A Study to Assess Adverse Events and Change in Disease Activity of Risankizumab Subcutaneous Induction Treatment for Moderately to Severely Active Crohn's Disease.

Crohn's disease (CD) is a long-lasting disease that causes severe inflammation (redness, swelling), in the digestive tract, most often affecting the bowels. It can cause many different symptoms including abdominal pain, diarrhea, tiredness, and weight loss. This study will assess how safe and effective risankizumab subcutaneous (SC) induction treatment is in treating moderately to severely active CD in adult participants. Risankizumab is an approved drug for adults with CD. This study comprises of a Period A, a Period B, and a Period C. In Period A, participants are placed in 1 of 2 groups to receive either risankizumab SC Dose A or Placebo. In Period B, based on response, participants will receive risankizumab SC Dose B or Placebo. Participants who do not have improvement in CD symptoms at Week 12 will receive risankizumab SC Dose C and participants with worsening CD symptoms in period B will receive risankizumab SC. In Period C, eligible participants will receive open-label risankizumab SC Dose D. Approximately 276 adult participants with a diagnosis of moderately to severely active CD will be enrolled in approximately 250 sites globally. Participants will receive SC induction treatment of risankizumab or matching placebo for up to 24 weeks in Period A and B followed by an open-label risankizumab extension in Period C for 52 weeks. The duration of the study will be approximately 93 weeks.