Switching from Dose-Intensified intravenous to SubCutaneoUS infliximab in Inflammatory Bowel Disease (DISCUS-IBD): protocol for a multicentre randomised controlled trial.

Introduction: A substantial proportion of patients with inflammatory bowel disease (IBD) on intravenous infliximab require dose intensification. Accessing additional intravenous infliximab is labour-intensive and expensive, depending on insurance and pharmaceutical reimbursement. Observational data suggest that subcutaneous infliximab may offer a convenient and safe alternative to maintain disease remission in patients requiring dose-intensified infliximab. A prospective, controlled trial is required to confirm that subcutaneous infliximab is as effective as dose-intensified intravenous infliximab, to identify predictors of disease flare and to establish the role of subcutaneous infliximab therapeutic drug monitoring.
Methods and Analysis: The DISCUS-IBD trial is an investigator-initiated, prospective, multicentre, randomised, open-label non-inferiority study comparing the rate of disease flares in participants randomised to continue dose-intensified intravenous infliximab to those switched to subcutaneous infliximab after 48 weeks. Participants are adult patients with IBD in sustained corticosteroid-free remission on any regimen of dose-intensified infliximab up to a maximum of 10 mg/kg 4-weekly intravenously. Participants allocated to intravenous infliximab will continue infliximab at the same dose-intensified regimen they were receiving at study enrolment. Subcutaneous infliximab dosing will be stratified by prior intravenous infliximab dosing. Clinical (Harvey-Bradshaw Index, partial Mayo score), biochemical (C reactive protein, faecal calprotectin), pharmacokinetic (drug-level±antidrug antibodies) and qualitative data are collected 12-weekly until study conclusion at week 48. 13 sites across Australia will participate in recruitment to reach a calculated sample size of 120 participants.
Ethics and Dissemination: Multisite ethics approval was obtained from the Health District Human Research Ethics Committee (HREC) at The Alfred Hospital under a National Mutual Acceptance (NMA) agreement (HREC/90559/Alfred-2022; Local Reference: Project 618/22, version 1.6, 2 March 2023). Findings will be reported at national and international gastroenterology meetings and published in peer-reviewed journals. DISCUS-IBD was prospectively registered with the Australian and New Zealand Clinical Trials Registry (ANZCTR) prior to commencing recruitment.
Trial Registration Number: ACTRN12622001458729.
Competing Interests: Competing interests: RDL has received conference fees from Janssen and Celltrion Healthcare. AS has received speaker fees from Sandoz and received research support and advisory fees from AbbVie, Pfizer, and Arrow Pharmaceuticals. GJW has served as a speaker, a consultant or an advisory board member for Janssen, Galapagos, AbbVie, Ferring, Dr Falk Pharma, Nova Labs and Sandoz. GTM has received educational grants or research support from GESA, The Gutsy Group, NHMRC, MRFF, AbbVie, Janssen, Pfizer, Shire and Takeda; speaker fees from AbbVie, Ferring, Janssen, Orphan, Pfizer, Roche, Sandoz, Shire and Takeda and has serve on advisory boards for AbbVie, Emerge, Eli-Lilly, Gilead, Hospira, Janssen, Orphan, MSD, Pfizer, Shire and Takeda. KL declares speaker fees, advisory Board fees and/or conference travel/registration support from AbbVie, Bristol Myers Squibb, Chiesi, Dr Falk, Ferring, Gilead, Guidepoint, Intercept Pharmaceuticals, Janssen-Cilag, MSD, Norgine, Pfizer, Sandoz, Takeda and the RAH Research Fund. JA has served as a speaker, a consultant and an advisory board member for, and has received research funding from, Abbott, AbbVie, Allergan, Anatara, AstraZeneca, Bayer, Celgene, Falk, Ferring, Gilead, Hospira, Immunic, ImmunsanT, Janssen, MSD, Nestle, Progenity, Pfizer, Sandoz, Shire, Takeda, Vifor, RAH Research Fund, The Hospital Research Fund with all monies received by her department for research support. YKA reports grants from Janssen, during the conduct of the study; has received speaking and consulting fees from AbbVie, Bristol Myers Squibb, Celltrion, Chiesi, Dr Falk, Ferring, Janssen, Pfizer, Sandoz, Shire and Takeda; served on advisory boards for AbbVie, Bristol Myers Squibb, Chiesi, Janssen, NPS Medicine wise, Microba and received research and educational funding from Abbvie, Celltrion, Dr Falk, Janssen, Pfizer, Sandoz and Takeda. RVB has received grant/research support/speaker fees from AbbVie, Ferring, Janssen, Shire, Takeda, Bristol Myer Squibb and Emerge Health; and is a shareholder in Biomebank. SC declares advisory board participation, speaker fees, educational support and/or research support for Liverpool Hospital, South Western Sydney Local Health District (SWSLHD) Academic Unit or Crohn’s Colitis Cure from: AbbVie, Amgen, BMS, Celltrion, Chiesi, Eli-Lilly, Dr Falk, Ferring, Fresenius Kabi, Gilead, GSK, Janssen, MSD, Novartis, Organon, Pfizer, Sandoz, Takeda and non-pharmacological research support from Agency for Clinical Innovation, Gastroenterological Society of Australia, The Leona M and Harry B Helmsley Charitable Trust, Medical Research Future Fund, SWSLHD, Sydney Partnership for Health, Research and Enterprise (SPHERE). MG has served on the advisory board of Pfizer and has received speaker fees, research or travel grants from AbbVie, Celltrion, Dr Falk, Janssen, Pfizer, Pharmacosmos, Takeda. EKW declares speaker and consulting fees from AbbVie, BMS, Celltrion, Falk, Ferring, Janssen, Pfizer and research funding/support from AbbVie, Ferring, Janssen. JPS has received conference fees from Janssen, BMS, Takeda, educational grants from Pfizer, speaker fees from AbbVie, Takeda and Pfizer and an unrestricted grant from Tillots. PDC has served as a consultant, an advisory board member or a speaker for AbbVie, Baxter, Ferring, Janssen, Celltrion, Emerge Health, Shire and Takeda and received research support from Ferring, Shire, Janssen, AbbVie, and Takeda. MGW has received educational grants and speakers fees from AbbVie, Takeda and Ferring; travel grants from Pfizer; and has served on advisory boards for AbbVie. MPS has received educational grants or research support from Ferring, Orphan and Gilead; speakers fees from Janssen, AbbVie, Ferring, Takeda, Pfizer and Shire; and has served on advisory boards for Janssen, Takeda, Pfizer, Celgene, AbbVie, MSD, Emerge Health, Gilead and BMS. JM, PH, RBG, DC, MS, EC, LT, GH and AB declare no relevant competing interests.
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