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PAR-101/OPT-80 Versus Vancomycin for the Treatment of Clostridium Difficile-Associated Diarrhea (CDAD)

A Double-Blind Study to Compare the Safety and Efficacy of PAR-101 to Vancomycin in Subjects With Clostridium Difficile-Associated Diarrhea (CDAD)

Status
Completed
Phases
Phase 3
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT00468728
Enrollment
535
Registered
2007-05-03
Start date
2006-10-04
Completion date
2009-12-11
Last updated
2017-04-21

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

Conditions

Clostridium Infections, Diarrhea

Keywords

CDAD, Clostridium difficile, diarrhea, Clostridium difficile-Associated Diarrhea

Brief summary

This is a comparative study to investigate the safety and efficacy of PAR-101/OPT-80 (fidaxomicin) versus vancomycin in subjects with Clostridium difficile-associated diarrhea (CDAD).

Detailed description

The primary objective of this pivotal study is to investigate the safety and efficacy of PAR-101/OPT-80 versus vancomycin in subjects with Clostridium difficile-associated diarrhea (CDAD). The cure rates at end of therapy and recurrence rates will be evaluated and compared.

Interventions

DRUGPAR-101/OPT-80

capsules

DRUGVancomycin

Capsules

Sponsors

Optimer Pharmaceuticals LLC, a subsidiary of Merck & Co., Inc. (Rahway, New Jersey USA)
Lead SponsorINDUSTRY

Study design

Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
QUADRUPLE (Subject, Caregiver, Investigator, Outcomes Assessor)

Eligibility

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

Inclusion criteria

* Males/females with CDAD * Females must use adequate contraception * Signed informed consent

Exclusion criteria

* Life-threatening CDAD * Toxic megacolon * Pregnant * Concurrent use of diarrheal agents * Participation in other trials

Design outcomes

Primary

MeasureTime frameDescription
Cure Rate at End of TherapyStudy day 10 (+/- 2 days)Percentage of subjects with 3 or fewer unformed stools for 2 consecutive days and maintained through the end of therapy, and the subject no longer needed specific anti-Clostridium antibacterial treatment after completion of the course of study medication.

Secondary

MeasureTime frameDescription
RecurrenceStudy days 11-40Percentage of subjects with the re-establishment of diarrhea to an extent(based on frequency of passed unformed stools) that was greater than that noted on the last day of study medication, and the demonstration of either toxin A or B or both of C. difficile, and retreatment with CDI anti-infective therapy was needed.
Global CureEnd of StudyAchieving a cure response at end of treatment and not having a recurrence at any time up to the post-study visit.

Countries

Belgium, Canada, France, Germany, Italy, Spain, Sweden, United Kingdom, United States

Participant flow

Recruitment details

Subjects were enrolled from April 2007 to November 2009 by centers in the United States, Canada, France, Spain, Belgium, Germany, United Kingdom, Italy, and Sweden.

Participants by arm

ArmCount
Vancomycin
125 mg administered 4 times daily (q6hr)
256
PAR-101/OPT-80
200 mg administered twice daily (q12hr)
253
Total509

Withdrawals & dropouts

PeriodReasonFG000FG001
Follow-upmITT failure3431
Treatmentcriteria for mITT population411

Baseline characteristics

CharacteristicPAR-101/OPT-80TotalVancomycin
Age, Continuous64.1 years
STANDARD_DEVIATION 18
63.4 years
STANDARD_DEVIATION 18.1
62.7 years
STANDARD_DEVIATION 18.3
Region of Enrollment
Belgium
22 participants42 participants20 participants
Region of Enrollment
Canada
79 participants161 participants82 participants
Region of Enrollment
France
11 participants19 participants8 participants
Region of Enrollment
Germany
18 participants37 participants19 participants
Region of Enrollment
Italy
14 participants27 participants13 participants
Region of Enrollment
Spain
5 participants9 participants4 participants
Region of Enrollment
Sweden
4 participants11 participants7 participants
Region of Enrollment
United Kingdom
26 participants53 participants27 participants
Region of Enrollment
United States
74 participants150 participants76 participants
Sex: Female, Male
Female
149 Participants310 Participants161 Participants
Sex: Female, Male
Male
104 Participants199 Participants95 Participants

Adverse events

Event typeEG000
affected / at risk
EG001
affected / at risk
deaths
Total, all-cause mortality
— / —— / —
other
Total, other adverse events
177 / 260186 / 264
serious
Total, serious adverse events
58 / 26070 / 264

Outcome results

Primary

Cure Rate at End of Therapy

Percentage of subjects with 3 or fewer unformed stools for 2 consecutive days and maintained through the end of therapy, and the subject no longer needed specific anti-Clostridium antibacterial treatment after completion of the course of study medication.

Time frame: Study day 10 (+/- 2 days)

Population: Analysis data is modified intent to treat (mITT) population. The mITT population consists of subjects that had CDAD confirmed by \>3 unformed bowel movements in the 24 hours prior to randomization and a positive toxin assay and received at least one dose of study medication.

ArmMeasureValue (NUMBER)
VancomycinCure Rate at End of Therapy86.7 Percentage of Participants
PAR-101/OPT-80Cure Rate at End of Therapy87.7 Percentage of Participants
Comparison: H0: C(OPT-80) - C(VAN) \<= -10% Power calculation is based on cure rate of 85% in both treatment groups, non-inferiority margin of 10%, 2.5% (1-sided) type I error rate with approximately 90% power gives a total of 530 subjects.95% CI: [-4.8, 6.8]
Secondary

Global Cure

Achieving a cure response at end of treatment and not having a recurrence at any time up to the post-study visit.

Time frame: End of Study

Population: The analysis population is mITT, subjects that achieved a cure response at end of treatment and not having a recurrence at any time up to the Post-study visit.

ArmMeasureValue (NUMBER)
VancomycinGlobal Cure63.3 Percentage of Participants
PAR-101/OPT-80Global Cure76.7 Percentage of Participants
p-value: 0.00195% CI: [5.4, 21.1]Chi-squared
Secondary

Recurrence

Percentage of subjects with the re-establishment of diarrhea to an extent(based on frequency of passed unformed stools) that was greater than that noted on the last day of study medication, and the demonstration of either toxin A or B or both of C. difficile, and retreatment with CDI anti-infective therapy was needed.

Time frame: Study days 11-40

Population: The analysis population is mITT, for subjects who met the primary endpoint of cure, was analyzed for the recurrence rates of diarrhea up to the Poststudy Visit.

ArmMeasureValue (NUMBER)
VancomycinRecurrence27.0 Percentage of Participants
PAR-101/OPT-80Recurrence12.6 Percentage of Participants
p-value: <0.00195% CI: [-21.6, -7]Chi-squared

Source: ClinicalTrials.gov · Data processed: Mar 27, 2026