A Study to Evaluate the Safety and Efficacy of Ustekinumab Induction and Maintenance Therapy in Participants With Moderately to Severely Active Ulcerative Colitis

The purpose of this study is to evaluate the efficacy and safety of ustekinumab as intravenous (IV: into the vein) infusion in induction study in participants with moderately to severely active Ulcerative Colitis (UC) and as subcutaneous (SC) administration in maintenance study in participants with moderately to severely active Ulcerative Colitis (UC) who have demonstrated a clinical response to Induction treatment with IV ustekinumab.

This is a Phase 3, randomized (assignment of study drug by chance), double-blind (neither the participant or study staff will know the identity of study drugs), placebo-controlled (placebo is an inactive substance that is compared with a drug to test whether the drug has a real effect in a clinical trial), parallel-group (a medical research study comparing the response in 2 or more groups of participants receiving different interventions), multi-center (more than one clinical site will work on a medical research study), protocol of ustekinumab. The protocol will consist of 2 studies: an Induction study and a Maintenance study with unique endpoints. Screening period will be up to 8 Weeks. Induction study will be at least 8 weeks duration for each participant. Participant with clinical response in the Induction study will be eligible for the Maintenance study. The Maintenance study will be 44 weeks duration. After completion of the maintenance study, a long term extension will follow eligible participants for an additional 3 years. Clinical remission will be evaluated at Week 8 in the Induction study. Clinical remission among ustekinumab Induction responders will be evaluated at week 44 in the Maintenance study. Participants' safety will be monitored throughout.

Eligibility Criteria:
Inclusion Criteria:

* Has a clinical diagnosis of Ulcerative Colitis (UC) at least 3 months before Screening
* Has moderately to severely active UC, defined as a Baseline (Week 0) Mayo score of 6 to 12, including a Screening endoscopy subscore of the Mayo score greater than or equal to (\>=) 2 as determined by a central reading of the video endoscopy
* Have failed biologic therapy, that is, have received treatment with 1 or more tumour necrosis factor (TNF) antagonists or vedolizumab at a dose approved for the treatment of UC, and have a documented history of failure to respond to or tolerate such treatment; OR Be naïve to biologic therapy (TNF antagonists or vedolizumab) or have received biologic therapy but have not demonstrated a history of failure to respond to, or tolerate, a biologic therapy and have a prior or current UC medication history that includes at least 1 of the following: a. Inadequate response to or failure to tolerate current treatment with oral corticosteroids or immunomodulators (6-mercaptopurine \[6-MP\] or azathioprine \[AZA\]) OR b. History of failure to respond to, or tolerate, at least 1 of the following therapies: oral or IV corticosteroids or immunomodulators (6-MP or AZA) OR c. History of corticosteroid dependence (that is, an inability to successfully taper corticosteroids without a return of the symptoms of UC)
* Before the first administration of study agent, the following conditions must be met: vedolizumab must have been discontinued for at least 4 months and anti-tumor necrosis factors (TNFs) for at least 8 weeks

Exclusion Criteria:

* Has severe extensive colitis and is at imminent risk of colectomy
* Has UC limited to the rectum only or to \< 20 centimeters (cm) of the colon
* Presence of a stoma or history of a fistula
* Participants with history of extensive colonic resection (for example, less than 30 cm of colon remaining) that would prevent adequate evaluation of the effect of study agent on clinical disease activity
* Participants with history of colonic mucosal dysplasia. Participants will not be excluded from the study because of a pathology finding of "indefinite dysplasia with reactive atypia''