Allogenic stem cells for Crohn's anal fistulas: Treating early improves the deep remission rate

The aim of this study was to evaluate the real-life clinical and radiological efficacy of darvadstrocel injection into complex perianal fistulas in Crohn's disease. Secondary endpoints were to assess symptomatic efficacy, adverse effects and factors associated with complete combined clinical-radiological response (deep remission).After marketing the product in France, all first patients treated consecutively were included. A complete clinical response was defined by a complete closure of all external openings with no discharge on pressure. A complete radiological response (MRI), evaluated at least after six months of follow-up, was defined by a completely fibrotic sequela without abscess. A deep remission was defined as the association of a complete clinical response with a complete radiological response.A total of 43 patients were included (M/F: 22/21, median age 37 [26-45] years). The fistulas were already drained with seton(s) and were on biologic treatment. After a median follow-up of 383 (359-505) days, 28 (65%) patients showed a clinical response (22 complete and 6 partial) and 16 (37%) achieved a deep remission. The Perineal Disease Activity Index decreased significantly after treatment: 39 (91%) patients reported symptomatic improvement in terms of discharge, pain, and induration, and 28 (65%) no longer had any perineal symptoms. No severe adverse events were reported. A short history of Crohn's disease <3 years was significantly associated with deep remission (OD 4.5 [1.0-19.1], p = 0.04).Darvadstrocel injection resulted in a clinical response for two thirds of patients and deep remission for one third. A shorter duration of Crohn's disease was associated with deep remission.