A Study to Evaluate Efficacy and Safety of Ustekinumab Re-induction Therapy in Participants With Moderately to Severely Active Crohn's Disease

This study compares the efficacy and safety of a single weight-tiered based IV re-induction dose of approximately 6 mg/kg ustekinumab versus continuing with regular SC q8w 90 mg ustekinumab administration. It consists of screening (5 weeks); treatment period (Week 0 to 24); and safety follow up visit (20 weeks after last dose). The primary hypothesis is that a single IV re-induction dose of ustekinumab is superior to continuing with regular SC q8w maintenance treatment as measured by clinical response after 16 weeks of treatment. Study assessments will include Crohn's disease activity index (CDAI), video ileocolonoscopy, patient-reported outcomes (PROs), laboratory evaluations, biomarkers, review of concomitant medications and adverse events (AEs), and evaluation of serum concentrations of study agent as well as development of antibodies to study agent. All participants will be randomly assigned to receive either ustekinumab IV re-induction or regular SC q8w 90 mg ustekinumab injection at baseline in a double dummy design. No participants will be treated with placebo only.