Percentage of Participants With Sustained Clinical Response (SCR) at EOT +9 Days
SCR at EOT + 9 days was defined as CCR (EOT + 2 days) without CDAD recurrence until assessment at EOT +9 days during the follow-up period. Recurrence for ages from birth to < 2 years was defined as re-establishment of watery diarrhea after CCR to an extent that was greater than that noted on the last day of study drug with positive direct or indirect testing for the presence of toxigenic Clostridium difficile (C. difficile) in stool and that, in the investigator's opinion, required retreatment with CDAD anti-infective therapy. Recurrence for ages ≥ 2 years < 18 years was defined as re-establishment of diarrhea after CCR to an extent (as measured by the frequency of UBMs) that was greater than that noted on the last day of study drug with positive direct or indirect testing for the presence of toxigenic C. difficile in stool and that, in the investigator's opinion, required retreatment with CDAD anti-infective therapy.
Percentage of Participants With Global Cure (GC) at EOT +9 Days
GC was reported as a positive (Yes) or negative (No) outcome and was calculated using SCR and ICR/CCR values according to the following conditions: ● if ICR/CCR=Yes and SCR=Yes, then Global Cure was Yes. ● if ICR/CCR=Yes and SCR =No, then Global Cure was No. ● if ICR/CCR=No (SCR not assessed), then Global Cure was No. ● if ICR/CCR=Missing (SCR not assessed), then Global Cure was set to No. No multiple imputation method (MI) was used for global cure at EOT + 9 days.
Percentage of Participants With Recurrence of CDAD at EOT +9 Days
Recurrence for ages from birth to < 2 years was defined as re-establishment of watery diarrhea after CCR to an extent that was greater than that noted on the last day of study drug with positive direct or indirect testing for the presence of toxigenic C. difficile in stool and that, in the investigator's opinion, required retreatment with CDAD anti-infective therapy. Recurrence for ages ≥ 2 years < 18 years was defined as re-establishment of diarrhea after CCR to an extent (as measured by the frequency of UBMs) that was greater than that noted on the last day of study drug with positive direct or indirect testing for the presence of toxigenic C. difficile in stool and that, in the investigator's opinion, required retreatment with CDAD anti-infective therapy.
Percentage of Participants With SCR at EOT +16 Days
SCR at EOT + 16 days was defined as CCR (EOT + 2 days) without CDAD recurrence until assessment at EOT + 16 days during the follow-up period. Recurrence for ages from birth to < 2 years was defined as re-establishment of watery diarrhea after CCR to an extent that was greater than that noted on the last day of study drug with positive direct or indirect testing for the presence of toxigenic C. difficile in stool and that, in the investigator's opinion, required retreatment with CDAD anti-infective therapy. Recurrence for ages ≥ 2 years < 18 years was defined as re-establishment of diarrhea after CCR to an extent (as measured by the frequency of UBMs) that was greater than that noted on the last day of study drug with positive direct or indirect testing for the presence of toxigenic C. difficile in stool and that, in the investigator's opinion, required retreatment with CDAD anti-infective therapy.
Percentage of Participants With GC at EOT +16 Days
GC was reported as a positive (Yes) or negative (No) outcome and was calculated using SCR and ICR/CCR values according to the following conditions: ● if ICR/CCR=Yes and SCR=Yes, then Global Cure was Yes. ● if ICR/CCR=Yes and SCR =No, then Global Cure was No. ● if ICR/CCR=No (SCR not assessed), then Global Cure was No. ● if ICR/CCR=Missing (SCR not assessed), then Global Cure was set to No. No multiple imputation method (MI) was used for global cure at EOT + 16 days.
Percentage of Participants With Recurrence of CDAD at EOT +16 Days
Recurrence for ages from birth to < 2 years was defined as re-establishment of watery diarrhea after CCR to an extent that was greater than that noted on the last day of study drug with positive direct or indirect testing for the presence of toxigenic C. difficile in stool and that, in the investigator's opinion, required retreatment with CDAD anti-infective therapy. Recurrence for ages ≥ 2 years < 18 years was defined as re-establishment of diarrhea after CCR to an extent (as measured by the frequency of UBMs) that was greater than that noted on the last day of study drug with positive direct or indirect testing for the presence of toxigenic C. difficile in stool and that, in the investigator's opinion, required retreatment with CDAD anti-infective therapy.
Percentage of Participants With SCR at EOT +23 Days
SCR at EOT + 23 days was defined as CCR (EOT + 2 days) without CDAD recurrence until assessment at EOT + 16 days during the follow-up period. Recurrence for ages from birth to < 2 years was defined as re-establishment of watery diarrhea after CCR to an extent that was greater than that noted on the last day of study drug with positive direct or indirect testing for the presence of toxigenic C. difficile in stool and that, in the investigator's opinion, required retreatment with CDAD anti-infective therapy. Recurrence for ages ≥ 2 years < 18 years was defined as re-establishment of diarrhea after CCR to an extent (as measured by the frequency of UBMs) that was greater than that noted on the last day of study drug with positive direct or indirect testing for the presence of toxigenic C. difficile in stool and that, in the investigator's opinion, required retreatment with CDAD anti-infective therapy.
Percentage of Participants With GC at EOT +23 Days
GC was reported as a positive (Yes) or negative (No) outcome and was calculated using SCR and ICR/CCR values according to the following conditions: ● if ICR/CCR=Yes and SCR=Yes, then Global Cure was Yes. ● if ICR/CCR=Yes and SCR =No, then Global Cure was No. ● if ICR/CCR=No (SCR not assessed), then Global Cure was No. ● if ICR/CCR=Missing (SCR not assessed), then Global Cure was set to No. No multiple imputation method (MI) was used for global cure at EOT + 23 days.
Percentage of Participants With Recurrence of CDAD at EOT +23 Days
Recurrence for ages from birth to < 2 years was defined as re-establishment of watery diarrhea after CCR to an extent that was greater than that noted on the last day of study drug with positive direct or indirect testing for the presence of toxigenic C. difficile in stool and that, in the investigator's opinion, required retreatment with CDAD anti-infective therapy. Recurrence for ages ≥ 2 years < 18 years was defined as re-establishment of diarrhea after CCR to an extent (as measured by the frequency of UBMs) that was greater than that noted on the last day of study drug with positive direct or indirect testing for the presence of toxigenic C. difficile in stool and that, in the investigator's opinion, required retreatment with CDAD anti-infective therapy.
Percentage of Participants With SCR at End of Study (EOS) (EOT +30 Days)
SCR at EOS was defined as CCR (EOT + 2 days) without CDAD recurrence until assessment at EOS (EOT + 30 days) during the follow-up period. Recurrence for ages from birth to < 2 years was defined as re-establishment of watery diarrhea after CCR to an extent that was greater than that noted on the last day of study drug with positive direct or indirect testing for the presence of toxigenic C. difficile in stool and that, in the investigator's opinion, required retreatment with CDAD anti-infective therapy. Recurrence for ages ≥ 2 years < 18 years was defined as re-establishment of diarrhea after CCR to an extent (as measured by the frequency of UBMs) that was greater than that noted on the last day of study drug with positive direct or indirect testing for the presence of toxigenic C. difficile in stool and that, in the investigator's opinion, required retreatment with CDAD anti-infective therapy.
Percentage of Participants With GC at EOS (EOT +30 Days)
GC was reported as a positive (Yes) or negative (No) outcome and was calculated using SCR and ICR/CCR values according to the following conditions: ● if ICR/CCR=Yes and SCR=Yes, then Global Cure was Yes. ● if ICR/CCR=Yes and SCR =No, then Global Cure was No. ● if ICR/CCR=No (SCR not assessed), then Global Cure was No. ● if ICR/CCR=Missing (SCR not assessed), then Global Cure was set to No. Global Cure at EOT +30 days was derived using MI in case ICR/CCR=Missing (SCR not assessed) following Rubin's multiple imputation method.
Percentage of Participants With Recurrence of CDAD at EOS (EOT +30 Days)
Recurrence for ages from birth to < 2 years was defined as re-establishment of watery diarrhea after CCR to an extent that was greater than that noted on the last day of study drug with positive direct or indirect testing for the presence of toxigenic C. difficile in stool and that, in the investigator's opinion, required retreatment with CDAD anti-infective therapy. Recurrence for ages ≥ 2 years < 18 years was defined as re-establishment of diarrhea after CCR to an extent (as measured by the frequency of UBMs) that was greater than that noted on the last day of study drug with positive direct or indirect testing for the presence of toxigenic C. difficile in stool and that, in the investigator's opinion, required retreatment with CDAD anti-infective therapy.
Time to Resolution of Diarrhea (TTROD)
TTROD for ages from birth < 2 years was defined as time elapsing (hours rounded up from minutes > 30) from treatment start (time of first study drug dose) to diarrhea resolution (time of last episode of watery diarrhea the day prior to the first of 2 consecutive days without watery diarrhea sustained through EOT). TTROD for ages ≥ 2 years to < 18 years was defined as time elapsing (hours rounded up from minutes > 30) from treatment start (time of first dose) to diarrhea resolution (time of the last UBM the day prior to the first of 2 consecutive days of < 3 UBMs sustained through EOT). TTROD by Kaplan-Meier Method. Those who completed treatment but did not show diarrhea resolution until EOT were censored at Day 10/240 hours. Those who did not complete treatment, discontinued earlier but did not show diarrhea resolution until disc. day were censored at disc. (days converted to hours). Those whose diarrhea did not continue after first dose were included with a TTROD of 1 hour.
Time to Recurrence of CDAD for Participants With CCR at EOT +2 Days
Time to recurrence was defined as the time (days) from CCR until the onset of recurrence. Time to recurrence of CDAD by Kaplan-Meier Method. Data for median was estimated and the 95% CI could not be estimated due to low event rate. Data not estimable denoted as NA. Participants with CCR at EOT+2 days, who completed the follow-up period but did not experience a recurrence of CDAD were censored at EOT+30 days and those who did not complete the follow-up period and discontinued during this period and did not experience a recurrence of CDAD were censored at day of discontinuation.
Number of Participants With Adverse Events (AEs)
An adverse event (AE) was defined as any untoward medical occurrence in a participant administered a study drug or who had undergone study procedures which did not necessarily have a causal relationship with this treatment. This included abnormal laboratory tests, vital signs, electrocardiogram data or physical examinations that were defined as AEs if the abnormality induced clinical signs or symptoms, required active intervention, interruption or discontinuation of study drug or was clinically significant in the investigator's opinion. The following standard with 3 grades was used to measure the severity of AEs, including abnormal clinical laboratory values: ● Mild: No disruption of normal daily activities ● Moderate: Affected normal daily activities ● Severe: Inability to perform daily activities. A treatment-emergent adverse event (TEAE) was defined as an AE observed after starting administration of the test drug/comparative drug.
Plasma Concentrations of Fidaxomicin
Drug concentration was derived from the blood samples collected.
Plasma Concentrations of Metabolite OP-1118
Drug concentration was derived from the blood samples collected.
Metabolite-to-Parent Ratio (MPRconc)
Drug concentration was derived from the blood samples collected.
Fecal Concentrations of Fidaxomicin
Drug concentration was derived from the stool samples collected.
Fecal Concentrations of Metabolite OP-1118
Drug concentration was derived from the stool samples collected.
MPRconc Within 24 Hours of a Dose
Drug concentration was derived from the stool samples collected.
Acceptance of Formulation (Palatability Assessment) in All Participants at First Administration of Study Drug and at Day 7
Acceptance of formulation was evaluated in all participants who received fidaxomicin oral suspension and vancomycin oral liquid (i.e., participants from birth to =< 6 years and participants > 6 years unable to swallow tablets) by means of a five-point rating scale (awful, poor, fair, good, excellent) by unblinded staff if hospitalized, and by the participant/parents/legal guardian when at home.