INTRODUCTION: Infliximab (IFX), a monoclonal chimeric antibody against tumour necrosis factor (TNF) α, is effective for induction and maintenance of remission in moderate to severe Crohn's disease. Discontinuation of IFX maintenance therapy in patients in remission should be considered in order to reduce the potential long-term side effects and lower costs.

METHODS AND ANALYSIS: This is a prospective, double-blind, randomised, placebo-controlled, multicentre study of patients with luminal Crohn's disease who have been treated with IFX for at least 1 year and are in sustained complete clinical, biochemical and endoscopic remission (ie, Crohn's Disease Activity Index (CDAI) score <150, complete mucosal healing and biochemical markers of inflammation within the normal range). These patients are randomised to receive placebo infusions or continue IFX maintenance therapy. The primary end point is the proportion of patients in maintained remission after 48 weeks (def. CDAI <150).

ETHICS AND DISSEMINATION: It is estimated that the knowledge gained about how to optimally handle patients with Crohn's disease in complete long-term sustained remission on IFX is proportionate to the risks and inconveniences related to participation in this study. Prolonged exposure to IFX may cause severe side effects and increased risk of malignancies. Conversely, IFX discontinuation should not unnecessarily create a high risk of relapse. Thus, empirical evidence is needed concerning the safety of discontinuing IFX once a patient exhibits sustained remission. Study results will be published in an English language scientific medical journal. The study is approved by the Danish Medicines Agency (EudraCT-number: 2012-002702-51) and the Regional Ethics Committee of Region Hovedstaden Denmark (Approval-number: H-4-2012-099). The project is reported to the Danish Data Protection Agency (ID-number: 2007-58-0015/HEH.750.89-27), registered at Clinicaltrials.gov, and monitored by independent GCP units for the University of Copenhagen, Odense and Aarhus. The current approved protocol is V.3.2, dated 1 June 2014.

TRIAL REGISTRATION NUMBER: http://clinicaltrials.gov/show/NCT01817426.