INTRODUCTION: Ustekinumab is a human monoclonal antibody directed against the 
shared p40 subunit of interleukins 12 and 23. Ustekinumab is currently approved 
for the treatment of psoriatic arthritis (PsA) and moderate to severe plaque 
psoriasis, and is being evaluated in Crohn's disease (CD).
AREAS COVERED: The first evidence supporting the efficacy of ustekinumab in the 
treatment of moderate to severe CD was published in 2008. Results from 
subsequent phase II and phase III randomized controlled trials (RCTs) have shown 
promising data on the clinical efficacy of induction and remission of moderate 
to severe CD. These data and the safety profile of ustekinumab will be reviewed. 
Expert commentary: As a significant proportion of individuals with CD have 
ongoing symptoms and inflammation despite existing therapies, there is a 
clinical need for new agents like ustekinumab directed at different targets on 
the inflammatory pathway. Looking forward, more studies are needed to evaluate 
dosing escalation or de-escalation in addition to timing of therapy switches. In 
addition, further data is required to gauge the comparative effectiveness of 
ustekinumab to the biologic agents that are currently used in the treatment of 
CD.