Long-Term Outcomes of Biological Therapy in Crohn's Disease Complicated With Internal Fistulizing Disease: BIOSCOPE Study From GETECCU

The prevalence of penetrating complications in Crohn's disease (CD) increases progressively over time, but evidence on the medical treatment in this setting is limited. The aim of this study was to evaluate the effectiveness of biologic agents in CD complicated with internal fistulizing disease.Adult patients with CD-related fistulae who received at least one biologic agent for this condition from the prospectively-maintained ENEIDA registry were included. Exclusion criteria involved those receiving biologics for perianal disease, enterocutaneous, rectovaginal, anastomotic or periostomal fistulae. The primary endpoint was fistula-related surgery. Predictive factors associated with surgery and fistula closure were evaluated by multivariate logistic regression and survival analyses.A total of 760 patients from 53 hospitals (673 receiving anti-TNFs, 69 ustekinumab, and 18 vedolizumab) were included. After a median follow-up of 56 months (IQR, 26-102), 240 patients required surgery, with surgery rates of 32%, 41%, 24% among those under anti-TNF, vedolizumab, or ustekinumab, respectively. Fistula closure was observed in 24% of patients. Older patients, ileocolonic disease, entero-urinary fistulae, or an intestinal stricture distal to the origin of the fistula were associated with a higher risk of surgery, while non-smokers, and combination therapy with an immunomodulator reduced this risk.Biologic therapy is beneficial in approximately three quarters of patients with fistulizing CD, achieving fistula closure in 24%. However, around one third still undergo surgery due to refractory disease. Some patient and lesion-related factors can identify patients who will obtain more benefit from these drugs.