A Phase IB/IIA Study of Ex Vivo Expanded Allogeneic Bone Marrow Derived Mesenchymal Stem Cells for the Treatment of Perianal Fistulizing Crohn's Disease

Mesenchymal stem cells have been used for the treatment of perianal Crohn's fistulizing disease by direction injection. However, no studies to date have included patients with proctitis, anal canal involvement, and multiple branching tracts.To determine safety and efficacy of mesenchymal stem cells for refractory perianal Crohn's disease.Phase IB/IIA randomized control trial.Tertiary inflammatory bowel disease referral center.Adult Crohn's patients with perianal fistulizing disease.75 million mesenchymal stem cells were administered with a 22G needle by direct injection after curettage and primary closure of the fistula tract. A repeat injection of 75 million mesenchymal stem cells at 3 months was given if complete clinical and radiographic healing were not achieved.Adverse and serious adverse events at post procedure day 1, week 2, week 6, month 3, month 6 and month 12. Clinical healing, radiographic healing per magnetic resonance imaging, and patient reported outcomes at the same time points.A total of 23 patients were enrolled and treated; 18 were treatment and 5 were control. There were no adverse or serious adverse events reported related to mesenchymal stem cells therapy. At six months, 83% of the treatment group and 40% of the control had complete clinical and radiographic healing. The perianal Crohn's disease activity index, Wexner incontinence score, and VanAssche score had all significantly decreased in treatment patients at six months; none significantly decreased in the control group.Single institution and single blinded.Bone marrow derived mesenchymal stem cells offer a safe and effective alternative treatment approach for severe perianal fistulizing Crohn's disease. See Video Abstract at http://links.lww.com/DCR/C128.