P0985 Real-world experience of subcutaneous infliximab use in children with inflammatory bowel disease (IBD) at a tertiary paediatric centre
Authors: Eldredge J , Kaur R , Tano M , Chidgey T , Singh N , Chuah C W , Magoffin A , Thacker K , O’Loughlin E , Dutt S 
Published: January 2025

Abstract

Background
Subcutaneous infliximab (SC-IFX) offers comparable efficacy and safety profiles to intravenous infliximab (IV-IFX) use in patients with inflammatory bowel disease (IBD), with relative pharmacokinetic stability demonstrated 1, 2. Minimal experience with SC-IFX use in paediatric IBD has been described3, 4. We aimed to assess the clinical tolerability of SC-IFX use in children with IBD requiring anti-tumour-necrosis factor (anti-TNF) treatment.

Methods
A prospectively identified cohort of children with IBD commenced 120mg fortnightly SC-IFX dosing between February to July 2024 in an Australian tertiary paediatric centre. Treatment followed switch from stable intravenous infliximab (IV-IFX) biosimilar maintenance dosing, or as part of induction treatment. Baseline and four-weekly biochemical and clinical disease activity assessments were undertaken over a 12 week period of follow-up.

Results
Thirty-one of thirty-three patients completed the 12-week period of treatment follow-up. Median age was 15 years (IQR 14-16.5 years) and 76% (25/33) were male. Twenty-seven patients (82%) had a Crohn’s disease diagnosis. SC-IFX was prescribed as part of induction dosing in 18% (6/33). Biochemical parameters are outlined in Table 1. Median infliximab level increased by 10mg/L to 17.6mg/L at week 12, with a statistically significant increase between baseline level and all other timepoints over the follow-up period (Figure 1). Sixteen patients (48%) had a serum infliximab level greater than 20mg/L at 12 week follow-up. There was no statistically significant change in clinical disease activity indices (Paediatric Crohn’s Disease Activity Index [PCDAI] or Paediatric Ulcerative Colitis Activity Index [PUCAI]) assessed across study timepoints. No correlation between patient characteristics, including demographics, immunomodulator use and previous (if any) IV-IFX regimen, and biochemical markers at baseline or week 12 was seen. High tolerability and treatment persistence were observed in our patient group without any safety concerns.

Conclusion
We describe the largest cohort of children with IBD prescribed SC-IFX with short-term follow-up. Serum infliximab level increased by 10mg/L over the study period, without significant change in faecal calprotectin and clinical disease activity indices. We observed high treatment persistence in our patient group. Our real-world experience suggests paediatric SC-IFX use may be a reasonable alternative to IV-IFX dosing in children in with IBD. Further large-cohort studies and long-term paediatric data is required.

References
1)Schreiber S, Ben-Horin S, Leszczyszyn J et al. Randomized Controlled Trial: Subcutaneous vs Intravenous Infliximab CT-P13 Maintenance in Inflammatory Bowel Disease. Gastroenterology 2021; 160: 2340-53.
2)Buisson A, Nachury M, Bazoge M et al. Long-term effectiveness and acceptability of switching from intravenous to subcutaneous infliximab in patients with inflammatory bowel disease treated with intensified doses: The REMSWITCH-LT study. Aliment Pharmacol Ther 2024; 59: 526-34.
3)Gianolio L, Armstrong K, Swann E et al. Effectiveness of Switching to Subcutaneous Infliximab in Pediatric Inflammatory Bowel Disease Patients on Intravenous Maintenance Therapy. J Pediatr Gastroenterol Nutr 2023; 77: 235-9.
4)Gianolio L, Armstrong K, Swann E et al. OC5 Effectiveness and safety of switching to subcutaneous infliximab in paediatric inflammatory bowel disease patients on established intravenous biosimilar infliximab maintenance therapy: real world data from a regional cohort. Frontline Gastroenterology 2024; 15: A4-A.