Safety and Pharmacokinetic Study of Fidaxomicin in Children With Clostridium difficile-Associated Diarrhea: A phase 2A multicenter clinical trial

Molly A. O'Gorman, Marian G. Michaels, Sheldon L. Kaplan, Anthony Otley, Larry K. Kociolek, Edward J. Hoffenberg, Kwang Sik Kim, Sharon Nachman, Marian D. Pfefferkorn, Timothy Sentongo, Janice E. Sullivan, Pamela Sears

Research output: Contribution to journalArticlepeer-review

9 Scopus citations


Background: Fidaxomicin is an approved therapy for Clostridium difficile-associated diarrhea (CDAD) in adults. The safety of fidaxomicin in children has not been reported. Methods: In this study ( identifier NCT01591863), pediatric patients with CDAD received twice-daily oral fidaxomicin at a dose of 16 mg/kg per day (up to 200 mg) for 10 days in an open-label study. Plasma and fecal samples were collected for pharmacokinetic assessments. The primary outcome measure was safety, which was assessed by adverse-event (AE), laboratory, and physical examination/vital-sign monitoring. Efficacy was determined through early and sustained clinical response rates (clinical response without recurrence of CDAD). Results: The study enrolled 40 patients (11 months to 17 years of age), many with underlying comorbidity, including neoplasm (23.7%), gastrointestinal disorder (78.9%), and history of CDAD (60.5%). Plasma fidaxomicin and OP-1118 (the major fidaxomicin metabolite) 3- to 5-hour postdose concentrations were 0.6 to 87.4 and 2.4 to 882.0 ng/mL, respectively, and no age-related trends were seen. Fecal fidaxomicin concentrations within 24 hours of the last dose averaged 3228 µg/g, and higher concentrations and greater variability in the youngest age group were found. AEs were reported in 73.7% of the patients; most of them were mild (44.7%) to moderate (21.1%) and were considered treatment-related in 15.8% of the patients. Overall, the early clinical response rate was 92.1%. The rate of sustained clinical response (clinical response without recurrence through 28 days after treatment) was 65.8% overall. Conclusions: Fidaxomicin was well tolerated in children with CDAD and has a pharmacokinetic profile in children similar to that in adults. The clinical response rate was high.

Original languageEnglish (US)
Pages (from-to)210-218
Number of pages9
JournalJournal of the Pediatric Infectious Diseases Society
Issue number3
StatePublished - Aug 17 2018


  • Clostridium difficile infection
  • Clostridium difficile-associated diarrhea
  • Fidaxomicin
  • Pediatrics
  • Pharmacokinetics

ASJC Scopus subject areas

  • Pediatrics, Perinatology, and Child Health
  • Infectious Diseases


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