Allogenic Stem Cells in Anal Fistulas of Crohn’s Disease: From Promising Premises to Real Life Experience

Abstract

Abstract Background Allogenic adipocyte stem cells represent an unprecedented opportunity for regenerative therapy to treat Crohn anal fistulas. Apart from the results of one 8-year-old trial, scientific evidence remains scarce. Methods Data from consecutive patients treated with darvadstrocel for Crohn anal fistulas were reviewed at 6 first tertiary reference centers. The judgment criteria combined asymptomatic status plus clinical occlusion of the fistula tract and MRI-confirmed healing of the tract (no inflammation and/or disappearance of the tract). Both clinical and MRI-confirmed healing of the tract defined a deep remission. Clinical remission was defined by an absence of complaint, occlusion of all external openings, and no fistula discharge. Results A total of 116 patients were extracted (median follow-up after cell stem injection: 11 [6-14] months). No severe adverse events were reported after surgery except for subsequent anal surgery in 29 (25%) patients. Fifty-one (44%) patients had clinical remission defined by the absence of complaints, the occlusion of all external openings, and the presence of no fistula discharge. Deep remission was observed in 23 (29%) patients. Patients with clinical remission more often received combined therapy (immunosuppressant antitumor necrosis factors) than those with no improvement (31 of 51 [61%] vs 23 of 65 [35%]; P = .007). Regression analysis showed that high fistulas (odds ratio, 3.8 [1.1-12.5]; P = .03) and younger age (<38 years, odds ratio, 2.3 [1.0-58;4]; P = .02) were associated with a better outcome. Conclusions Allogeneic stem cell treatment of Crohn’s anal fistulas results in complete remission in less than half of patients, with a significant reintervention rate.