Higher Trough Concentrations of Infliximab are Associated with Clinical Remission and Mucosal Healing in Patients with Inflammatory Bowel Disease

Objective: Few studies have correlated the infliximab (IFX) trough concentration, clinical remission (CM) and mucosal healing (MH). The purpose of the study was to determine if higher IFX trough levels are associated with MH and CR, in a group of Brazilian inflammatory bowel disease patients. Methods: Cross-sectional study of 51 IBD patients in IFX maintenance therapy, at a medical center, in Brazil. IFX serum levels were obtained from blood samples collected immediately before drug infusion. The IFX trough levels were correlated with clinical and endoscopic scores and a univariate analysis was conducted to identify factors associated with CR and MH. Results: IFX trough concentration ≥ 2 μg/mL was associated with higher CR (84.2% vs. 28.1%; P<0.001) and MH (83.3% vs. 25.0%; P=0.001). Trough levels of 2.0 μg/mL were 89% specific for CR (sensibility=66%; P<0.001) and 89% specific for MH (sensibility =64%; P<0.001). On univariate analysis, IFX trough concentration was the only variable associated with CR and MH. Conclusion: The study found a significant association between IFX trough level ≥ 2 μg/mL, CR and MH. Therapeutic drug monitoring is an important tool in IBD patients and should routinely be performed to optimize treatment.