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Efficacy and Safety of Cadazolid Versus Vancomycin in Subjects With Clostridium Difficile - Associated Diarrhea

A Multi-center, Randomized, Double-blind Study to Compare the Efficacy and Safety of Cadazolid Versus Vancomycin in Subjects With Clostridium Difficile-associated Diarrhea (CDAD)

Status
Completed
Phases
Phase 3
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT01987895
Enrollment
632
Registered
2013-11-20
Start date
2014-03-27
Completion date
2017-03-24
Last updated
2025-02-04

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

Conditions

Clostridium Difficile Infection

Keywords

Post-antibiotic diarrhea, Clostridium difficile infection

Brief summary

This clinical study is conducted to assess the efficacy of cadazolid compared to vancomycin in subjects with Clostridium difficile-associated diarrhea (CDAD).

Detailed description

Subjects selected to participate in the study are treated either with cadazolid or vancomycin for 10 days. At the end of treatment, clinical cure is assessed; subjects are then followed-up to assess any disease recurrence.

Interventions

Cadazolid 250 mg as oral suspension twice daily.

DRUGVancomycin

Vancomycin 125 mg as oral capsules 4 times daily.

Placebo matching cadazolid and administered orally twice daily

Placebo capsules matching vancomycin and administered orally 4 times per day

Sponsors

Actelion
Lead SponsorINDUSTRY

Study design

Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
DOUBLE (Subject, Investigator)

Eligibility

Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No

Inclusion criteria

* Signed Informed Consent. * Male or female ≥ 18 years of age. Females of childbearing potential must agree to use an adequate and reliable method of contraception. * Subject with a diagnosis of mild-moderate or severe CDAD (first occurrence or first recurrence within 3 months) with: Diarrhea: a change in bowel habits with \> 3 liquid or unformed bowel movements (UBM) within 24 hours prior to randomization, AND Positive C. difficile toxin test on a stool sample produced within 72 hours prior to randomization.

Exclusion criteria

* More than one previous episode of CDAD in the 3-month period prior to randomization. * Evidence of life-threatening or fulminant CDAD. * Likelihood of death within 72 hours from any cause. * History of inflammatory colitides, chronic abdominal pain, or chronic diarrhea. * Antimicrobial treatment active against CDAD administered for \> 24 hours except for metronidazole treatment failures (MTF) * Known hypersensitivity or contraindication to study drugs, oxazolidinones, or quinolones. * Unable or unwilling to comply with all protocol requirements. * Any circumstances or conditions, which, in the opinion of the investigator, may affect full participation in the study or compliance with the protocol

Design outcomes

Primary

MeasureTime frameDescription
Clinical Cure Rate (CCR) in the Modified Intent-to-treat PopulationUp to Day 12 on average (end-of-treatment + 2 days)Clinical Cure (CC) is defined as: • Resolution of Diarrhea (≤ 3 unformed bowel movement per day for at least 2 consecutive days) on study treatment and maintained for 2 days after end-of-treatment (EOT), AND • No additional antimicrobial treatment active against Clostridium difficile-associated diarrhea (CDAD) or fecal microbiota transplant between first dose of study drug and 2 days after EOT. CCR is the percentage of subjects with Clinical Cure. Analyses are performed on two analysis sets. Results on the modified intent-to-treat set (mITT) are reported below.
Clinical Cure Rate (CCR) in the Per-protocol PopulationUp to Day 12 on average (end-of-treatment + 2 days)Clinical Cure (CC) is defined as: • Resolution of Diarrhea (≤ 3 unformed bowel movement per day for at least 2 consecutive days) on study treatment and maintained for 2 days after end-of-treatment (EOT), AND • No additional antimicrobial treatment active against Clostridium difficile-associated diarrhea (CDAD) or fecal microbiota transplant between first dose of study drug and 2 days after EOT. CCR is the percentage of subjects with Clinical Cure. Analyses are performed on two analysis sets. Results on the per-protocol set (PPS) are reported below.

Secondary

MeasureTime frameDescription
Sustained Cure Rate (SCR) in the Modified Intent-to-treat PopulationBetween Day 38 and Day 42 on average (end-of-treatment + 28-32 days)Sustained Cure is defined for each subject having Clinical Cure and no recurrence. SCR is the percentage of subjects with Sustained Cure. The main analysis is performed on the modified intent-to-treat set (mITT).
Kaplan-Meier Estimates for Resolution of DiarrheaUp to Day 10Resolution of Diarrhea (ROD) is defined as no more than 3 unformed bowel movements per day for at least two consecutive days for subjects on study treatment. The Kaplan-Meier estimates (KM estimates) for having an event (ROD) are reported for each time point.
Change From Baseline to Day 3 in Clostridium Difficile Infection (CDI) Daily Symptoms Patient-Reported Outcome (CDI-DaySyms PRO) Domain ScoresDay 1 (baseline) and Day 3CDI-DaySyms PRO is a questionnaire assessing 10 symptoms relevant to subjects with CDAD and grouped into 3 domains: Diarrhea symptoms, Abdominal symptoms and Systemic/Other. The subjects rate the severity of each item as None, Mild, Moderate, Severe or Very severe, converted to numeric scores from 0 to 4, respectively. The daily domain score is calculated as the mean of the non-missing responses for that domain on that day. A negative value for change from baseline corresponds to an improvement in domain score. The three domains are evaluated in a hierarchical manner, starting with Diarrhea Symptoms, then Abdominal Symptoms, and finally Systemic/Other Symptoms. The least squares means (LSM) are computed on the scores.

Other

MeasureTime frameDescription
Investigator's Assessment of Clinical Response (ICR) Rate at Visit 4 in the Modified Intent-to-treat PopulationUp to Day 12 on average (up to end-of-treatment + 2 to 4 days)ICR rate (%) is the percentage of subjects with clinical response assessed as cured according to the investigator's own judgement. Subjects with missing assessment are considered as not cured for the analysis. ICR rate is used as a supportive measure of the primary efficacy endpoint (CCR). Analyses are performed on two analysis sets. Results on the modified intent-to-treat set (mITT) are reported below.
Investigator's Assessment of Sustained Response Rate (ISR Rate) at Visit 5Between Day 38 and Day 42 on average (end-of-treatment + 28 to 32 days)ISR rate (%) is the percentage of subjects assessed as Sustained Cure at Visit 5, according to the investigator's own judgement. Sustained Cure is defined for each subject having Clinical Cure and no recurrence. Subjects with missing assessment are considered as having 'Not Sustained Cure' for the analysis. ISR rate is used as a supportive measure of the secondary efficacy endpoint (SCR). Analyses are performed on the modified intent-to-treat set (mITT).
Investigator's Assessment of Clinical Response (ICR) Rate at Visit 4 in the Per-protocol PopulationUp to Day 12 on average (up to end-of-treatment + 2 to 4 days)ICR rate (%) is the percentage of subjects with clinical response assessed as cured according to the investigator's own judgement. ICR rate (%) is the percentage of subjects with ICR assessed as cured. Subjects with missing assessment are considered as not cured for the analysis. ICR rate is used as a supportive measure of the primary efficacy endpoint (CCR). Analyses are performed on two analysis sets. Results on the per-protocol set (PPS) are reported below.
Sustained Cure Rate (SCR) in the Per-protocol PopulationBetween Day 38 and Day 42 on average (end-of-treatment + 28-32 days)Sustained Cure is defined for each subject having Clinical Cure and no recurrence. SCR is the percentage of subjects with Sustained Cure. The analyses performed on the modified intent-to- treat set (mITT) are repeated on the per-protocol set (PPS) for sensitivity.
Recurrence RateBetween Day 13 and Day 40 on average (from end-of-treatment + 3 days and end-of-treatment + 30 days)Recurrence is defined as the occurrence of a new episode of diarrhea (\> 3 unformed bowel movements on any day between end-of-treatment + 3 days and end-of-treatment + 30 days ) Recurrence rates is the percentage of subjects assessed as having a recurrence out of subjects with Clinical Cure.

Participant flow

Recruitment details

904 patients at 70 sites in 12 countries were screened, among whom 632 were enrolled in the IMPACT 1 trial at 64 sites located in North & South America, Europe and Australia.

Participants by arm

ArmCount
Cadazolid
Subjects receive oral cadazolid 250 mg twice daily (bid) and oral vancomycin-matching placebo 4 times per day (qid) for 10 days
302
Vancomycin
Subjects receive oral vancomycin 125 mg qid and oral cadazolid-matching placebo bid for 10 days
318
Total620

Withdrawals & dropouts

PeriodReasonFG000FG001
Overall StudyDeath77
Overall StudyLost to Follow-up35
Overall StudyPhysician Decision810
Overall Studyrandomized before giving IC01
Overall StudyWithdrawal by Subject127

Baseline characteristics

CharacteristicCadazolidVancomycinTotal
Age, Customized
18-64 years
180 Participants203 Participants383 Participants
Age, Customized
65-74 years
73 Participants70 Participants143 Participants
Age, Customized
75 years and older
49 Participants45 Participants94 Participants
CDAD episode type strata
First occurrence
238 Participants253 Participants491 Participants
CDAD episode type strata
First recurrence
64 Participants65 Participants129 Participants
CDAD severity at baseline
Mild-Moderate
227 Participants243 Participants470 Participants
CDAD severity at baseline
Severe
59 Participants51 Participants110 Participants
CDAD severity at baseline
Unable to determine
16 Participants24 Participants40 Participants
Initial strain of Clostridium difficile
Hypervirulent strains
58 Participants82 Participants140 Participants
Initial strain of Clostridium difficile
Non-hypervirulent strains
226 Participants215 Participants441 Participants
Initial strain of Clostridium difficile
Unable to determine
18 Participants21 Participants39 Participants
Race/Ethnicity, Customized
Asian
2 Participants3 Participants5 Participants
Race/Ethnicity, Customized
Black or African American
3 Participants9 Participants12 Participants
Race/Ethnicity, Customized
Missing
6 Participants3 Participants9 Participants
Race/Ethnicity, Customized
Native Hawaiian or Other Pacific Islander
1 Participants0 Participants1 Participants
Race/Ethnicity, Customized
Other
2 Participants4 Participants6 Participants
Race/Ethnicity, Customized
White
288 Participants299 Participants587 Participants
Region of Enrollment
Canada
83 Participants88 Participants171 Participants
Region of Enrollment
Europe
111 Participants117 Participants228 Participants
Region of Enrollment
Other
7 Participants5 Participants12 Participants
Region of Enrollment
United States
101 Participants108 Participants209 Participants
Sex: Female, Male
Female
183 Participants195 Participants378 Participants
Sex: Female, Male
Male
119 Participants123 Participants242 Participants

Adverse events

Event typeEG000
affected / at risk
EG001
affected / at risk
deaths
Total, all-cause mortality
7 / 3047 / 322
other
Total, other adverse events
33 / 30449 / 322
serious
Total, serious adverse events
19 / 30426 / 322

Outcome results

Primary

Clinical Cure Rate (CCR) in the Modified Intent-to-treat Population

Clinical Cure (CC) is defined as: • Resolution of Diarrhea (≤ 3 unformed bowel movement per day for at least 2 consecutive days) on study treatment and maintained for 2 days after end-of-treatment (EOT), AND • No additional antimicrobial treatment active against Clostridium difficile-associated diarrhea (CDAD) or fecal microbiota transplant between first dose of study drug and 2 days after EOT. CCR is the percentage of subjects with Clinical Cure. Analyses are performed on two analysis sets. Results on the modified intent-to-treat set (mITT) are reported below.

Time frame: Up to Day 12 on average (end-of-treatment + 2 days)

Population: All subjects who received at least one dose of study drug and had a confirmed diagnosis of CDAD.

ArmMeasureValue (NUMBER)
CadazolidClinical Cure Rate (CCR) in the Modified Intent-to-treat Population83.8 Percentage of participants
VancomycinClinical Cure Rate (CCR) in the Modified Intent-to-treat Population85.2 Percentage of participants
95% CI: [-7.2, 4.3]
Comparison: Sensitivity analysis with imputation for a single day with missing UBM data between one day before end-of-treatment (EOT) and 2 days after EOT95% CI: [-8.1, 3.2]
Primary

Clinical Cure Rate (CCR) in the Per-protocol Population

Clinical Cure (CC) is defined as: • Resolution of Diarrhea (≤ 3 unformed bowel movement per day for at least 2 consecutive days) on study treatment and maintained for 2 days after end-of-treatment (EOT), AND • No additional antimicrobial treatment active against Clostridium difficile-associated diarrhea (CDAD) or fecal microbiota transplant between first dose of study drug and 2 days after EOT. CCR is the percentage of subjects with Clinical Cure. Analyses are performed on two analysis sets. Results on the per-protocol set (PPS) are reported below.

Time frame: Up to Day 12 on average (end-of-treatment + 2 days)

Population: All subjects who received at least one dose of study drug and had a confirmed diagnosis of CDAD and without protocol deviations that might affect the evaluation of the effect of the study drug on the primary variable.

ArmMeasureValue (NUMBER)
CadazolidClinical Cure Rate (CCR) in the Per-protocol Population87.6 Percentage of participants
VancomycinClinical Cure Rate (CCR) in the Per-protocol Population91.7 Percentage of participants
95% CI: [-9.2, 1]
Secondary

Change From Baseline to Day 3 in Clostridium Difficile Infection (CDI) Daily Symptoms Patient-Reported Outcome (CDI-DaySyms PRO) Domain Scores

CDI-DaySyms PRO is a questionnaire assessing 10 symptoms relevant to subjects with CDAD and grouped into 3 domains: Diarrhea symptoms, Abdominal symptoms and Systemic/Other. The subjects rate the severity of each item as None, Mild, Moderate, Severe or Very severe, converted to numeric scores from 0 to 4, respectively. The daily domain score is calculated as the mean of the non-missing responses for that domain on that day. A negative value for change from baseline corresponds to an improvement in domain score. The three domains are evaluated in a hierarchical manner, starting with Diarrhea Symptoms, then Abdominal Symptoms, and finally Systemic/Other Symptoms. The least squares means (LSM) are computed on the scores.

Time frame: Day 1 (baseline) and Day 3

Population: All subjects from the modified intent-to-treat population, excluding those who participated in the validation sub-study. No imputation of missing scores is performed prior to deriving response status. Subjects with missing values at baseline or at Day 3 are considered to be non-responders.

ArmMeasureGroupValue (LEAST_SQUARES_MEAN)
CadazolidChange From Baseline to Day 3 in Clostridium Difficile Infection (CDI) Daily Symptoms Patient-Reported Outcome (CDI-DaySyms PRO) Domain ScoresDiarrhea symptoms-1.233 Score on a scale
CadazolidChange From Baseline to Day 3 in Clostridium Difficile Infection (CDI) Daily Symptoms Patient-Reported Outcome (CDI-DaySyms PRO) Domain ScoresAbdominal symptoms-0.623 Score on a scale
CadazolidChange From Baseline to Day 3 in Clostridium Difficile Infection (CDI) Daily Symptoms Patient-Reported Outcome (CDI-DaySyms PRO) Domain ScoresOther symptoms-0.639 Score on a scale
VancomycinChange From Baseline to Day 3 in Clostridium Difficile Infection (CDI) Daily Symptoms Patient-Reported Outcome (CDI-DaySyms PRO) Domain ScoresDiarrhea symptoms-1.235 Score on a scale
VancomycinChange From Baseline to Day 3 in Clostridium Difficile Infection (CDI) Daily Symptoms Patient-Reported Outcome (CDI-DaySyms PRO) Domain ScoresAbdominal symptoms-0.710 Score on a scale
VancomycinChange From Baseline to Day 3 in Clostridium Difficile Infection (CDI) Daily Symptoms Patient-Reported Outcome (CDI-DaySyms PRO) Domain ScoresOther symptoms-0.689 Score on a scale
Comparison: Comparison of the diarrhea domain scoresp-value: 0.981495% CI: [-0.2, 0.2]ANOVA
Comparison: Comparison of the abdominal symptoms domain scoresp-value: 0.287995% CI: [-0.07, 0.25]ANOVA
Comparison: Comparison of the systemic / other symptoms domain scoresp-value: 0.48895% CI: [-0.09, 0.19]ANOVA
Secondary

Kaplan-Meier Estimates for Resolution of Diarrhea

Resolution of Diarrhea (ROD) is defined as no more than 3 unformed bowel movements per day for at least two consecutive days for subjects on study treatment. The Kaplan-Meier estimates (KM estimates) for having an event (ROD) are reported for each time point.

Time frame: Up to Day 10

Population: The analyses were performed on the modified intention-to-treat population: all subjects who received at least one dose of study drug and had a confirmed diagnosis of CDAD

ArmMeasureGroupValue (NUMBER)
CadazolidKaplan-Meier Estimates for Resolution of DiarrheaDay 146.7 KM estimate (%)
CadazolidKaplan-Meier Estimates for Resolution of DiarrheaDay 681.1 KM estimate (%)
CadazolidKaplan-Meier Estimates for Resolution of DiarrheaDay 369.9 KM estimate (%)
CadazolidKaplan-Meier Estimates for Resolution of DiarrheaDay 782.5 KM estimate (%)
CadazolidKaplan-Meier Estimates for Resolution of DiarrheaDay 883.4 KM estimate (%)
CadazolidKaplan-Meier Estimates for Resolution of DiarrheaDay 472.8 KM estimate (%)
CadazolidKaplan-Meier Estimates for Resolution of DiarrheaDay 983.8 KM estimate (%)
CadazolidKaplan-Meier Estimates for Resolution of DiarrheaDay 262.6 KM estimate (%)
CadazolidKaplan-Meier Estimates for Resolution of DiarrheaDay 1083.8 KM estimate (%)
CadazolidKaplan-Meier Estimates for Resolution of DiarrheaDay 577.8 KM estimate (%)
VancomycinKaplan-Meier Estimates for Resolution of DiarrheaDay 1085.2 KM estimate (%)
VancomycinKaplan-Meier Estimates for Resolution of DiarrheaDay 371.1 KM estimate (%)
VancomycinKaplan-Meier Estimates for Resolution of DiarrheaDay 145.9 KM estimate (%)
VancomycinKaplan-Meier Estimates for Resolution of DiarrheaDay 260.7 KM estimate (%)
VancomycinKaplan-Meier Estimates for Resolution of DiarrheaDay 477.7 KM estimate (%)
VancomycinKaplan-Meier Estimates for Resolution of DiarrheaDay 580.2 KM estimate (%)
VancomycinKaplan-Meier Estimates for Resolution of DiarrheaDay 681.8 KM estimate (%)
VancomycinKaplan-Meier Estimates for Resolution of DiarrheaDay 885.2 KM estimate (%)
VancomycinKaplan-Meier Estimates for Resolution of DiarrheaDay 985.2 KM estimate (%)
VancomycinKaplan-Meier Estimates for Resolution of DiarrheaDay 784.6 KM estimate (%)
p-value: 0.601695% CI: [0.8, 1.14]Log Rank
Secondary

Sustained Cure Rate (SCR) in the Modified Intent-to-treat Population

Sustained Cure is defined for each subject having Clinical Cure and no recurrence. SCR is the percentage of subjects with Sustained Cure. The main analysis is performed on the modified intent-to-treat set (mITT).

Time frame: Between Day 38 and Day 42 on average (end-of-treatment + 28-32 days)

Population: All subjects who received at least one dose of study drug and had a confirmed diagnosis of CDAD.

ArmMeasureValue (NUMBER)
CadazolidSustained Cure Rate (SCR) in the Modified Intent-to-treat Population65.6 Percentage of participants
VancomycinSustained Cure Rate (SCR) in the Modified Intent-to-treat Population62.3 Percentage of participants
95% CI: [-4.3, 10.8]
Other Pre-specified

Investigator's Assessment of Clinical Response (ICR) Rate at Visit 4 in the Modified Intent-to-treat Population

ICR rate (%) is the percentage of subjects with clinical response assessed as cured according to the investigator's own judgement. Subjects with missing assessment are considered as not cured for the analysis. ICR rate is used as a supportive measure of the primary efficacy endpoint (CCR). Analyses are performed on two analysis sets. Results on the modified intent-to-treat set (mITT) are reported below.

Time frame: Up to Day 12 on average (up to end-of-treatment + 2 to 4 days)

Population: All subjects who received at least one dose of study drug and had a confirmed diagnosis of CDAD.

ArmMeasureValue (NUMBER)
CadazolidInvestigator's Assessment of Clinical Response (ICR) Rate at Visit 4 in the Modified Intent-to-treat Population89.7 Percentage of participants
VancomycinInvestigator's Assessment of Clinical Response (ICR) Rate at Visit 4 in the Modified Intent-to-treat Population91.5 Percentage of participants
Comparison: Exploratory analysis95% CI: [-6.5, 2.9]
Other Pre-specified

Investigator's Assessment of Clinical Response (ICR) Rate at Visit 4 in the Per-protocol Population

ICR rate (%) is the percentage of subjects with clinical response assessed as cured according to the investigator's own judgement. ICR rate (%) is the percentage of subjects with ICR assessed as cured. Subjects with missing assessment are considered as not cured for the analysis. ICR rate is used as a supportive measure of the primary efficacy endpoint (CCR). Analyses are performed on two analysis sets. Results on the per-protocol set (PPS) are reported below.

Time frame: Up to Day 12 on average (up to end-of-treatment + 2 to 4 days)

Population: All subjects who received at least one dose of study drug and had a confirmed diagnosis of CDAD and without protocol deviations that might affect the evaluation of the effect of the study drug on the primary variable.

ArmMeasureValue (NUMBER)
CadazolidInvestigator's Assessment of Clinical Response (ICR) Rate at Visit 4 in the Per-protocol Population92.2 Percentage of participants
VancomycinInvestigator's Assessment of Clinical Response (ICR) Rate at Visit 4 in the Per-protocol Population94.1 Percentage of participants
Comparison: Exploratory analysis95% CI: [-6.2, 2.3]
Other Pre-specified

Investigator's Assessment of Sustained Response Rate (ISR Rate) at Visit 5

ISR rate (%) is the percentage of subjects assessed as Sustained Cure at Visit 5, according to the investigator's own judgement. Sustained Cure is defined for each subject having Clinical Cure and no recurrence. Subjects with missing assessment are considered as having 'Not Sustained Cure' for the analysis. ISR rate is used as a supportive measure of the secondary efficacy endpoint (SCR). Analyses are performed on the modified intent-to-treat set (mITT).

Time frame: Between Day 38 and Day 42 on average (end-of-treatment + 28 to 32 days)

Population: All subjects who received at least one dose of study drug and had a confirmed diagnosis of CDAD.

ArmMeasureValue (NUMBER)
CadazolidInvestigator's Assessment of Sustained Response Rate (ISR Rate) at Visit 573.8 Percentage of participants
VancomycinInvestigator's Assessment of Sustained Response Rate (ISR Rate) at Visit 570.1 Percentage of participants
Comparison: Exploratory analysis95% CI: [-3.4, 10.7]
Other Pre-specified

Recurrence Rate

Recurrence is defined as the occurrence of a new episode of diarrhea (\> 3 unformed bowel movements on any day between end-of-treatment + 3 days and end-of-treatment + 30 days ) Recurrence rates is the percentage of subjects assessed as having a recurrence out of subjects with Clinical Cure.

Time frame: Between Day 13 and Day 40 on average (from end-of-treatment + 3 days and end-of-treatment + 30 days)

Population: Subjects from the modified intent-to-treat analysis set with clinical cure

ArmMeasureValue (NUMBER)
CadazolidRecurrence Rate15 percentage of participants
VancomycinRecurrence Rate21.4 percentage of participants
Other Pre-specified

Sustained Cure Rate (SCR) in the Per-protocol Population

Sustained Cure is defined for each subject having Clinical Cure and no recurrence. SCR is the percentage of subjects with Sustained Cure. The analyses performed on the modified intent-to- treat set (mITT) are repeated on the per-protocol set (PPS) for sensitivity.

Time frame: Between Day 38 and Day 42 on average (end-of-treatment + 28-32 days)

Population: All subjects who received at least one dose of study drug and had a confirmed diagnosis of CDAD and without protocol deviations that might affect the evaluation of the effect of the study drug on the primary variable.

ArmMeasureValue (NUMBER)
CadazolidSustained Cure Rate (SCR) in the Per-protocol Population68.8 Percentage of participants
VancomycinSustained Cure Rate (SCR) in the Per-protocol Population67.7 Percentage of participants
95% CI: [-6.5, 8.7]

Source: ClinicalTrials.gov · Data processed: Mar 8, 2026