Study to Evaluate the Pharmacokinetics of Fidaxomicin in Inflammatory Bowel Disease (IBD) Subjects With Clostridium Difficile Infection (CDI)

Open Label Study to Evaluate the Pharmacokinetics of Fidaxomicin in Inflammatory Bowel Disease (IBD) Subjects With Clostridium Difficile Infection (CDI)

The purpose of this study is to investigate the plasma pharmacokinetics (PK) of fidaxomicin (FDX) and primary metabolite OP-1118 in Subjects with Inflammatory Bowel Disease (IBD) and C. difficile Infection (CDI).

This study will also compare CDI clinical response to the microbiological response in terms of magnitude of reduction of C. difficile total viable count and spore count during treatment with FDX and if achieved; the time to microbial eradication; determine time to negative CDI toxin assay in stool specimens during treatment with FDX; assess the stool concentrations of FDX and metabolite OP-1118 throughout therapy; assess the length of hospital stay, readmissions and resource utilization for IBD patients receiving FDX; record the incidence and severity of Adverse Events (AEs) and document the impact of treatment on Quality of Life as measured by the changes in Short Inflammatory Bowel Disease Questionnaire (IBDQ) score.

Inclusion Criteria:

• Confirmed diagnosis or history of IBD for at least 3 months

• Subject has have active IBD defined by :

  • partial MAYO score (ulcerative colitis subjects) of 2 or more, where at least 1 point has to originate from blood in stool
  • Harvey-Bradshaw Index (HBI) (Crohn's disease subjects) of 5 or more, excluding points for complications

• CDI confirmed positive according to local standard testing for the presence of C. difficile within 48 hr prior to enrollment

• Female subject is not breastfeeding at Screening or while participating in this study

• Subject agrees to practice effective birth control from Screening and while participating in this study

• Subject agrees not to participate in another interventional study while participating in this study

• Male partner agrees not to donate sperm starting at screening and throughout the investigational period.

Exclusion Criteria:

• Subject has received more than one day of dosing of any CDI therapy within the 48 hrs prior to enrollment
• Subject is unable to swallow oral study medication
• Presence of an ostomy or short bowel syndrome
• Subject has a current diagnosis of toxic megacolon
• Subject is not willing to adhere to the provisions of treatment and observation specified in the protocol
• Subject has been enrolled into this study previously, has taken any investigational drug within 28 days or 5 half-lives, whichever is longer, prior to enrollment, or is currently participating in another clinical study which may influence the assessment of efficacy and/or safety endpoints of this study, in the opinion of the Sponsor
• Subject has previously participated in a CDI vaccine study
• Subject has hypersensitivity to FDX or any of its components
• Subject has a condition which, in the Investigator's opinion, makes the Subject unsuitable for study participation