Continuous effectiveness and safety after a hospital-wide switch to adalimumab biosimilar: an observational study in rheumatoid arthritis patients
Abstract Objectives Only few observational studies have investigated the actual effectiveness of switching to biosimilars in daily clinical practice in unselected patients. The objective of this study was to examine the maintenance of effect and safety after a hospital-wide switch for economic reasons from adalimumab originator Humira® to biosimilar Amgevita® in real-world rheumatoid arthritis (RA) patients and patient satisfaction with the switch. Methods A single centre retrospective observational study of RA patients on the course of their disease activity (DAS28, ESR and CRP), health-related quality of life (SF-36) and functional disability (HAQ-DI) before and up to one year after the switch, supplemented with a cross-sectional survey on satisfaction and experienced side effects approximately 18 months after the switch. Treatment outcomes were analysed with linear mixed modelling and generalized estimation equations. Results On November 1st 2018, 239 rheumatology patients switched to the adalimumab biosimilar. Of 52 RA patients who met the inclusion criteria sufficient data were available. Disease activity levels, the proportion of patients in remission (DAS28 < 2.6), and SF-36 and HAQ-DI scores did not significantly change from before the switch. 38 of the 52 analysed patients returned the questionnaire. Overall, patients were satisfied with the switch. Three patients (7.9%) stopped the biosimilar due to side effects. Conclusion Switching to the adalimumab biosimilar did not result in increased disease activity or worse patient-reported outcomes over an observation period of 9 to 12 months. Also, there was no apparent evidence of increased side effects. Patients themselves were mostly satisfied with the switching experience.