Impact of Introducing Infliximab Biosimilars on Total Infliximab Consumption and Originator Infliximab Prices in Eight Regions: An Interrupted Time-Series Analysis

Objective: We aimed to assess whether the introduction of the first infliximab biosimilar was associated with changes in overall infliximab consumption (originator and biosimilars) and price changes to the originator infliximab. Methods: An interrupted time series analysis using infliximab sales data from 2010 to 2020 from the IQVIA Multinational Integrated Data Analysis System for eight selected regions: Australia, Canada, Hong Kong, Korea, India, Japan, the UK, and the USA. Quarterly measures of infliximab consumption and list prices were respectively defined as the number of standard units (SU)/1000 inhabitants and as 2020 USA dollars (USD)/SU. Results: Following the introduction of infliximab biosimilars, overall infliximab consumption increased in Australia [immediate change: 0.145 SU/1000 inhabitants (P = 0.014); long-term change: 0.022 SU/1000 inhabitants per quarter (P < 0.001)], Canada [immediate change 0.415 (P = 0.008)], the UK [long-term change 0.024 (P < 0.001)], and Hong Kong [immediate change: 0.042 (P < 0.001)]. The list price of originator infliximab also decreased following biosimilar introduction in Australia [immediate change: − 187.84 USD/SU (P < 0.001); long-term change − 6.46 USD/SU per quarter (P = 0.043)], Canada [immediate change: − 145.58 (P < 0.001)], the UK [immediate change: − 34.95 (P = 0.010); long-term change: − 4.77 (P < 0.001)], and Hong Kong [long-term change: − 4.065 (P = 0.046)]. Consumption and price changes were inconsistent in India, Japan, Korea, and the USA. Conclusions: Introduction of the first infliximab biosimilar was not consistently associated with increased consumption across regions. Additional policy and healthcare system interventions to support biosimilar infliximab adoption are needed.