P428 Pharmacist-led proactive therapeutic drug monitoring with infliximab (PROXIMO): Utility of and cost-saving associated with the use of a rapid assay for assessing drug level

Abstract Background Optimised infliximab (IFX) dosing in patients with IBD is required to achieve therapeutic drug levels. Rapid assays enable same-day dose adjustment with the potential benefits of faster dose-optimisation, improved clinical outcomes, and reduced risks associated with high levels. To compare a rapid IFX assay to standard ELISA, assess effect of proactive dose adjustment on disease activity, and compare cost-effectiveness of this approach to standard therapy. Methods In a 12-month prospective single-centre study of adult IBD patients receiving 8-weekly 5 mg/kg maintenance IFX therapy, trough IFX concentrations were assessed via the rapid test (Bühlmann) before each infusion with immediate dose adjustment targeting 3–7 μg/ml. Disease activity was assessed using the Harvey Bradshaw index for Crohn’s disease and simple clinical colitis activity index for ulcerative colitis, CRP (