Experience of Mass Switching to Biosimilar Drugs in Patients with Immune-Mediated Inflammatory Rheumatic Diseases. Effectiveness and Safety. Intercambiosim Project

Abstract

Abstract Background A biosimilar is a biological medicine that contains a version of the active principle of a previously authorized original biological medicine (reference drug).Objective To evaluate the efficacy and safety of biosimilars in the treatment of immune-mediated inflammatory rheumatic diseases.Methods Retrospective observational and descriptive study of patients diagnosed with immune-mediated inflammatory rheumatic disease. Patients who had switched from a biological medicine to a biosimilar antiTNF and rituximab, for at least 24 weeks were included. Statistical tests such as the chi-square test were used to assess the independence of categorical variables, and Mann-Whitney U test was used to assess the independence between categorical and numerical variables, considering the heteroscedasticity of the groups.Results 364 patients who met the inclusion criteria were selected. 29.95% of patients discontinued treatment with the biosimilar: inefficacy in 87 patients (52 with primary failure and 35 with secondary failure), adverse effects in 18 patients and 4 patients discontinued it by their own decision. The mean disease activity at the beginning of the medication switch was 1.73 (± 0.93) in ASDAS, 8.73 (± 12.20) in DAPSA, and 2.60 (± 1.20) in DAS28, while at 24 weeks after the switch, the mean activity was 1.79 in ASDAS, 8.39 in DAPSA, and 2.62 in DAS28.Conclusions In our study, it was observed that 29.95% of the participants had to discontinue the use of the biosimilar drug, mainly due to its lack of efficacy, which exceeds the average reported in the current literature. Only 18 patients experienced some type of adverse effect, of which only 2 cases were severe. The mean activity levels measured by ASDAS, DAPSA, and DAS28 remained similar both at the beginning and at 24 weeks after the treatment switch, although patients with higher activity at the beginning of the switch presented higher activity levels at 24 weeks. Our data obtained in a real-life setting suggest that biosimilar drugs can be considered an effective and safe option in the treatment of inflammatory rheumatic diseases. However, it is important to note that there is a significant rate of discontinuation of biosimilar use.