Objectives: The aim of the study was to summarize short-term effectiveness, safety, and cost of using infliximab biosimilar (IFX-B) drugs, (Inflectra [Hospira] and Remsima [NAAP]) compared to originator infliximab (IFX-O) (Remicade [MSD]) in biologic naive pediatric inflammatory bowel disease in the United Kingdom.

Methods: Prospective audit of patients starting anti-tumour necrosis factor (TNF) therapy. Disease severity, response to treatment, and remission rate was measured by Pediatric Crohn's Disease Activity Index (PCDAI) and/or Physician Global Assessment.

Results: Between March 2015 and February 2016, 278 patients (175 IFX-O, 82 IFX-B, and 21 Adalimumab) were started on anti-TNF therapy. This was compared with collected data on 398 patients started on IFX-O from 2011 to 2015. At initiation, median PCDAI was 36 (20,48) (n = 42) in the IFX-O group and 28 (20,40) (n = 29) in the IFX-B group, (P = 0.08). Immunosuppression rates were similar: 150/175 (86%) for IFX-O and 65/82 (79%) for IFX-B (P > 0.05). Post induction, median PCDAI score was 5 (0,11) (n = 19) and 0 (0,8) (n = 15) in the IFX-O and IFX-B groups, respectively (P = 0.35). There was no difference in response to treatment using Physician Global Assessment 85% (n = 28) in IFX-O group and 86% (n = 19) in IFX-B group (P > 0.05). Adverse events at initiation and post induction were not different between both groups (P > 0.05). Using conservative calculations, £875,000 would have been saved for a 1-year period with universal adoption of biosimilars in patients who were instead treated with IFX-O.

Conclusions: IFX-B is likely as effective as IFX-O in treating IBD in comparable pediatric populations. Sites should adopt infliximab biosimilar for new starts due to cost reduction with no difference in other parameters.