P379 Infliximab or adalimumab: Which should be used first for Crohn’s disease? A multicentre retrospective observational study

We have debated which of the anti-TNF agents we should use first for the biologic-naïve Crohn’s disease (CD) patients; infliximab (IFX) or adalimumab (ADA). There are few multicentre studies to compare the efficacy between those agents. The aim of this study was to clarify the long-term efficacy of those agents in the treatment of CD patients. We enrolled 263 biologic-naïve CD patients [median age, 39 years (IQR 30–48)] from 13 institutions in Japan and performed retrospective analysis of their characteristics and clinical courses. All the CD patients were administered IFX (n = 183) or ADA (n = 81) as a first biologics between June 2002 and March 2016, and followed for more than one year. Sixty-seven (26%) patients received an immunomodulator concomitantly at the initiation of anti-TNF agents. The primary endpoints were steroid-free remission at 32 weeks and at one year. Steroid-free remission rates at 32 weeks and at 1 year were 46.6% and 54.1% on IFX monotherapy, 66% and 74% on IFX combotherapy, 52.4% and 61.9% on ADA monotherapy, and 52.9% and 60.5% on ADA combotherapy, respectively. Significant differences were observed between IFX monotherapy and IFX combotherapy at 32 weeks and at 1 year (p = 0.021, and p = 0.018, respectively). On the other hand, there were no significant differences between ADA and IFX, and between ADA monotherapy and ADA combotherapy. Adverse events leading to drug discontinuation were observed in 12% on IFX and 5% on ADA, respectively (p = 0.11). In this retrospective, multicentre, observational study, similar long-term efficacy was observed in biologics-naïve CD patients between IFX first and ADA first. The efficacy of combination with an immunomodulator was observed in patients with IFX first, but not observed in patients with ADA first.