Efficacy and Safety of Stem Cell Therapy in the Treatment of Fistulizing Crohn's Disease and the Role of Autologous Stem Cell Transplantation: A Systematic Review

Background: Crohn's Disease (CD), especially its fistulizing form, presents significant treatment challenges. Stem cell transplantation, particularly autologous stem cell transplantation, has emerged as a novel approach for these difficult-to-treat cases. This systematic review concentrates on evaluating the efficacy and safety of stem cell transplantation in treating fistulizing CD.

Methods: We searched PubMed, Embase, and Cochrane Library up to June 2023. Both randomized controlled trials and non-randomized clinical trials involving adult patients (18 years or older) with CD and utilizing various forms of stem cell therapy were included. Primary outcomes were efficacy and safety of stem cell therapy. Data were extracted and synthesized narratively.

Results: The review included nine studies with interventions ranging from mesenchymal stem cell treatment (Darvadstrocel, Cx601), autologous adipose-derived stem cells, to autologous hematopoietic stem cell transplantation (HSCT). Across these studies, significant efficacy was noted in the closure of fistulas and clinical remission with treatments like Darvadstrocel and Cx601. Reductions in Crohn's Disease Activity Index (CDAI) and corticosteroid dosage were observed with treatments like Umbilical Cord Mesenchymal Stem Cells (UC-MSCs). In autologous HSCT, a proportion of patients achieved steroid-free clinical remission and complete endoscopic healing, but with a higher incidence of serious adverse events. Adverse events varied across studies, with some treatments showing manageable profiles while others, notably HSCT, demonstrated significant risks.

Conclusion: Stem cell transplantation, particularly autologous stem cells, demonstrates potential as an effective treatment for fistulizing CD. However, further research with more focused and standardized protocols is essential to validate these findings and establish a clear treatment guideline.