P882 A Phase I/II clinical trial of ex-vivo expanded human bone marrow derived allogeneic mesenchymal stromal cells in adult patients with perianal fistulizing Crohn’s Disease

Abstract

Abstract Background Perianal fistulas affect one-third patients with Crohn’s disease with limited therapeutic options. There is dearth of literature on safety and efficacy of bone marrow-derived mesenchymal stromal cells in this population. Methods An open-label, phase I/II, single-arm study was conducted involving local administration of human allogeneic bone marrow-derived mesenchymal stromal cells in perianal fistula of patients with Crohn’s disease refractory to standard therapies. Clinical severity and biomarkers were assessed at baseline and periodically till 104 weeks, and MRI at 24 and 104 weeks. Primary and secondary objectives were to assess safety and efficacy respectively. Fistula remission was complete closure of fistula openings with <2cm perianal collection on MRI, and fistula response was decrease in drainage by ≥50%. Change in perianal disease activity index, quality-of-life and Van Assche index on MRI over time was assessed using mixed-effect linear regression model. Results Ten patients (male:8, mean age:27.4±12.0years) were recruited. Self-resolving procedure-related adverse events occurred in three patients, with no follow-up adverse events. In intention to treat analysis at week 24, two patients (20%) achieved fistula remission and seven (70%) had fistula response. At week 52, two (20%) patients were in remission and seven (70%) maintained response. At 104 weeks, two (20%) patients maintained response and one (10%) was in remission. Statistically significant decrease in perianal disease activity index(P=0.008), Van Assche Index(P=0.008) and improvement in quality-of-life(P=0.001) were observed over time. Conclusion Allogeneic BMSCs are safe and effective for the treatment of PF in CD with significant improvement in clinical severity and radiological healing.