A Study of Darvadstrocel for Treating Complex Perianal Fistulas in Children and Teenagers With Crohn's Disease

A perianal fistula is an abnormal passageway that develops between the rectum and the skin near the anus. The fistula is considered complex if it branches into several openings or an abscess is also present. The main aim of this study is to learn if complex perianal fistulas in children and teenagers close after treatment with darvadstrocel. 2 to 3 weeks before treatment with darvadstrocel, each participant will have surgery to clean the fistula and to drain any abscesses. On the day of treatment, each participant will have the fistula cleaned and will receive an injection of darvadstrocel near the fistula, under anesthetic. For up to 1 year after treatment, participants will regularly visit the clinic for follow-up. The fistula will be examined and any side effects from the treatment will be recorded. Participants will have an MRI at one clinic visit (about 24 weeks after treatment).