \<=100 mm, Grade 3: \>100 mm. Solicited systemic reactions: fever, headache, malaise, myalgia, and arthralgia. Fever: Grade 1: \>= 38.0°C to \<=38.4°C or \>= 100.4° Fahrenheit (F) to \<=101.1°F, Grade 2: \>=38.5°C to \<= 38.9°C or \>=101.2°F to \<=102.0°F, Grade 3: \>=39.0°C or \>=102.1°F. Headache, malaise, and myalgia: Grade 1: no interference with activity, Grade 2: some interference with activity, Grade 3: significant; prevents daily activity; Arthralgia: Grade 1: free range of motion but complains of pain or discomfort, Grade 2: decreased range of motion due to pain or discomfort, Grade 3: unwilling to move due to pain. |
| Serum Antibody Concentrations Against Toxins A and B Measured by ELISA in Participants With CDI | Day 0 and Day 60 | Serum antibody concentrations against toxins A and B were measured by ELISA and expressed as GMC. The 2-sided 95% CI GMC was based on the Student t-distribution. Symptomatic PCR-confirmed CDI cases were defined as the number of participants with combination of clinical and laboratory findings. Clinical components were: \>= 3 loose stools in \<= 24 hours, loose stools (defined as type 6 \[fluffy pieces with ragged edges, mushy\] or type 7 \[watery, no solid pieces\] according to the Bristol Stool Chart) lasting \>= 24 hours. Laboratory findings were: stool sample positive for C. difficile Toxin B by PCR at central laboratory or diagnosis of pseudomembranous colitis visualized at colonoscopy. |
Countries
Australia, Brazil, Canada, Colombia, Costa Rica, Denmark, Dominican Republic, Finland, France, Germany, Guatemala, Japan, Mexico, Panama, Peru, Philippines, Poland, Puerto Rico, Singapore, South Korea, Spain, Sweden, Taiwan, Thailand, United Kingdom, United States
Participant flow
Recruitment details
Study participants were enrolled in the study from 30 July 2013 to 17 November 2017.
Pre-assignment details
A total of 9302 participants were enrolled and randomized in the study.
Participants by arm
| Arm | Count |
|---|---|
| C. Difficile Vaccine Group Participants received 1 injection of 0.5 mL C. difficile toxoid vaccine at Days 0 (Injection 1), 7 (Injection 2), and 30 (Injection 3). | 6,201 |
| Placebo Group Participants received 1 injection of 0.5 mL placebo matched to vaccine at Days 0 (Injection 1), 7 (Injection 2), and 30 (Injection 3). | 3,101 |
| Total | 9,302 |
Withdrawals & dropouts
| Period | Reason | FG000 | FG001 |
|---|---|---|---|
| Overall Study | Lost to Follow-up | 163 | 74 |
| Overall Study | Other | 122 | 58 |
| Overall Study | Other Adverse Event | 34 | 15 |
| Overall Study | Protocol Violation | 67 | 37 |
| Overall Study | Serious adverse event | 400 | 198 |
| Overall Study | Withdrawal by Subject | 606 | 349 |
Baseline characteristics
| Characteristic | Placebo Group | Total | C. Difficile Vaccine Group |
|---|---|---|---|
| Age, Continuous | 65.8 years STANDARD_DEVIATION 8.87 | 65.8 years STANDARD_DEVIATION 8.86 | 65.9 years STANDARD_DEVIATION 8.86 |
| Ethnicity (NIH/OMB) Hispanic or Latino | 171 Participants | 501 Participants | 330 Participants |
| Ethnicity (NIH/OMB) Not Hispanic or Latino | 1390 Participants | 4170 Participants | 2780 Participants |
| Ethnicity (NIH/OMB) Unknown or Not Reported | 1540 Participants | 4631 Participants | 3091 Participants |
| Race (NIH/OMB) American Indian or Alaska Native | 6 Participants | 12 Participants | 6 Participants |
| Race (NIH/OMB) Asian | 398 Participants | 1193 Participants | 795 Participants |
| Race (NIH/OMB) Black or African American | 102 Participants | 308 Participants | 206 Participants |
| Race (NIH/OMB) More than one race | 5 Participants | 13 Participants | 8 Participants |
| Race (NIH/OMB) Native Hawaiian or Other Pacific Islander | 4 Participants | 9 Participants | 5 Participants |
| Race (NIH/OMB) Unknown or Not Reported | 1099 Participants | 3297 Participants | 2198 Participants |
| Race (NIH/OMB) White | 1487 Participants | 4470 Participants | 2983 Participants |
| Sex: Female, Male Female | 1294 Participants | 3923 Participants | 2629 Participants |
| Sex: Female, Male Male | 1807 Participants | 5379 Participants | 3572 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | 255 / 6,113 | 127 / 3,057 |
| other Total, other adverse events | 1,347 / 6,113 | 401 / 3,057 |
| serious Total, serious adverse events | 1,662 / 6,113 | 851 / 3,057 |
Outcome results
Primary
Number of Participants With Symptomatic Polymerase Chain Reaction (PCR)-Confirmed Primary C. Difficile Infection (CDI) Cases
Symptomatic PCR-confirmed CDI cases were defined as the number of participants with combination of clinical and laboratory findings. Clinical components were: \>= 3 loose stools in \<= 24 hours, loose stools (defined as type 6 \[fluffy pieces with ragged edges, mushy\] or type 7 \[watery, no solid pieces\] according to the Bristol Stool Chart) lasting \>= 24 hours. Laboratory findings were: stool sample positive for C. difficile Toxin B by PCR at central laboratory or diagnosis of pseudomembranous colitis visualized at colonoscopy.
Time frame: Up to 3 years post injection 1
Population: Analysis was performed on modified intent-to-treat (mITT) population which included all participants who received at least 1 injection and were analyzed according to the group to which they were randomized.
| Arm | Measure | Value (COUNT_OF_PARTICIPANTS) |
|---|---|---|
| C. Difficile Vaccine Group | Number of Participants With Symptomatic Polymerase Chain Reaction (PCR)-Confirmed Primary C. Difficile Infection (CDI) Cases | 34 Participants |
| Placebo Group | Number of Participants With Symptomatic Polymerase Chain Reaction (PCR)-Confirmed Primary C. Difficile Infection (CDI) Cases | 16 Participants |
Secondary
Number of Participants With Loose Stool Episodes
Loose stools were defined as type 6 (fluffy pieces with ragged edges, mushy) or type 7 (watery, no solid pieces) according to the Bristol Stool Chart. In this outcome measure, participants with number of loose stool episodes (categorized as: loose stool episodes less than 3, 3 to 6, 7 to 10, 11 to 15 and greater than 15) were reported.
Time frame: Up to 3 years post injection 1
Population: Analysis was performed on participants with protocol-defined PCR confirmed CDI cases.
| Arm | Measure | Group | Value (COUNT_OF_PARTICIPANTS) |
|---|---|---|---|
| C. Difficile Vaccine Group | Number of Participants With Loose Stool Episodes | 3 to 6 | 7 Participants |
| C. Difficile Vaccine Group | Number of Participants With Loose Stool Episodes | 11 to 15 | 7 Participants |
| C. Difficile Vaccine Group | Number of Participants With Loose Stool Episodes | 7 to 10 | 7 Participants |
| C. Difficile Vaccine Group | Number of Participants With Loose Stool Episodes | >15 | 13 Participants |
| C. Difficile Vaccine Group | Number of Participants With Loose Stool Episodes | <3 | 0 Participants |
| Placebo Group | Number of Participants With Loose Stool Episodes | >15 | 6 Participants |
| Placebo Group | Number of Participants With Loose Stool Episodes | <3 | 0 Participants |
| Placebo Group | Number of Participants With Loose Stool Episodes | 3 to 6 | 4 Participants |
| Placebo Group | Number of Participants With Loose Stool Episodes | 7 to 10 | 2 Participants |
| Placebo Group | Number of Participants With Loose Stool Episodes | 11 to 15 | 4 Participants |
Secondary
Number of Participants With Severe PCR-Confirmed Primary CDI Cases
Severe CDI cases were defined as number of participants with at least one of the following symptoms: fever \>= 38.5 degree Celsius (°C), white blood cell count \>= 15,000 cells/mm\^3, ileus, pseudomembranous colitis, serum albumin \<3 gram per deciliter, abdominal distension, abdominal tenderness, or admission to the intensive care unit within 7 days of CDI diagnosis.
Time frame: Up to 3 years post injection 1
Population: Analysis was performed on participants with protocol-defined (PCR confirmed) primary CDI cases.
| Arm | Measure | Value (COUNT_OF_PARTICIPANTS) |
|---|---|---|
| C. Difficile Vaccine Group | Number of Participants With Severe PCR-Confirmed Primary CDI Cases | 9 Participants |
| Placebo Group | Number of Participants With Severe PCR-Confirmed Primary CDI Cases | 6 Participants |
Secondary
Number of Participants With Symptomatic PCR Confirmed CDI Cases: Per-Protocol Population
Symptomatic PCR confirmed CDI cases were defined as the number of participants with combination of clinical and laboratory findings. Clinical components were: \>= 3 loose stools in \<= 24 hours, loose stools (defined as type 6 \[fluffy pieces with ragged edges, mushy\] or type 7 \[watery, no solid pieces\] according to the Bristol Stool Chart) lasting \>= 24 hours. Laboratory findings were: stool sample positive for C. difficile Toxin B by PCR at central laboratory or diagnosis of pseudomembranous colitis visualized at colonoscopy. Analysis was performed on per-protocol efficacy analysis set (PPEAS).
Time frame: Up to 3 years post injection 1
Population: PPEAS: participants who had at least 1 injection, no relevant protocol deviations (not meet inclusion criteria/ met exclusion criteria, not receive any vaccine/not received in proper time window, received different vaccine than randomized, preparation and / or administration of vaccine not done per protocol, received protocol-restricted therapy).
| Arm | Measure | Value (COUNT_OF_PARTICIPANTS) |
|---|---|---|
| C. Difficile Vaccine Group | Number of Participants With Symptomatic PCR Confirmed CDI Cases: Per-Protocol Population | 23 Participants |
| Placebo Group | Number of Participants With Symptomatic PCR Confirmed CDI Cases: Per-Protocol Population | 13 Participants |
Secondary
Percentage of Participants Reporting Solicited Injection Site and Systemic Reactions
Solicited injection site reactions: pain, erythema, and swelling. Pain: Grade 1: no interference with activity, Grade 2: some interference with activity, Grade 3: significant; prevents daily activity; Erythema and swelling: Grade 1: \>= 25 to \<=50 mm, Grade 2: \>51 to \<=100 mm, Grade 3: \>100 mm. Solicited systemic reactions: fever, headache, malaise, myalgia, and arthralgia. Fever: Grade 1: \>= 38.0°C to \<=38.4°C or \>= 100.4° Fahrenheit (F) to \<=101.1°F, Grade 2: \>=38.5°C to \<= 38.9°C or \>=101.2°F to \<=102.0°F, Grade 3: \>=39.0°C or \>=102.1°F. Headache, malaise, and myalgia: Grade 1: no interference with activity, Grade 2: some interference with activity, Grade 3: significant; prevents daily activity; Arthralgia: Grade 1: free range of motion but complains of pain or discomfort, Grade 2: decreased range of motion due to pain or discomfort, Grade 3: unwilling to move due to pain.
Time frame: Day 0 to Day 6 after any vaccination
Population: Analysis was performed on all participants who received vaccine and were evaluable for reactogenicity. Here, 'number analyzed' = participants with available data for each specified category.
| Arm | Measure | Group | Value (NUMBER) |
|---|---|---|---|
| C. Difficile Vaccine Group | Percentage of Participants Reporting Solicited Injection Site and Systemic Reactions | Injection site Pain | 38.6 percentage of participants |
| C. Difficile Vaccine Group | Percentage of Participants Reporting Solicited Injection Site and Systemic Reactions | Injection site Erythema | 4.2 percentage of participants |
| C. Difficile Vaccine Group | Percentage of Participants Reporting Solicited Injection Site and Systemic Reactions | Injection site Swelling | 3.8 percentage of participants |
| C. Difficile Vaccine Group | Percentage of Participants Reporting Solicited Injection Site and Systemic Reactions | Fever | 4.8 percentage of participants |
| C. Difficile Vaccine Group | Percentage of Participants Reporting Solicited Injection Site and Systemic Reactions | Headache | 25.3 percentage of participants |
| C. Difficile Vaccine Group | Percentage of Participants Reporting Solicited Injection Site and Systemic Reactions | Malaise | 23.9 percentage of participants |
| C. Difficile Vaccine Group | Percentage of Participants Reporting Solicited Injection Site and Systemic Reactions | Myalgia | 26.6 percentage of participants |
| C. Difficile Vaccine Group | Percentage of Participants Reporting Solicited Injection Site and Systemic Reactions | Arthralgia | 19.5 percentage of participants |
| Placebo Group | Percentage of Participants Reporting Solicited Injection Site and Systemic Reactions | Arthralgia | 16.7 percentage of participants |
| Placebo Group | Percentage of Participants Reporting Solicited Injection Site and Systemic Reactions | Injection site Pain | 13.5 percentage of participants |
| Placebo Group | Percentage of Participants Reporting Solicited Injection Site and Systemic Reactions | Headache | 22.5 percentage of participants |
| Placebo Group | Percentage of Participants Reporting Solicited Injection Site and Systemic Reactions | Injection site Erythema | 0.0 percentage of participants |
| Placebo Group | Percentage of Participants Reporting Solicited Injection Site and Systemic Reactions | Myalgia | 21.2 percentage of participants |
| Placebo Group | Percentage of Participants Reporting Solicited Injection Site and Systemic Reactions | Injection site Swelling | 0.3 percentage of participants |
| Placebo Group | Percentage of Participants Reporting Solicited Injection Site and Systemic Reactions | Malaise | 19.6 percentage of participants |
| Placebo Group | Percentage of Participants Reporting Solicited Injection Site and Systemic Reactions | Fever | 5.7 percentage of participants |
Secondary
Percentage of Participants With >= 2 and 4-Fold Rise in Serum Antibody Concentrations From Baseline Against Toxins A and B Measured by ELISA
Percentage of Participants with \>= 2 and 4-fold rise in serum antibody concentrations against toxins A and B were measured by ELISA. The 2-sided 95% Cl of the percentage was based on Exact method calculations.
Time frame: Day 60
Population: Analysis was performed on Per Protocol Immunogenicity Analysis Set. Here, 'overall number of participants analyzed' = participants evaluable for this outcome measure and 'number analyzed' = participants with available data for each specified category.
| Arm | Measure | Group | Value (NUMBER) |
|---|---|---|---|
| C. Difficile Vaccine Group | Percentage of Participants With >= 2 and 4-Fold Rise in Serum Antibody Concentrations From Baseline Against Toxins A and B Measured by ELISA | Toxin A IgG: >=2 | 93.3 percentage of participants |
| C. Difficile Vaccine Group | Percentage of Participants With >= 2 and 4-Fold Rise in Serum Antibody Concentrations From Baseline Against Toxins A and B Measured by ELISA | Toxin A IgG: >=4 | 88.9 percentage of participants |
| C. Difficile Vaccine Group | Percentage of Participants With >= 2 and 4-Fold Rise in Serum Antibody Concentrations From Baseline Against Toxins A and B Measured by ELISA | Toxin B IgG: >=2 | 82.2 percentage of participants |
| C. Difficile Vaccine Group | Percentage of Participants With >= 2 and 4-Fold Rise in Serum Antibody Concentrations From Baseline Against Toxins A and B Measured by ELISA | Toxin B IgG: >=4 | 73.2 percentage of participants |
| Placebo Group | Percentage of Participants With >= 2 and 4-Fold Rise in Serum Antibody Concentrations From Baseline Against Toxins A and B Measured by ELISA | Toxin B IgG: >=4 | 0.5 percentage of participants |
| Placebo Group | Percentage of Participants With >= 2 and 4-Fold Rise in Serum Antibody Concentrations From Baseline Against Toxins A and B Measured by ELISA | Toxin A IgG: >=2 | 0.9 percentage of participants |
| Placebo Group | Percentage of Participants With >= 2 and 4-Fold Rise in Serum Antibody Concentrations From Baseline Against Toxins A and B Measured by ELISA | Toxin B IgG: >=2 | 4.6 percentage of participants |
| Placebo Group | Percentage of Participants With >= 2 and 4-Fold Rise in Serum Antibody Concentrations From Baseline Against Toxins A and B Measured by ELISA | Toxin A IgG: >=4 | 0.0 percentage of participants |
Secondary
Percentage of Participants With >= 2 and 4-Fold Rise in Serum Antibody Concentrations From Baseline Against Toxins A and B Measured by TNA
Percentage of Participants with \>= 2 and 4-fold rise in serum antibody concentrations against toxins A and B were measured by TNA. The 2-sided 95% CI of the percentage was based on Exact method calculations.
Time frame: Day 60
Population: Analysis was performed on Per Protocol Immunogenicity Analysis Set. Here, overall number of participants analyzed signifies participants evaluable for this outcome measure and 'number analyzed' = participants with evaluable data for each specified category.
| Arm | Measure | Group | Value (NUMBER) |
|---|---|---|---|
| C. Difficile Vaccine Group | Percentage of Participants With >= 2 and 4-Fold Rise in Serum Antibody Concentrations From Baseline Against Toxins A and B Measured by TNA | Toxin A TNA: >=2 | 85.6 percentage of participants |
| C. Difficile Vaccine Group | Percentage of Participants With >= 2 and 4-Fold Rise in Serum Antibody Concentrations From Baseline Against Toxins A and B Measured by TNA | Toxin A TNA: >=4 | 78.2 percentage of participants |
| C. Difficile Vaccine Group | Percentage of Participants With >= 2 and 4-Fold Rise in Serum Antibody Concentrations From Baseline Against Toxins A and B Measured by TNA | Toxin B TNA: >=2 | 30.9 percentage of participants |
| C. Difficile Vaccine Group | Percentage of Participants With >= 2 and 4-Fold Rise in Serum Antibody Concentrations From Baseline Against Toxins A and B Measured by TNA | Toxin B TNA: >=4 | 27.4 percentage of participants |
| Placebo Group | Percentage of Participants With >= 2 and 4-Fold Rise in Serum Antibody Concentrations From Baseline Against Toxins A and B Measured by TNA | Toxin B TNA: >=4 | 1.8 percentage of participants |
| Placebo Group | Percentage of Participants With >= 2 and 4-Fold Rise in Serum Antibody Concentrations From Baseline Against Toxins A and B Measured by TNA | Toxin A TNA: >=2 | 0.5 percentage of participants |
| Placebo Group | Percentage of Participants With >= 2 and 4-Fold Rise in Serum Antibody Concentrations From Baseline Against Toxins A and B Measured by TNA | Toxin B TNA: >=2 | 2.8 percentage of participants |
| Placebo Group | Percentage of Participants With >= 2 and 4-Fold Rise in Serum Antibody Concentrations From Baseline Against Toxins A and B Measured by TNA | Toxin A TNA: >=4 | 0.5 percentage of participants |
Secondary
Serum Antibody Concentrations Against Toxins A and B Measured by ELISA in Participants With CDI
Serum antibody concentrations against toxins A and B were measured by ELISA and expressed as GMC. The 2-sided 95% CI GMC was based on the Student t-distribution. Symptomatic PCR-confirmed CDI cases were defined as the number of participants with combination of clinical and laboratory findings. Clinical components were: \>= 3 loose stools in \<= 24 hours, loose stools (defined as type 6 \[fluffy pieces with ragged edges, mushy\] or type 7 \[watery, no solid pieces\] according to the Bristol Stool Chart) lasting \>= 24 hours. Laboratory findings were: stool sample positive for C. difficile Toxin B by PCR at central laboratory or diagnosis of pseudomembranous colitis visualized at colonoscopy.
Time frame: Day 0 and Day 60
Population: Analysis was performed on participants with protocol-defined (PCR confirmed) primary CDI cases. Here, 'number analyzed' = participants with available data for each specified category.
| Arm | Measure | Group | Value (GEOMETRIC_MEAN) |
|---|---|---|---|
| C. Difficile Vaccine Group | Serum Antibody Concentrations Against Toxins A and B Measured by ELISA in Participants With CDI | Toxin A IgG: Day 0 | 1.15 EU/mL |
| C. Difficile Vaccine Group | Serum Antibody Concentrations Against Toxins A and B Measured by ELISA in Participants With CDI | Toxin A IgG: Day 60 | 42.1 EU/mL |
| C. Difficile Vaccine Group | Serum Antibody Concentrations Against Toxins A and B Measured by ELISA in Participants With CDI | Toxin B IgG: Day 0 | 1.41 EU/mL |
| C. Difficile Vaccine Group | Serum Antibody Concentrations Against Toxins A and B Measured by ELISA in Participants With CDI | Toxin B IgG: Day 60 | 19.3 EU/mL |
| Placebo Group | Serum Antibody Concentrations Against Toxins A and B Measured by ELISA in Participants With CDI | Toxin B IgG: Day 60 | 1.13 EU/mL |
| Placebo Group | Serum Antibody Concentrations Against Toxins A and B Measured by ELISA in Participants With CDI | Toxin A IgG: Day 0 | 1.04 EU/mL |
| Placebo Group | Serum Antibody Concentrations Against Toxins A and B Measured by ELISA in Participants With CDI | Toxin B IgG: Day 0 | 1.05 EU/mL |
| Placebo Group | Serum Antibody Concentrations Against Toxins A and B Measured by ELISA in Participants With CDI | Toxin A IgG: Day 60 | 1.06 EU/mL |
Secondary
Serum Antibody Concentrations Against Toxins A and B Measured by Enzyme-Linked Immunosorbent Assay (ELISA)
Serum antibody concentrations against toxins A and B were measured by ELISA and expressed as geometric mean concentration (GMC). The 2-sided 95% Confidence Interval (CI) of GMC was based on the Student t-distribution. Analysis was performed on Per Protocol Immunogenicity Analysis Set, which included participants who had at least 1 injection, no relevant protocol deviations (not met inclusion criteria/ met exclusion criteria, not received vaccine/ not received in proper time window, received different vaccine than randomized, preparation and/ or administration of vaccine not per protocol, protocol-restricted therapy, not provided post-dose serology sample/serology sample did not produced a valid test result).
Time frame: Day 0, Day 14, Day 30, Day 60, Day 210, Day 390, Day 570, Day 750, Day 930, and Day 1110
Population: Analysis was performed on Per Protocol Immunogenicity Analysis Set. Here, 'number analyzed' = participants with available data for each specified category.
| Arm | Measure | Group | Value (GEOMETRIC_MEAN) |
|---|---|---|---|
| C. Difficile Vaccine Group | Serum Antibody Concentrations Against Toxins A and B Measured by Enzyme-Linked Immunosorbent Assay (ELISA) | Toxin A ImunnoglobulinG (IgG): Day 0 | 0.957 ELISA units per milliliter (EU/mL) |
| C. Difficile Vaccine Group | Serum Antibody Concentrations Against Toxins A and B Measured by Enzyme-Linked Immunosorbent Assay (ELISA) | Toxin A IgG: Day 14 | 3.19 ELISA units per milliliter (EU/mL) |
| C. Difficile Vaccine Group | Serum Antibody Concentrations Against Toxins A and B Measured by Enzyme-Linked Immunosorbent Assay (ELISA) | Toxin A IgG: Day 30 | 12.2 ELISA units per milliliter (EU/mL) |
| C. Difficile Vaccine Group | Serum Antibody Concentrations Against Toxins A and B Measured by Enzyme-Linked Immunosorbent Assay (ELISA) | Toxin A IgG: Day 60 | 43.7 ELISA units per milliliter (EU/mL) |
| C. Difficile Vaccine Group | Serum Antibody Concentrations Against Toxins A and B Measured by Enzyme-Linked Immunosorbent Assay (ELISA) | Toxin A IgG: Day 210 | 12.0 ELISA units per milliliter (EU/mL) |
| C. Difficile Vaccine Group | Serum Antibody Concentrations Against Toxins A and B Measured by Enzyme-Linked Immunosorbent Assay (ELISA) | Toxin A IgG: Day 390 | 6.02 ELISA units per milliliter (EU/mL) |
| C. Difficile Vaccine Group | Serum Antibody Concentrations Against Toxins A and B Measured by Enzyme-Linked Immunosorbent Assay (ELISA) | Toxin A IgG: Day 570 | 4.50 ELISA units per milliliter (EU/mL) |
| C. Difficile Vaccine Group | Serum Antibody Concentrations Against Toxins A and B Measured by Enzyme-Linked Immunosorbent Assay (ELISA) | Toxin A IgG: Day 750 | 4.02 ELISA units per milliliter (EU/mL) |
| C. Difficile Vaccine Group | Serum Antibody Concentrations Against Toxins A and B Measured by Enzyme-Linked Immunosorbent Assay (ELISA) | Toxin A IgG: Day 930 | 3.83 ELISA units per milliliter (EU/mL) |
| C. Difficile Vaccine Group | Serum Antibody Concentrations Against Toxins A and B Measured by Enzyme-Linked Immunosorbent Assay (ELISA) | Toxin A IgG: Day 1110 | 3.75 ELISA units per milliliter (EU/mL) |
| C. Difficile Vaccine Group | Serum Antibody Concentrations Against Toxins A and B Measured by Enzyme-Linked Immunosorbent Assay (ELISA) | Toxin B IgG: Day 0 | 1.40 ELISA units per milliliter (EU/mL) |
| C. Difficile Vaccine Group | Serum Antibody Concentrations Against Toxins A and B Measured by Enzyme-Linked Immunosorbent Assay (ELISA) | Toxin B IgG: Day 14 | 4.36 ELISA units per milliliter (EU/mL) |
| C. Difficile Vaccine Group | Serum Antibody Concentrations Against Toxins A and B Measured by Enzyme-Linked Immunosorbent Assay (ELISA) | Toxin B IgG: Day 30 | 10.0 ELISA units per milliliter (EU/mL) |
| C. Difficile Vaccine Group | Serum Antibody Concentrations Against Toxins A and B Measured by Enzyme-Linked Immunosorbent Assay (ELISA) | Toxin B IgG: Day 60 | 24.8 ELISA units per milliliter (EU/mL) |
| C. Difficile Vaccine Group | Serum Antibody Concentrations Against Toxins A and B Measured by Enzyme-Linked Immunosorbent Assay (ELISA) | Toxin B IgG: Day 210 | 6.62 ELISA units per milliliter (EU/mL) |
| C. Difficile Vaccine Group | Serum Antibody Concentrations Against Toxins A and B Measured by Enzyme-Linked Immunosorbent Assay (ELISA) | Toxin B IgG: Day 390 | 3.98 ELISA units per milliliter (EU/mL) |
| C. Difficile Vaccine Group | Serum Antibody Concentrations Against Toxins A and B Measured by Enzyme-Linked Immunosorbent Assay (ELISA) | Toxin B IgG: Day 570 | 3.37 ELISA units per milliliter (EU/mL) |
| C. Difficile Vaccine Group | Serum Antibody Concentrations Against Toxins A and B Measured by Enzyme-Linked Immunosorbent Assay (ELISA) | Toxin B IgG: Day 750 | 2.86 ELISA units per milliliter (EU/mL) |
| C. Difficile Vaccine Group | Serum Antibody Concentrations Against Toxins A and B Measured by Enzyme-Linked Immunosorbent Assay (ELISA) | Toxin B IgG: Day 930 | 2.42 ELISA units per milliliter (EU/mL) |
| C. Difficile Vaccine Group | Serum Antibody Concentrations Against Toxins A and B Measured by Enzyme-Linked Immunosorbent Assay (ELISA) | Toxin B IgG: Day 1110 | 3.46 ELISA units per milliliter (EU/mL) |
| Placebo Group | Serum Antibody Concentrations Against Toxins A and B Measured by Enzyme-Linked Immunosorbent Assay (ELISA) | Toxin B IgG: Day 750 | 1.11 ELISA units per milliliter (EU/mL) |
| Placebo Group | Serum Antibody Concentrations Against Toxins A and B Measured by Enzyme-Linked Immunosorbent Assay (ELISA) | Toxin A ImunnoglobulinG (IgG): Day 0 | 0.999 ELISA units per milliliter (EU/mL) |
| Placebo Group | Serum Antibody Concentrations Against Toxins A and B Measured by Enzyme-Linked Immunosorbent Assay (ELISA) | Toxin B IgG: Day 0 | 1.49 ELISA units per milliliter (EU/mL) |
| Placebo Group | Serum Antibody Concentrations Against Toxins A and B Measured by Enzyme-Linked Immunosorbent Assay (ELISA) | Toxin A IgG: Day 14 | 0.913 ELISA units per milliliter (EU/mL) |
| Placebo Group | Serum Antibody Concentrations Against Toxins A and B Measured by Enzyme-Linked Immunosorbent Assay (ELISA) | Toxin B IgG: Day 390 | 1.24 ELISA units per milliliter (EU/mL) |
| Placebo Group | Serum Antibody Concentrations Against Toxins A and B Measured by Enzyme-Linked Immunosorbent Assay (ELISA) | Toxin A IgG: Day 30 | 0.959 ELISA units per milliliter (EU/mL) |
| Placebo Group | Serum Antibody Concentrations Against Toxins A and B Measured by Enzyme-Linked Immunosorbent Assay (ELISA) | Toxin B IgG: Day 14 | 1.56 ELISA units per milliliter (EU/mL) |
| Placebo Group | Serum Antibody Concentrations Against Toxins A and B Measured by Enzyme-Linked Immunosorbent Assay (ELISA) | Toxin A IgG: Day 60 | 0.933 ELISA units per milliliter (EU/mL) |
| Placebo Group | Serum Antibody Concentrations Against Toxins A and B Measured by Enzyme-Linked Immunosorbent Assay (ELISA) | Toxin B IgG: Day 1110 | 0.966 ELISA units per milliliter (EU/mL) |
| Placebo Group | Serum Antibody Concentrations Against Toxins A and B Measured by Enzyme-Linked Immunosorbent Assay (ELISA) | Toxin A IgG: Day 210 | 0.944 ELISA units per milliliter (EU/mL) |
| Placebo Group | Serum Antibody Concentrations Against Toxins A and B Measured by Enzyme-Linked Immunosorbent Assay (ELISA) | Toxin B IgG: Day 30 | 1.46 ELISA units per milliliter (EU/mL) |
| Placebo Group | Serum Antibody Concentrations Against Toxins A and B Measured by Enzyme-Linked Immunosorbent Assay (ELISA) | Toxin A IgG: Day 390 | 0.955 ELISA units per milliliter (EU/mL) |
| Placebo Group | Serum Antibody Concentrations Against Toxins A and B Measured by Enzyme-Linked Immunosorbent Assay (ELISA) | Toxin B IgG: Day 570 | 1.15 ELISA units per milliliter (EU/mL) |
| Placebo Group | Serum Antibody Concentrations Against Toxins A and B Measured by Enzyme-Linked Immunosorbent Assay (ELISA) | Toxin A IgG: Day 570 | 0.908 ELISA units per milliliter (EU/mL) |
| Placebo Group | Serum Antibody Concentrations Against Toxins A and B Measured by Enzyme-Linked Immunosorbent Assay (ELISA) | Toxin B IgG: Day 60 | 1.42 ELISA units per milliliter (EU/mL) |
| Placebo Group | Serum Antibody Concentrations Against Toxins A and B Measured by Enzyme-Linked Immunosorbent Assay (ELISA) | Toxin A IgG: Day 750 | 0.856 ELISA units per milliliter (EU/mL) |
| Placebo Group | Serum Antibody Concentrations Against Toxins A and B Measured by Enzyme-Linked Immunosorbent Assay (ELISA) | Toxin B IgG: Day 930 | 1.13 ELISA units per milliliter (EU/mL) |
| Placebo Group | Serum Antibody Concentrations Against Toxins A and B Measured by Enzyme-Linked Immunosorbent Assay (ELISA) | Toxin A IgG: Day 930 | 0.902 ELISA units per milliliter (EU/mL) |
| Placebo Group | Serum Antibody Concentrations Against Toxins A and B Measured by Enzyme-Linked Immunosorbent Assay (ELISA) | Toxin B IgG: Day 210 | 1.31 ELISA units per milliliter (EU/mL) |
| Placebo Group | Serum Antibody Concentrations Against Toxins A and B Measured by Enzyme-Linked Immunosorbent Assay (ELISA) | Toxin A IgG: Day 1110 | 1.09 ELISA units per milliliter (EU/mL) |
Secondary
Serum Antibody Concentrations Against Toxins A and B Measured by TNA in Participants With CDI
Serum antibody concentrations against toxins A and B were measured by TNA and were expressed as GMT. The 2-sided 95% CI GMC was based on the Student t-distribution. Symptomatic PCR confirmed CDI cases were defined as the number of participants with combination of clinical and laboratory findings. Clinical components were: \>= 3 loose stools in \<= 24 hours, loose stools (defined as type 6 \[fluffy pieces with ragged edges, mushy\] or type 7 \[watery, no solid pieces\] according to the Bristol Stool Chart) lasting \>= 24 hours. Laboratory findings were: stool sample positive for C. difficile Toxin B by PCR at central laboratory or diagnosis of pseudomembranous colitis visualized at colonoscopy.
Time frame: Day 0 and Day 60
Population: Analysis was performed on participants with protocol-defined (PCR confirmed) primary CDI cases. Here, 'number analyzed' = participants with available data for each specified category.
| Arm | Measure | Group | Value (GEOMETRIC_MEAN) |
|---|---|---|---|
| C. Difficile Vaccine Group | Serum Antibody Concentrations Against Toxins A and B Measured by TNA in Participants With CDI | Toxin A TNA: Day 0 | 12.4 Titer (1/dilution) |
| C. Difficile Vaccine Group | Serum Antibody Concentrations Against Toxins A and B Measured by TNA in Participants With CDI | Toxin A TNA: Day 60 | 176 Titer (1/dilution) |
| C. Difficile Vaccine Group | Serum Antibody Concentrations Against Toxins A and B Measured by TNA in Participants With CDI | Toxin B TNA: Day 0 | 16.7 Titer (1/dilution) |
| C. Difficile Vaccine Group | Serum Antibody Concentrations Against Toxins A and B Measured by TNA in Participants With CDI | Toxin B TNA: Day 60 | 53.0 Titer (1/dilution) |
| Placebo Group | Serum Antibody Concentrations Against Toxins A and B Measured by TNA in Participants With CDI | Toxin B TNA: Day 60 | 13.1 Titer (1/dilution) |
| Placebo Group | Serum Antibody Concentrations Against Toxins A and B Measured by TNA in Participants With CDI | Toxin A TNA: Day 0 | 12.0 Titer (1/dilution) |
| Placebo Group | Serum Antibody Concentrations Against Toxins A and B Measured by TNA in Participants With CDI | Toxin B TNA: Day 0 | 11.1 Titer (1/dilution) |
| Placebo Group | Serum Antibody Concentrations Against Toxins A and B Measured by TNA in Participants With CDI | Toxin A TNA: Day 60 | 10.7 Titer (1/dilution) |
Secondary
Serum Antibody Concentrations Against Toxins A and B Measured by Toxin Neutralization Assay (TNA)
Serum antibody concentrations against toxins A and B were measured by TNA and expressed as geometric mean titer (GMT). The 2-sided 95% Cl of GMT was based on the Student t-distribution.
Time frame: Day 0, Day 14, Day 30, Day 60, Day 210, Day 390, Day 570, Day 750, Day 930, and Day 1110
Population: Analysis was performed on Per Protocol Immunogenicity Analysis Set. Here, 'number analyzed' = participants with available data for each specified category.
| Arm | Measure | Group | Value (GEOMETRIC_MEAN) |
|---|---|---|---|
| C. Difficile Vaccine Group | Serum Antibody Concentrations Against Toxins A and B Measured by Toxin Neutralization Assay (TNA) | Toxin A TNA: Day 60 | 269 Titer (1/dilution) |
| C. Difficile Vaccine Group | Serum Antibody Concentrations Against Toxins A and B Measured by Toxin Neutralization Assay (TNA) | Toxin A TNA: Day 0 | 9.86 Titer (1/dilution) |
| C. Difficile Vaccine Group | Serum Antibody Concentrations Against Toxins A and B Measured by Toxin Neutralization Assay (TNA) | Toxin A TNA: Day 14 | 28.5 Titer (1/dilution) |
| C. Difficile Vaccine Group | Serum Antibody Concentrations Against Toxins A and B Measured by Toxin Neutralization Assay (TNA) | Toxin A TNA: Day 30 | 50.5 Titer (1/dilution) |
| C. Difficile Vaccine Group | Serum Antibody Concentrations Against Toxins A and B Measured by Toxin Neutralization Assay (TNA) | Toxin A TNA: Day 210 | 269 Titer (1/dilution) |
| C. Difficile Vaccine Group | Serum Antibody Concentrations Against Toxins A and B Measured by Toxin Neutralization Assay (TNA) | Toxin A TNA: Day 390 | 217 Titer (1/dilution) |
| C. Difficile Vaccine Group | Serum Antibody Concentrations Against Toxins A and B Measured by Toxin Neutralization Assay (TNA) | Toxin A TNA: Day 570 | 184 Titer (1/dilution) |
| C. Difficile Vaccine Group | Serum Antibody Concentrations Against Toxins A and B Measured by Toxin Neutralization Assay (TNA) | Toxin A TNA: Day 750 | 186 Titer (1/dilution) |
| C. Difficile Vaccine Group | Serum Antibody Concentrations Against Toxins A and B Measured by Toxin Neutralization Assay (TNA) | Toxin A TNA: Day 930 | 173 Titer (1/dilution) |
| C. Difficile Vaccine Group | Serum Antibody Concentrations Against Toxins A and B Measured by Toxin Neutralization Assay (TNA) | Toxin A TNA: Day 1110 | 212 Titer (1/dilution) |
| C. Difficile Vaccine Group | Serum Antibody Concentrations Against Toxins A and B Measured by Toxin Neutralization Assay (TNA) | Toxin B TNA: Day 0 | 12.3 Titer (1/dilution) |
| C. Difficile Vaccine Group | Serum Antibody Concentrations Against Toxins A and B Measured by Toxin Neutralization Assay (TNA) | Toxin B TNA: Day 14 | 32.7 Titer (1/dilution) |
| C. Difficile Vaccine Group | Serum Antibody Concentrations Against Toxins A and B Measured by Toxin Neutralization Assay (TNA) | Toxin B TNA: Day 30 | 37.8 Titer (1/dilution) |
| C. Difficile Vaccine Group | Serum Antibody Concentrations Against Toxins A and B Measured by Toxin Neutralization Assay (TNA) | Toxin B TNA: Day 60 | 43.9 Titer (1/dilution) |
| C. Difficile Vaccine Group | Serum Antibody Concentrations Against Toxins A and B Measured by Toxin Neutralization Assay (TNA) | Toxin B TNA: Day 210 | 41.4 Titer (1/dilution) |
| C. Difficile Vaccine Group | Serum Antibody Concentrations Against Toxins A and B Measured by Toxin Neutralization Assay (TNA) | Toxin B TNA: Day 390 | 38.4 Titer (1/dilution) |
| C. Difficile Vaccine Group | Serum Antibody Concentrations Against Toxins A and B Measured by Toxin Neutralization Assay (TNA) | Toxin B TNA: Day 570 | 35.7 Titer (1/dilution) |
| C. Difficile Vaccine Group | Serum Antibody Concentrations Against Toxins A and B Measured by Toxin Neutralization Assay (TNA) | Toxin B TNA: Day 750 | 34.3 Titer (1/dilution) |
| C. Difficile Vaccine Group | Serum Antibody Concentrations Against Toxins A and B Measured by Toxin Neutralization Assay (TNA) | Toxin B TNA: Day 930 | 31.0 Titer (1/dilution) |
| C. Difficile Vaccine Group | Serum Antibody Concentrations Against Toxins A and B Measured by Toxin Neutralization Assay (TNA) | Toxin B TNA: Day 1110 | 46.8 Titer (1/dilution) |
| Placebo Group | Serum Antibody Concentrations Against Toxins A and B Measured by Toxin Neutralization Assay (TNA) | Toxin B TNA: Day 750 | 14.6 Titer (1/dilution) |
| Placebo Group | Serum Antibody Concentrations Against Toxins A and B Measured by Toxin Neutralization Assay (TNA) | Toxin B TNA: Day 0 | 13.2 Titer (1/dilution) |
| Placebo Group | Serum Antibody Concentrations Against Toxins A and B Measured by Toxin Neutralization Assay (TNA) | Toxin A TNA: Day 0 | 10.1 Titer (1/dilution) |
| Placebo Group | Serum Antibody Concentrations Against Toxins A and B Measured by Toxin Neutralization Assay (TNA) | Toxin B TNA: Day 390 | 13.5 Titer (1/dilution) |
| Placebo Group | Serum Antibody Concentrations Against Toxins A and B Measured by Toxin Neutralization Assay (TNA) | Toxin A TNA: Day 14 | 9.86 Titer (1/dilution) |
| Placebo Group | Serum Antibody Concentrations Against Toxins A and B Measured by Toxin Neutralization Assay (TNA) | Toxin B TNA: Day 14 | 13.3 Titer (1/dilution) |
| Placebo Group | Serum Antibody Concentrations Against Toxins A and B Measured by Toxin Neutralization Assay (TNA) | Toxin A TNA: Day 30 | 9.97 Titer (1/dilution) |
| Placebo Group | Serum Antibody Concentrations Against Toxins A and B Measured by Toxin Neutralization Assay (TNA) | Toxin A TNA: Day 60 | 9.82 Titer (1/dilution) |
| Placebo Group | Serum Antibody Concentrations Against Toxins A and B Measured by Toxin Neutralization Assay (TNA) | Toxin B TNA: Day 1110 | 14.0 Titer (1/dilution) |
| Placebo Group | Serum Antibody Concentrations Against Toxins A and B Measured by Toxin Neutralization Assay (TNA) | Toxin A TNA: Day 210 | 10.3 Titer (1/dilution) |
| Placebo Group | Serum Antibody Concentrations Against Toxins A and B Measured by Toxin Neutralization Assay (TNA) | Toxin B TNA: Day 30 | 13.4 Titer (1/dilution) |
| Placebo Group | Serum Antibody Concentrations Against Toxins A and B Measured by Toxin Neutralization Assay (TNA) | Toxin A TNA: Day 390 | 10.1 Titer (1/dilution) |
| Placebo Group | Serum Antibody Concentrations Against Toxins A and B Measured by Toxin Neutralization Assay (TNA) | Toxin B TNA: Day 570 | 13.7 Titer (1/dilution) |
| Placebo Group | Serum Antibody Concentrations Against Toxins A and B Measured by Toxin Neutralization Assay (TNA) | Toxin A TNA: Day 570 | 9.86 Titer (1/dilution) |
| Placebo Group | Serum Antibody Concentrations Against Toxins A and B Measured by Toxin Neutralization Assay (TNA) | Toxin B TNA: Day 60 | 14.3 Titer (1/dilution) |
| Placebo Group | Serum Antibody Concentrations Against Toxins A and B Measured by Toxin Neutralization Assay (TNA) | Toxin A TNA: Day 750 | 10.2 Titer (1/dilution) |
| Placebo Group | Serum Antibody Concentrations Against Toxins A and B Measured by Toxin Neutralization Assay (TNA) | Toxin B TNA: Day 930 | 17.0 Titer (1/dilution) |
| Placebo Group | Serum Antibody Concentrations Against Toxins A and B Measured by Toxin Neutralization Assay (TNA) | Toxin A TNA: Day 930 | 10.7 Titer (1/dilution) |
| Placebo Group | Serum Antibody Concentrations Against Toxins A and B Measured by Toxin Neutralization Assay (TNA) | Toxin B TNA: Day 210 | 13.2 Titer (1/dilution) |
| Placebo Group | Serum Antibody Concentrations Against Toxins A and B Measured by Toxin Neutralization Assay (TNA) | Toxin A TNA: Day 1110 | 10.2 Titer (1/dilution) |