A Study to Assess the Efficacy and Safety of Induction Therapy With Afimkibart (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, enterovaginal, high output enterocutaneous fistula, enterovesical fistulas or perianal fistulas with >3 openings
* Participants with symptomatic bowel strictures, fulminant colitis, or toxic megacolon
* Current diagnosis or suspicion of primary sclerosing cholangitis
* Pregnancy or breastfeeding, or intention of becoming pregnant during the study
* Any past or current evidence of cancer of gastrointestinal tract, high-grade colonic dysplasia and participants with low-grade dysplasia are eligible if lesions have been completely removed
* History of non-gastrointestinal cancer, with the exception of adequately treated non-metastatic basal cell or squamous cell skin 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) during screening
* 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