EXTEND

To evaluate whether the extended duration fidaxomicin therapy is superior to the standard vancomycin therapy in sustained clinical cure of CDI at 30 days after end of

treatment (Day 40 or Day 55).

• To compare sustained clinical cure of CDI at Day 40, Day 55 and Day 90
• To compare clinical response of CDI at 2 days after EOT Day 12 or Day 27
• To compare clinical response of CDI at Day 12
• To compare the rate of relapse at Day 90 as determined by whole genome sequencing
  
  of isolates from subjects who have recurrence after TOC
• To compare TTROD in hours
• To compare recurrence rate of CDI at Day 40, Day 55 and Day 90
• To compare time to recurrence after EOT (only for subjects with clinical response)
• [....]

1. Subject is 60 years of age or over.

2. CDI is confirmed by clinical symptoms (either >3 unformed bowel movements or ≥200ml of unformed stool (for subjects having rectal collection devices)) in the 24 hours prior to randomization and CDI test confirmed positive for presence of C. difficile toxin

A or B in stool within 48 hr prior to randomization.

3. Independent Ethics Committee (IEC) approved written Informed Consent and privacy language as per national regulations must be obtained from the subject or legally

authorized representative prior to any study-related procedures (including withdrawal of prohibited medication, if applicable).

4. Subject agrees not to participate in another interventional study whilst participating in

this study.

1.Subject is taking or requiring to be treated with prohibited medications listed in Section 5.1.3

2. Subject has received more than one day of dosing of any therapy for CDI within the last 48 hours

3. Subject has experienced more than 2 previous episodes of CDI in the 3 months prior to study enrolment

4. Subject is unable to swallow oral study medication.

5. Subject has a current diagnosis of toxic megacolon.

6. Subject is not willing to adhere to the provisions of treatment and observation specified in the protocol.

7. Subject has been randomized 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.

8. Subject has previously participated in a CDI vaccine study

9. Subject has hypersensitivity to fidaxomicin, vancomycin or any of their components.

10. Any clinical condition which, in the opinion of the Investigator, would not allow safe

completion of this study.

Day 1-10: 4x/day Vancomycin 125mg oral capsules

or

Day 1-5: 2x/day Fidaxomicin oral tablets

and

Day 7-25: 1x/every second day Fidaxomicin 200mg oral tablets