Impact of switching from the originator adalimumab to a biosimilar: a retrospective cohort study

Adalimumab is a monoclonal antibody that is used to treat autoimmune and inflammatory diseases. Biosimilars for adalimumab, including Hyrimoz, have been developed. We aimed to evaluate the effectiveness and adverse effects of Hyrimoz after switching.

The cohort consisted of patients treated with adalimumab at the Clinical Immunology Outpatient Department of the Erasmus Medical Center between February 2021 and February 2023. Data were collected through electronic patient files and questionnaires sent to the patients. The primary outcome was the number of flares after switching to Hyrimoz, compared to a similar period before the switch. The secondary outcomes were reported adverse effects and patient experience using Hyrimoz.

A total of 185 patients were eligible for inclusion. There was no significant difference in the occurrence of flares between Humira and Hyrimoz (P = 0.456). Forty-six of the 185 patients reported adverse effects (24.9%). A total of 25/185 (13.5%) patients reported pain during injection, which was the most frequently reported adverse effect. During the course of this study, 60/185 (32.4%) patients discontinued Hyrimoz treatment because of flares (n = 17 [9.2%]), adverse effects (n = 27 [14.6%]), or more subjective complaints (n = 15 [8.1%]) related to the underlying disease. One patient discontinued treatment because of inactive disease.

The number of flares before and after switching to Hyrimoz was comparable. However, adverse effects and increased subjective complaints have been reported after switching to this new biosimilar.