Crohn's disease (CD) is a chronic inflammatory bowel disease (IBD) that can highly alter patients' quality of life and lead to bowel damage due to its transmural pattern. The current guidelines recommend to use treat-to-target strategies to achieve the combination of steroid-free clinical remission and endoscopic remission. However, the implementation of these strategies and endpoints are limited by the need of repeated colonoscopies, which dramatically reduced patients' acceptability and adherence to such a management. The concept of transmural healing has emerged as a promising therapeutic target. It has been associated with longer time spent in steroid-free clinical remission, decreased risk of hospitalization, slower progression of bowel damage and reduced risk of subsequent surgery. Furthermore, recent works suggested that transmural healing could lead to better outcomes, such as prevention of bowel damage progression, than endoscopic remission. Recently, the DEVISE-CD project proposed validated definitions of transmural healing and response (TR50 and TR25) using the modified Clermont score (C-score). Thus, transmural healing will become the next reference target in the near future. Although most data were generated using MRI, intestinal ultrasound (IUS) is an interesting alternative to assess transmural response thanks to its lower cost and high patients' acceptability enabling repeated procedures. IUS is now part of routine practice in day-care units.

Recently, Risankizumab, the first in-class anti-IL23 targeting p19 subunit in CD, demonstrated high level of efficacy to achieve and maintain clinical and endoscopic remission. However, no data are hitherto available on the kinetics and the efficacy of risankizumab to achieve transmural healing.

This will be a prospective, multicenter study (5 centers) based on routine clinical practice, without any additional procedures. Data will be collected from electronic medical records and entered in a pseudonymized manner into the electronic case report form (RedCAP).

The data collected in this study include: demographic data (age, sex); disease-related data (date of diagnosis, disease duration, location, and phenotype); data on risankizumab treatment (start date, dosage, adverse events); clinical data (symptoms); laboratory data (CRP and fecal calprotectin); and radiological data (intestinal ultrasounds). These data will be collected, when available, at treatment initiation with SKYRIZI, and at weeks 4 and 12 as part of routine care.

Inclusion Criteria:

• Adult Patients (≥ 18 years old) diagnosed with Crohns disease according to ECCO guidelines
• Initiating risankizumab therapy in routine practice
• Undergoing IUS procedures before and after risankizumab therapy

Exclusion Criteria:

• Ulcerative colitis and unclassified colitis
• Follow-up shorter than 3 months (except for those discontinuing risankizumab due to side effect or failure)

Patient with Crohn's disease initiating treatment with risankizumab.