Study design and clinical end points
DIFICID was studied in adults vs vancomycin in two phase 3 Clostridioides (formerly Clostridium) difficile–associated diarrhea (CDAD) trials.
Study design
Two randomized, double-blind, noninferiority trials
Patients
- 1,105 patients ≥18 years of age
- Diagnosis of C. difficile–associated diarrhea as defined by:
- >3 unformed bowel movements (UBM) (or >200 mL of unformed stool for subjects having rectal collection devices) in the 24 hours before randomization
- Presence of C. difficile toxin A or B in stool sample within 48 hours of randomization
- No more than 24 hours of pretreatment with vancomycin or metronidazole
- No more than one prior C. difficile–associated diarrhea episode in past 3 months
- 37% of patients had severe C. difficile–associated diarrhea (defined as ≥10 UBM per day or white blood cell (WBC) ≥15,000/mm
3
) - 16% of patients studied had a prior episode of CDAD within the last 3 months
- 50% of patients were ≥65 years of age and 31% were ≥75 years of age
- Exclusion criteria : Life-threatening/fulminant infection, hypotension, septic shock, peritoneal signs, significant dehydration, or toxic megacolon.
Treatment regimens
Clinical end points
Primary end point: Clinical response rate at the end of 10-day treatment
- Clinical response was defined as improvement in diarrhea or other symptoms, such that further C. difficile–associated diarrhea treatment was not needed.
Additional efficacy end point: Sustained response 25 days after the end of treatment
- Sustained response was defined as clinical response at the end of treatment and survival without proven or suspected C. difficile–associated diarrhea recurrence through 25 days beyond the end of treatment.