Here is the design of a clinical trial:

Official Title: Prospective Multicenter Randomized Controlled Double-blind Label Study of the Prophylaxis of Recurrent Pouchitis After Fecal Microbiota Transplant in UC With Ileo-anal Anastomosis

Included conditions:
- Pouchitis

Study Armgroups:
- {'label': 'fecal microbiota', 'type': 'EXPERIMENTAL', 'interventionNames': ['Other: fecal microbiota']}
- {'label': 'placebo', 'type': 'PLACEBO_COMPARATOR', 'interventionNames': ['Other: Placebo']}

Interventions:
- {'type': 'OTHER', 'name': 'fecal microbiota', 'description': 'fecal microbiota in suspension', 'armGroupLabels': ['fecal microbiota']}
- {'type': 'OTHER', 'name': 'Placebo', 'description': 'sterile saline', 'armGroupLabels': ['placebo']}

Primary Outcomes:
- {'measure': 'Number of days between the date of transplantation and the date of relapse according to physiological and endoscopic parameter (pochitis disease activity index)', 'timeFrame': '106 weeks'}

Please estimate the sample size based on the assumption: 
Statistical power of 80%, 48-month enrollment period, 24-month follow-up period, and interim analysis at the first 16 observed events.
Sample size evaluation
        This superiority study is designed to have a statistical power of 80% to detect a significant treatment effect on the first onset of pouchitis. We estimate a survival rate of 25% in the control group versus 60% in the treatment group at 6 months (hazard ratioâ=â0.3685).
        These figures are based on the work on probiotics of Gionchetti and Mimura [18, 19].
        A total of 32 events are needed to ensure a statistical power of 80%. For a 48-month enrollment period and 24-month follow-up period, 40 patients are needed to observe 32 events. To ensure this statistical power, a total of 42 patients will be randomized.
        This sample size calculation takes into account the interim analysis planned at the first 16 observed events.