Evaluation of Local Co-administration of Autologous ADIpose Derived Stromal Vascular Fraction With Microfat for Refractory Perianal CROHN's Fistulas.

Autologous ADSVF constitutes an innovative therapeutic strategy that concentrates various types of regenerative stem cells and paracrine factors able to promote angiogenesis and tissue repair. Together with the ease of collection from a minimally manipulated lipoaspirate, the unique properties of ADSVF offer new opportunities for fistulas' healing in patients with CD. The use of ADSVF is currently developed in many clinical fields based on safety and efficacy data. Our ADICROHN pilot study evaluating safety and tolerance of local administration of autologous ADSVF with microfat in CD patients with complex perianal fistula refractory to conventional medical and surgical therapy showed that this novel therapeutic approach appears feasible and safe. However the therapeutic potential of local this combined treatment in healing refractory perianal Crohn's fistulas still remains to be demonstrated. The main objective of this study is to assess the efficacy of local injection of autologous ADSVF and microfat versus placebo for the treatment of complex refractory perianal Crohn's fistulas at week 24. The efficacy will be assessed on clinical assessment of closure of all the external openings that were drained at baseline, and MRI confirmation of absence of collections \> 2 cm of the treated perianal fistulas at week 24.