Switching from infliximab-originator to infliximab-biosimilar in rheumatologic patients: The clinical impact in Tuscan Region, Italy

Background: In 2015, Tuscan Health Authority recommended to physicians the prescription of biosimilar infliximab (BI), thus promoting the switching from originator infliximab (OI) to BI. Objectives: To assess the clinical impact of the recommendation for the use of BI in Tuscan rheumatoid arthritis (RA) patients. Methods: We conducted two interrupted time series analyses on RA patients in the Tuscan healthcare administrative databases. The analysis 1 included naïve patients who started infliximab between January 1st, 2012 and December 31st, 2016. We followed patients up to 1 year. The analysis 2 included prevalent infliximab users recorded from January 1st to December 31st, 2013 (group 1) and from January 1st to December 31st, 2015 (group 2). Both groups were followed for 2 years. In both analyses, we described the patterns of treatment as well as the occurrence of rheumatologic visits, emergency department visits (EDV) and hospitalizations for any causes. Results: In the analysis 1, 214 patients were included (52 in 2012, 64 in 2013, 31 in 2014, 29 in 2015 and 38 in 2016). Patients starting with BI were 18 (62.1%) in 2015 and 33 (86.8%) in 2016. Switching from OI to BI occurred since 2014, and no switch from BI to OI was recorded. We observed neither relevant differences in the pattern of treatment (frequency of treatment persistence, switching to another anti‐TNF or swapping to another non‐anti TNF) nor in the frequency of the rheumatologic visits, EDV and hospitalizations over the observation years. In the analysis 2, 354 patients were included in group 1 and 334 in group 2. All patients started with OI. In the group 2, we observed that: 96 (28.7%) patients switched to BI; 66 patients (19.8%) switched to another anti‐ TNF drug, versus 55 patients (15.5%) of group 1; 7 patients (2.1%) swapped to other non‐anti‐TNF drugs versus 6 patients (1.7%) in group 1. The mean number of rheumatologic visits per patient increased from 2.8 (group 1) to 3.9 (group 2). The proportion of patients with at least one EDV increased from 35.9% (group 1) to 45.5% (group 2). The proportion of hospitalized patients increased from 34.5% to 37.4%; the mean number of hospitalizations per patient did not vary. Conclusions: Over the study period, the recommendation of Tuscan Health Authority was associated with an increased utilization of BI in RA patients. In naïve users, no impact was observed on the patterns of use and outcomes. Likewise, in prevalent users, no major changes in the patterns of use were observed. The increase in EDV and rheumatologic visits could be explained with a cautious approach to BI by both physicians and patients.