A Study to Assess the Efficacy and Safety of Induction and Maintenance Therapy With RO7790121 in Participants With Moderately to Severely Active Crohn's Disease

Inclusion criteria:

• Confirmed diagnosis of CD
• Moderately to severely active CD
• Bodyweight >= 40 kilogram (kg)
• Demonstrated inadequate response, loss of response and/or intolerance to at least one protocol-specified conventional or advanced CD therapy
• Males and females of childbearing potential must meet protocol criteria for contraception requirements

Exclusion criteria:

• Current diagnosis of ulcerative colitis (UC) or indeterminate colitis, ischemic colitis, infectious colitis, radiation colitis, microscopic colitis
• Participant with a history of >= 3 bowel resections (> 2 missing segments of the 5 following segments: terminal ilelium, right colon, transverse colon, sigmoid and left colon, and rectum)
• Diagnosis of short gut or short bowel syndrome
• Presence of an ileostomy, colostomy or ileoanal pouch
• Participants with symptomatic bowel strictures, fulminant colitis, or toxic megacolon
• Presence of abdominal or perianal abscess
• Presence of rectovaginal fistulas or perianal fistulas with >3 openings
• Current diagnosis or suspicion of primary sclerosing cholangitis
• Pregnancy or breastfeeding, or intention of becoming pregnant during the study
• Past or current evidence of definite low-grade or high-grade colonic dysplasia or adenomas or neoplasia not completely removed
• History of malignancy within 5 years, with the exception of malignancies adequately treated with resection for non-metastatic basal cell or squamous cell cancer or in situ cervical cancer
• Evidence of infection with Clostridioides difficile (C. difficile; formerly known as Clostridium difficile), cytomegalovirus (CMV), human immunodeficiency virus (HIV), Hepatitis B (HBV), Hepatitis C (HCV)
• Has evidence of active tuberculosis (TB), latent TB not successfully treated (per local guidance) or inadequately treated TB
• Has received protocol-specified prohibited medicines, including known exposure to any type of anti-TL1A therapy