Background With the success of immunotherapy in oncology for the past 5-10 years, there are also associated toxicities, including colitis. The current management strategy is mainly steroid, infliximab and/or vedolizumab based on small case reports and case series (1-6). These treatments are all associated with different toxicities. We are presenting alternative treatment of FMT for a very difficult case with ITIC. Case 50 year old WF with urothelial carcinoma since 01/2016, went through multiple chemo regimens and radical cystectomy and ileo-conduit. She stayed in remission for one year, with disease progression since 03/2017, for which she was started ipilimumab and nivolumab. In 2 weeks, she developed grade 2 diarrhea with scope showing patchy erythema in the distal colon. Symptoms improved with steroid + infliximab, however worsened again with bloody diarrhea grade 3, significant dehydration and anemia requiring prolonged hospitalization. Rescope showed deep large ulcerations with diffuse erythema in the distal colon. She failed 2nd dose of infliximab, total 3 months duration of steroid, and 1 dose of vedolizumab. She received FMT on 06/13/2017 via colonoscopy. Within 1 week, she went in steroid free complete remission. Repeat scope 1 month later showed healing or partial healing of ulcers and normalization of mucosal inflammation. Post FMT stool analysis showed the new addition of bacteroidetes and akkermansia species from donor. Conclusion ICI-C has been recognized as the second most common toxicities in cancer patients. Current immunosuppressive treatments carry additional toxicities. FMT appeared to be a safer and effective quick treatment alternative for ICI-C. Large scale study is warranted for further clarification of the role of microbiome in this condition.
