Recommendations by the Tuscan Health Authority to Use Infliximab-Biosimilar in the Clinical Practice: Safety Impact

Background/Introduction: In 2015, the Tuscan Health Authority introduced the use of infliximab-biosimilar, recommending its prescription in naı¨ve patients and the switching in those under treatment with infliximab-originator [1]. Aim: To assess the safety impact of these recommendations in infliximab users. Methods: A retrospective cohort study was performed on patients treated with infliximab at January 1st, 2013 (group 1—no infliximabbiosimilar available) and January 1st, 2016 (group 2—infliximab biosimilar recommended) for any indication. Data were extracted from Tuscan healthcare administrative databases. Patients were identified by diagnosis codes of hospital discharge records and Emergency Department (ED) visits. Patterns of use were evaluated over 2 years for each group. Groups were matched for age, sex, diagnoses and duration of treatment. Odd ratio (OR) for hospitalizations, ED accesses for any cause, and any access to rheumatologic, gastroenterological and dermatological visit was estimated as proxy of safety outcome. Results: Overall, 454 (group 1) and 434 (group 2) patients were identified. Women were 41% and the mean age was 40 years. Infliximab was used for 3.07 years (mean, standard deviation [SD] ± 2.76) in group 1, and 1.81 years (mean, SD ± 1.91) in group 2, p.001. Out of patients with 1 diagnosis, 177 patients and 161 had a rheumatologic disease, 76 and 101 had a gastroenterological diagnosis, and 34 and 12 had psoriasis in group 1 and group 2, respectively. After matching, 303 patients remained in each group, 100% (303) and 55.8% (169) were treated with infliximab-originator in 2013 and 2016, respectively. Patients with at least one specialist visit were 210 (69.3%) in group 1 and 242 (79.9%) in group 2 (overall visits: adjusted OR 1.83, confidence interval [CI]95% 1.25–2.68). Out of these, the majority was a rheumatologic visit (111 and 139 in group 1 and group 2 respectively, adjusted OR 1.52, CI 95% 1.05–2.20). Of note, in 2016 patients with at least one access to specialist visit increased among infliximab-originator users (137, 81.1% versus 210, 69.3% in 2013; p.05). In group 2, the distribution of patients with at least one hospitalization (111, 36.6% in 2013 and 115, 38.0% in 2016) and one ED visit (117, 38.6% in 2013 and 135, 44.6% in 2016) did not increase significantly (adjusted OR hospitalizations: 1.08, CI 95% 0.76–1.52; adjusted OR ED visits: 1.31, CI 95% 0.94–1.82). Conclusions: No difference was observed in ED accesses and hospitalizations after the Tuscan recommendations on infliximab biosimilar. However, an increase in the access to specialist visits was recorded. This could be explained by safety or efficacy issues with the biosimilar or by cautionary approach by physicians in the management of patients with the new drug.