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* = Presenting author

P617 Immunogenicity after switching from reference infliximab to biosimilar in children with Crohn’s disease

J. Sieczkowska*, D. Jarzebicka, G. Oracz, M. Meglicka, M. Dadalski, J. Kierkus

The Children’s Memorial Health Institute, Department of Gastroenterology, Hepatology, Feeding Disorders and Paediatrics, Warsaw, Poland

Background

Infliximab biosimilars’ immunogenicity has been assessed in several clinical trials in rheumatology. Based on these studies, biosimilars have been approved to be used in the same indications as originator. Because of their lower price and better availability, there is sometimes necessity to switch patients to biosimilar infliximab during the course of biologic therapy. The aim of the study was to compare products’ immunogenicity before and after switching.

Methods

Paediatric patients with Crohn’s disease who had switch from reference infliximab to biosimilar in the course of therapy were enrolled to the study. All of them were sampled for assessment of drug level and presence of anti-tumour necrosis factor (TNF) antibodies (ATI) with ELISA tests within the time of switching a 5 dose of biosimilar. PCDAI (Paediatric Crohn’s Disease Activity Index), patient characteristics, and laboratory data were recorded and related to drug and ATI concentrations.

Results

Enrolled in the study were 16 CD patients (11 M and 5 F). Mean age was 12.7 (14.1; 3.7–7.4). Amongst them, 14 out of 16 patients had therapeutic level of IFX (>1.5 ug/mL) at time of switching, and 7 of them presented positive ATI concentration (> 2 ng/mL). Further, 1 patient had subtherapuetic concentration of IFX with presence of ATI, and 1 presented with undetectable concentration of IFX (< 0.035 μg/mL) with negative ATI (< 2ng/mL). There were no significant correlations between IFX level, presence of ATI, disease activity, and laboratory data (albumin, CRP). Assessment of immunogenicity after switching has been performed in 15 patients. All 15 patients had therapeutic IFX concentrations, and only 4 out of 15 had ATI > 2ng/mL and higher antibody concentration corresponded to lower drug concentration. No significant correlation between drug level and laboratory data was identified.

Conclusion

This is the first study regarding immunogenicity in paediatric Crohn’s disease patients who had switched from originator to biosimilar infliximab. No attributes of higher immunogenicity after switching were found. Further analyses are needed.