Patients Eligible for Trials of Microbe-Based Therapeutics Do Not Represent the Population With Recurrent Clostridioides difficile Infection

BACKGROUND & AIMS: Although there are many industry-funded trials of microbe-based therapeutics for Clos- tridioides (formerly Clostridium) difficile infection (CDI), not all patients are eligible for these trials, due to their strict enrollment criteria. Furthermore, given the widespread availability of fecal microbiota transplantation (FMT) and overwhelming evidence to support its efficacy, patients might refuse enrollment in trials with a placebo group. We analyzed willingness and eligibility of patients with recurrent CDI to participate in randomized controlled trials of microbe-based therapeutic agents. METHODS: We performed a retrospective study of 199 patients referred to 4 tertiary referral centers for treatment of CDI from August 1, 2018 through January 31, 2019. We collected data on eligibility for FMT and enrollment in randomized controlled trials. RESULTS: Of 130 patients deemed appropriate for FMT, 98 patients (75%) were ineligible for participation in a randomized controlled trial and 16 patients (17%) were eligible but refused to enroll. Immune compromise and inflammatory bowel diseases were the most common reasons for exclusion from trials. CONCLUSIONS: Most patients with CDI who meet the guideline criteria for FMT are ineligible or unwilling to participate in randomized controlled trials of microbe-based therapeutics. Trial populations therefore do not represent the population of patients with CDI.