This is an open-label, phase IV trial. Adult patients, with moderately to severe, steroid dependent, acute ulcerative colitis not previously exposed to anti-TNF, will receive subcutaneous golimumab treatment, according to EU marketing authorization from baseline through week 14.

At week 16, patients achieving clinical and endoscopic remission will continue with Golimumab, 50 mg or 100 mg (depending on body weight) every 4 weeks, through week 52.

Patients not achieving clinical and endoscopic remission will be treated with infliximab, according to marketing authorization, and followed through week 52. This is not considered as an interventional arm but, since infliximab in Italy is considered as the first-line treatment for UC patients, as the usual clinical practice.

Inclusion Criteria:

• patients aged 18-65 years
• ability to understand the study procedures and sign the informed consent
• ulcerative colitis diagnosed at least 6 months before
• no previous exposure to anti-TNFs
• Global Mayo score ≥ 6 (with endoscopic sub-score ≥2) at baseline
• steroid-dependent disease
• women of childbearing potential must accept effective contraception during study participation and for at leas 6 months after the end of study participation

Exclusion Criteria:

• Crohn's disease or undetermined colitis
• active infections or previous infections not completely resolved at baseline
• malignancies in the previous 5 years
• suspected latent tuberculosis infection
• every other potentially harmful clinical condition, in the opinion of the investigator
• patients with moderately to severe heart failure (NYHA class III/IV)
• hepatic or renal failure
• pregnant or lactating women or women planning a pregnancy between baseline and the 3 months after study completion
• not permitted concomitant medications