A Phase I Study of Bone Marrow Derived Mesenchymal Stem Cells (MSCs) for the Treatment of Medically Refractory Pouchitis

Proctocolectomy with ileal pouch anal anastomosis (IPAA) remains the procedure of choice for patients with chronic ulcerative colitis (CUC). IPAA allows at-risk tissue to be removed with restoration of intestinal continuity while maintaining favorable long-term functional outcomes and quality of life.

While less than 30% of patients experience short-term postoperative morbidity following IPAA, up to 15% of pouches will ultimately fail due to technical or inflammatory complications, the majority of which manifest as a fistula from the pouch to the perianal or vaginal locations. After anastomotic leak, the second leading cause of pouch fistulas is the development of Crohn's disease of the pouch. While the majority of pouches are constructed for CUC, up to 25% will end up having a change in diagnosis to CD which manifests as refractor pouchitis, strictures of the proximal small bowel, or most often as peripouch fistulas. Pouch failure due to refractory pouchitis are notoriously difficult to treat, and reconstructive pouch surgery or transanal repairs are often not offered due to suspicion of recurrent pouchitis following pouch reconstruction. The reality is that patients with refractory pouchitis will end up with a major reconstructive transabdominal operation in a select few for attempt at pouch salvage, or, most likely, a permanent end ileostomy after pouch excision. This can be a devastating outcome in some patients as it impacts body image and quality of life.

Similar to refractory pouchitis, Crohn's related perianal and rectovaginal fistula are other phenotypes of inflammatory bowel disease that are also notoriously difficult to treat with conventional medical and surgical options. Despite an ever expanding repertoire of biologic therapy and surgical intervention, sustained healing rates are less than 30%. This has driven investigators to search for alternative approaches, and in 2003 investigators reported successful healing of a refractory Crohn's rectovaginal fistula following injection of mesenchymal stem cells (MSCs). Following this success, several phase I, II, and III trials designed to study the safety and efficacy of MSCs for perianal CD, all of which have reported encouraging results with superior efficacy compared to conventional medical and surgical therapies. Over 300 perianal CD patients have now been treated without increase in adverse events and no risk of incontinence.

Given the high safety profile, and substantial success in treating perianal CD, the investigators are using a GMP grade allogeneic adipose derived MSCs to establish safety and secondarily monitor for healing in patients with medically refractory pouchitis. This trial will use allogeneic bone marrow derived mesenchymal stem cells (MSCs) to produce regenerative signals which alter the ileal pouch microbiome and local inflammatory mileau. Patients with CD of the pouch suffer chronic immunosuppression and surgical intervention and desperately need an improved therapeutic. The research aims to address the root cause of this inflammation, especially the interactions of the intestinal microbiome and host immune response through a novel therapeutic approach. The specific rationale for MSCs in medical refractory pouchitis is based opon 1) their anti-inflammatory properties; 2) published experience of MSC in this condition and perianal Crohn's fistula demonstrating efficacy and safety; 3) existence of cGMP methods for their isolation and growth.

The study will enroll adult patients with medically refractory pouchitis, whose next option in the treatment plan would be major reconstructive abdominal surgery or pouch excision with a permanent end ileostomy.