Utilisation patterns and clinical impact of the introduction of infliximab-biosimilar in Tuscany, Italy: real world evidence following the recommendation of switching for non-medical reasons.

This study was aimed at assessing the impact of a non-medical recommendation on drug-utilisation patterns and clinical outcomes in a central Region of Italy (Tuscany). We performed a pre-post study on data collected in Tuscan healthcare administrative databases. We included patients with diagnosis of rheumatoid arthritis, or psoriatic arthritis, or ankylosing spondylitis, or ulcerative colitis, or Crohn's disease, or psoriasis. The first analysis compared patients treated with infliximab on January 1st, 2013 (originator only available) to those on January 1st, 2016 (both originator and biosimilar available). The second analysis compared infliximab-originator users with infliximab-biosimilar ones. Adjusted odds ratios (OR) of persistence on treatment, Emergency Department (ED) admissions, hospitalisations and specialist visits were calculated. The first analysis included 606 patients and the second 434. In both analyses, we did not observe any significant difference in persistence. In the first analysis, the 2016 infliximab-originator cohort showed a significant association with the risk of having at least one ED admission (OR 1.54, 95% CI 1.02 to 2.31). A significant difference of accessing a specialist visit (more frequently rheumatologic) was observed in the 2016 cohort (OR 1.52, 95% CI 1.05 to 2.20). In the second analysis, the risk of having at least one hospitalisation decreased significantly in switchers to infliximab-biosimilar (OR 0.49, 95% CI 0.26 to 0.96). Our study showed no relevant changes in the clinical outcomes following the introduction of infliximab-biosimilar. The few observed differences observed can be explained mainly by a selective switching to infliximab-biosimilar in patients with lower burden of disease.