A Study to Assess Adverse Events, Change in Disease Activity, and How Intravenous and Subcutaneous Risankizumab Moves Through the Body of Pediatric Participants With Moderately to Severely Active Crohn's Disease

Cohort 3 (Substudy 2): Percentage of Participants Achieving Pediatric Crohn's Disease Activity Index (PCDAI) Clinical Remission,Cohort 3 (Substudy 2): Percentage of Participants Achieving Endoscopic Response per Simple Endoscopic Score for Crohn's Disease (SES-CD),Cohorts 1 & 2: Maximum Observed Serum Concentration (Cmax) of Risankizumab,Cohorts 1 & 2: Time to Cmax (Tmax) of Risankizumab,Cohorts 1 & 2: Area Under the Serum Concentration-Time Curve Over the Dosing Interval (AUCtau) of Risankizumab

Crohn's Disease (CD) is a gastrointestinal disease that can cause chronic diarrhea with or
 without gross bleeding, abdominal pain, weight loss, and fever. This study will assess the
 pharmacokinetics, efficacy, and safety of risankizumab in pediatric participants with
 moderately to severely active CD aged 2 to 18 years old who have had intolerance or
 inadequate response to other therapies.
 
 Risankizumab is an approved drug for adults with plaque psoriasis, psoriatic arthritis, and
 CD and is being developed for the treatment of CD in pediatrics. This study is comprised of 3
 cohorts that may participate in 3 substudies (SS). Cohort 1 will enroll participants with
 ages from 6 to less than 18 years. Cohort 2 will enroll participants with ages from 2 to less
 than 6 years. Cohort 3 will enroll participants with ages from 2 to less than 18 years. SS1
 is an open-label induction period where participants will receive a weight-based induction
 regimen of risankizumab. SS2 is a double-blind maintenance period where participants will be
 randomized to receive 1 of 2 doses of weight-based induction regimen of risankizumab. SS3 is
 an open-label extension period where participants will receive risankizumab based off of
 their response in SS2. Around 110 pediatric participants with CD will be enrolled at around
 100 sites worldwide.
 
 Participants in SS1 will receive risankizumab intravenously during the 12-week induction
 period. Participants in SS2 will receive risankizumab subcutaneously during the 52-week
 randomized maintenance period. Participants in SS3 will receive risankizumab subcutaneously
 during the 208-week open label period. Participants will be followed-up for approximately 140
 days.
 
 There may be higher treatment burden for participants in this trial compared to their
 standard of care. Participants will attend regular visits during the study at a hospital or
 clinic. The effect of the treatment will be checked by medical assessments, blood tests,
 checking for side effects and completing questionnaires.