Study to Assess the Safety and Efficacy of Expanded Allogenic Adipose-derived Stem Cells (eASCs) (Cx601), for Treatment of Complex Perianal Fistulas in Perianal Crohn's Disease.

Inclusion Criteria: * Signed informed consent. * Subjects with Crohn's disease diagnosed at least 12 months earlier in accordance with accepted clinical, endoscopic, anatomopathological and/or radiologic criteria. * Presence of complex perianal fistula with 3 or fewer fistulous tracts assessed by MRI, * Subjects with persistent and active complex perianal fistula and non active luminal CD defined by a CDAI ≤ 200. * Subjects of either sex aged over 18 years. Good general state of health according to the findings of the clinical history and the physical examination. Exclusion Criteria: * Presence of severe proctitis (prominent friability, spontaneous bleeding, multiple erosions, deep ulcers) or dominant active luminal disease requiring immediate therapy, assessed by rectosigmoidoscopy * Subjects with a CDAI ≥ 221. * Subjects with an abscess (unless a complete toilet of the area with drainage of the collections and the absence of abscess and other collections is confirmed prior to treatment start). * The presence of setons unless removed prior to treatment start. * Presence of \>3 fistulous tracts and/or external openings. * Subjects with rectal and/or anal stenosis evaluated by rectoscopy or EUA. * Subjects who have received infliximab or any other anti-TNF agent in the 8 weeks before the cell treatment administration. * Subjects who have received tracrolimus or ciclosporine in the 4 weeks before the cell treatment administration. * Subjects with rectovaginal fistula, anal fistula(s), and/or non-perianal enterocutaneous fistula. * Subjects with a history of abuse of alcohol or other addictive substances in the 6 months prior to inclusion. * Subjects with malignant tumor, except for basal cell or cutaneous squamous cell carcinoma, or Subjects with a prior history of malignant tumors, unless the neoplastic disease has been in remission for the previous 5 years. * Subjects with cardiopulmonary disease which, in the opinion of the investigator, is unstable or sufficiently serious to exclude the patient from the study. * Subjects with any type of medical or psychiatric disease which, in the opinion of the investigator, could be grounds for exclusion from the study. * Subjects with congenital or acquired immunodeficiencies. * Subjects with abnormal laboratory test findings that contraindicate their inclusion in the study. * Subjects allergic to anesthetics or MRI contrast. * MRI is unfeasible, (e.g. due to the presence of pacemakers, hip replacements or severe claustrophobia) * Subjects in need of surgery in the perianal region for reasons other than fistulas at the time of inclusion in the study, or a need for such surgery is foreseen in this region in the 26 weeks after treatment administration. * Subjects who have suffered major surgery or severe trauma in the prior 6 months. * Pregnant or breastfeeding women. (Both men and women should use appropriate birth control methods defined by the investigator). * Subjects currently receiving, or having received within 1 month prior to enrolment into this clinical trial, any investigational drug.