This is the first pediatric, randomized, placebo-controlled trial that suggests the efficacy and safety of a highly concentrated mixture of probiotic bacterial strains (VSL#3) in active UC and demonstrates its role in maintenance of remission.

In a multicenter collaboration, this trial accrued the highest number of patients published so far, and results are comparable to the best single-institution series. The RT boost, when feasible, seemed effective in improving prognosis. Even after multiple procedures, complete resection confirmed its prognostic strength, along with tumor grade. Biological parameters emerging in this series will be the object of future correlatives and reports.