Intravenous versus subcutaneous infliximab in inflammatory bowel disease: a systematic review and meta-analysis

Background: Subcutaneous [SC] infliximab may provide multiple benefits over intravenous [IV] formulations. However, studies for efficacy and safety in inflammatory bowel disease [IBD] have been constrained by small sizes that limit the interpretation of outcomes, particularly for subgroups potentially at high risk of disease relapse. Methods: We conducted a systematic review and random-effects meta-analysis up to January 2023, to evaluate the change in clinical remission after transitioning from IV to SC infliximab in patients with IBD in clinical remission. The primary outcome was measured using the relative risk for meta-analysis. Results: We identified 15 studies of patients established ≥ 3 months on IV infliximab, consisting of 1371 patients and 840 patient-years of follow-up. There was no loss of clinical remission in the IBD cohort overall, Crohn's disease [CD], or perianal CD [p = 0.55 and p = 0.11 at 9-12 months, and p = 0.50 at 6 months, respectively]. Neither prior IV dose [≤ 10 mg/kg 6-weekly] [p = 0.48] nor IBD disease subtype was associated with an increased clinical relapse rate at 6 months (p = 0.48 and p = 0.45 [UC vs CD], respectively). Conclusion: Changing patients established on IV infliximab to an SC formulation is associated with a high ongoing clinical remission and a low adverse event rate. Furthermore, there are no signals for adverse outcomes among different IBD disease subtypes, nor in those on escalated IV infliximab dosing schedules up to 10 mg/kg 6-weekly. These data should provide patients and clinicians alike with confidence in SC infliximab use in IBD.