Multizentrische, randomisierte, doppelblinde, Placebo kontrollierte, 52 wöchige Erhaltungs- und offene Fortsetzungsstudie zur Wirksamkeit und Sicherheit von Risankizumab bei Patienten mit Morbus Crohn, die auf die Induktionsbehandlung in Studie M16-006 oder M15-991 angesprochen haben.

Drug: Placebo for Risankizumab SC;Drug: Risankizumab IV;Drug: Placebo for Risankizumab IV;Drug: Risankizumab SC;Drug: Risankizumab On-Body Injector (OBI)

Inclusion Criteria:

- Participants who have entered and completed Study M16-006 or Study M15-991 or other
AbbVie risankizumab Crohn's disease study.

- Participants have completed the study M16-006 or M15-991 and have achieved clinical
response.

- Sub-Study 4:

- Participants receiving maintenance treatment in Sub-study 3 and willing to comply
with the requirements of Sub-study 4, including self-administration of
sub-cutaneous injections using the on-body injector (OBI).

- Participant has received at least 16 weeks of stable dosing with risankizumab in
Sub-study 3 (i.e., no rescue within 16 weeks and participant has surpassed the
72-week mark).

Exclusion Criteria:

- Participants should not be enrolled in Study M16-000 with high grade colonic dysplasia
or colon cancer identified during Study M15-991, Study M16-006 or another AbbVie
risankizumab Crohn's disease study if the final endoscopy was performed prior to enter
Study M16-000 OR is considered by the Investigator, for any reason, to be an
unsuitable candidate for the study.

- Participant who has a known hypersensitivity to risankizumab or the excipients of any
of the study drugs or the ingredients of Chinese hamster ovary (CHO), OR had an
adverse event (AE) during Studies M16-006, M15-991 or another AbbVie risankizumab
Crohn's disease study that in the Investigator's judgment makes the participant
unsuitable for this study.

- Participant is not in compliance with prior and concomitant medication requirements
throughout Studies M16-006, M15-991 or another AbbVie risankizumab Crohn's disease
study.

- Confirmed positive urine pregnancy test at the Final Visit of Study M16-006, Study
M15-991 or another AbbVie risankizumab Crohn's disease study.

- Have a known history of lymphoproliferative disease, including lymphoma, or signs and
symptoms suggestive of possible lymphoproliferative disease, such as lymphadenopathy
and/or splenomegaly.

- Any active or chronic recurring infections based on the Investigator's assessment
makes the participant an unsuitable candidate for the study.