Closing the internal opening with a rectal advancement flap increases the efficacy of mesenchymal stem cell injection for complex Crohn's disease anal fistulas.

BACKGROUND: The efficacy of injections of mesenchymal stem cells (MSC) for anal fistula treatment may be impaired by the persistence of stools passing into the fistula, causing bacterial contamination and a local inflammatory reaction. We aimed to compare remission rates between patients treated by MSC injection with simple sutures and those treated with a rectal advancement flap. METHODS: This single-center prospective study compared the first patients who underwent internal opening closure with sutures with the subsequent patients treated with a flap. Complete clinical remission was defined as complete closure of the external opening(s) without pain or discharge, and complete radiological remission was defined as a Magnifi-CD score of 0. RESULTS: We compared the first 42 patients who had sutures with the 20 subsequent patients who had an advancement flap. The median follow-up was 15.5 [8.8-24.9] months. The cumulative incidence of complete clinical response at M12 was 53.8% [38.1-69.6%] in the suture group versus 93.3% [77.4-100.0] in the flap group (p < 0.001). The Magnifi-CD score was 0 for 41.7% [25.5-59.2%]) of patients treated with sutures versus 72.7% [39.0-63.9%]) of patients treated with a flap (p = 0.093). Anal incontinence score did not differ between the two groups. Practicing an advancement flap was the only significant factor associated with complete clinical remission over time (adjusted HR [95% CI] of 2.6 [1.4-4.9], p = 0.003). CONCLUSIONS: Complete clinical remission rates following MSC injection are significantly higher after closure of the internal opening with a rectal flap than after closure with sutures, without consequences on anal continence.

Deep remission improves the quality of life of patients with Crohn's disease and anoperineal fistula treated with darvadstrocel: results of a French pilot study.

BACKGROUND: The injection of allogeneic adipose tissue-derived mesenchymal stem cells (MSC) into anal fistulas in patients with Crohn's disease has never been evaluated in "real-life" conditions in France. METHODS: We prospectively studied the first patients receiving MSC injections at our center and undergoing 12 months of follow-up. The primary endpoint was the clinical and radiological response rate. The secondary endpoints were symptomatic efficacy, safety, anal continence, quality of life (Crohn's anal fistula-quality of life scale, CAF-QoL), and predictive factors of success. RESULTS: We included 27 consecutive patients. The complete clinical and radiological response rates at M12 were 51.9% and 50%, respectively. The combined complete clinical-radiological response (deep remission) rate was 34.6%. No major adverse effects or changes in anal continence were reported. The perianal disease activity index decreased from 6.4 to 1.6 (p < 0.001) for all patients. The CAF-QoL score also decreased from 54.0 to 25.5 (p < 0.001). At the end of the study, M12, the CAF-QoL score was significantly lower only in patients with a complete combined clinical-radiological response relative to those without a complete clinical-radiological response (15.0 versus 32.8, p = 0.01). Having a multibranching fistula and infliximab treatment were associated with a combined complete clinical-radiological response. CONCLUSIONS: This study confirms reported efficacy data for the injection of MSC for complex anal fistulas in Crohn's disease. It also shows a positive impact on the quality of life of patients, particularly those for whom a combined clinical-radiological response was achieved.