Adults between 18 and 80 years of age with ulcerative colitis can participate in this study. This is a study for people for whom previous treatment was not successful or who stopped previous treatment. The purpose of this study is to find out whether BI 3032950 helps people with ulcerative colitis.

This study has 2 parts. In Part A, participants get BI 3032950 as an infusion into a vein every 4 weeks. After 12 weeks, doctors check whether the signs and symptoms of ulcerative colitis have improved. Before the results of this assessment are available, participants move on to Part B and get BI 3032950 as an injection under the skin. Participants whose results show clinical response after 12 weeks can continue treatment with BI 3032950. They get BI 3032950 injections under the skin every 4 weeks for up to 2 years.

Participants visit their doctors every 4 weeks. During these visits, the doctors check the signs and symptoms of ulcerative colitis. This includes taking blood and stool samples. Doctors also do endoscopies. This is a procedure that uses a tube with a camera to look inside the body.

The doctors also regularly check participants' health and take note of any unwanted effects.

Inclusion criteria

• Female and male participants aged 18 to 80 years (inclusive) at the time of informed consent,
• Diagnosis of ulcerative colitis (UC) ≥3 months prior to screening by clinical and endoscopic evidence corroborated by a histopathology report,
• Inadequate response, loss of response, or intolerance to treatment with biologic/targeted therapy or termination of treatment with biologic/targeted therapy for any other reason,
• Female participants of childbearing potential must be ready and able to use highly effective methods of birth control and male participants are required to use condoms,
• Further inclusion criteria apply.

Exclusion criteria

• Diagnosis of indeterminate colitis, ischemic colitis, radiation colitis, diverticular disease associated with colitis, microscopic colitis, or Crohn's disease (CD),
• Findings suggestive of CD (e.g. fistulae, granulomas on biopsy),
• Evidence of colonic moderate/severe mucosal dysplasia or colonic adenomas, unless properly removed,
• Gastrointestinal neoplasia, primary sclerosing cholangitis, or known colonic stricture,
• Evidence of fulminant colitis or toxic megacolon at screening,
• Current ileal-pouch anal anastomosis, ileostomy, colostomy, or known fixed symptomatic stenosis of the intestine,
• Previous surgery or anticipated surgical intervention for UC (trial participants with previous colonic surgery may be allowed based on investigator's judgement after discussion with the sponsor),
• Any current or prior abscesses, unless they have been drained and treated at least 6 weeks prior to first trial drug administration and are not anticipated to require surgery,
• Further exclusion criteria apply.

Once the criteria in section "Time Frame" are fulfilled, researchers can use the following link https://www.clinicalstudies.boehringer-ingelheim.com/msw/datasharing to request access to the clinical study documents regarding this study, and upon a signed "Document Sharing Agreement".

Furthermore, researchers can request access to the clinical study data, for this and other listed studies, after the submission of a research proposal and according to the terms outlined on the website.

One year after the approval has been granted by major Regulatory Authorities and after the primary manuscript has been accepted for publication, or after termination of the development program.

For study documents - upon signing of a "Document Sharing Agreement". For study data -

1. after the submission and approval of the research proposal (checks will be performed by the sponsor and/or the independent review panel, including checking that the planned analysis does not compete with sponsor's publication plan);
2. and upon signing of a legal agreement.