RecruitingPhase 3Drug trialA Long-term Extension (LTE) Study of Guselkumab in Pediatric ParticipantsThe purpose of this study is to evaluate long-term safety of subcutaneous guselkumab in pediatric participants with moderately to severely active ulcerative colitis, or moderately to severely active Crohn's disease, or juvenile psoriatic arthritis (jPsA).