Treatment optimization of subcutaneous infliximab in patients with inflammatory bowel disease

Abstract

Introduction: Subcutaneous infliximab (SC-IFX) is an efficacious medication for inflammatory bowel disease (IBD). However, there is limited information about treatment optimization following loss of response (LOR), the role of therapeutic drug monitoring (TDM), and combination therapy with an immunomodulator (IMM) and efficacy of SC-IFX in perianal fistulizing Crohn's disease (CD).

Areas covered: This narrative review will provide an overview of the efficacy of SC-IFX in IBD including perianal fistulising CD, the effectiveness of dose escalation after LOR, and the role of TDM and IMM use. A literature search was performed using PubMed and reviewed references from applicable manuscripts and abstracts from major gastrointestinal medical congresses between January 2021 and 20 May 2025.

Expert opinion: Current data suggest that SC-IFX is effective in the treatment of IBD. Moreover, cumulative data suggest that dose escalation is effective in recapturing response in patients with LOR, and that higher drug concentrations are associated with better outcomes. However, there are still major gaps in understanding the role of drug clearance, immunogenicity, and the role of TDM for optimizing SC-IFX. Moreover, the impact of body mass index and concomitant IMM therapy on clinical outcomes as well as the efficiency of SC-IFX in more complicated IBD phenotypes remains to be elucidated.

Keywords: Crohn’s disease; Inflammatory bowel disease; drug clearance; escalation; immunogenicity; subcutaneous infliximab; therapeutic drug monitoring; ulcerative colitis.