OBJECTIVES: During 2014-2015, infliximab was the fourth most expensive drug for the National Health Service (NHS) in England. The availability of less costly infliximab biosimilar products (IFX-BSPs), might help in relieving the financial burden of prescribing infliximab. Since the IFX-BSP launch in February 2015, there have been many initiatives to promote IFX-BSP utilisation. This study aimed to categorise English Acute Trusts based on their dominant prescribing practice of infliximab (IFX-BSP or the reference ‘R-BMP’ i.e. original biologic).

METHODS: Prescribing percentages from the medicines optimisation dashboard and purchasing data reported by NHS Digital were obtained. Over a one year period, for each trust, total R-BMP prescribed per quarter was calculated by combining both datasets. The quarterly change in both total infliximab purchased and R-BMP prescribed were calculated. Trusts were categorised into as initiators; switchers and initiators; or non-users by comparing change in total infliximab with change in R-BMP. Wherever there was a greater decline in the R-BMP prescribed compared to the change in total infliximab the trust was categorised as switcher and initiators