Outcomes Following Adalimumab Bio-originator to Biosimilar Switch—A Comparison Using Real-world Patient- and Physician-Reported Data in European Countries

Abstract Introduction The aim of this work is to compare real-world outcomes of patients with rheumatoid arthritis (RA) receiving adalimumab (ADA) bio-originator (non-switchers) to those who had switched from ADA bio-originator to an ADA biosimilar (switchers) on the basis of the hypothesis that these outcomes would differ. Methods Data were drawn from the Adelphi RA Disease Specific Programme™, a point-in-time survey of physicians and their patients in Europe (France, Germany, Italy, Spain, UK) in 2020. Physicians completed a questionnaire for their next ten adult patients with RA, followed by four additional patients who had switched from ADA bio-originator to an ADA biosimilar (switchers). Physician- and patient-reported outcomes (PROs) for switchers and non-switchers were compared by propensity score matching. Results Three hundred and three rheumatologists provided data for 160 non-switchers and 225 switchers, 140 patients provided data; 51 non-switchers, 89 switchers. According to physician-reported disease activity, non-switchers were more likely to improve on their current ADA treatment than switchers (68%, n = 108 vs. 26%, n = 59 p