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.