Low-dose naltrexone for the induction of remission in patients with mild to moderate Crohn's disease: protocol for the randomised, double-blinded, placebo-controlled, multicentre LDN Crohn study.

introductionCrohn's disease (CD) is an inflammatory bowel disease (IBD). Several drugs exist to induce and maintain remission, but a significant part of the patients is refractory to current IBD drugs or experiences side effects. Whether low-dose naltrexone (LDN) is a safe and easily accessible alternative treatment option for these patients needs to be investigated. The aim of this study is to assess the efficacy of LDN for the induction of remission in patients with mild to moderate CD. METHODS AND ANALYSIS: The LDN Crohn study is a randomised, double-blinded, placebo-controlled multicentre trial. Patients with CD are randomised 1:1 to receive treatment with either LDN 4.5 mg once daily or placebo for 12 weeks. The primary objective is endoscopic remission at week 12, defined as Simple Endoscopic Score-CD≤2 and ulcerated surface subscore ≤1 in all five segments. Secondary aims include clinical and endoscopic response, changes in laboratory measures of inflammation, adverse events and patient-reported outcomes. To have 85% power to detect a true difference in the primary outcome measure between placebo and LDN, 61 patients will be needed in both groups. ETHICS AND DISSEMINATION: The study is approved by the Medical Ethics Committee of the Erasmus MC, Rotterdam, the Netherlands (registration number NL69149.078.19, MEC-2019-0602). Results will be published in peer-reviewed journals and presented at international conferences. TRIAL REGISTRATION NUMBERS: EudraCT2019-000852-32; NL9259.