Extension Study of Long-term Safety and Efficacy of Tulisokibart in Participants With Crohn's Disease or Ulcerative Colitis (MK-7240-011)

Participants receive a low dose subcutaneous (SC) tulisokibart regimen.

Drug: Tulisokibart

Participants receive a high dose SC tulisokibart regimen.

Drug: Tulisokibart

Participants receive a blinded high dose SC tulisokibart regimen.

Drug: Tulisokibart

Participants receive a blinded low dose SC tulisokibart regimen.

Drug: Tulisokibart · Drug: Placebo to tulisokibart

Humanized monoclonal antibody that binds human tumor necrosis factor-like cytokine 1A (TL1A), administered subcutaneously

Placebo matching SC tulisokibart

Plazo: Up to approximately 378 weeks

An AE is any untoward medical occurrence in a participant, temporally associated with the use of study treatment, whether or not considered related to the study treatment. The number of participants who experience an AE will be reported.

Plazo: Up to approximately 364 weeks

An AE is any untoward medical occurrence in a participant, temporally associated with the use of study treatment, whether or not considered related to the study treatment. The number of participants who discontinue study treatment due to an AE will be reported.

Plazo: Up to Week 364

The percentage of participants who enrolled in their parent study with Crohn's disease who achieve clinical remission, as defined by CDAI score \<150, at Week 364 will be presented.

Plazo: Up to Week 364

The percentage of participants who enrolled in their parent study with Crohn's disease achieving clinical remission at Week 364 per stool frequency/abdominal pain score (SF/APS), as defined by average daily SF ≤2.8 and average daily APS ≤1.0 and both not greater than baseline will be presented.

Plazo: Up to Week 364

The Simplified Endoscopic Score for Crohn's Disease (SES-CD) measures ileocolonoscopic findings in Crohn's Disease. Each segment of the ileo-colon (terminal ileum; ascending, transverse, and descending colon; rectum) is scored from 0 (normal or inactive disease) to 12 (severe disease; no more than one segment can have a score of 12, in which case the other 4 segments must each be ≤11), and the scores summed to produce an SES-CD ranging from 0 (overall least severe disease) to 56 (overall most severe disease). Endoscopic remission is defined as an SES-CD ≤4 and at least 2-point reduction from baseline and no subscore \>1 in any individual variable, as scored by central reader.

Plazo: Up to Week 364

The Modified Mayo Score (MMS) is a composite score of ulcerative colitis (UC) disease activity on a scale of increasing severity from 0-9, calculated by summing three subscores: Endoscopic subscore (ES), scored on a scale of increasing severity from 0 (normal or inactive disease) to 3 (severe disease, such as spontaneous bleeding or ulceration); Stool frequency subscore (SFS), scored on a scale of increasing frequency from 0 (normal number of stools) to 3 (≥5 stools more than normal per day for the participant); and rectal bleeding subscore (RBS), scored on a scale of increasing severity from 0 (no blood seen) to 3 (blood alone passed). Clinical Remission is defined as an ES of 0 or 1, RBS of 0, and SFS of 0 or 1 and not greater than the baseline SFS.

A Phase 3 Extension Study to Evaluate the Long-term Safety and Efficacy of Tulisokibart in Participants With Crohn's Disease or Ulcerative Colitis