A Pilot Study of the Effectiveness and Safety of Subcutaneous Infliximab in Chronic Inflammatory Pouch Conditions: The St. Mark’s Experience

<b>Background/Objectives</b>: Infliximab (IFX) is commonly used in chronic inflammatory conditions of the ileo-anal pouch. A subcutaneous (SC) formulation has been developed, with studies in inflammatory bowel disease (IBD) patients showing that switching from intravenous (IV) to SC IFX is safe with a low risk of relapse. However, so far, it has not been specifically investigated in chronic inflammatory pouch conditions. The aim of our study was to evaluate the effectiveness and safety of SC IFX in patients with chronic inflammatory pouch conditions. <b>Methods</b>: This was an observational retrospective study. We included patients with chronic inflammatory pouch conditions, initially treated with IV IFX and subsequently switched to SC IFX, who had a follow-up of at least 1 year. The primary outcome was SC IFX treatment persistence, defined as continuation of SC IFX throughout the study period. The secondary outcome was pouch failure, defined by the need for a defunctioning ileostomy or pouch excision. <b>Results</b>: A total of seven patients were included. The mean age was 50.6 years. The average follow-up length was 101.3 months (range 70.4-132.6 months). All seven patients continued SC IFX throughout the study period. No patient experienced pouch failure. The median IFX serum concentration was 18.1 mg/L. There were no cases of serious infections or malignancy. <b>Conclusions</b>: Switching clinically stable patients with chronic inflammatory pouch conditions from IV to SC IFX formulation appears feasible. These findings warrant confirmation in larger patient cohorts.