Stool Transplant to Control Treatment-related Diarrhea

This study will test the safety, effectiveness, and feasibility of a treatment called fecal microbiota transplantation (FMT) to reduce the symptoms of ICI-related diarrhea. FMT uses a liquid preparation of stool collected from a healthy donor with normal (healthy) bacteria; this liquid is infused into the small or large intestine of a recipient during a colonoscopy procedure. The study researchers think that the healthy bacteria in the transplanted stool will grow and replace the unhealthy bacteria and return the intestines and colon of the recipient to a healthy state.