This phase III, double-blind, multi-center treat-through study will evaluate the efficacy and safety of Afimkibart (also known as RO7790121) in children with moderately to severely active Crohn's Disease (CD).

Inclusion Criteria:

• Body weight >= 10 kilogram (kg)
• Active CD confirmed by endoscopy (ileocolonoscopy)
• Moderately to severely active CD, defined as a Pediatric Crohn's Disease Activity Index (PCDAI) score >= 30, and Simple Endoscopic Score Crohn's Disease (SES-CD) >=6 (or >=4 for isolated ileal disease) confirmed through centrally-read ileocolonoscopy
• Inadequate response, loss of response, and/or intolerance to at least one of the following conventional therapies (aminosalicylates, corticosteroids and/or immunosuppressants) or advanced therapies (including anti-tumor necrosis factor, anti-interleukin, anti-integrin, or Janus Kinase (JAK) inhibitors)

Exclusion Criteria:

• Monogenic disorder pertaining to infant onset Inflammatory Bowel Disease (IBD)
• History of >= 3 bowel resections: > 2 missing segments of the following five segments: terminal ileum, right colon, transverse colon, sigmoid and left colon, and rectum
• Current diagnosis of ulcerative colitis (UC), abdominal/intraabdominal/perianal fistula and/or abscess, indeterminant colitis, IBD-unclassified, microscopic colitis, ischemic colitis, infectious colitis, radiation colitis, or active diverticular disease.
• Symptomatic bowel strictures, fulminant colitis, or toxic megacolon
• Presence of abdominal or perianal abscess
• Current diagnosis or suspicion of primary sclerosing cholangitis

For eligible studies, qualified researchers may request access to individual patient level clinical data. See Roche's commitment to transparency of clinical study information here: https://go.roche.com/data\_sharing