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In one series, a standardized filtered, frozen, and then thawed preparation of stool from pre-screened universal donors showed cure rates equal to or better than those from patient-identified donors (103). Of these 77 subjects, four developed an autoimmune disease (rheumatoid arthritis, Sjogrens syndrome, idiopathic thrombocytopenic purpura, and peripheral neuropathy) at some time after the FMT, although a clear relationship between the new disease and the FMT was not evident (101).
RCTs are necessary to prove the efficacy of FMT and to determine the optimal route of administration among other variables and safety in immunosuppressed patients needs to be established.
An RCT of donor feces administered by duodenal infusion with gut lavage showed significant efficacy compared to vancomycin or vancomycin with gut lavage without donor feces (104). The study was terminated early because it was deemed unethical to continue as the cure rate was 81 compared to 23 with vancomycin alone and 31 with vancomycin and gut lavage.