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

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.

Keywords: Crohn’s disease; anal fistula; darvadstrocel; deep remission; stem cell therapy.