A Study to Evaluate the Efficacy and Safety of Tulisokibart (MK-7240) in Participants With Moderate to Severe Crohn's Disease (MK-7240-008)

The purpose of this protocol is to evaluate the efficacy and safety of tulisokibart in participants with moderately to severely active Crohn's disease. Study 1's primary hypotheses are that at least 1 tulisokibart dose level is superior to placebo in the proportion of participants achieving clinical remission per Crohn's Disease Activity Index score (\<150, US/FDA) or per stool frequency and abdominal pain score (EU/EMA) and in the proportion of participants achieving endoscopic response at Week 52 (US/FDA and EU/EMA), and that at least 1 tulisokibart dose level is superior to placebo in the proportion of participants achieving clinical remission per Crohn's Disease Activity Index score (\<150, US/FDA) or per stool frequency and abdominal pain score (EU/EMA) and in the proportion of participants achieving endoscopic response at Week 12 (US/FDA and EU/EMA). Study 2's primary hypothesis is that at least 1 tulisokibart dose level is superior to placebo in the proportion of participants achieving clinical remission per Crohn's Disease Activity Index score (\<150, US/FDA) or stool frequency and abdominal pain score (EU/EMA) and in the proportion of participants achieving endoscopic response at Week 12 (US/FDA and EU/EMA).

The protocol consists of 2 studies. Study 1 includes induction and maintenance treatment, and Study 2 includes only induction treatment. Each study has its own hypotheses and outcome measures that will be assessed independently.

Eligibility Criteria:
The main inclusion and exclusion criteria include but are not limited to the following:

Inclusion Criteria:

* Has had a diagnosis of CD at least 3 months before study.
* Has moderately to severely active CD.
* Demonstrated inadequate response, loss of response, or intolerance to one or more of the following categories of drugs: oral locally acting steroids, systemic steroids, immunomodulators, biologic and/or small molecule advanced therapies.
* Adolescent participants ≥16 and \<18 years of age can participate if approved by the country or regulatory/health authority.

Exclusion Criteria:

* Has diagnosis of ulcerative colitis (UC) or indeterminate colitis.
* Has CD isolated to the stomach, duodenum, jejunum, or perianal region, without colonic and/or ileal involvement.
* Currently has any of the following complications of CD: suspected or diagnosed with intra-abdominal or perianal abscess, known symptomatic stricture or colonic stenosis not passable in endoscopy, fulminant colitis, toxic megacolon, or any other manifestation that might require surgery while enrolled in the study.
* Has current stoma or need for colostomy or ileostomy.
* Is missing \>2 segments of the following 5 segments: terminal ileum, right colon, transverse colon, sigmoid and left colon, and rectum.
* Has been diagnosed with short gut or short bowel syndrome, or any other uncontrolled chronic diarrhea besides Crohn's disease.
* Has surgical bowel resection within 3 months of study.
* Has prior or current gastrointestinal dysplasia.
* Has chronic infection requiring ongoing antimicrobial treatment.
* Has a history of cancer (except fully treated non-melanoma skin cell cancers or cervical carcinoma in situ after complete surgical removal) and is disease free for \<5 years.
* Is infected with Hepatitis B virus (HBV), Hepatitis C virus (HCV), or human immunodeficiency virus (HIV).
* Has active tuberculosis.
* Has confirmed or suspected coronavirus disease of 2019 (COVID-19) infection.
* Prior exposure to tulisokibart (MK-7240, PRA023) or another anti-TL1A antibody.