P590 Outcomes of patients treated with sequential anti-TNF therapy in a tertiary referral centre

Abstract

Abstract Background Anti-TNF agents are administered intravenously(iv) or subcutaneously(SC).Factors such as speed of onset and patient preference influence that decision. The aim of this study was to assess the characteristics and outcomes of patients transitioned between iv and sc anti-TNF therapy. Methods Patients attending a single tertiary referral centre, treated with two different anti-TNF drugs were included. Patient and disease characteristics, biochemical, endoscopic and radiological data were collated. Results 69 patients were included. Table 1 describes the patient cohort. 28 (40.6%) patients transitioned from SC anti-TNF to infliximab (IFX). N=35 (50.7%) switched from IFX to Adalimumab and 6 to Golimumab. 31 patients demonstrated some degree of endoscopic activity prior to anti-TNF switch;14/16 (87.5%) demonstrated radiological activity. 48 patients had endoscopic assessment post-switch; 28 (58.3%) had endoscopic remission.Of the 19 patients with post-transition imaging, 42.1% (8/19) had no active disease. 43 (79.6%) patients had therapeutic trough concentrations of the current anti-TNF. 13 (26%) were previously on combination therapy, while 22 (32.8%) currently are. 24 (39.3%) patients had detectable anti-drug antibodies to their prior anti-TNF, 10 (16.4%) had primary non-response and 12 (19.7%) had loss of response with adequate drug levels. There were significantly more patients with antibody formation in the group switching from IFX to SC anti-TNF (n = 20; p = 0.001). A significantly higher proportion of patients who were transitioned from IFX to SC anti-TNF currently have therapeutic/supratherapeutic drug levels when compared with patients transitioning SC to IFX (p = 0.01). There is no significant difference in the proportion currently on combination therapy (p = 0.668). There is a significant improvement in c-reactive protein, albumin and haemoglobin in the cohort as a whole. However, there is no significant difference in rates of clinical remission (p = 0.556) or endoscopic remission (p = 0.89) after switching from one mode of delivery to another. Conclusion Patients converted from IFX to SC anti-TNF have similar rates of endoscopic and clinical remission to those transitioned to IFX. However, many patients had previous antibody formation. Subsequently, this group has significantly higher rates of therapeutic or supra-therapeutic drug concentrations, suggesting the conscientious use of therapeutic drug monitoring to optimise response.