Infliximab original has changed the natural history of inﬂammatory bowel diseases (IBD) over the past two decades. However, the recent expiration of its patent has allowed the entry of the first Infliximab biosimilar into the European and Spanish markets. Currently switching drugs data in IBD are limited.
To compare the efficacy of infliximab biosimilar, CT-P13, against infliximab original, analyzing the loss of response of both at the 12 mo follow-up in patients with IBD.
An observational study of two cohorts has been conducted. One retrospective cohort that included patients with IBD treated with Infliximab original, and a prospective cohort of patients who were switching from infliximab original to infliximab biosimilar (CT-P13). We had analyzed the overall efficacy and loss of efficacy in patients in remission at the end of one year after treatment with the original drug compared to the results of the year of treatment with the biosimilar.
98 patients (CD 67, CU 31) were included in both cohorts. The overall efficacy for infliximab original per year of treatment was 71% 
The overall efficacy and loss of treatment response with infliximab biosimilar (CT-P13) is similar to that observed with infliximab original in patients who were switching at the 12 mo follow-up. There is no difference in the rate of adverse events.