Subcutaneous Infliximab Concentration Thresholds for Mucosal and Transmural Healing in Patients With Crohn's Disease.

ABSTRACT Background Aims Methods Results Conclusions Predose trough concentrations (Ctrough) of intravenous infliximab (IV‐IFX) during maintenance therapy are associated with therapeutic outcomes in patients with Crohn's disease (CD). A subcutaneous formulation of infliximab (SC‐IFX) has shown high Ctrough values due to its favourable pharmacokinetics.To evaluate the association of Ctrough of SC‐IFX with therapeutic outcomes and the threshold of SC‐IFX Ctrough for achieving mucosal healing (MH) and transmural healing (TH) in patients with CD.We performed this cross‐sectional study in patients with CD who had received SC‐IFX maintenance therapy for ≥ 6 months. We measured SC‐IFX Ctrough immediately before SC‐IFX injection. We performed ileocolonoscopy/single‐balloon enteroscopy and/or magnetic resonance enterography within 3 months of SC‐IFX Ctrough measurement. MH was defined as SES‐CD–ulcerated surface subscore of 0. TH was defined as simplified MaRIA score of 0.We enrolled 124 patients with MH in 77.9% (74/95) and TH in 36.3% (37/102). SC‐IFX Ctrough was significantly higher in patients with MH (24.1 vs.16.9 μg/mL; p = 0.001) and TH (26.0 vs. 20.5 μg/mL; p = 0.007) than in those without. ROC analysis identified that the threshold of SC‐IFX Ctrough for MH and TH were 17.5 and 30.3 μg/mL, respectively. Multivariate logistic regression showed that SC‐IFX Ctrough was significantly associated with MH (OR 1.16; 95% CI 1.05–1.27; p = 0.002) and TH (OR 1.08; 95% CI 1.02–1.14; p = 0.005).SC‐IFX Ctrough was positively associated with MH (≥ 18 μg/mL) and TH (≥ 30 μg/mL) in patients with CD, which may guide treatment decisions to optimise therapeutic response in the era of treat‐to‐target. [ABSTRACT FROM AUTHOR]