An open-label, mono center study to evaluate the feasibility of fecal microbiota transplantation in patients with immune-related enterocolitis

 The intestinal microbiome forms a symbiotic relationship with the human host and continuously interacts with the immune system. Specific compositions of the intestinal microbiome in patients with cancer have been linked to the onset of immune-related enterocolitis (irEC). The driver of irEC is an increase in numbers and activity of CD8+ cytotoxic T cells within the intestinal mucosa. Previous case series or small clinical studies demonstrated the feasibility and safety of fecal microbiota transplantation (FMT) to modulate the intestinal microbiome composition and improve irEC in cancer patients under cancer immunotherapy. The feces used for this FMT approach were taken from healthy individuals. Thus, the next step will be to demonstrate the feasibility of the FMT approach applied one-time via colonoscopy to modulate the frequency of CD8+ T-cells within the intestinal mucosa as a marker for a local anti-inflammatory immune response. To demonstrate that FMT is indeed able to modulate the frequency of CD8+ T-cells in the intestinal mucosa in patients with cancer and suffering from irEC, would lay the premises to use FMT for the treatment of patients suffering from irEC later on in follow-up studies. Thus, the current trial consists in applying the FMT intervention using feces from healthy individuals to patients with cancer under treatment with standard-of-care cancer immunotherapy and suffering from irEC. The feasibility in this project will be judged by studying the effect of healthy donor-derived FMT on the frequency of CD8+ T-cells in the intestinal mucosa as a marker for an anti-inflammatory immune response in cancer patients suffering from irEC. We will make no selection regarding the inclusion of the immune-mediated colitis patients according to sex/gender or age of the patients and thus collect a real life immune-mediated colitis patient collective for our feasibility study. Due to the relatively small numbers of patients included in the study, a further stratification according to different sex/gender or age groups would not be feasible.