Fecal Microbiota Transplantation in Treating Immune-Checkpoint Inhibitor Induced-Diarrhea or Colitis in Genitourinary Cancer Patients

PRIMARY OBJECTIVES: * To assess the safety and tolerability of fecal microbiota transplantation (FMT). * To assess the efficacy of FMT for clinical remission/response of immune-related diarrhea/colitis. SECONDARY OBJECTIVES: \- To measure the recurrence rate after achieving clinical remission/response of immune-related diarrhea/colitis. EXPLORATORY OBJECTIVES: * To assess the efficacy of FMT to achieve endoscopic remission of immune-related diarrhea/colitis. * To assess the efficacy of FMT to achieve histological remission of immune-related diarrhea/colitis. * To assess the efficacy of FMT on recurrence of immune-related diarrhea/colitis after resumption of immune checkpoint inhibitors (ICPI). * To assess immunological, molecular and microbiome changes in tissue/blood/stool. To study the efficacy and/ or benefit of PuraStat gel in the healing of mucosal ulcers and its hemostatic effect on bleeding lesions OUTLINE: Patients receive loperamide orally (PO). After 4 hours, patients undergo FMT via colonoscopy over 15-30 minutes. After completion of study treatment, patients are followed up at 2, 4, and 8 weeks, and then at 3 months.