IBD consists of either ulcerative colitis or Crohn's disease.

The main aim of this study is to describe real-world treatment patterns in adults with moderate to severe ulcerative colitis or Crohn's disease when treated with vedolizumab. This will include how vedolizumab is given, which can either be an infusion through a vein (intravenous or IV), or an injection just under the skin (subcutaneous injection, or SC).

This is a non-interventional, prospective study of participants with moderately to severely active IBD (UC or CD) who are initiating or currently ongoing induction or maintenance treatment with vedolizumab according to the current SmPC in the real world setting.

The study will enroll approximately 200 participants. The data will be collected prospectively and will be recorded into electronic case report forms (e-CRFs). All the participants will be assigned to a single observational cohort:

• Participants with IBD

This multi-center study will be conducted in Belgium at specialized gastroenterology centers.

Inclusion Criteria:

1. Has moderately to severely active IBD (UC or CD), initiating or ongoing IV induction treatment with vedolizumab in accordance with the current SmPC at baseline OR IBD participants receiving ongoing/maintenance IV vedolizumab treatment, with the option to switch to SC vedolizumab maintenance treatment.

Exclusion Criteria:

1. Prior history of intolerability, hypersensitivity, or other contraindications (active severe infections such as tuberculosis, sepsis, cytomegalovirus, listeriosis, and opportunistic infections such as Progressive Multifocal Leukoencephalopathy) to vedolizumab therapy as defined in the current SmPC.
2. Current or planned participation in an interventional clinical trial for CD or UC.
3. Cognitive incapacity, unwillingness or language barriers precluding adequate understanding or cooperation.

Adult participants with moderately to severely active UC or CD receiving vedolizumab treatment in accordance with the approved SmPC.

Takeda provides access to the de-identified individual participant data (IPD) for eligible studies to aid qualified researchers in addressing legitimate scientific objectives (Takeda's data sharing commitment is available on https://clinicaltrials.takeda.com/takedas-commitment?commitment=5). These IPDs will be provided in a secure research environment following approval of a data sharing request, and under the terms of a data sharing agreement.

IPD from eligible studies will be shared with qualified researchers according to the criteria and process described on https://vivli.org/ourmember/takeda/. For approved requests, the researchers will be provided access to anonymized data (to respect patient privacy in line with applicable laws and regulations) and with information necessary to address the research objectives under the terms of a data sharing agreement.