Thiopurines (TP) have been a historical mainstay in the treatment of pediatric IBD since the 1990s. However, the advent of anti-TNF therapy and increasing concerns about long-term safety of TP has prompted some clinicians to re-evaluate their role. DEVELOP is a multicenter, prospective, observational registry started in 2007 that examines the long-term safety and clinical status of 6070 pediatric patients with inflammatory bowel disease (IBD), including 4039 with Crohn’s disease (CD), treated with originator infliximab (REM) and/or other medical therapies for IBD as part of routine clinical care.