First-line treatment of fecal microbiota transplantation for immune-mediated colitis.

2510 Background: The management of moderate to severe immune-mediated colitis (IMC) includes immunosuppression with steroids and/or biologic agents. Long-term immunosuppression increases the risk for infections and steroid side-effects. Fecal microbiota transplantation (FMT) is increasingly used for the treatment of refractory IMC but has not been studied in the front-line setting. Here we aim to test the hypothesis that front-line FMT can alleviate IMC symptoms while reducing unnecessary exposure to steroids and their complications. Methods: We will report interim data from a prospective clinical trial exploring the efficacy and safety of FMT as a first-line treatment for IMC. To be included, patients had to 1) have symptoms of immune-mediated diarrhea or colitis grade ≥ 2 within 45 days of FMT and 2) not have received any immunosuppressive treatment for IMC or any other indication around the time of FMT. Results: Seven patients have been enrolled in the trial thus far. Patients received front-line FMT within a median of 35 days (IQR: 18-57 days) from IMC onset. Five (71.4%) patients had symptom improvement within a median of 1 day (IQR: 1-5 days) after FMT. The only FMT-related adverse events reported were transient fever and self-resolving abdominal cramping in three patients (42.8%) within the first week of FMT. All patients stopped immunotherapy due to IMC. Six (85.7%) were able to resume cancer treatment after FMT with 4 patients (57.1%) resuming immunotherapy. Four patients (57.1%) had colitis remission by the end of the study period, with one additional patient showing signs of symptom improvement but passing away before IMC outcome could be assessed. Conclusions: This study is the first to evaluate the safety and efficacy of front-line FMT for the treatment of IMC. While more patients are needed before final conclusions can be drawn, our initial results suggest that FMT can be an effective first-line treatment for IMC that can be delivered in a timely manner and quickly provide symptom relief in a majority of patients while avoiding the use of steroids and allowing the safe resumption of immunotherapy. Therefore, first-line FMT may be a safe and effective steroid sparing alternative to the current standard of care treatment for IMC. Clinical trial information: NCT04038619 . [Table: see text]