A Study Testing How BI 655130 Works in Patients With Fistulizing Crohn's Disease

Inclusion criteria * 18-75 years at date of signing informed consent * Male or female patients. Women of childbearing potential (WOCBP)1 must be ready and able to use highly effective methods of birth control per ICH M3 (R2) that result in a low failure rate of less than 1% per year when used consistently and correctly. Restrictions regarding women of childbearing potential. Restrictions regarding contraception for female patients are not applicable for Screening Cohort * Diagnosis of clinical Crohn´s Disease ≥ 3 months prior to screening by clinical and endoscopic evidence and corroborated by a histopathology report * Has ≥ 1 perianal active\* fistula(s) with clinical indication for seton drainage (≥ 4 weeks duration before enrolment, as a complication of CD) \*\* \* Criteria for Active Fistula: As per clinical evaluation: Presence of spontaneous drainage or drainage after gentle finger compression at the external openings \& as confirmed by radiological (MRI) exploration \*\* Patients who are screened with a seton drainage in place are eligible provided the drainage has not been in place for \> 3 months and the patient meets the rest of the eligibility criteria * Absent, mild or moderate clinical activity with CDAI \< 250. CDAI is not applicable for Screening Cohort * Demonstrated in the past inadequate fistula response or loss of response or have had unacceptable side effects with approved doses of at least one of the following compounds: immunosuppressive agents (e…