Infliximab Trough Levels at Induction to Predict Treatment Failure During Maintenance

Infliximab Trough Levels at Induction to Predict Treatment Failure During Maintenance. Liefferinckx C1, Minsart C, Toubeau JF, Cremer A, Amininejad L, Quertinmont E, Devière J, Gils A, van Gossum A, Franchimont D. BACKGROUND: Infliximab (IFX) is indicated for the treatment of inflammatory bowel diseases (IBD). Nevertheless, loss of response (LOR) to IFX is reported in up to 10% to 30% of patients within the first year of treatment. Our objective was to evaluate the impact of the pharmacokinetics of IFX at induction on treatment failure. METHODS: This is a longitudinal cohort study on 269 patients with IBD treated with IFX in a single center. A total of 2331 blood samples were prospectively collected from 2007 until March 2015 with a retrospective analysis of clinical data. IFX trough levels (TLs) were measured by enzyme-linked immunosorbent assay. Antibodies to IFX were measured by drug-sensitive bridging assay. RESULTS: During follow-up, patients were defined according to treatment outcome. At week 6, median IFX TL in patients requiring a switch to another treatment due to LOR (LOR switched group) (2.32 μg/mL [0.12-19.93 μg/mL]) was lower than in patients with long-term response (long-term responders) (8.66 μg/mL [0.12-12.09 μg/mL], P = 0.007) and in patients responding to …