Trial design and proposed sample collection for FMT clinical trial for the treatment of UC. Strategy for (A, B) re-randomization and (C, D) treat-through approach, wherein, respectively, patients could be re-randomized after the induction phase to placebo or (un)supervised FMT or maintained on sham/FMT derived from the same donor. At the different study visits, different samples should be collected including biopsies (baseline and primary endpoint), blood, and fecal samples. Additionally, also dietary and physical activity questionnaires should be collected. Abbreviations: FMT, fecal microbiota transplantation; UC, ulcerative colitis; Wk, week.