P815 Infliximab drug monitoring: proactive or reactive: a North West England NHS 3 trust retrospective study

Abstract

Abstract Background Therapeutic drug monitoring (TDM) plays a vital role in the management of patients on Infliximab. (1) The British Society of Gastroenterology (BSG) recommends TDM assessment ideally takes place 2-4 weeks after the initial loading doses, however the European Crohns and Colitis Organisation (ECCO) do not make particular proactive or reactive recommendations for TDM. (1,2,3) Methods Three North West England NHS trusts retrospectively collected data on 75 patients who had Infliximab trough and antibody levels done within a 12 month time frame. The aim was to establish if collectively TDM was done proactively or reactively and the overall outcomes from the monitoring. Results The demographic profile gave us 37 females and 38 males with the disease distribution predominantly Crohns disease ( N=53). There were more participants in the 18-50 age range (N=53) with 22 patients being 31-40 years of age, less participants in the 51-70+ age range ( N=22). Dual therapy with either Mercaptopurine or Azathioprine accounted for 49 out of the 75 participants with a majority favouring Azathioprine. Clinical management and routine use of TDM was seen in 40.5% ( N= 54) of patients indicating proactive use of monitoring in this study. TDM was undertaken after induction and annually in 48 patients whilst the remaining 27 patients received monitoring as ‘maintenance’, this is similar to the BSG recommendations and in a study by Sagar et al in 2021 ( 4). Conclusion Although the three participating trusts may use differing assays for the TDM, the outcomes show that it is used proactively for the majority of patients after induction and annually in keeping with BSG recommendations (3). From the data collected a further examination of results regarding subcutaneous versus intravenous TDM outcomes is proposed as the trusts move towards providing patients with both modes of administration of Infliximab.