Clinical and experimental gastroenterology
Infliximab Serum Level Assessment After Switching from Intravenous to Subcutaneous Administration: The ISLASIS Study
By Schiavetti BLP and Gasparini RG.
Abstract
Introduction
Subcutaneous infliximab (SC-IFX) has emerged as an alternative maintenance therapy for inflammatory bowel disease (IBD), offering absorption and sustained systemic exposure. Although higher and more stable serum concentrations have been reported with SC-IFX, prospective real-world data evaluating pharmacokinetic evolution after transition from intravenous infliximab (IV-IFX) remain limited, particularly in Latin America. We assessed infliximab trough concentrations following transition from IV-IFX to SC-IFX and explored associations with biomarkers and clinical outcomes.
Methods
ISLASIS was a prospective, open-label study including adults with Crohn's disease (CD) or ulcerative colitis (UC) receiving IV-IFX. All transitioned to SC-IFX and were evaluated at baseline (V1), week 12 (V2), and week 24 (V3). Infliximab trough concentrations were measured at each visit. Fecal calprotectin and clinical indices were assessed at baseline and week 24. Subgroup analyses explored pharmacokinetic behavior according to disease phenotype, prior biologic exposure, and IV regimen.